- Email: [email protected]
The Italian translation of the Celiac Disease-specific Quality of Life Scale in celiac patients on gluten free diet
Digestive and Liver Disease 45 (2013) 115–118
Contents lists available at SciVerse ScienceDirect
Digestive and Liver Disease journal homepage: www.elsevier.com/locate/dld
Alimentary Tract
The Italian translation of the Celiac Disease-specific Quality of Life Scale in celiac patients on gluten free diet Fabiana Zingone a , Alessandro Iavarone b , Raffaella Tortora c , Nicola Imperatore c , Lucienne Pellegrini a , Teresa Russo c , Spencer D. Dorn d , Carolina Ciacci a,∗ a
University of Salerno, Department of Medicine and Surgery, Salerno, Italy Neurological and Stroke Unit, CTO Hospital, AORN “Ospedali dei Colli, Naples, Italy c University of Naples Federico II, Department of Clinical and Experimental Medicine, Naples, Italy d Center for Functional GI and Motility Disorders, University of North Carolina, United States b
a r t i c l e
i n f o
Article history: Received 24 July 2012 Accepted 11 October 2012 Available online 6 December 2012 Keywords: Celiac disease Quality of life Questionnaire Validation
a b s t r a c t Background: A recently devised tool, the Celiac Disease-specific Quality of Life Scale has been proposed to assess specifically quality of life in celiac patients. Aim: To assess the validity and reliability of the Italian translation of the Celiac Disease-specific Quality of Life Scale. Methods: The Celiac Disease-specific Quality of Life Scale underwent forward/backward translation. Adults patients on gluten free diet by at least one year, consecutively recruited, completed SF36 questionnaire, the Italian version of Celiac Disease-specific Quality of Life Scale, the Health Related Quality of Life question and an abdominal pain scale. The study fulfilled criteria for acceptable psychometric assessment according to the International Quality of Life Assessment project. Results: Two-hundred-thirty celiac patients were recruited after about nine years from diagnosis. Factor analysis indicates that there are some similarities and discrepancies between the English and the Italian questionnaires. Despite this, the Italian Celiac Disease-specific Quality of Life Scale was able to identify the same four factors characterizing the patients’ answers (dysphoria, limitations, health concerns, inadequate treatment). Conclusion: The Celiac Disease-specific Quality of Life Scale is useful for assessing Celiac Disease-related Quality of Life. A wide use of the Italian Celiac Disease-specific Quality of Life Scale may be of help in obtaining comparable data on QOL in different setting and countries. © 2012 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.
1. Introduction Celiac disease (CD) is a chronic condition that impairs quality of life [1–5]. Compared to the general population, celiac patients who are symptomatic at diagnosis report a lower quality of life, while subclinical patients report a preserved quality of life [3]. Adherence to a gluten free diet (GFD) improves quality of life in most celiac patient [4,5]. Notably, most attempts to evaluate CD-related quality of life have relied on generic instruments, such as the Short Form-36 [6]. Because these generic instruments do not capture the attitudes, perceptions, and needs specifically related to celiac disease [7] they may be insensitive and unresponsive to changes over time.
∗ Corresponding author at: University of Salerno Medical School, Baronissi Campus, via Salvador Allende, 84081 Baronissi, SA, Italy. Tel.: +39 089965032. E-mail address: [email protected] (C. Ciacci).
Recently, Dorn et al. [8] developed a CD-specific Quality of Life Scale (CD-QOL) tailored to assess the special profile of celiac patients. The tool is a questionnaire that considers the specific perception of patient’s life during treatment, including affected individuals’ concerns, fears and limits related with this disease and with the starting a GFD. It is composed by four dimensions (dysphoria, limitations, health concerns, inadequate treatment). The aim of the present study was to devise and to describe psychometric properties of the Italian version of this instrument, the Italian CD-QOL (CD-QOL-I). 2. Materials and methods The Italian translation of the CD-QOL questionnaire, devised and previously validated in English by Dorn et al. [8] was performed according to the Rome translation project and approved by the Rome Foundation appointed clinician. Furthermore, the study fulfilled criteria for acceptable psychometric assessment according to the International Quality of Life Assessment (IQOL) project [9].
