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Reliability and validity of the Health Outcomes Burn Questionnaire for infants and children in The Netherlands
Burns 32 (2006) 357–365 www.elsevier.com/locate/burns
Reliability and validity of the Health Outcomes Burn Questionnaire for infants and children in The Netherlands M.E. van Baar a,*, M.L. Essink-Bot a, I.M.M.H. Oen b,c, J. Dokter b, H. Boxma b, M.I. Hinson d, N.E.E. van Loey c, A.W. Faber c,e, E.F. van Beeck a a
Department of Public Health, Erasmus MC, University Medical Center Rotterdam, The Netherlands b Burn Centre Rotterdam, Medical Centre Rijnmond Zuid, Location Zuider, The Netherlands c Association of Dutch Burn Centres, Beverwijk, The Netherlands d Shriners Hospital for Children, Boston, MA, USA e Burn Centre Groningen, Martini Hospital, The Netherlands Accepted 6 October 2005
Abstract The Health Outcomes Burn Questionnaire (HOBQ) is a self-administered questionnaire to monitor outcome after burns in young children. This study aimed to assess feasibility, reliability and validity of the Dutch version of the HOBQ. The HOBQ was adapted into Dutch and tested in a population of children aged 0–4 years with a primary admission to a Dutch burn centre in March 2001–February 2004. Parents of 413 children were sent a questionnaire. To assess validity, a generic outcome instrument was included, the Infant Toddler Quality of Life Questionnaire (ITQOL). The response rate was 50.0% (n = 196). Mean self-reported completion time was 16.7 min. The internal consistency of all the HOBQscales was good (Cronbach’s alpha’s >0.69). Test–retest results showed no differences in 7 out of 10 scales. High correlations between HOBQ-scales and conceptually equivalent ITQOL and scales were found in 5 out of 7 comparisons. The majority of the HOBQ-scales (7 out of 10) showed significant differences in the expected direction between children with a long versus short length of stay. Our data support the reliability and validity of the Dutch HOBQ. The HOBQ can be used as a research tool, to monitor functional outcome after burns in young children. Further research in other samples is recommend to fully establish the reliability and validity of the HOBQ. # 2005 Elsevier Ltd and ISBI. All rights reserved. Keywords: Children; Outcome; Burns; Reliability; Validity
1. Introduction In recent years, attention for functional outcome after burns has grown. Because of major improvements in burn care in the past decades, even patients with major burns have high survival rates [1,2]. However, survivors of major burns * Corresponding author. Present address: Department of Public Health, Julius Center for Health Sciences and Primary Care, Stratenum 6.131, University Medical Center Utrecht, P.O. Box 85500, 3508 GA Utrecht, The Netherlands. Tel.: +31 30 2509378; fax: +31 30 2505482. E-mail address: [email protected] (M.E. van Baar). 0305-4179/$30.00 # 2005 Elsevier Ltd and ISBI. All rights reserved. doi:10.1016/j.burns.2005.10.004
often experience major problems in physical, mental and social perspective. In addition, also small burns can have a substantial impact, especially when functional areas are affected [3]. This growing attention for functional outcome after burns is also reflected in the publications on this topic. In a review on functional outcome after burns it was found that the majority of the publications was published from 1998 onwards [4]. In adults, a validated burn specific quality of life instrument is available to measure functional outcome after
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burns. The Burn Specific Health Scale was first published in 1982 [5], since then several adaptations/versions have been developed [6–8]. Until recently no burn specific quality of life instrument was available for children. In 2002, the Health Outcomes Burn Questionnaire for infants and children 5 years of age and younger (HOBQ) was published by Kazis et al. [9]. The HOBQ was developed by the American Burn Association/Shriners Hospitals for Children Outcomes Task Force. This multidimensional questionnaire consists of 10 scales, varying form play to appearance. The HOBQ could potentially become a standard instrument for measuring functional consequences of burns among 0–5-yearold children, but has not yet been applied outside the USA. To be able to use the HOBQ in our country, we adapted the questionnaire into Dutch and tested it in a Dutch population of young children with burn injuries. This could be a possible first step in extending the use of the HOBQ towards Europe and elsewhere. The aim of our study was to evaluate the Dutch version of the Health Outcomes Burn Questionnaire for infants and children. We assessed:
Health Outcomes Burn Questionnaire again to assess test– retest reliability. The completed questionnaires were returned by mail. The Medical Ethical Committee of the Erasmus University MC, University Medical Center Rotterdam, approved of this study. 2.2. Health Outcomes Burn Questionnaire
2. Methods
The Health Outcomes Burn Questionnaire for infants and children 5 years of age and younger (HOBQ) consists of 10 subscales (Table 1). The number of items per scale ranges from two to nine. All subscales relate to the past month, except the subscale ‘satisfaction’. In addition to the subscales, the HOBQ consists of items on standardised socio-demographic variables, prevalence of chronic conditions and recent treatment, and living situation [9]. The HOBQ was translated into Dutch according to international guidelines [12]. A standardised procedure, including independent forward and backward translations was followed. Experts in the field of burn care (IO) and health-related quality of life research (HG, MLE, MvB) made four independent forward translations. The final forward translation was made by consensus. A native American speaker made the backward translation. This version was compared to the original questionnaire, to control for differences and make adaptations if necessary. Similar to Kazis et al., scale scores were calculated by taking the average of all scale items, after adjustment for opposite scored items and for the number of actually answered items. At least half of the number of items per scale must be answered [9]. Crude scales were transformed linearly to a 0–100 scale, with higher scores indicating a better outcome.
2.1. Study population and data collection
2.3. General health status
The study population consisted of all children aged 0–4 at reference date March 1, 2004, with a primary admission for burn injuries in a burn centre in the period March 2001– February 2004 (n = 413). Children aged 5 years were excluded, The American Burns Association (ABA) developed two questionnaires for the assessment of outcome after burns; both are applicable for children aged 5, the HOBQ and de Burn Outcome Questionnaire (BOQ) [9,10]. We chose to include children aged 5 years in a study aimed at the validation of the BOQ. In addition, this restriction to pre-school children (up to 4 years) enabled us to use a single generic outcome instrument for the total study population (ITQOL [11], see further). Deceased children were excluded as well. No further prior exclusions were made within this study population. All burn centres in The Netherlands (n = 3) participated in the study. In May 2004, questionnaires were mailed to the parents of the children in our study population. Two weeks later, a reminder letter was sent. At the same time point, a random subgroup of the participating parents (n = 134) received the
We used the Infant Toddler Quality of Life Questionnaire (ITQOL) to test the validity of the HOBQ. The ITQOL is a recently developed multidimensional generic measure of health-related quality of life for use among preschool children [11]. The ITQOL is conceptually similar to the Child Health Questionnaire [13]. The ITQOL includes items that measure 13 concepts and is suitable for parents of children aged 2 months up to 4 years. The ITQOL has an acceptable reliability and validity [11].
(1) the feasibility of the Dutch HOBQ, indicated by response rate, missing answers and content of written comments; (2) the reliability of the Dutch HOBQ-scales (internal consistency and test–retest reliability) and (3) the validity of the Dutch HOBQ indicated by the relation with general health status measurement (concurrent validity) and the ability to discriminate between groups with different burn severity (discriminant validity).
2.4. Burn centre registration Participating burn centres provided background information on all included patients. Information was delivered about age, sex, aetiology, location of the burn, percentage of total body surface area burned (TBSA), percentage TBSA third degree, artificial respiration, surgery, intensive care admission, date of admission and length of stay (LOS).
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Table 1 Health Outcomes Burn Questionnaire-scales, items per scale and interpretation of low and high scores HOBQ-scales
n Items
Description low score
Description high score
Play
5
Child is not limited or able to play in most situations
Language
4
Fine motor skills
7
Gross motor skills
7
Behaviour
9
Family
5
Pain/itching
7
Appearance
3
Satisfaction
5
Concern/worry
7
Child is very limited or unable to play because of the burn injury (e.g. does not show interest in others or does not take turn in play) Child is very limited or unable to use language appropriate for its age because of the burn injury Child is very limited or unable to perform self-care activities because of the burn injury (e.g. finger feed and put on a T-shirt) Child is very limited or unable to perform physical activities because of the burn injury (e.g. creeping walking and climbing) Child’s mood is unhappy, withdrawn or anxious, etc. because of the burn injury Child’s health always limits or interrupts family activities or is a source of family tension Child has very severe pain and itching, and has been scratching, required medicine and awakened because of itching all of the time Child is unattractive to others; changes in appearance have interfered with relationships and parent is uncomfortable taking child in public because of appearance, because of the burn injury. Parent is very dissatisfied with child’s symptom Relief, appearance, sleep, function and overall medical care Parent has a great deal of worry or concern about child’s pain and suffering and future health
2.5. Statistical analysis A non-response analysis was performed by comparing children’s characteristics of respondents versus non-respondents. For this comparison, we used burn centre information on age, sex, aetiology, location of the burn (head (y/n), hands (y/n)), percentage TBSA, third degree TBSA (y/n), artificial respiration (y/n), surgery (y/n), intensive care (y/n), LOS and time since admission. We used the Chi-square test (categorical variables), the t-test (age, time since admission) and the Mann–Whitney U-test (TBSA, LOS) to test for statistical differences. Evaluation of feasibility consisted of the assessment of the response rate and the frequency of missing answers per item. In addition, respondents considering the questionnaire difficult/very difficult were compared to other respondents on respondent’s characteristics (age, sex and number of respondents (1 or >1)), family characteristics (education level, employment and living situation) and children’s characteristics (socio-demographic, burn-related characteristics based on burn centre information and reported outcome on HOBQ). We used the Chi-square test (categorical variables), the t-test (age, time since admission) and the Mann–Whitney U-test (TBSA, LOS, scales HOBQ) to test for statistical differences.
