Construct validity of a multidimensional electronic pain diary for adolescents with arthritis

Pain 136 (2008) 281–292 www.elsevier.com/locate/pain

Construct validity of a multidimensional electronic pain diary for adolescents with arthritis Jennifer N. Stinson a,b,*, Bonnie J. Stevens a,b, Brian M. Feldman b,d,e,f,h, David Streiner g,i, Patrick J. McGrath j,k, Annie Dupuis b, Navreet Gill b, Guy C. Petroz b,c b

a Lawrence S. Bloomberg Faculty of Nursing, University of Toronto, Toronto, Ont., Canada The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, Ont., Canada M5G 1X8 c Department of Anesthesia, University of Toronto, Toronto, Ont., Canada d Department of Pediatrics, University of Toronto, Toronto, Ont., Canada e Department of Health Policy Management & Evaluation, University of Toronto, Toronto, Ont., Canada f Department of Public Health Sciences, University of Toronto, Toronto, Ont., Canada g Department of Psychiatry, University of Toronto, Toronto, Ont., Canada h Bloorview Kids Rehab, Toronto, Ont., Canada i Baycrest Centre for Geriatric Care, Toronto, Ont., Canada j Department of Psychology, Dalhousie University, NS, Canada k IWK Health Centre, Halifax, NS, Canada

Received 11 January 2007; received in revised form 8 June 2007; accepted 9 July 2007

Abstract The aim of this study was to evaluate the construct validity and feasibility of a multidimensional electronic pain diary (e-OuchÓ) in adolescents with juvenile idiopathic arthritis (JIA). Two descriptive studies with repeated measures were conducted between January and December 2005. Participants were drawn from a large metropolitan rheumatology clinic in a university affiliated pediatric tertiary care centre. In Study 1, 76 adolescents with active arthritis recorded their pain three times a day for 2 weeks using the e-OuchÓ. In Study 2, 36 adolescents recorded their pain three times a day for 1 week before and 2 weeks after joint injections. Adolescents in both studies completed multiple measures to determine the construct validity and feasibility of the e-OuchÓ. Adolescents reported mild levels of pain intensity, unpleasantness, and interference as well as stiffness, and mild to moderate levels of fatigue. e-OuchÓ average weekly pain unpleasantness and interference scores were higher in adolescents with higher pain intensity scores. Correlations between average weekly pain ratings on the e-OuchÓ and scores from: (a) recalled least, average and worst weekly pain, (b) health-related quality of life and pain coping, and (c) disease activity were as predicted. Pain ratings were significantly lower following joint injections with effect sizes in the low to moderate and moderate to high ranges at the first and second week post-injection, respectively. These findings provide evidence of the construct validity and feasibility of the e-OuchÓ electronic diary in adolescents with JIA. Use of real-time data capture approaches should be considered in future studies of chronic arthritis. Ó 2007 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. Keywords: Electronic diary; e-OuchÓ; Visual analogue scale; Juvenile idiopathic arthritis; Pain; Adolescent

*

Corresponding author. Address: Child Health Evaluative Sciences, The Hospital for Sick Children, University of Toronto, 555 University Avenue, Toronto, Ont., Canada M5G 1X8. Tel.: +1 416 813 7654x4514; fax: +1 416 813 2143. E-mail address: [email protected] (J.N. Stinson).

1. Introduction Chronic pain is a significant health problem for children (Palermo, 2000). Chronic pain significantly impairs childrens’ health-related quality of life (HRQL)

0304-3959/$34.00 Ó 2007 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved. doi:10.1016/j.pain.2007.07.002