1590-8658/$36.00 © 2012 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.dld.2012.10.018
116
F. Zingone et al. / Digestive and Liver Disease 45 (2013) 115–118
2.1. Subjects Adults with celiac disease who had followed a GFD for at least one year were consecutively recruited between November 2010 and March 2012 from the Celiac Disease Centre of Federico II University of Naples, Italy. Questionnaires were administered in the morning of the routine follow-up visit. For all celiac patients, the CD diagnosis was based on the presence of anti-transglutaminase (ab-tTg) IgA and anti-endomysium antibodies (EMA), as well as histological damage in intestinal biopsy samples, defined as the presence of a type III a or higher enteropathy, according to modified Marsh classification [10]. The data collected included gender, age at first recorded diagnosis of CD, symptoms/signs at diagnosis (divided in classical CD, non-classical CD or subclinical CD according to Oslo definition [11], the presence of other immune-mediated diseases, age at time of testing, years on gluten free diet (GFD), dietetic interview and VAS scale [1–10] to evaluate adherence to GFD and years of schooling. The inclusion criteria of the study cohort were, age 16–70 years, a controlled gluten free diet (ab-tTg negative), absence of major psychiatric disorders, cancer, and pregnancy. All subjects gave their written informed consent to the study, which was carried on in agreement with the Declaration of Helsinki and approved by the local ethics committee. 2.2. Procedures Patients were evaluated by means of the following tools: CD-QOL questionnaire. CD-QOL is a specific celiac disease assessment instrument, composed by 20 items across four clinically relevant subscales. CD-QOL has been designed to assess the impact of CD diagnosis in celiac patients and to evaluate the feelings of depression and discomfort (dysphoria, DY). The instrument evaluates the psychological consequences of the disease, its diagnosis, and the GFD; for example, the fear of gluten contamination of food (limitations, LM), the fear of complication such as cancer (health concerns, HC) and the expectation of future therapy of the disease different by the simple GFD (inadequate treatment, IT). Higher scores correspond to a better quality of life and lesser impact of illness on daily life [8]. SF-36 questionnaire. The SF-36 survey consists of a 36-item questionnaire including eight components: physical functioning, role limitations due to physical health, bodily pain, general health, vitality, social functioning, role limitations due to emotional health and mental health. The eight domains contribute to two health dimension scales: the physical (PCS) and mental (MCS) scales. The SF-36 subscales are presented as means and standard deviations, with higher scores indicating better health and well-being. Lower scores on the PCS indicate limitations in physical/role tasks and general health, and bodily pain. Lower scores on the MCS suggest limitations in psychosocial health, emotional problems and reduced vitality [6,12,13]. Single-item Health Related Quality of Life (HRQOL) question. Subjects were asked ‘How would you rate your quality of life related to your illness?’ Response categories included the following: 1 = poor, 2 = fair, 3 = good, 4 = very good and 5 = excellent [8]. Average daily abdominal pain (VAS). Abdominal pain was evaluated using average daily scores on a Visual Analogue Scale (VAS) (100 mm; 0 = ‘none’, 100 = ‘very severe’) over a 2 week period [8]. 2.3. Statistical analysis Descriptive statistics were used to report continuous variables as means ± standard deviation (SD). Categorical data were given as counts and percentages. Chi-square and ANOVA were used for analysis of categorical and continuous data, respectively. Correlation
Table 1 Demographic, diagnostic and therapeutic characteristics of the validating population. Celiac disease patients N Male sex Age at CD diagnosis (years) 0–15 >15 Celiac disease presentation Classical CD Non-classical Subclinical Age at time of testing <30 years 30–50 years >50 years Years on gluten free diet ≤5 years >5 years Education (years of schooling) ≤18 years >18 years
230 48 (20.9%) 59 (25.7%) 171 (74.3%) 114 (49.6%) 98 (42.6%) 18 (7.8%) 89 (38.7%) 106 (46.1%) 35 (15.2%) 119 (51.7%) 111 (48.3%) 131 (57%) 99 (43%)
between CD-QOL and other dependent variables were described by Pearson correlation test. The effect of general and demographic variables on CD-QOL scores has been evaluated by multiple regression analysis. The Cronbach alpha and Cohen k have been computed in order to assess internal consistency and test–retest reliability, respectively. The factorial validity of the CD-QOL has been explored by means of a principal components analysis with Varimax rotation (method of extraction: roots > 1). The Statistical Package for Social Sciences (SPSS 15.0 package for Windows) was used to analyze the data. All tests were two-tailed with significance level set at p < 0.05. 3. Results 3.1. Study population Two-hundred-thirty CD patients were recruited after an average of 8.53 ± 9.83 years from CD diagnosis. Demographic, diagnostic and therapeutic data are shown in Table 1. All patients were found negative for serum markers of CD at the time of followup; self-reported compliance to a gluten-free diet was good: 86.5% (199 cases) of patients reported total adherence to a gluten-free diet; 13.5% (31 cases) were on a fairly strict gluten-free regimen (1–3 transgressions/month), nobody reported continuous transgressions. Eleven patients had also other immune-mediated diseases (8 patients with Hashimoto thyroiditis, 1 with type one diabetes, 2 with psoriasis). All patients completed CD-QOL-I, while a randomly selected subgroup also completed SF-36, HRQOL question and a VAS to pain. This sub-group had comparable demographic/diagnostic characteristics to the patients that completed only CD-QOL-I. 3.2. Questionnaires results Scores on all CD-QOL-I subscales were generally high. Total score was 81.03 ± 13.286; dysphoria subscale score was 87.93 ± 14.120; limitation subscale score was 81.18 ± 16.206; health concerns score was 76.87 ± 18.325, and inadequate treatment subscale score was 76.96 ± 21.323. In fifty-four patients we evaluated also the SF-36 questionnaire: the MCS scored 46.09 ± 9.2, while the PCS scored 53.68 ± 6.07. Fifty-one patients completed the single-item HRQOL question and the answer was poor in 3.9%, fair in 15.7%, good in 45.1%, very good in 23.5% and excellent in 11.8%.
F. Zingone et al. / Digestive and Liver Disease 45 (2013) 115–118
Finally, fifty-one completed a VAS (0–100) to pain, the mean ± SD was 18.94 ± 23.75. The multiple regression analysis, assuming CD-QOL-I scores as dependent variable vs the four general and demographic independents (age, sex, education and age at diagnosis) was not significant (F(4,229) = 1.757, p = ns). The CD-QOL-I scores were similar in patients with classical CD (mean 81.29, SD = 12.87), in patients with non-classical CD (mean 80.52, SD = 14.18) and in patients with subclinical CD (mean 82.08, SD = 11.37), neither a relationship was found between CD-QOL-I scores and time since the diagnosis (r = 0.083, p = ns). Similarly, there was no correlation between CD-QOL-I total score and length of GFD when patients were divided according to years on GFD, more or less 5 year. In fact, in 119 patients that were on GFD for less than five years the CD-QOL-I total score was 81.07 (SD 13.23) while in 111 patients that were on GFD for at least five years it was 80.99 (SD 13.40), p = 0.964.