Child is not limited or able to use language appropriate for its age in most situations Child is not limited or able to perform self-care activities in most situations Child is not limited or able to perform physical activities
Child’s mood is not unhappy, withdrawn or anxious, etc. because of the burn injury Child’s health never limits or interrupts family activities nor is a source of family tension Child has no pain or itching, and has never been scratching nor required medicine or awakened because of itching Child is not unattractive to others; changes in appearance have not interfered with relationships and parent is not uncomfortable taking child in public because of appearance
Parent is very satisfied with child’s symptom relief, appearance, sleep, function and overall medical care Parent has no worry or concern at all about child’s pain and suffering and future health
We used Cronbach’s alpha to evaluate the internal consistency of the scales of the HOBQ. For scales used as a research tool, when groups are compared, an alpha of 0.7 is satisfactory. For scales used in the clinical situation, when the value of an individual is of interest, an alpha of at least 0.9 is satisfactory [14]. We calculated average correlation coefficients (Pearson’s Product Moment correlation) between items and their own scale (without the item under consideration) and between items and every other scale to evaluate whether the items were well chosen and if the scales represent different domains. The average corrected item-own scale coefficients are expected to be higher than the average item-other scale correlation coefficients. We assessed test–retest reliability of the HOBQ-scales at the group level, relevant for use as a research tool, by the two-sided Wilcoxon signed rank tests. We performed nonparametric tests because of the skewness of the data, representing ceiling effects. We calculated the intraclass correlation coefficient (ICC) to assess test–retest reliability at the individual level [15]. This information is relevant for use in the clinical situation. We tested whether HOBQ-scales correlated better with their a priori assumed conceptually equivalent general health domain (ITQOL) than with any other domain, as measured
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with Spearman rank order correlation coefficients between scales (concurrent validity). We expected the highest correlations between 7 HOBQ-scales and equivalent ITQOL-scales and 4 HOBQ. For instance, the highest correlation of HOBQ-scale ‘Pain/itching’ was expected with ITQOL-scale ‘Bodily pain’. The correlations between a priori assumed equivalent scales are in bold in Table 3. We also assessed the ability of the HOBQ to discriminate between the consequences of burns of different severity levels (discriminative validity). We used the Mann–Whitney U-test or the Kruskall–Wallis one way analysis of variance to determine differences in scale scores between two and three groups. We made comparisons for several indicators of severity: length of stay in burn centre, %TBSA, %TBSA third degree, surgery (y/n), artificial respiration (y/n), duration since admission, comorbidity (y/n), head involved (y/n) and hands involved (y/n). Analyses were performed using SPSS 11.0.
3. Results 3.1. Response and characteristics of parents and children with burns Of the 413 distributed questionnaires, 18 questionnaires were undeliverable. A total of 196 questionnaires were returned, including two incomplete questionnaires (50% response). One hundred thirty-four retest questionnaires were sent and 93 were returned (69% response). The children of the respondents and non-respondents differed in four out of twelve characteristics. Parents with a daughter with burns were more likely to respond, compared to parents with a son with burns (55.4% versus 42.0%, p = 0.01). In respondents’ children, the proportion with any third degree burns was higher (42% versus 32%, p = 0.03), the length of stay was longer (median 8 days versus 5 days, p = 0.02) and the time since admission was shorter (at time of mailing the questionnaire mean 17.3 months versus 20.3 months, p = 0.00). The mean respondents age was 33.5 years (S.D. 5.6), 77.2% were mothers. In 34.6%, at least one of the parents/caregivers had completed higher vocational education/university, 9.8% had only elementary or no education, and in most families (84.4%) at least one parent was employed. The mean age of the children with burns was 36.7 months (range 5–63), 53.6% were male and 24.6% were of a nonDutch ethnicity. The majority (88.6%) lived with both mother and father. A mean number of 0.2 co-morbid conditions were reported; 14.4% received treatment for such a condition at this moment. The median percentage of total body surface area burned was 6.0 (range 0–66). One child with a TBSA = 0 was admitted because of smoke inhalation. 42.1% had a ‘third degree’ burn (% TBSA third degree >0; range 0–60). Burns were most frequently the result of scalds (90.1%), 2.1% had
needed artificial respiration, and 36.8% had needed surgery. The median length of stay was 8 days (range 1–56). The mean time since admission (at completion of the questionnaire) was 17.5 months (S.D. = 9.8; range 2.8–38.8). 3.2. Feasibility The number of missing responses in the Health Outcomes Burn Questionnaire varied between 0.5 and 5.2%, with the exception of four items of the gross motor scale (‘walk holding onto people or furniture’ 8.8%, ‘walk without support’ 6.2%, ‘carry objects’ 7.2%, ‘pull to stand’ 6.2%), and two items of the satisfaction scale (‘pain/itch relief’ 9.3%, ‘appearance’ 5.7%). In addition, the measure provided patents the opportunity to answer that their child was too young on 23 items concerning play, language, fine motor and gross motor skills. This answer was chosen in 0.5–9.3% of the children, with the exception of five items (‘shows awareness’ 15.5%, ‘suggest new things’ 25.8%, ‘tell a simple story’ 11.3%, ‘put on front opening shirt’ 20.6% and ‘put on T-shirt’ 16.3%). Median self-reported completion time was 15 min (range 2– 135). Eleven percent considered the questionnaire to be difficult/very difficult; 40% found it neither difficult nor easy and 50% considered it to be easy/very easy. Respondents reporting difficulties with the questionnaire differed from other respondents in 12 out of 30 characteristics. Respondents reporting difficulties were more often living in families with a low education level (22.6% versus 7.9%, p = 0.02), without paid jobs (28.6% versus 7.5%, p = 0.00), without both parents (23.8% versus 8.9%, p = 0.04). Children of these respondents were more often of a non-Dutch ethnicity (23.9% versus 6.3%, p = 0.00), with a higher TBSA (median 7.5% versus 5%, p = 0.04) and LOS (median 19 days versus 8 days, p = 0.01). In addition, respondents reporting difficulties reported a worse outcome on 6 out 10 HOBQ-scales (play (median 90 versus 100, p = 0.02), language (median 88100, p = 0.02), gross motor (median 100 versus 100, p = 0.00), family (median 80 versus 90, p = 0.04), appearance (median 75 versus 100, p = 0.02), and concern/worry (median 50 versus 87, p = 0.00)). Spontaneous comments on the questionnaire were limited. Several parents reported problems with the attribution ‘because of the burns’. They found it difficult to say whether outcome could be attributed to the burn injury or not, especially in burns of some time ago. Also, parents of very young children reported difficulty in answering some questions, for instance ‘interference with relationships’. In addition, some remarks were made about pain and itch relief: no appropriate response option was available if no pain or no itch was prevalent. 3.3. Scoring distributions and internal consistencies More than half of the children had maximal scores on five HOBQ-scales (play, language, fine motor skills, gross motorskills and appearance) (ceiling effect) (Table 2).