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(Hunfeld et al., 2001). Although precise estimates of the prevalence of chronic pain are difficult to ascertain, approximately 25% of children are estimated to experience recurrent and chronic pain (Perquin et al., 2000). The complexity of chronic pain requires reliable and valid assessment of the multiple dimensions of pain (i.e., sensory, affective, and cognitive) to comprehensively evaluate pain treatments (Dworkin et al., 2005). Existing measures: (a) rely on recall (influenced by most salient and current levels of pain) (Stone et al., 2000), (b) do not allow for prospective longitudinal assessment in naturalistic environments (e.g., home, school), and (c) fail to incorporate the multidimensional nature of pain (Stinson et al., 2006a). Paper and electronic diary methods, using real-time data capture (RTDC), minimize recall bias by enabling collection of real-time momentary data from participants (Stone and Shiffman, 1994). Despite the advantages and widespread use of paper diaries in clinical trials, there are several important limitations including participant non-compliance and inaccuracies in data entry (Stone et al., 2003b; Palermo et al., 2004). Using a paper pain diary instrumented with a photosensor to track diary use, Stone et al. (2003b) demonstrated that participants’ actual compliance with making scheduled diary entries was only 11%, while ‘‘faked’’ compliance (i.e., backfilling to appear compliant) exceeded 90%. There is also evidence that methods relying on recall (e.g., average weekly pain) produce a larger placebo response with patients improving in clinical trials when no intervention has occurred compared to RTDC approaches (Williams et al., 2004). Furthermore, electronic (i.e., Personal Digital Assistant or PDA) pain diaries have been used as an effective way to maximize participants’ compliance with completing chronic pain intensity ratings (Stone et al., 2003a,b; Palermo et al., 2004) and the validity of those ratings in adults (Peters et al., 2000; Jamison et al., 2001). However, research on the use of electronic pain diaries in children is limited to a single study where researchers examined the compliance, accuracy, and acceptability of this approach using end-of-day ratings (Palermo et al., 2004). The major issues of recall bias and validity, including the ability of the diary to detect change, were not addressed. Establishing valid and feasible approaches that support the multidimensional measurement of chronic pain is crucial to evaluate the effectiveness of pain interventions and prevent unnecessary suffering in children. We conducted two studies to evaluate an RTDC approach (e-OuchÓ electronic pain diary) to assess pain in adolescents with Juvenile Idiopathic Arthritis (JIA). As JIA is the most frequent cause of chronic musculoskeletal pain in adolescents (Schanberg and Sandstrom, 1999), we tested the newly developed electronic measure in this population. Study 1 was designed to determine the diary’s construct validity and feasibility. Study 2 sought to determine the ability

of the diary to detect change in a sample of adolescents undergoing joint injections. 2. Methods 2.1. Study 1 2.1.1. Study design and hypotheses A prospective descriptive study design with repeated measures was used to test the construct validity and feasibility of the multidimensional electronic chronic pain diary measure. The real-time electronic chronic pain dairy was developed to measure the sensory–discriminant (pain intensity), affective– motivational (pain unpleasantness), and cognitive–evaluative (pain’s interference with aspects of HRQL adapted with permission from the Brief Pain Inventory – Short Form; Cleeland, 2003) dimensions of pain as well as other symptoms commonly experienced by children with JIA (i.e., stiffness and fatigue) using visual analogue scales (VAS) in an electronic format (i.e., 5 cm). It is important to measure the affective and cognitive dimensions of pain as these dimensions are conceptually and empirically distinct from the sensory aspects of pain (Price, 1999, 2001). However, pain unpleasantness and pain’s interference with HRQL are not completely independent from pain intensity (Price, 2001). To test for convergent validity of the real-time electronic pain intensity, unpleasantness, and interference VAS scales, we examined correlations between average weekly pain intensity, unpleasantness, and interference scores on the e-OuchÓ pain diary and scores from: (a) recalled average weekly pain intensity, unpleasantness, and interference and hypothesized (H 1) that they would be positive in direction and moderate to high in magnitude (>.5–.75) based on previous research (Varni et al., 1987; Gragg et al., 1996). While we argue that recalled pain ratings suffer from recall bias and inaccuracies, we chose to compare the real-time electronic pain VAS to a recalled pain diary using VAS as recalled diary methods are used most commonly in clinical research (Stinson et al., 2006b). To test the discriminant validity of the real-time electronic pain intensity, unpleasantness, and interference VAS we examined correlations between average weekly pain intensity, unpleasantness, and interference scores on the e-OuchÓ pain diary and (a) overall and disease-specific HRQL (Varni et al., 2001; Sawyer et al., 2004) and pain coping (Reid et al., 1998; Thastum et al., 1999) and hypothesized (H 2) that they would be low to moderate in magnitude (.25–.50) and (b) disease activity scores and hypothesized (H 3) that they would be low in magnitude (<.25) based on previous research (Schanberg et al., 1997; Sa¨llfors et al., 2003; Malleson et al., 2004). We also hypothesized (H 4) that real-time electronic average weekly pain unpleasantness and interference VAS scores would be higher in adolescents with higher average weekly pain intensity VAS scores compared to those with lower average weekly pain intensity VAS scores (Beales et al., 1983). 2.1.2. Setting and patients This study was undertaken between January and June, 2005, in an integrated rheumatology clinic that is housed in two university affiliated pediatric tertiary care centres, that