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Table 2 Correlation between the Italian Celiac Disease-specific Quality of Life Scale and other scales (concurrent validity).
SF36 PCS SF36 MCS Abdominal pain Self-rated QOL
N
R
p
54 54 51 51
0.267 0.554 −0.296 0.621
0.05 <0.001 0.035 <0.001
PCS, physical component scale; MCS, mental component scale; QOL, quality of life.
3.6. Test–retest reliability It was investigated on thirty-one randomly selected patients who were re-administered the CD-QOL-I after about two weeks by the first assessment. On this sub-sample, the Cohen test gave a k value of 0.63. 3.7. Internal consistency
3.3. Psychometric properties The criteria for acceptable psychometric proprieties according to the IQOL project [9] were satisfied in our population.
The internal consistency was very high, as shown by a Cronbach alpha = 0.88 (standard alpha = 0.89), with a mean correlation between items of 0.30. 3.8. Factor analysis
3.4. Data quality Floor effect was absent overall and for all subscales. Ceiling effect was present overall in one case, dysphoria in 28.7%, limitations in 3.9%, health concerns in 6.1% and inadequate treatment in 27.4% of cases. The completeness of data was optimal with 100% of items answered. 3.5. Concurrent validity The concurrent validity showed a significant correlation between the CD-QOL-I and other scales (Table 2).
The scores of each of the twenty items of the CD-QOL-I entered a principal components analysis with Varimax rotation. The analysis had a Bartlett’s chi-square = 1997.87 (p < 0.0001) and generated six factors which explained about 68% of the Variance. The first factor had a magnitude of 6.866 (variance 0.343), and loaded on items 5, 10, 13, 14, 16; this has been called “dysphoria”. The second factor (magnitude 1.82, variance 0.091) was related to items 2, 3, 4, 20; it has been labelled “health concerns”. The third factor (magnitude 1.573, variance 0.079) loaded on items 6, 7, 15, 17, 18 and has been called “limitation”. All the remaining three factors loaded on only one item (Table 3); however, all these items were referred
Table 3 Principal component analysis of the Italian Celiac Disease-specific Quality of Life Scale: reference structure matrix after rotation (Varimax procedure). Values > 0.50 are in bold. Factor 1 1. I feel limited by this disease 2. I feel worried that I will suffer from this disease 3. I feel concerned that this disease will cause other health problems 4. I feel worried about my increased risk of cancer from this disease 5. I feel socially stigmatized for having this disease 6. I feel like I’m limited in eating meals with co workers 7. I feel like I am not able to have special foods like birthday cake and pizza 8. I feel that the diet is insufficient treatment for my disease 9. I feel that there are not enough choices for treatment 10. I feel depressed because of my disease 11. I feel frightened by having this disease 12. I feel like I don’t know enough about the disease 13. I feel overwhelmed about having this disease 14. I have trouble socializing because of my disease 15. I find it difficult to travel or take long trips because of my disease 16. I feel like I cannot live a normal life because of my disease 17. I feel afraid to eat out because my food may be contaminated 18. I feel worried about the increased risk of one of my family members having celiac disease 19. I feel like I think about food all the time 20. I feel concerned that my long term health will be affected
Factor2
Factor 3
Factor 4
Factor 5
Factor6
0.304 0.289 −0.011
0.343 0.644 0.856
0.190 −0.080 0.022
−0.416 −0.042 −0.156
0.125 −0.132 −0.014
0.027 0.051 0.074
0.023
0.678
−0.002
0.104
0.181
−0.049
0.715 0.302 0.034
0.001 −0.032 −0.082
−0.017 −0.036 −0.246
0.041 0.089 0.309
0.004
0.004
−0.040
0.045
0.868
0.151
−0.026 0.532 0.371 −028 0.687 0.757 0.120
0.058 0.148 0.298 −0.14 0.77 0.115 −0.095
0.175 0.004 −0.085 0.118 −0.095 −0.156 0.566
0.052 0.333 0.386 0.785 0.150 −0.107 −0.030
0.195 −0.040 0.068 0.47 −0.086 0.078 0.016
0.809 0.030 −0.225 0.110 −0.041 −0.056 0.237
0.603
0.123
0.046
−0.030
0.048
0.025
−0.064
0.117
0.546
0.140
0.271
−0.086
−0.330
0.218
0.615
0.121
−0.027
−0.121
0.435 0.171
−0.001 0.569
0.119 0.128
−0.071 0.284
0.354 −0.090
−0.464 0.029
1.393E−4 0.520 0.573
−2.57E−4 −0.102 0.116
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Table 4 English version vs. Italian version (the factor analyses of the Italian Celiac Diseasespecific Quality of Life Scale excluded three questions: 1, 11, 19).