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Table 2 Score distribution and internal consistency of Health Outcomes Burn Questionnaire-scales for 194 patients aged 0–4 years HOBQ-scales
N
Median
25th–75th percentile
% mina
% maxb
Alpha
Average item-own scale correlationc
Average item-other scale correlation
Play Language Fine motor Gross motor Behaviour Family Pain/itching Appearance Satisfaction Concern/worry
182 149 181 183 190 193 193 189 191 191
100.0 100.0 100.0 100.0 72.2 90.0 92.9 100.0 95.0 87.5
88–100 88–100 90–100 100–100 56–83 70–100 80–100 75–100 80–100 50–100
1 3 1 3 0 0 0 0 0 7
66 72 67 80 9 38 38 54 42 45
0.92 0.91 0.91 0.96 0.78 0.84 0.91 0.77 0.69 0.83
0.79 0.81 0.74 0.88 0.47 0.65 0.75 0.62 0.47 0.71
0.39 0.36 0.35 0.37 0.20 0.28 0.34 0.22 0.18 0.36
a b c
Percentage of respondents with lowest possible score (0). Percentage of respondents with highest possible score (100). Each item was correlated with the applicable scale excluding the item under consideration from the scale score.
similar ITQOL-domains, than with other domains (see Table 3). Three scales (language, gross motor skills and concern/worry) were correlated to the expected domains, but even more to other ITQOL-domains. The scales ‘play’ and ‘pain/itching’ were not correlated to the expected equivalent ITQOL-domains. The ability of the HOBQ to discriminate between children of different burn severity was assessed (discriminative validity). In all but three HOBQ-scales (‘language’, ‘fine motor skills’ and ‘gross motor skills’) outcome was significantly worse in children with a long length of hospital stay (>10 days), compared to children with a short length of stay (10 days), (see Table 4). In 6 out of 10 scales outcome was significantly worse in children with a high TBSA (>10%) compared to children with low TBSA (10%) (see Table 5). Similar differences were found for another three indicators of severity: TBSA third degree (<5% versus >5%), artificial respiration and surgery (no/yes) (data available upon request).
All scales had a good internal consistency (Cronbach’s alpha 9 scales 0.70, one scale 0.69). Five scales had an alpha >0.9. All scales had higher average corrected itemown scale correlation coefficients than the corresponding average item-other scale correlation coefficients. 3.4. Test–retest reliability At the group level, only 3 out of 10 HOBQ-scales showed a significant difference in mean scale score between test and retest (play, 90 versus 92, p = 0.02; ‘pain/itching’ 84 versus 87, p = 0.02; ‘satisfaction’ 88 versus 84, p = 0.02). At the individual level, data also were strongly related (all intra class correlation coefficients 0.70 and significant). 3.5. Validity We assumed seven HOBQ-scales to be related to specified ITQOL-domains. Two out of these HOBQ-scales (behaviour and family), correlated better with the expected Table 3 Correlationa of HOBQ and ITQOL Infant Toddler Quality of Life Questionnaire Growth and development HOBQ-scales Play Language Fine motor Gross motor Behaviour Family Pain/itching Appearance Satisfaction Concern/worry
0.19 0.33 0.27 0.07 0.40 0.38 0.22 0.35 0.33 0.18
Bodily pain
0.06 0.03 0.09 0.06 0.15 0.13 0.17 0.16 0.24 0.14
Temperament and moves
General behaviour
Getting along
General health perceptions
Parental impact emotional
Parental impact time
Family cohesion
Family activity
Physical functioning
0.37 0.30 0.35 0.29 0.53 0.55 0.36 0.32 0.35 0.35
0.39 0.37 0.34 0.25 0.44 0.44 0.27 0.31 0.26 0.24
0.34 0.30 0.30 0.15 0.52 0.48 0.22 0.30 0.35 0.25
0.27 0.25 0.25 0.25 0.30 0.39 0.36 0.42 0.35 0.35
0.25 0.16 0.22 0.08 0.43 0.45 0.21 0.27 0.30 0.27
0.22 0.34 0.35 0.22 0.33 0.40 0.21 0.14 0.31 0.23
0.06 0.21 0.07 0.02 0.25 0.15 0.11 0.18 0.16 0.07
0.18 0.28 0.28 0.18 0.48 0.63 0.20 0.22 0.34 0.25
0.32 0.33 0.27 0.25 0.24 0.31 0.32 0.27 0.34 0.29
Correlations with predefined equivalent CHQ-IT-domains are in bold. a Spearman’s rho correlation coefficient. Correlation >0.19 is significant at the 0.01 level (two-tailed).
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Table 4 Median scores of the HOBQ-scales for children with short length of stay burn centre (LOS <10 days) vs. longer LOS (>10 days) HOBQ-scales
Length of stay 10 days (n = 108)
Play Language Fine motor Gross motor Behaviour Family Pain/itching Appearance Satisfaction Concern/worry a
p-Valuea
>10 days (n = 85)
Median
(25th, 75th percentile)
Median
(25th, 75th percentile)
100 100 100 100 78 95 96 100 100 78
(90, 100) (88, 100) (92, 100) (100, 100) (61, 89) (80, 100) (85, 100) (88, 100) (85, 100) (63, 100)
100 100 100 100 61 85 89 92 90 63
(79, 100) (83, 100) (90, 100) (100, 100) (50, 78) (65, 100) (68, 100) (75, 100) (70, 100) (38, 100)
0.03 0.86 0.29 0.58 0.00 0.00 0.00 0.00 0.00 0.01
Mann–Whitney U-test.
Table 5 Median scores of the HOBQ for children with low TBSA (<10%) and high TBSA (>10%) HOBQ-scales
TBSA <10% (n = 167)
Play Language Fine motor Gross motor Behaviour Family Pain/itching Appearance Satisfaction Concern/worry a
p-Valuea
>10% (n = 26)
Median
(25th, 75th percentile)
Median
(25th, 75th percentile)
100 100 100 100 72 90 93 100 95 88
(88, 100) (88, 100) (90, 100) (100, 100) (56, 83) (75, 100) (82, 100) (83, 100) (81, 100) (50, 100)
100 100 100 100 61 73 86 75 83 50
(78, (56, (85, (86, (49, (50, (45, (50, (60, (25,
100) 100) 100) 100) 76) 85) 94) 100) 98) 81)
0.23 0.22 0.80 0.46 0.01 0.00 0.01 0.00 0.01 0.00
Mann–Whitney U-test.
In addition, the severity-indicators ‘time since admission’ and ‘comorbidity’ were tested. One out of 10 scales (‘pain/ itching’) showed a difference in outcome related to the time since admission. Pain and itching were worse in children with a more recent admission, compared to children with a longer time since admission (see Table 6). Comparable
results were found for the indicator ‘co morbidity’ (data available upon request). In children with burns of the head a significantly lower score on ‘appearance’ was found, compared to children without head involvement. In children with hands involved, a significantly lower score on ‘fine motor skills’ was found,
Table 6 Median scores of the HOBQ-scales for children with short time since admission (<1 year), moderate (>1 and <2 year) and long time since admission (>2 year) HOBQ-scales
Play Language Fine motor Gross motor Behaviour Family Pain/itching Appearance Satisfaction Concern/worry a b
Time since admission (in years) <1 (n = 69)a
>1–2 (n = 68)a
>2 (n = 56)a
p-Value b
100 (80, 100) 100 (75, 100) 100 (86, 100) 100 (93, 100) 72 (61, 83) 90 (75, 100) 91 (70, 96) 100 (83, 100) 95 (80, 100) 81 (38, 100)
100 (88, 100) 100 (84, 100) 100 (86, 100) 100 (100, 100) 67 (56, 83) 85 (70, 100) 93 (80, 100) 92 (75, 100) 90 (76, 100) 100 (63, 100)
100 (90, 100) 100 (100, 100) 100 (100, 100) 100 (100, 100) 72 (56, 89) 88 (70, 100) 98 (85, 100) 100 (75, 100) 100 (80, 100) 88 (50, 100)
0.37 0.11 0.12 0.36 0.31 0.99 0.02 0.21 0.42 0.08
Median (25th, 75th percentile). Kruskal–Wallis one way analysis of variance.
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compared to children without affection of the hands. No other significant differences in scales were found (data available upon request).