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serve a large metropolitan area in central and northern Ontario in Canada. A convenience sampling method was used. Eligibility inclusion criteria included adolescents who were: (a) between the ages of 9 and 18 years, (b) diagnosed with JIA by a rheumatologist and having at least one active joint, and (c) able to speak and read English. Exclusion criteria included adolescents with: (a) major cognitive or psychiatric disorder (e.g., developmental delay, clinical depression) that may interfere with their ability to complete self-reported daily pain ratings on e-OuchÓ; (b) other major medical disorders (e.g., Crohn’s disease, fibromyalgia) that may contribute to acute, recurrent, or chronic pain; (c) severe vision problems (e.g., cataracts, glaucoma) that would interfere with their ability to see the e-OuchÓ screen; and (d) severe hand deformities that would hinder their use of the e-OuchÓ. 2.1.3. Measures 2.1.3.1. e-OuchÓ multidimensional electronic pain diary. The multidimensional electronic pain diary was developed to obtain three daily pain ratings (upon waking, after school, and before bed) (Stinson and Stevens, 2004) and used a signal contingent approach (audible alarms at fixed times with 30min compliance windows). The Tungsten Wä was used for the electronic data collection. This PDA has an ultra-sharp color display screen, uses Palm Operating System, and has wireless capability. The software, which managed the screen displays and then tabulated and stored the user responses to the displayed scales, was developed using Appforgeä. Appforgeä was used to custom design a software program for the electronic diary, called GraalPad (Petroz and Stinson, 2004). The specific components and usability testing of the e-OuchÓ electronic pain diary have previously been described (Stinson et al., 2006a). 2.1.4. Procedures The study was approved by the Institutional Review Boards at the participating institutions. Once consent was obtained, the participant’s rheumatologist provided the number of active joints and a global assessment of disease severity using a 10-cm VAS. The investigator abstracted relevant socio-demographic and disease-related data from the participant’s medical chart. Once these baseline measures had been completed, participants were given a 15–20 minute demonstration of the e-OuchÓ in the clinic or their homes using a set of standardized pain vignettes. Participants were asked to complete diary entries three times a day for a 2-week period. At the end of the first week participants were reminded to: (a) record their current pain, and recalled least, average and worst pain intensity, unpleasantness, and interference ratings for the preceding week using the Recalled Pain Inventory (RPI) and (b) to use the e-OuchÓ for the remainder of the study period. On the final day of the study participants completed multiple measures including the PedsQL Inventory 4.0 (Varni, 1998a), 3.0 Arthritis Module (Varni, 1998b), and Pain Coping Questionnaire (Reid et al., 1998) to determine construct validity of the e-OuchÓ electronic diary. These measures have all been validated for use in adolescents with JIA. A questionnaire examining the acceptability of the diary was administered electronically the morning following completion of the last diary entry.