Dysphoria Health concerns Limitations Inadequate treatment
Question no. English version
Question no. Italian version
10, 11, 12, 13 2, 3, 4, 18, 20 1, 5, 6, 7, 14, 15, 16, 17, 19 8, 9
5, 10, 13, 14, 16 2, 3, 4, 20 6, 7, 15, 17, 18 8, 9, 12
to feelings of “inadequate treatment”. In comparing the structure of the CD-QOL-I and the CD-QOL, we found discrepancies and similarities (Table 4). 4. Discussion The study produced the CD-QOL-I, a culturally and psychometrically validated instrument that is easy for Italian CD patients to understand, and ready for use in clinical practice. Our results demonstrate that the CD-QOL-I can be performed in all celiac patients because is not influenced by demographic variables, symptoms at diagnosis, or time from diagnosis. The CD-QOL-I has excellent psychometric proprieties, including good internal consistency reliability, high test-retest reliability, and a strong correlation with other generic QOL scales. There are some discrepancies between the English and the Italian version: for example, there are three questions in the dimension “dysphoria” in CD-QOL-I (I feel socially stigmatized, I have trouble socializing, I feel like I cannot live a normal life) that are grouped among dimension “limitations” in the original version. Question 18 (I feel worried about the increased risk of one of my family members having CD) in the English version is related to “health concerns” while in the Italian version is related to “limitations”. These can be attributed to a variety of reasons: different population and socioeconomic variables, availability of medical care that in Italy is under the coverage of the National Health System, and younger age of the Italian patients than US ones (35.02 ± 12.43 vs 48.3 ± 15.8 years). The CD-QOL-I is not the first condition-specific quality of life measure for CD; specific questionnaires were developed for paediatric [14] and adult patients [15]. In 2007 Hauser et al. [15] developed the celiac disease questionnaire, CDQ which is more focused on quantifying symptoms and impairment in daily function. The CD-QOL is instead focused on the perception of limits and troubles of everyday life of a CD patient and his/her expectancy. It is easy to understand and appears to be a useful tool for the physician to identify some QOL issues requiring specific action to improve the daily life of CD patients. There are some limitations in our study. The first is that to better assess the impact of CD diagnosis; the CD-QOL-I should be administered to patients who are closer to diagnosis. Accordingly, we compared patients’ CD-QOL-I scores among those diagnosed within
the prior five years to those diagnosed earlier. The results were similar, thus proving that the length of GFD does not affect the perceptions of quality of life in CD patients. Another limitation is that our patients were all recruited from a tertiary outpatient referral centre. These patients reported a good health status, low emotional stress specifically due to the disease, and a relatively high level of quality of life. One reason for this may be that at tertiary referral centres the diagnosis is followed by an accurate education of the patient and family about the dietetic restrictions and the CD-related health issues. Only a wider use of this questionnaire and in a larger number of CD patients will allow to have precise figures about Italian CD patients perception of quality of life and give the possibility of obtaining comparable data for comparison in different settings and countries. Conflict of interest There are no conflicts of interest to be disclosed. References [1] Ciacci C, D’Agate C, De Rosa A, et al. Self-rated quality of life in celiac disease. Digestive Diseases and Sciences 2003;48:2216–20. [2] Lee AR, Ng DL, Diamond B, et al. Living with coeliac disease: survey results from the USA. Journal of Human Nutrition and Dietetics 2012;25:233–8. [3] Johnston SD, Rodgers C, Watson RG. Quality of life in screen-detected and typical coeliac disease and the effect of excluding dietary gluten. European Journal of Gastroenterology and Hepatology 2004;16:1281–6. ˜ E, Vázquez H, et al. Quality of life in celiac disease patients. [4] Nachman F, Maurino Prospective analysis on the importance of clinical severity at diagnosis and the impact of treatment. Digestive and Liver Disease 2009;41:15–25. [5] Nachman F, del Campo MP, González A, et al. Long-term deterioration of quality of life in adult patients with celiac disease is associated with treatment noncompliance. Digestive and Liver Disease 2010;42:685–91. [6] Riddle DL, Lee MS, Stratford PW. Use of SF-36 and SF-12 health status measures a quantitative comparison for groups versus individual patients. Medical Care 2001;30:867–78. [7] Book Review, Spilker B. Quality of life and pharmacoeconomics in clinical trials. 2nd ed. Philadelphia: Lippincott-Raven; 1996. [8] Dorn SD, Hernandez L, Minaya MT, et al. The development and validation of a new coeliac disease quality of life survey (CD-QOL). Alimentary Pharmacology and Therapeutics 2010;31:666–75. [9] Gandek B, Ware Jr JE. Methods for validating and norming translations of health status questionnaires: the IQOLA Project approach. International Quality of Life Assessment. Journal of Clinical Epidemiology 1998;51:953–9. November. [10] Rostami K, Kerckhaert J, Tiemessen R, von Blomberg BM, Meijer JW, Mulder CJ. Sensitivity of antiendomysium and antigliadin antibodies in untreated celiac disease: disappointing in clinical practice. American Journal of Gastroenterology 1999;94:888–94. [11] Ludvigsson JF, Leffler DA, Bai JC, et al. The Oslo definitions for coeliac disease and related terms. Gut 2012, in press. [12] Ware JE, Kosinski M, Keller SD. SF-36 physical and mental health summary scales: a user’s manual. Boston, MA: The Health Institute, New England Medical Center; 1994. [13] Ware JE. SF-36 health survey update. Spine 2000;25:3130–9. [14] van Doorn RK, Winkler LM, Zwinderman KH, et al. CDDUX: a disease-specific health-related questionnaire for children with celiac disease. Journal of Pediatric Gastroenterology and Nutrition 2008;47:147–52. [15] Häuser W, Gold J, Stallmach A, et al. Development and validation of the Celiac Disease Questionnaire (CDQ), a disease-specific health-related quality of life measure for adult patients with celiac disease. Journal of Clinical Gastroenterology 2007;41:157–66.