4. Discussion In this article, we report upon our project to adapt and test the Health Outcomes Burn Questionnaire for infants and children in a Dutch population. We assessed the feasibility, reliability and validity of the Dutch version of the HOBQ. We assessed feasibility by analysing the response rate and the missing items. We found a response rate of 50%, which is rather low but comparable to other studies assessing outcome after burns by mail [16–18]. Our study sample comprised all children with an admission to a burn centre, including children of nonDutch ethnicity. Non-response is probably partly related to problems with the Dutch language in this subpopulation. Response rates between burn centres varied between 47% in a multicultural city and 56% in the more rural Northern region. Children of respondents more often had a non-Dutch ethnicity in this city (43%), compared to the Northern region (9%). Thus, though we have reached a substantial group of children with a non-Dutch ethnicity, we could have missed information from this population. A small percentage of the responding parents (11%) reported difficulties with the questionnaire. These respondents differed from other responding parents in several aspects. In general, these parents were worse-off in several ways. Parents reporting difficulties with the questionnaire were more often of a nonDutch ethnicity. In future research, other data collection methods, such as a telephone survey and translations of the questionnaire in other languages, can be added to improve response rates. It is unclear whether the socio-economic position of parents has influenced response. In our sample, parents reporting difficulties with the questionnaire were more often of a low socio-economic position. However, the HOBQ was considered to be an easy questionnaire by half of the respondents, and median completion time (15 min) was limited. Therefore, we do not expect substantial nonresponse in parents with a low socio-economic position. We found some indications for a selective response by severity level. Parents of children with more severe burns or more recent burns more frequently returned the questionnaire. Although the differences were not very substantial, our sample does not fully represent the Dutch children with an admission to a burn centre. However, parents of children with more higher TBSA and longer LOS also more frequently reported difficulties with the questionnaires. Thus, although response is higher in parents of children with more severe burns, they also report more difficulties with the questionnaire. In addition, parents with difficulties with the questionnaire reported a worse children’s outcome on six out of 10 HOBQ-scales. These explorative analyses suggest that feasibility is related to the
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clinical situation of the child. This topic deserves future study, also to enhance future response rates. The HOBQ was originally developed for infants and children up to 5 years of age. In our sample, we excluded children aged 5. The ABA developed two questionnaires for the assessment of outcome after burns; both are applicable for children aged 5 years the HOBQ and de Burn Outcome Questionnaire (BOQ) [9,10]. We chose to include children aged 5 years in a study aimed at the evaluation of the BOQ. In addition, this restriction to pre-school children (up to 4) enabled us to use the ITQOL, as single generic outcome instrument for the total study population. Scales scores in our sample are in general high (mean 84.1 on a 0–100% scale), reflecting a good outcome after burns in this population of young children. More than half of the children had maximal scores on the scales ‘play’, ‘language’, ‘fine motor skills’, ‘gross motor skills’ and ‘appearance’. The lowest mean scores were found in the domains ‘behaviour’ and ‘concern/worry’. This probably reflects the long-term psychosocial consequences of burns, also after physical recovery. This good outcome after burns is probably related to the relatively long time since admission in our study population (17.5 months). The internal consistency of 9 out of 10 scales was >0.7, indicating that these scales can be used as a research tool, to compare groups. In five scales, and alpha >0.9 was found, indicating that these scales can be used to evaluate individuals in clinical settings [14]. In the US data, the latter applied only to two scales: gross motor and pain/ itching [9]. Two scales (behaviour and satisfaction), however, showed a relatively low average item-own scale correlation (<0.4). Further analysis revealed low item-to-scale correlations (<0.4) in four items of the scale ‘behaviour’ and in one item of the scale ‘satisfaction’. Therefore, evaluation of the scales ‘behaviour’ and ‘satisfaction’ seems to deserve further attention. These findings indicate some base psychometric limitations in the original questionnaire. We could not address these limitations in our adaptation study. However, the HOBQ possibly can be improved by reconsideration of these scales. Comparison with US data from the Shriners study is hampered by the different data presentation. US data were standardised to a non-burn US sample while our data are not. Comparison of study populations revealed a lower burn severity in the Dutch generally sample (mean TBSA 6.8% versus 16.9% in the US sample). In Dutch burn centres children are admitted following the criteria of Emergency management of severe burns [19]. In addition, children can be referred to burn centres if treating physicians prefer the expertise and facilities of a burn centre above their own expertise and facilities. Consequently, also patients with less severe burns are treated in a Dutch burn centre. In addition, in the Dutch sample longer period of time existed between
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the burn accident and assessment. The meantime since admission in the Dutch sample is 17.5 months, compared to 8.6 months in the US sample [9]. The test–retest correlations were high and statistically significant on the majority of scales. However, three scales (play, pain/itching and satisfaction) had significant but small differences between test and retest. In the US sample, low correlations (<0.4) were also found for two of these scales (play and satisfaction). Thus, further test–retest studies are recommended. In the meantime, small changes in scales play, satisfaction and also pain/itching should be interpreted with caution. The comparison of HOBQ-scales with equivalent ITQOL-domains supported the validity of the HOBQ. In two comparisons, the HOBQ-scales correlated higher with equivalent scales than with other scales; in another three comparisons high (but not the highest) correlations were found. We found low correlations between HOBQ-scales ‘play’ and ‘pain/itching’ and the equivalent ITQOL-scales, which can be explained by the different nature of the items in the domains. The HOBQ-scale ‘play’ is restricted to play, while the ITQOL-scale ‘growth and development’ is concerned with satisfaction with development in a broad area, including, physical growth, motor skills, language and cognitive function. The HOBQ-scale ‘pain/itching’ is related to both pain and itching while the ITQOL-scale ‘pain’ is related to pain and other complaints in general. We refrained from further study into the concurrent validity of the HOBQ. Only one generic outcome instrument (ITQOL) was included in this paper, because of the lack of well-validated generic outcome instruments for young children. In addition, we did not conduct behaviour observation or interviews by professionals (psychological testing). Such research would have contributed to our knowledge, but remains to be done. The majority of the HOBQ-scales discriminated very well between children with a low versus high burn severity, indicated by length of hospital stay, %TBSA, %TBSA third degree, artificial respiration and surgery. Four scales did not discriminate between these groups (play, language, fine motor and gross motor function). This can probably be explained by the relatively long period of time since the burn accident in our sample. Problems in these domains may be predominantly present in the first 6 months after the burns, as illustrated in Kazis et al. [9]. After this period, most problems in these domains have disappeared en mean scale scores are relatively high and stable. Our results contribute to the findings of Kazis et al. [9], and support the discriminant ability of the questionnaire. Further research is recommended in a more recent sample to evaluate the discriminant ability of the HOBQ-scales ‘play’, ‘language’, ‘fine motor function’ and ‘gross motor function’. Kazis et al. have studied changes overtime, by comparing results of the first assessment 8 months after the burn injury with a second assessment 6 months later. Significant improvements were found for 7 out of 10 scales [9]. At
this moment, no HOBQ-data are available from a longitudinal study starting during admission and with regular follow-ups. Such a study would provide further insight in the responsiveness to change of the HOBQ. In conclusion, our study showed that the Dutch HOBQ is a feasible instrument to measure outcome after burns. Our data generally support the reliability and validity of the Dutch HOBQ. At this moment, the HOBQ is available for use as a research tool in the Dutch language-area, if small changes in some specific scales (‘play’, ‘satisfaction’ and pain/itching) are interpreted with caution. Further research in other samples, for instance in children with more recent burns, is recommended to fully establish the reliability and validity of the HOBQ. A prospective study of children, with multiple assessments overtime and starting during admission in a burn centre, would enable us to study responsiveness of the HOBQ. In the near future, the Dutch HOBQ will be used as a research tool to evaluate functional outcome after burns in 0–4-year-old children. Acknowledgement This study was funded by the Dutch Burns Foundation, grant 2003.14. We would like to thank Hanny Groenewoud MD, Ph.D. for her contribution to the translation of the questionnaire, Jeanne M. Landgraf MD, Ph.D. and Hein Raat MD, Ph.D. for the availability of the ITQOL, Lewis E. Kazis, Sc.D. for his contribution to the statistical analysis, and the participating burn centres Burn Centre Groningen, Burn Centre Beverwijk and Burn Centre Rotterdam for their contribution to the data collection.
References [1] Sheridan R, Hinson M, Liang M, et al. Long-term outcomes of children surviving massive burns. JAMA 2000;283:69–73. [2] Herndon D, Le Master J, Beard S, et al. The quality of life after major thermal injury in children: an analysis of 12 survivors with greater than or equal to 80% total body 70% third-degree burns. J Trauma 1986;26:609–19. [3] Shakespeare V. Effect of small burn injury on physical, social and psychological health at 3–4 months after discharge. Burns 1998;24:739–44. [4] van Baar ME, Essink-Bot ML, Oen I, Dokter J, Boxma H, van Beeck EF. Functional outcome after burn injuries: a review. Burns, in press. [5] Blades B, Mellis N, Munster A. A burn specific health scale. J Trauma 1982;22:872–5. [6] Munster A, Horowitz G, Tudahl L. The abbreviated burn-specific health scale. J Trauma 1987;27:425–8. [7] Blalock S, Bunker B, DeVellis R. Measuring health status among survivors of burn injury: revisions of the Burn Specific Health Scale. J Trauma 1994;36:508–15. [8] Kildal M, Andersson G, Fugl-Meyer A, Lannerstam K, Gerdin B. Development of a brief version of the Burn Specific Health Scale (BSHS-B). J Trauma 2001;51:740–6. [9] Kazis L, Liang M, Lee A, et al. The development, validation and testing of a Health Outcomes Burn Questionnaire for infants and
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children 5 years of age and younger: American Burn Association/ Shriners Hospitals for Children. J Burn Care Rehabil 2002;23:196– 207. Daltroy L, Liang M, Philips C, et al. American Burn Association/ Shriners Hospitals forChildren Burn Outcomes Questionnaire: construction and psychometric properties. J Burn Care Rehabil 2000;21:29–39. Klassen A, Landgraf J, Lee S, et al. Health related quality of life in 3 and 4 year old children and their parents: preliminary findings about a new questionnaire. Health Qual Life Outomes 2003;1:81. Guillemin F, Bombardier C, Beaton D. Cross-cultural adaptation of health-related quality of life measures: literature review and proposed guidelines [see comments]. J Clin Epidemiol 1993;46:1417–32. Landgraf JM, Abetz L, Ware JE. The CHQ user’s manual Boston: The Health Institute, New England Medical Center; 1996.
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[14] Bland JM, Altman DG. Cronbach’s alpha. BMJ 1997;314:572. [15] Deyo RA, Diehr P, Patrick DL. Reproducibility and responsiveness of health status measures Statistics and strategies for evaluation. Control Clin Trials 1991;12:142S–58S. [16] Saffle J, Tuohig G, Sullivan J, Shekby J, Morris S, Mone M. Return to work as a measure of outcome in adults hospitalized foracute burn treatment. J Burn Care Rehabil 1996;17:353–61. [17] Kimmo T, Jyrki V, Sirpa A. Health status after recovery from burn injury. Burns 1998;24:293–8. [18] Patterson D, Questad K, Boltwood M, et al. Patient self-reports three months after sustaining a major burn. J Burn Care Rehabil 1987;8:274–9. [19] Emergency management of severe burns (EMSB). Course manual (Dutch version). Copyright: Australia and NewZealand Burn Association, 1996. Beverwijk: Dutch Burn Foundation, 2005.
Reliability and validity of the Health Outcomes Burn Questionnaire for infants and children in The Netherlands M.E. van Baar a,*, M.L. Essink-Bot a, I.M.M.H. Oen b,c, J. Dokter b, H. Boxma b, M.I. Hinson d, N.E.E. van Loey c, A.W. Faber c,e, E.F. van Beeck a a
Department of Public Health, Erasmus MC, University Medical Center Rotterdam, The Netherlands b Burn Centre Rotterdam, Medical Centre Rijnmond Zuid, Location Zuider, The Netherlands c Association of Dutch Burn Centres, Beverwijk, The Netherlands d Shriners Hospital for Children, Boston, MA, USA e Burn Centre Groningen, Martini Hospital, The Netherlands Accepted 6 October 2005
Abstract The Health Outcomes Burn Questionnaire (HOBQ) is a self-administered questionnaire to monitor outcome after burns in young children. This study aimed to assess feasibility, reliability and validity of the Dutch version of the HOBQ. The HOBQ was adapted into Dutch and tested in a population of children aged 0–4 years with a primary admission to a Dutch burn centre in March 2001–February 2004. Parents of 413 children were sent a questionnaire. To assess validity, a generic outcome instrument was included, the Infant Toddler Quality of Life Questionnaire (ITQOL). The response rate was 50.0% (n = 196). Mean self-reported completion time was 16.7 min. The internal consistency of all the HOBQscales was good (Cronbach’s alpha’s >0.69). Test–retest results showed no differences in 7 out of 10 scales. High correlations between HOBQ-scales and conceptually equivalent ITQOL and scales were found in 5 out of 7 comparisons. The majority of the HOBQ-scales (7 out of 10) showed significant differences in the expected direction between children with a long versus short length of stay. Our data support the reliability and validity of the Dutch HOBQ. The HOBQ can be used as a research tool, to monitor functional outcome after burns in young children. Further research in other samples is recommend to fully establish the reliability and validity of the HOBQ. # 2005 Elsevier Ltd and ISBI. All rights reserved. Keywords: Children; Outcome; Burns; Reliability; Validity
1. Introduction In recent years, attention for functional outcome after burns has grown. Because of major improvements in burn care in the past decades, even patients with major burns have high survival rates [1,2]. However, survivors of major burns * Corresponding author. Present address: Department of Public Health, Julius Center for Health Sciences and Primary Care, Stratenum 6.131, University Medical Center Utrecht, P.O. Box 85500, 3508 GA Utrecht, The Netherlands. Tel.: +31 30 2509378; fax: +31 30 2505482. E-mail address: [email protected] (M.E. van Baar). 0305-4179/$30.00 # 2005 Elsevier Ltd and ISBI. All rights reserved. doi:10.1016/j.burns.2005.10.004
often experience major problems in physical, mental and social perspective. In addition, also small burns can have a substantial impact, especially when functional areas are affected [3]. This growing attention for functional outcome after burns is also reflected in the publications on this topic. In a review on functional outcome after burns it was found that the majority of the publications was published from 1998 onwards [4]. In adults, a validated burn specific quality of life instrument is available to measure functional outcome after
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burns. The Burn Specific Health Scale was first published in 1982 [5], since then several adaptations/versions have been developed [6–8]. Until recently no burn specific quality of life instrument was available for children. In 2002, the Health Outcomes Burn Questionnaire for infants and children 5 years of age and younger (HOBQ) was published by Kazis et al. [9]. The HOBQ was developed by the American Burn Association/Shriners Hospitals for Children Outcomes Task Force. This multidimensional questionnaire consists of 10 scales, varying form play to appearance. The HOBQ could potentially become a standard instrument for measuring functional consequences of burns among 0–5-yearold children, but has not yet been applied outside the USA. To be able to use the HOBQ in our country, we adapted the questionnaire into Dutch and tested it in a Dutch population of young children with burn injuries. This could be a possible first step in extending the use of the HOBQ towards Europe and elsewhere. The aim of our study was to evaluate the Dutch version of the Health Outcomes Burn Questionnaire for infants and children. We assessed:
Health Outcomes Burn Questionnaire again to assess test– retest reliability. The completed questionnaires were returned by mail. The Medical Ethical Committee of the Erasmus University MC, University Medical Center Rotterdam, approved of this study. 2.2. Health Outcomes Burn Questionnaire
2. Methods
The Health Outcomes Burn Questionnaire for infants and children 5 years of age and younger (HOBQ) consists of 10 subscales (Table 1). The number of items per scale ranges from two to nine. All subscales relate to the past month, except the subscale ‘satisfaction’. In addition to the subscales, the HOBQ consists of items on standardised socio-demographic variables, prevalence of chronic conditions and recent treatment, and living situation [9]. The HOBQ was translated into Dutch according to international guidelines [12]. A standardised procedure, including independent forward and backward translations was followed. Experts in the field of burn care (IO) and health-related quality of life research (HG, MLE, MvB) made four independent forward translations. The final forward translation was made by consensus. A native American speaker made the backward translation. This version was compared to the original questionnaire, to control for differences and make adaptations if necessary. Similar to Kazis et al., scale scores were calculated by taking the average of all scale items, after adjustment for opposite scored items and for the number of actually answered items. At least half of the number of items per scale must be answered [9]. Crude scales were transformed linearly to a 0–100 scale, with higher scores indicating a better outcome.
2.1. Study population and data collection
2.3. General health status
The study population consisted of all children aged 0–4 at reference date March 1, 2004, with a primary admission for burn injuries in a burn centre in the period March 2001– February 2004 (n = 413). Children aged 5 years were excluded, The American Burns Association (ABA) developed two questionnaires for the assessment of outcome after burns; both are applicable for children aged 5, the HOBQ and de Burn Outcome Questionnaire (BOQ) [9,10]. We chose to include children aged 5 years in a study aimed at the validation of the BOQ. In addition, this restriction to pre-school children (up to 4 years) enabled us to use a single generic outcome instrument for the total study population (ITQOL [11], see further). Deceased children were excluded as well. No further prior exclusions were made within this study population. All burn centres in The Netherlands (n = 3) participated in the study. In May 2004, questionnaires were mailed to the parents of the children in our study population. Two weeks later, a reminder letter was sent. At the same time point, a random subgroup of the participating parents (n = 134) received the
We used the Infant Toddler Quality of Life Questionnaire (ITQOL) to test the validity of the HOBQ. The ITQOL is a recently developed multidimensional generic measure of health-related quality of life for use among preschool children [11]. The ITQOL is conceptually similar to the Child Health Questionnaire [13]. The ITQOL includes items that measure 13 concepts and is suitable for parents of children aged 2 months up to 4 years. The ITQOL has an acceptable reliability and validity [11].
(1) the feasibility of the Dutch HOBQ, indicated by response rate, missing answers and content of written comments; (2) the reliability of the Dutch HOBQ-scales (internal consistency and test–retest reliability) and (3) the validity of the Dutch HOBQ indicated by the relation with general health status measurement (concurrent validity) and the ability to discriminate between groups with different burn severity (discriminant validity).