Contents lists available at SciVerse ScienceDirect
Digestive and Liver Disease journal homepage: www.elsevier.com/locate/dld
Alimentary Tract
The Italian translation of the Celiac Disease-specific Quality of Life Scale in celiac patients on gluten free diet Fabiana Zingone a , Alessandro Iavarone b , Raffaella Tortora c , Nicola Imperatore c , Lucienne Pellegrini a , Teresa Russo c , Spencer D. Dorn d , Carolina Ciacci a,∗ a
University of Salerno, Department of Medicine and Surgery, Salerno, Italy Neurological and Stroke Unit, CTO Hospital, AORN “Ospedali dei Colli, Naples, Italy c University of Naples Federico II, Department of Clinical and Experimental Medicine, Naples, Italy d Center for Functional GI and Motility Disorders, University of North Carolina, United States b
a r t i c l e
i n f o
Article history: Received 24 July 2012 Accepted 11 October 2012 Available online 6 December 2012 Keywords: Celiac disease Quality of life Questionnaire Validation
a b s t r a c t Background: A recently devised tool, the Celiac Disease-specific Quality of Life Scale has been proposed to assess specifically quality of life in celiac patients. Aim: To assess the validity and reliability of the Italian translation of the Celiac Disease-specific Quality of Life Scale. Methods: The Celiac Disease-specific Quality of Life Scale underwent forward/backward translation. Adults patients on gluten free diet by at least one year, consecutively recruited, completed SF36 questionnaire, the Italian version of Celiac Disease-specific Quality of Life Scale, the Health Related Quality of Life question and an abdominal pain scale. The study fulfilled criteria for acceptable psychometric assessment according to the International Quality of Life Assessment project. Results: Two-hundred-thirty celiac patients were recruited after about nine years from diagnosis. Factor analysis indicates that there are some similarities and discrepancies between the English and the Italian questionnaires. Despite this, the Italian Celiac Disease-specific Quality of Life Scale was able to identify the same four factors characterizing the patients’ answers (dysphoria, limitations, health concerns, inadequate treatment). Conclusion: The Celiac Disease-specific Quality of Life Scale is useful for assessing Celiac Disease-related Quality of Life. A wide use of the Italian Celiac Disease-specific Quality of Life Scale may be of help in obtaining comparable data on QOL in different setting and countries. © 2012 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.
1. Introduction Celiac disease (CD) is a chronic condition that impairs quality of life [1–5]. Compared to the general population, celiac patients who are symptomatic at diagnosis report a lower quality of life, while subclinical patients report a preserved quality of life [3]. Adherence to a gluten free diet (GFD) improves quality of life in most celiac patient [4,5]. Notably, most attempts to evaluate CD-related quality of life have relied on generic instruments, such as the Short Form-36 [6]. Because these generic instruments do not capture the attitudes, perceptions, and needs specifically related to celiac disease [7] they may be insensitive and unresponsive to changes over time.
∗ Corresponding author at: University of Salerno Medical School, Baronissi Campus, via Salvador Allende, 84081 Baronissi, SA, Italy. Tel.: +39 089965032. E-mail address: [email protected] (C. Ciacci).
Recently, Dorn et al. [8] developed a CD-specific Quality of Life Scale (CD-QOL) tailored to assess the special profile of celiac patients. The tool is a questionnaire that considers the specific perception of patient’s life during treatment, including affected individuals’ concerns, fears and limits related with this disease and with the starting a GFD. It is composed by four dimensions (dysphoria, limitations, health concerns, inadequate treatment). The aim of the present study was to devise and to describe psychometric properties of the Italian version of this instrument, the Italian CD-QOL (CD-QOL-I). 2. Materials and methods The Italian translation of the CD-QOL questionnaire, devised and previously validated in English by Dorn et al. [8] was performed according to the Rome translation project and approved by the Rome Foundation appointed clinician. Furthermore, the study fulfilled criteria for acceptable psychometric assessment according to the International Quality of Life Assessment (IQOL) project [9].