2.4. Burn centre registration Participating burn centres provided background information on all included patients. Information was delivered about age, sex, aetiology, location of the burn, percentage of total body surface area burned (TBSA), percentage TBSA third degree, artificial respiration, surgery, intensive care admission, date of admission and length of stay (LOS).
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Table 1 Health Outcomes Burn Questionnaire-scales, items per scale and interpretation of low and high scores HOBQ-scales
n Items
Description low score
Description high score
Play
5
Child is not limited or able to play in most situations
Language
4
Fine motor skills
7
Gross motor skills
7
Behaviour
9
Family
5
Pain/itching
7
Appearance
3
Satisfaction
5
Concern/worry
7
Child is very limited or unable to play because of the burn injury (e.g. does not show interest in others or does not take turn in play) Child is very limited or unable to use language appropriate for its age because of the burn injury Child is very limited or unable to perform self-care activities because of the burn injury (e.g. finger feed and put on a T-shirt) Child is very limited or unable to perform physical activities because of the burn injury (e.g. creeping walking and climbing) Child’s mood is unhappy, withdrawn or anxious, etc. because of the burn injury Child’s health always limits or interrupts family activities or is a source of family tension Child has very severe pain and itching, and has been scratching, required medicine and awakened because of itching all of the time Child is unattractive to others; changes in appearance have interfered with relationships and parent is uncomfortable taking child in public because of appearance, because of the burn injury. Parent is very dissatisfied with child’s symptom Relief, appearance, sleep, function and overall medical care Parent has a great deal of worry or concern about child’s pain and suffering and future health
2.5. Statistical analysis A non-response analysis was performed by comparing children’s characteristics of respondents versus non-respondents. For this comparison, we used burn centre information on age, sex, aetiology, location of the burn (head (y/n), hands (y/n)), percentage TBSA, third degree TBSA (y/n), artificial respiration (y/n), surgery (y/n), intensive care (y/n), LOS and time since admission. We used the Chi-square test (categorical variables), the t-test (age, time since admission) and the Mann–Whitney U-test (TBSA, LOS) to test for statistical differences. Evaluation of feasibility consisted of the assessment of the response rate and the frequency of missing answers per item. In addition, respondents considering the questionnaire difficult/very difficult were compared to other respondents on respondent’s characteristics (age, sex and number of respondents (1 or >1)), family characteristics (education level, employment and living situation) and children’s characteristics (socio-demographic, burn-related characteristics based on burn centre information and reported outcome on HOBQ). We used the Chi-square test (categorical variables), the t-test (age, time since admission) and the Mann–Whitney U-test (TBSA, LOS, scales HOBQ) to test for statistical differences.
Child is not limited or able to use language appropriate for its age in most situations Child is not limited or able to perform self-care activities in most situations Child is not limited or able to perform physical activities
Child’s mood is not unhappy, withdrawn or anxious, etc. because of the burn injury Child’s health never limits or interrupts family activities nor is a source of family tension Child has no pain or itching, and has never been scratching nor required medicine or awakened because of itching Child is not unattractive to others; changes in appearance have not interfered with relationships and parent is not uncomfortable taking child in public because of appearance
Parent is very satisfied with child’s symptom relief, appearance, sleep, function and overall medical care Parent has no worry or concern at all about child’s pain and suffering and future health
We used Cronbach’s alpha to evaluate the internal consistency of the scales of the HOBQ. For scales used as a research tool, when groups are compared, an alpha of 0.7 is satisfactory. For scales used in the clinical situation, when the value of an individual is of interest, an alpha of at least 0.9 is satisfactory [14]. We calculated average correlation coefficients (Pearson’s Product Moment correlation) between items and their own scale (without the item under consideration) and between items and every other scale to evaluate whether the items were well chosen and if the scales represent different domains. The average corrected item-own scale coefficients are expected to be higher than the average item-other scale correlation coefficients. We assessed test–retest reliability of the HOBQ-scales at the group level, relevant for use as a research tool, by the two-sided Wilcoxon signed rank tests. We performed nonparametric tests because of the skewness of the data, representing ceiling effects. We calculated the intraclass correlation coefficient (ICC) to assess test–retest reliability at the individual level [15]. This information is relevant for use in the clinical situation. We tested whether HOBQ-scales correlated better with their a priori assumed conceptually equivalent general health domain (ITQOL) than with any other domain, as measured
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with Spearman rank order correlation coefficients between scales (concurrent validity). We expected the highest correlations between 7 HOBQ-scales and equivalent ITQOL-scales and 4 HOBQ. For instance, the highest correlation of HOBQ-scale ‘Pain/itching’ was expected with ITQOL-scale ‘Bodily pain’. The correlations between a priori assumed equivalent scales are in bold in Table 3. We also assessed the ability of the HOBQ to discriminate between the consequences of burns of different severity levels (discriminative validity). We used the Mann–Whitney U-test or the Kruskall–Wallis one way analysis of variance to determine differences in scale scores between two and three groups. We made comparisons for several indicators of severity: length of stay in burn centre, %TBSA, %TBSA third degree, surgery (y/n), artificial respiration (y/n), duration since admission, comorbidity (y/n), head involved (y/n) and hands involved (y/n). Analyses were performed using SPSS 11.0.
3. Results 3.1. Response and characteristics of parents and children with burns Of the 413 distributed questionnaires, 18 questionnaires were undeliverable. A total of 196 questionnaires were returned, including two incomplete questionnaires (50% response). One hundred thirty-four retest questionnaires were sent and 93 were returned (69% response). The children of the respondents and non-respondents differed in four out of twelve characteristics. Parents with a daughter with burns were more likely to respond, compared to parents with a son with burns (55.4% versus 42.0%, p = 0.01). In respondents’ children, the proportion with any third degree burns was higher (42% versus 32%, p = 0.03), the length of stay was longer (median 8 days versus 5 days, p = 0.02) and the time since admission was shorter (at time of mailing the questionnaire mean 17.3 months versus 20.3 months, p = 0.00). The mean respondents age was 33.5 years (S.D. 5.6), 77.2% were mothers. In 34.6%, at least one of the parents/caregivers had completed higher vocational education/university, 9.8% had only elementary or no education, and in most families (84.4%) at least one parent was employed. The mean age of the children with burns was 36.7 months (range 5–63), 53.6% were male and 24.6% were of a nonDutch ethnicity. The majority (88.6%) lived with both mother and father. A mean number of 0.2 co-morbid conditions were reported; 14.4% received treatment for such a condition at this moment. The median percentage of total body surface area burned was 6.0 (range 0–66). One child with a TBSA = 0 was admitted because of smoke inhalation. 42.1% had a ‘third degree’ burn (% TBSA third degree >0; range 0–60). Burns were most frequently the result of scalds (90.1%), 2.1% had
needed artificial respiration, and 36.8% had needed surgery. The median length of stay was 8 days (range 1–56). The mean time since admission (at completion of the questionnaire) was 17.5 months (S.D. = 9.8; range 2.8–38.8). 3.2. Feasibility The number of missing responses in the Health Outcomes Burn Questionnaire varied between 0.5 and 5.2%, with the exception of four items of the gross motor scale (‘walk holding onto people or furniture’ 8.8%, ‘walk without support’ 6.2%, ‘carry objects’ 7.2%, ‘pull to stand’ 6.2%), and two items of the satisfaction scale (‘pain/itch relief’ 9.3%, ‘appearance’ 5.7%). In addition, the measure provided patents the opportunity to answer that their child was too young on 23 items concerning play, language, fine motor and gross motor skills. This answer was chosen in 0.5–9.3% of the children, with the exception of five items (‘shows awareness’ 15.5%, ‘suggest new things’ 25.8%, ‘tell a simple story’ 11.3%, ‘put on front opening shirt’ 20.6% and ‘put on T-shirt’ 16.3%). Median self-reported completion time was 15 min (range 2– 135). Eleven percent considered the questionnaire to be difficult/very difficult; 40% found it neither difficult nor easy and 50% considered it to be easy/very easy. Respondents reporting difficulties with the questionnaire differed from other respondents in 12 out of 30 characteristics. Respondents reporting difficulties were more often living in families with a low education level (22.6% versus 7.9%, p = 0.02), without paid jobs (28.6% versus 7.5%, p = 0.00), without both parents (23.8% versus 8.9%, p = 0.04). Children of these respondents were more often of a non-Dutch ethnicity (23.9% versus 6.3%, p = 0.00), with a higher TBSA (median 7.5% versus 5%, p = 0.04) and LOS (median 19 days versus 8 days, p = 0.01). In addition, respondents reporting difficulties reported a worse outcome on 6 out 10 HOBQ-scales (play (median 90 versus 100, p = 0.02), language (median 88100, p = 0.02), gross motor (median 100 versus 100, p = 0.00), family (median 80 versus 90, p = 0.04), appearance (median 75 versus 100, p = 0.02), and concern/worry (median 50 versus 87, p = 0.00)). Spontaneous comments on the questionnaire were limited. Several parents reported problems with the attribution ‘because of the burns’. They found it difficult to say whether outcome could be attributed to the burn injury or not, especially in burns of some time ago. Also, parents of very young children reported difficulty in answering some questions, for instance ‘interference with relationships’. In addition, some remarks were made about pain and itch relief: no appropriate response option was available if no pain or no itch was prevalent. 3.3. Scoring distributions and internal consistencies More than half of the children had maximal scores on five HOBQ-scales (play, language, fine motor skills, gross motorskills and appearance) (ceiling effect) (Table 2).
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Table 2 Score distribution and internal consistency of Health Outcomes Burn Questionnaire-scales for 194 patients aged 0–4 years HOBQ-scales
N
Median
25th–75th percentile
% mina
% maxb
Alpha
Average item-own scale correlationc
Average item-other scale correlation
Play Language Fine motor Gross motor Behaviour Family Pain/itching Appearance Satisfaction Concern/worry
182 149 181 183 190 193 193 189 191 191
100.0 100.0 100.0 100.0 72.2 90.0 92.9 100.0 95.0 87.5
88–100 88–100 90–100 100–100 56–83 70–100 80–100 75–100 80–100 50–100
1 3 1 3 0 0 0 0 0 7
66 72 67 80 9 38 38 54 42 45
0.92 0.91 0.91 0.96 0.78 0.84 0.91 0.77 0.69 0.83
0.79 0.81 0.74 0.88 0.47 0.65 0.75 0.62 0.47 0.71
0.39 0.36 0.35 0.37 0.20 0.28 0.34 0.22 0.18 0.36
a b c
Percentage of respondents with lowest possible score (0). Percentage of respondents with highest possible score (100). Each item was correlated with the applicable scale excluding the item under consideration from the scale score.
similar ITQOL-domains, than with other domains (see Table 3). Three scales (language, gross motor skills and concern/worry) were correlated to the expected domains, but even more to other ITQOL-domains. The scales ‘play’ and ‘pain/itching’ were not correlated to the expected equivalent ITQOL-domains. The ability of the HOBQ to discriminate between children of different burn severity was assessed (discriminative validity). In all but three HOBQ-scales (‘language’, ‘fine motor skills’ and ‘gross motor skills’) outcome was significantly worse in children with a long length of hospital stay (>10 days), compared to children with a short length of stay (10 days), (see Table 4). In 6 out of 10 scales outcome was significantly worse in children with a high TBSA (>10%) compared to children with low TBSA (10%) (see Table 5). Similar differences were found for another three indicators of severity: TBSA third degree (<5% versus >5%), artificial respiration and surgery (no/yes) (data available upon request).
All scales had a good internal consistency (Cronbach’s alpha 9 scales 0.70, one scale 0.69). Five scales had an alpha >0.9. All scales had higher average corrected itemown scale correlation coefficients than the corresponding average item-other scale correlation coefficients. 3.4. Test–retest reliability At the group level, only 3 out of 10 HOBQ-scales showed a significant difference in mean scale score between test and retest (play, 90 versus 92, p = 0.02; ‘pain/itching’ 84 versus 87, p = 0.02; ‘satisfaction’ 88 versus 84, p = 0.02). At the individual level, data also were strongly related (all intra class correlation coefficients 0.70 and significant). 3.5. Validity We assumed seven HOBQ-scales to be related to specified ITQOL-domains. Two out of these HOBQ-scales (behaviour and family), correlated better with the expected Table 3 Correlationa of HOBQ and ITQOL Infant Toddler Quality of Life Questionnaire Growth and development HOBQ-scales Play Language Fine motor Gross motor Behaviour Family Pain/itching Appearance Satisfaction Concern/worry
0.19 0.33 0.27 0.07 0.40 0.38 0.22 0.35 0.33 0.18
Bodily pain
0.06 0.03 0.09 0.06 0.15 0.13 0.17 0.16 0.24 0.14
Temperament and moves
General behaviour
Getting along
General health perceptions
Parental impact emotional
Parental impact time
Family cohesion
Family activity
Physical functioning
0.37 0.30 0.35 0.29 0.53 0.55 0.36 0.32 0.35 0.35
0.39 0.37 0.34 0.25 0.44 0.44 0.27 0.31 0.26 0.24
0.34 0.30 0.30 0.15 0.52 0.48 0.22 0.30 0.35 0.25
0.27 0.25 0.25 0.25 0.30 0.39 0.36 0.42 0.35 0.35
0.25 0.16 0.22 0.08 0.43 0.45 0.21 0.27 0.30 0.27
0.22 0.34 0.35 0.22 0.33 0.40 0.21 0.14 0.31 0.23
0.06 0.21 0.07 0.02 0.25 0.15 0.11 0.18 0.16 0.07
0.18 0.28 0.28 0.18 0.48 0.63 0.20 0.22 0.34 0.25
0.32 0.33 0.27 0.25 0.24 0.31 0.32 0.27 0.34 0.29
Correlations with predefined equivalent CHQ-IT-domains are in bold. a Spearman’s rho correlation coefficient. Correlation >0.19 is significant at the 0.01 level (two-tailed).
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Table 4 Median scores of the HOBQ-scales for children with short length of stay burn centre (LOS <10 days) vs. longer LOS (>10 days) HOBQ-scales
Length of stay 10 days (n = 108)
Play Language Fine motor Gross motor Behaviour Family Pain/itching Appearance Satisfaction Concern/worry a
p-Valuea
>10 days (n = 85)
Median
(25th, 75th percentile)
Median
(25th, 75th percentile)
100 100 100 100 78 95 96 100 100 78
(90, 100) (88, 100) (92, 100) (100, 100) (61, 89) (80, 100) (85, 100) (88, 100) (85, 100) (63, 100)
100 100 100 100 61 85 89 92 90 63
(79, 100) (83, 100) (90, 100) (100, 100) (50, 78) (65, 100) (68, 100) (75, 100) (70, 100) (38, 100)
0.03 0.86 0.29 0.58 0.00 0.00 0.00 0.00 0.00 0.01
Mann–Whitney U-test.
Table 5 Median scores of the HOBQ for children with low TBSA (<10%) and high TBSA (>10%) HOBQ-scales
TBSA <10% (n = 167)
Play Language Fine motor Gross motor Behaviour Family Pain/itching Appearance Satisfaction Concern/worry a
p-Valuea
>10% (n = 26)
Median
(25th, 75th percentile)
Median
(25th, 75th percentile)
100 100 100 100 72 90 93 100 95 88
(88, 100) (88, 100) (90, 100) (100, 100) (56, 83) (75, 100) (82, 100) (83, 100) (81, 100) (50, 100)
100 100 100 100 61 73 86 75 83 50
(78, (56, (85, (86, (49, (50, (45, (50, (60, (25,
100) 100) 100) 100) 76) 85) 94) 100) 98) 81)
0.23 0.22 0.80 0.46 0.01 0.00 0.01 0.00 0.01 0.00
Mann–Whitney U-test.
In addition, the severity-indicators ‘time since admission’ and ‘comorbidity’ were tested. One out of 10 scales (‘pain/ itching’) showed a difference in outcome related to the time since admission. Pain and itching were worse in children with a more recent admission, compared to children with a longer time since admission (see Table 6). Comparable
results were found for the indicator ‘co morbidity’ (data available upon request). In children with burns of the head a significantly lower score on ‘appearance’ was found, compared to children without head involvement. In children with hands involved, a significantly lower score on ‘fine motor skills’ was found,
Table 6 Median scores of the HOBQ-scales for children with short time since admission (<1 year), moderate (>1 and <2 year) and long time since admission (>2 year) HOBQ-scales
Play Language Fine motor Gross motor Behaviour Family Pain/itching Appearance Satisfaction Concern/worry a b
Time since admission (in years) <1 (n = 69)a
>1–2 (n = 68)a
>2 (n = 56)a
p-Value b
100 (80, 100) 100 (75, 100) 100 (86, 100) 100 (93, 100) 72 (61, 83) 90 (75, 100) 91 (70, 96) 100 (83, 100) 95 (80, 100) 81 (38, 100)
100 (88, 100) 100 (84, 100) 100 (86, 100) 100 (100, 100) 67 (56, 83) 85 (70, 100) 93 (80, 100) 92 (75, 100) 90 (76, 100) 100 (63, 100)
100 (90, 100) 100 (100, 100) 100 (100, 100) 100 (100, 100) 72 (56, 89) 88 (70, 100) 98 (85, 100) 100 (75, 100) 100 (80, 100) 88 (50, 100)
0.37 0.11 0.12 0.36 0.31 0.99 0.02 0.21 0.42 0.08
Median (25th, 75th percentile). Kruskal–Wallis one way analysis of variance.