1590-8658/$36.00 © 2012 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.dld.2012.10.018
116
F. Zingone et al. / Digestive and Liver Disease 45 (2013) 115–118
2.1. Subjects Adults with celiac disease who had followed a GFD for at least one year were consecutively recruited between November 2010 and March 2012 from the Celiac Disease Centre of Federico II University of Naples, Italy. Questionnaires were administered in the morning of the routine follow-up visit. For all celiac patients, the CD diagnosis was based on the presence of anti-transglutaminase (ab-tTg) IgA and anti-endomysium antibodies (EMA), as well as histological damage in intestinal biopsy samples, defined as the presence of a type III a or higher enteropathy, according to modified Marsh classification [10]. The data collected included gender, age at first recorded diagnosis of CD, symptoms/signs at diagnosis (divided in classical CD, non-classical CD or subclinical CD according to Oslo definition [11], the presence of other immune-mediated diseases, age at time of testing, years on gluten free diet (GFD), dietetic interview and VAS scale [1–10] to evaluate adherence to GFD and years of schooling. The inclusion criteria of the study cohort were, age 16–70 years, a controlled gluten free diet (ab-tTg negative), absence of major psychiatric disorders, cancer, and pregnancy. All subjects gave their written informed consent to the study, which was carried on in agreement with the Declaration of Helsinki and approved by the local ethics committee. 2.2. Procedures Patients were evaluated by means of the following tools: CD-QOL questionnaire. CD-QOL is a specific celiac disease assessment instrument, composed by 20 items across four clinically relevant subscales. CD-QOL has been designed to assess the impact of CD diagnosis in celiac patients and to evaluate the feelings of depression and discomfort (dysphoria, DY). The instrument evaluates the psychological consequences of the disease, its diagnosis, and the GFD; for example, the fear of gluten contamination of food (limitations, LM), the fear of complication such as cancer (health concerns, HC) and the expectation of future therapy of the disease different by the simple GFD (inadequate treatment, IT). Higher scores correspond to a better quality of life and lesser impact of illness on daily life [8]. SF-36 questionnaire. The SF-36 survey consists of a 36-item questionnaire including eight components: physical functioning, role limitations due to physical health, bodily pain, general health, vitality, social functioning, role limitations due to emotional health and mental health. The eight domains contribute to two health dimension scales: the physical (PCS) and mental (MCS) scales. The SF-36 subscales are presented as means and standard deviations, with higher scores indicating better health and well-being. Lower scores on the PCS indicate limitations in physical/role tasks and general health, and bodily pain. Lower scores on the MCS suggest limitations in psychosocial health, emotional problems and reduced vitality [6,12,13]. Single-item Health Related Quality of Life (HRQOL) question. Subjects were asked ‘How would you rate your quality of life related to your illness?’ Response categories included the following: 1 = poor, 2 = fair, 3 = good, 4 = very good and 5 = excellent [8]. Average daily abdominal pain (VAS). Abdominal pain was evaluated using average daily scores on a Visual Analogue Scale (VAS) (100 mm; 0 = ‘none’, 100 = ‘very severe’) over a 2 week period [8]. 2.3. Statistical analysis Descriptive statistics were used to report continuous variables as means ± standard deviation (SD). Categorical data were given as counts and percentages. Chi-square and ANOVA were used for analysis of categorical and continuous data, respectively. Correlation
Table 1 Demographic, diagnostic and therapeutic characteristics of the validating population. Celiac disease patients N Male sex Age at CD diagnosis (years) 0–15 >15 Celiac disease presentation Classical CD Non-classical Subclinical Age at time of testing <30 years 30–50 years >50 years Years on gluten free diet ≤5 years >5 years Education (years of schooling) ≤18 years >18 years
230 48 (20.9%) 59 (25.7%) 171 (74.3%) 114 (49.6%) 98 (42.6%) 18 (7.8%) 89 (38.7%) 106 (46.1%) 35 (15.2%) 119 (51.7%) 111 (48.3%) 131 (57%) 99 (43%)
between CD-QOL and other dependent variables were described by Pearson correlation test. The effect of general and demographic variables on CD-QOL scores has been evaluated by multiple regression analysis. The Cronbach alpha and Cohen k have been computed in order to assess internal consistency and test–retest reliability, respectively. The factorial validity of the CD-QOL has been explored by means of a principal components analysis with Varimax rotation (method of extraction: roots > 1). The Statistical Package for Social Sciences (SPSS 15.0 package for Windows) was used to analyze the data. All tests were two-tailed with significance level set at p < 0.05. 3. Results 3.1. Study population Two-hundred-thirty CD patients were recruited after an average of 8.53 ± 9.83 years from CD diagnosis. Demographic, diagnostic and therapeutic data are shown in Table 1. All patients were found negative for serum markers of CD at the time of followup; self-reported compliance to a gluten-free diet was good: 86.5% (199 cases) of patients reported total adherence to a gluten-free diet; 13.5% (31 cases) were on a fairly strict gluten-free regimen (1–3 transgressions/month), nobody reported continuous transgressions. Eleven patients had also other immune-mediated diseases (8 patients with Hashimoto thyroiditis, 1 with type one diabetes, 2 with psoriasis). All patients completed CD-QOL-I, while a randomly selected subgroup also completed SF-36, HRQOL question and a VAS to pain. This sub-group had comparable demographic/diagnostic characteristics to the patients that completed only CD-QOL-I. 3.2. Questionnaires results Scores on all CD-QOL-I subscales were generally high. Total score was 81.03 ± 13.286; dysphoria subscale score was 87.93 ± 14.120; limitation subscale score was 81.18 ± 16.206; health concerns score was 76.87 ± 18.325, and inadequate treatment subscale score was 76.96 ± 21.323. In fifty-four patients we evaluated also the SF-36 questionnaire: the MCS scored 46.09 ± 9.2, while the PCS scored 53.68 ± 6.07. Fifty-one patients completed the single-item HRQOL question and the answer was poor in 3.9%, fair in 15.7%, good in 45.1%, very good in 23.5% and excellent in 11.8%.
F. Zingone et al. / Digestive and Liver Disease 45 (2013) 115–118
Finally, fifty-one completed a VAS (0–100) to pain, the mean ± SD was 18.94 ± 23.75. The multiple regression analysis, assuming CD-QOL-I scores as dependent variable vs the four general and demographic independents (age, sex, education and age at diagnosis) was not significant (F(4,229) = 1.757, p = ns). The CD-QOL-I scores were similar in patients with classical CD (mean 81.29, SD = 12.87), in patients with non-classical CD (mean 80.52, SD = 14.18) and in patients with subclinical CD (mean 82.08, SD = 11.37), neither a relationship was found between CD-QOL-I scores and time since the diagnosis (r = 0.083, p = ns). Similarly, there was no correlation between CD-QOL-I total score and length of GFD when patients were divided according to years on GFD, more or less 5 year. In fact, in 119 patients that were on GFD for less than five years the CD-QOL-I total score was 81.07 (SD 13.23) while in 111 patients that were on GFD for at least five years it was 80.99 (SD 13.40), p = 0.964.