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compared to children without affection of the hands. No other significant differences in scales were found (data available upon request).
4. Discussion In this article, we report upon our project to adapt and test the Health Outcomes Burn Questionnaire for infants and children in a Dutch population. We assessed the feasibility, reliability and validity of the Dutch version of the HOBQ. We assessed feasibility by analysing the response rate and the missing items. We found a response rate of 50%, which is rather low but comparable to other studies assessing outcome after burns by mail [16–18]. Our study sample comprised all children with an admission to a burn centre, including children of nonDutch ethnicity. Non-response is probably partly related to problems with the Dutch language in this subpopulation. Response rates between burn centres varied between 47% in a multicultural city and 56% in the more rural Northern region. Children of respondents more often had a non-Dutch ethnicity in this city (43%), compared to the Northern region (9%). Thus, though we have reached a substantial group of children with a non-Dutch ethnicity, we could have missed information from this population. A small percentage of the responding parents (11%) reported difficulties with the questionnaire. These respondents differed from other responding parents in several aspects. In general, these parents were worse-off in several ways. Parents reporting difficulties with the questionnaire were more often of a nonDutch ethnicity. In future research, other data collection methods, such as a telephone survey and translations of the questionnaire in other languages, can be added to improve response rates. It is unclear whether the socio-economic position of parents has influenced response. In our sample, parents reporting difficulties with the questionnaire were more often of a low socio-economic position. However, the HOBQ was considered to be an easy questionnaire by half of the respondents, and median completion time (15 min) was limited. Therefore, we do not expect substantial nonresponse in parents with a low socio-economic position. We found some indications for a selective response by severity level. Parents of children with more severe burns or more recent burns more frequently returned the questionnaire. Although the differences were not very substantial, our sample does not fully represent the Dutch children with an admission to a burn centre. However, parents of children with more higher TBSA and longer LOS also more frequently reported difficulties with the questionnaires. Thus, although response is higher in parents of children with more severe burns, they also report more difficulties with the questionnaire. In addition, parents with difficulties with the questionnaire reported a worse children’s outcome on six out of 10 HOBQ-scales. These explorative analyses suggest that feasibility is related to the
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clinical situation of the child. This topic deserves future study, also to enhance future response rates. The HOBQ was originally developed for infants and children up to 5 years of age. In our sample, we excluded children aged 5. The ABA developed two questionnaires for the assessment of outcome after burns; both are applicable for children aged 5 years the HOBQ and de Burn Outcome Questionnaire (BOQ) [9,10]. We chose to include children aged 5 years in a study aimed at the evaluation of the BOQ. In addition, this restriction to pre-school children (up to 4) enabled us to use the ITQOL, as single generic outcome instrument for the total study population. Scales scores in our sample are in general high (mean 84.1 on a 0–100% scale), reflecting a good outcome after burns in this population of young children. More than half of the children had maximal scores on the scales ‘play’, ‘language’, ‘fine motor skills’, ‘gross motor skills’ and ‘appearance’. The lowest mean scores were found in the domains ‘behaviour’ and ‘concern/worry’. This probably reflects the long-term psychosocial consequences of burns, also after physical recovery. This good outcome after burns is probably related to the relatively long time since admission in our study population (17.5 months). The internal consistency of 9 out of 10 scales was >0.7, indicating that these scales can be used as a research tool, to compare groups. In five scales, and alpha >0.9 was found, indicating that these scales can be used to evaluate individuals in clinical settings [14]. In the US data, the latter applied only to two scales: gross motor and pain/ itching [9]. Two scales (behaviour and satisfaction), however, showed a relatively low average item-own scale correlation (<0.4). Further analysis revealed low item-to-scale correlations (<0.4) in four items of the scale ‘behaviour’ and in one item of the scale ‘satisfaction’. Therefore, evaluation of the scales ‘behaviour’ and ‘satisfaction’ seems to deserve further attention. These findings indicate some base psychometric limitations in the original questionnaire. We could not address these limitations in our adaptation study. However, the HOBQ possibly can be improved by reconsideration of these scales. Comparison with US data from the Shriners study is hampered by the different data presentation. US data were standardised to a non-burn US sample while our data are not. Comparison of study populations revealed a lower burn severity in the Dutch generally sample (mean TBSA 6.8% versus 16.9% in the US sample). In Dutch burn centres children are admitted following the criteria of Emergency management of severe burns [19]. In addition, children can be referred to burn centres if treating physicians prefer the expertise and facilities of a burn centre above their own expertise and facilities. Consequently, also patients with less severe burns are treated in a Dutch burn centre. In addition, in the Dutch sample longer period of time existed between
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the burn accident and assessment. The meantime since admission in the Dutch sample is 17.5 months, compared to 8.6 months in the US sample [9]. The test–retest correlations were high and statistically significant on the majority of scales. However, three scales (play, pain/itching and satisfaction) had significant but small differences between test and retest. In the US sample, low correlations (<0.4) were also found for two of these scales (play and satisfaction). Thus, further test–retest studies are recommended. In the meantime, small changes in scales play, satisfaction and also pain/itching should be interpreted with caution. The comparison of HOBQ-scales with equivalent ITQOL-domains supported the validity of the HOBQ. In two comparisons, the HOBQ-scales correlated higher with equivalent scales than with other scales; in another three comparisons high (but not the highest) correlations were found. We found low correlations between HOBQ-scales ‘play’ and ‘pain/itching’ and the equivalent ITQOL-scales, which can be explained by the different nature of the items in the domains. The HOBQ-scale ‘play’ is restricted to play, while the ITQOL-scale ‘growth and development’ is concerned with satisfaction with development in a broad area, including, physical growth, motor skills, language and cognitive function. The HOBQ-scale ‘pain/itching’ is related to both pain and itching while the ITQOL-scale ‘pain’ is related to pain and other complaints in general. We refrained from further study into the concurrent validity of the HOBQ. Only one generic outcome instrument (ITQOL) was included in this paper, because of the lack of well-validated generic outcome instruments for young children. In addition, we did not conduct behaviour observation or interviews by professionals (psychological testing). Such research would have contributed to our knowledge, but remains to be done. The majority of the HOBQ-scales discriminated very well between children with a low versus high burn severity, indicated by length of hospital stay, %TBSA, %TBSA third degree, artificial respiration and surgery. Four scales did not discriminate between these groups (play, language, fine motor and gross motor function). This can probably be explained by the relatively long period of time since the burn accident in our sample. Problems in these domains may be predominantly present in the first 6 months after the burns, as illustrated in Kazis et al. [9]. After this period, most problems in these domains have disappeared en mean scale scores are relatively high and stable. Our results contribute to the findings of Kazis et al. [9], and support the discriminant ability of the questionnaire. Further research is recommended in a more recent sample to evaluate the discriminant ability of the HOBQ-scales ‘play’, ‘language’, ‘fine motor function’ and ‘gross motor function’. Kazis et al. have studied changes overtime, by comparing results of the first assessment 8 months after the burn injury with a second assessment 6 months later. Significant improvements were found for 7 out of 10 scales [9]. At
this moment, no HOBQ-data are available from a longitudinal study starting during admission and with regular follow-ups. Such a study would provide further insight in the responsiveness to change of the HOBQ. In conclusion, our study showed that the Dutch HOBQ is a feasible instrument to measure outcome after burns. Our data generally support the reliability and validity of the Dutch HOBQ. At this moment, the HOBQ is available for use as a research tool in the Dutch language-area, if small changes in some specific scales (‘play’, ‘satisfaction’ and pain/itching) are interpreted with caution. Further research in other samples, for instance in children with more recent burns, is recommended to fully establish the reliability and validity of the HOBQ. A prospective study of children, with multiple assessments overtime and starting during admission in a burn centre, would enable us to study responsiveness of the HOBQ. In the near future, the Dutch HOBQ will be used as a research tool to evaluate functional outcome after burns in 0–4-year-old children. Acknowledgement This study was funded by the Dutch Burns Foundation, grant 2003.14. We would like to thank Hanny Groenewoud MD, Ph.D. for her contribution to the translation of the questionnaire, Jeanne M. Landgraf MD, Ph.D. and Hein Raat MD, Ph.D. for the availability of the ITQOL, Lewis E. Kazis, Sc.D. for his contribution to the statistical analysis, and the participating burn centres Burn Centre Groningen, Burn Centre Beverwijk and Burn Centre Rotterdam for their contribution to the data collection.
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