117
Table 2 Correlation between the Italian Celiac Disease-specific Quality of Life Scale and other scales (concurrent validity).
SF36 PCS SF36 MCS Abdominal pain Self-rated QOL
N
R
p
54 54 51 51
0.267 0.554 −0.296 0.621
0.05 <0.001 0.035 <0.001
PCS, physical component scale; MCS, mental component scale; QOL, quality of life.
3.6. Test–retest reliability It was investigated on thirty-one randomly selected patients who were re-administered the CD-QOL-I after about two weeks by the first assessment. On this sub-sample, the Cohen test gave a k value of 0.63. 3.7. Internal consistency
3.3. Psychometric properties The criteria for acceptable psychometric proprieties according to the IQOL project [9] were satisfied in our population.
The internal consistency was very high, as shown by a Cronbach alpha = 0.88 (standard alpha = 0.89), with a mean correlation between items of 0.30. 3.8. Factor analysis
3.4. Data quality Floor effect was absent overall and for all subscales. Ceiling effect was present overall in one case, dysphoria in 28.7%, limitations in 3.9%, health concerns in 6.1% and inadequate treatment in 27.4% of cases. The completeness of data was optimal with 100% of items answered. 3.5. Concurrent validity The concurrent validity showed a significant correlation between the CD-QOL-I and other scales (Table 2).
The scores of each of the twenty items of the CD-QOL-I entered a principal components analysis with Varimax rotation. The analysis had a Bartlett’s chi-square = 1997.87 (p < 0.0001) and generated six factors which explained about 68% of the Variance. The first factor had a magnitude of 6.866 (variance 0.343), and loaded on items 5, 10, 13, 14, 16; this has been called “dysphoria”. The second factor (magnitude 1.82, variance 0.091) was related to items 2, 3, 4, 20; it has been labelled “health concerns”. The third factor (magnitude 1.573, variance 0.079) loaded on items 6, 7, 15, 17, 18 and has been called “limitation”. All the remaining three factors loaded on only one item (Table 3); however, all these items were referred
Table 3 Principal component analysis of the Italian Celiac Disease-specific Quality of Life Scale: reference structure matrix after rotation (Varimax procedure). Values > 0.50 are in bold. Factor 1 1. I feel limited by this disease 2. I feel worried that I will suffer from this disease 3. I feel concerned that this disease will cause other health problems 4. I feel worried about my increased risk of cancer from this disease 5. I feel socially stigmatized for having this disease 6. I feel like I’m limited in eating meals with co workers 7. I feel like I am not able to have special foods like birthday cake and pizza 8. I feel that the diet is insufficient treatment for my disease 9. I feel that there are not enough choices for treatment 10. I feel depressed because of my disease 11. I feel frightened by having this disease 12. I feel like I don’t know enough about the disease 13. I feel overwhelmed about having this disease 14. I have trouble socializing because of my disease 15. I find it difficult to travel or take long trips because of my disease 16. I feel like I cannot live a normal life because of my disease 17. I feel afraid to eat out because my food may be contaminated 18. I feel worried about the increased risk of one of my family members having celiac disease 19. I feel like I think about food all the time 20. I feel concerned that my long term health will be affected
Factor2
Factor 3
Factor 4
Factor 5
Factor6
0.304 0.289 −0.011
0.343 0.644 0.856
0.190 −0.080 0.022
−0.416 −0.042 −0.156
0.125 −0.132 −0.014
0.027 0.051 0.074
0.023
0.678
−0.002
0.104
0.181
−0.049
0.715 0.302 0.034
0.001 −0.032 −0.082
−0.017 −0.036 −0.246
0.041 0.089 0.309
0.004
0.004
−0.040
0.045
0.868
0.151
−0.026 0.532 0.371 −028 0.687 0.757 0.120
0.058 0.148 0.298 −0.14 0.77 0.115 −0.095
0.175 0.004 −0.085 0.118 −0.095 −0.156 0.566
0.052 0.333 0.386 0.785 0.150 −0.107 −0.030
0.195 −0.040 0.068 0.47 −0.086 0.078 0.016
0.809 0.030 −0.225 0.110 −0.041 −0.056 0.237
0.603
0.123
0.046
−0.030
0.048
0.025
−0.064
0.117
0.546
0.140
0.271
−0.086
−0.330
0.218
0.615
0.121
−0.027
−0.121
0.435 0.171
−0.001 0.569
0.119 0.128
−0.071 0.284
0.354 −0.090
−0.464 0.029
1.393E−4 0.520 0.573
−2.57E−4 −0.102 0.116
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F. Zingone et al. / Digestive and Liver Disease 45 (2013) 115–118
Table 4 English version vs. Italian version (the factor analyses of the Italian Celiac Diseasespecific Quality of Life Scale excluded three questions: 1, 11, 19).
Dysphoria Health concerns Limitations Inadequate treatment
Question no. English version
Question no. Italian version
10, 11, 12, 13 2, 3, 4, 18, 20 1, 5, 6, 7, 14, 15, 16, 17, 19 8, 9
5, 10, 13, 14, 16 2, 3, 4, 20 6, 7, 15, 17, 18 8, 9, 12
to feelings of “inadequate treatment”. In comparing the structure of the CD-QOL-I and the CD-QOL, we found discrepancies and similarities (Table 4). 4. Discussion The study produced the CD-QOL-I, a culturally and psychometrically validated instrument that is easy for Italian CD patients to understand, and ready for use in clinical practice. Our results demonstrate that the CD-QOL-I can be performed in all celiac patients because is not influenced by demographic variables, symptoms at diagnosis, or time from diagnosis. The CD-QOL-I has excellent psychometric proprieties, including good internal consistency reliability, high test-retest reliability, and a strong correlation with other generic QOL scales. There are some discrepancies between the English and the Italian version: for example, there are three questions in the dimension “dysphoria” in CD-QOL-I (I feel socially stigmatized, I have trouble socializing, I feel like I cannot live a normal life) that are grouped among dimension “limitations” in the original version. Question 18 (I feel worried about the increased risk of one of my family members having CD) in the English version is related to “health concerns” while in the Italian version is related to “limitations”. These can be attributed to a variety of reasons: different population and socioeconomic variables, availability of medical care that in Italy is under the coverage of the National Health System, and younger age of the Italian patients than US ones (35.02 ± 12.43 vs 48.3 ± 15.8 years). The CD-QOL-I is not the first condition-specific quality of life measure for CD; specific questionnaires were developed for paediatric [14] and adult patients [15]. In 2007 Hauser et al. [15] developed the celiac disease questionnaire, CDQ which is more focused on quantifying symptoms and impairment in daily function. The CD-QOL is instead focused on the perception of limits and troubles of everyday life of a CD patient and his/her expectancy. It is easy to understand and appears to be a useful tool for the physician to identify some QOL issues requiring specific action to improve the daily life of CD patients. There are some limitations in our study. The first is that to better assess the impact of CD diagnosis; the CD-QOL-I should be administered to patients who are closer to diagnosis. Accordingly, we compared patients’ CD-QOL-I scores among those diagnosed within
the prior five years to those diagnosed earlier. The results were similar, thus proving that the length of GFD does not affect the perceptions of quality of life in CD patients. Another limitation is that our patients were all recruited from a tertiary outpatient referral centre. These patients reported a good health status, low emotional stress specifically due to the disease, and a relatively high level of quality of life. One reason for this may be that at tertiary referral centres the diagnosis is followed by an accurate education of the patient and family about the dietetic restrictions and the CD-related health issues. Only a wider use of this questionnaire and in a larger number of CD patients will allow to have precise figures about Italian CD patients perception of quality of life and give the possibility of obtaining comparable data for comparison in different settings and countries. Conflict of interest There are no conflicts of interest to be disclosed. References [1] Ciacci C, D’Agate C, De Rosa A, et al. Self-rated quality of life in celiac disease. Digestive Diseases and Sciences 2003;48:2216–20. [2] Lee AR, Ng DL, Diamond B, et al. Living with coeliac disease: survey results from the USA. Journal of Human Nutrition and Dietetics 2012;25:233–8. [3] Johnston SD, Rodgers C, Watson RG. Quality of life in screen-detected and typical coeliac disease and the effect of excluding dietary gluten. European Journal of Gastroenterology and Hepatology 2004;16:1281–6. ˜ E, Vázquez H, et al. Quality of life in celiac disease patients. [4] Nachman F, Maurino Prospective analysis on the importance of clinical severity at diagnosis and the impact of treatment. Digestive and Liver Disease 2009;41:15–25. [5] Nachman F, del Campo MP, González A, et al. Long-term deterioration of quality of life in adult patients with celiac disease is associated with treatment noncompliance. Digestive and Liver Disease 2010;42:685–91. [6] Riddle DL, Lee MS, Stratford PW. Use of SF-36 and SF-12 health status measures a quantitative comparison for groups versus individual patients. Medical Care 2001;30:867–78. [7] Book Review, Spilker B. Quality of life and pharmacoeconomics in clinical trials. 2nd ed. Philadelphia: Lippincott-Raven; 1996. [8] Dorn SD, Hernandez L, Minaya MT, et al. The development and validation of a new coeliac disease quality of life survey (CD-QOL). Alimentary Pharmacology and Therapeutics 2010;31:666–75. [9] Gandek B, Ware Jr JE. Methods for validating and norming translations of health status questionnaires: the IQOLA Project approach. International Quality of Life Assessment. Journal of Clinical Epidemiology 1998;51:953–9. November. [10] Rostami K, Kerckhaert J, Tiemessen R, von Blomberg BM, Meijer JW, Mulder CJ. Sensitivity of antiendomysium and antigliadin antibodies in untreated celiac disease: disappointing in clinical practice. American Journal of Gastroenterology 1999;94:888–94. [11] Ludvigsson JF, Leffler DA, Bai JC, et al. The Oslo definitions for coeliac disease and related terms. Gut 2012, in press. [12] Ware JE, Kosinski M, Keller SD. SF-36 physical and mental health summary scales: a user’s manual. Boston, MA: The Health Institute, New England Medical Center; 1994. [13] Ware JE. SF-36 health survey update. Spine 2000;25:3130–9. [14] van Doorn RK, Winkler LM, Zwinderman KH, et al. CDDUX: a disease-specific health-related questionnaire for children with celiac disease. Journal of Pediatric Gastroenterology and Nutrition 2008;47:147–52. [15] Häuser W, Gold J, Stallmach A, et al. Development and validation of the Celiac Disease Questionnaire (CDQ), a disease-specific health-related quality of life measure for adult patients with celiac disease. Journal of Clinical Gastroenterology 2007;41:157–66.