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2.1.5. Statistical analyses The sample size was based on hypothesis 1. We hypothesized that the correlation between average weekly pain intensity, unpleasantness, and interference ratings on the e-OuchÓ and recalled pain diaries would be significantly higher than a moderate level of r = .50 based on previous research (Walco et al., 1992; Stone et al., 2003b). A sample size of 68 was required to achieve 80% power to consider a correlation of r = .75 as being significantly different from a modest correlation of r = .50 at a .01 significance level (Rosner, 2006). Data from the e-OuchÓ, demographic data, and other measures were analyzed using the SAS Version 9.1.3 statistical analysis software package (SAS Institute Inc., 2006). An alpha level of p < .01 was used to account for the multiple comparisons and to control for Type 1 error. Data were also evaluated to ensure that they met the assumptions of parametric statistical analysis (e.g., normal distribution). When these assumptions were not met, the non-parametric equivalent was used. The database was also examined to determine the extent of missing data and compliance with the electronic diary measure. Compliance with the diary for the 2week period was 78%. Since 22% of the diary data were missing across all respondents and compliance varied significantly by time of day (higher in the morning and lowest after school) and by week (higher in Week 1), several weighting options were examined. While weighting slightly increased the magnitude of the correlations, from a clinical perspective, the small differences did not support weighting. Therefore, unweighted (or raw) average weekly e-OuchÓ values were used for all analyses. Pearson’s correlation coefficients were computed among average weekly pain intensity, unpleasantness, and interference ratings on the e-OuchÓ (Weeks 1 and 2) and scores from the other measures to address Hypotheses 1–3. To examine the relationships between average weekly pain intensity, unpleasantness, and interference ratings (Hypothesis 4), average within subject correlations (averaged across all the subjects) and 95% confidence limits (using bootstrapping) were calculated for Week 1. RM-ANOVA was used to evaluate whether the means on average weekly e-OuchÓ pain intensity, unpleasantness, and interference ratings, and other symptoms (dependent variables) varied across time of day (Time Effect: morning, afternoon and evening), day of week (Day Effect: weekday versus weekend), and week (Week Effect: Weeks 1 and 2). When the RM-ANOVA was significant for Time Effect, follow-up analyses were conducted using pair-wise orthogonal contrasts. The basic assumptions underlying this test were also examined (i.e., normality and homogeneity of variance). While the dependent variables were positively skewed, square root transformation did not improve the distribution of the residuals; therefore analyses were conducted using the raw data. To deal with the correlated errors and missing data, the data were summarized over time of day, day of week, and week as follows: within each week, diary entries were averaged across morning, afternoon, and evening separately, within weekdays and weekends. Thus each patient contributed six data points within each week; the average scores for morning, afternoon, and evening entries for weekdays and the average scores for morning, afternoon, and evening entries for weekends, for a

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total of 12 data points per participant. Data were analyzed using PROC GLM (SAS Institute Inc., Cary, NC) with patient entered as a random effect and time of day, day of week, and week entered as fixed effects. Compliance was calculated by examining the observed and expected number of diary entries completed overall for each sample. Compliance was operationally defined as being 100% when data were entered by participants three times a day for 14 days. Paired t-tests were used to determine whether compliance differed during the weekend versus weekday. RM-ANOVA was used to determine if there were differences in compliance by time of day (morning, afternoon, and evening) and week (Week 1 and 2). Independent t-tests were conducted to examine if there were differences in compliance rates by age, sex, and technical problems. Data from the e-OuchÓ Evaluation Questionnaire were used to examine adolescents’ likes and dislikes of the electronic pain diary. 2.2. Study 2 2.2.1. Study design and hypotheses A prospective descriptive study design with repeated measures was used to determine the longitudinal construct validity (i.e., ability to detect change) and feasibility of the multidimensional electronic chronic pain diary measure. The ability of a measure to detect the overall effect of an intervention of known efficacy is commonly referred to as sensitivity to change and is considered a facet of construct validity (Streiner and Norman, 2005). Liang (2000) defines sensitivity to change as ‘‘the ability of an instrument to measure change in a state regardless of whether it is relevant or meaningful to the decision maker’’ (p. 85). While there is no standardized approach to determining the sensitivity of a measure, commonly used methods are comparison of F ratios and effect sizes (Liang, 2000; Liang et al., 2002). Study 2 hypotheses were: (1) Adolescents’ e-OuchÓ average weekly pain scores would be lower following joint injections compared to their pre-treatment scores (Brostro¨m et al., 2004; Magni-Manzoni et al., 2005). (2) The effect size would be in the low to moderate range at the first week post-joint injection and in the moderate to high effect size range at the second week post-joint injection (Brostro¨m et al., 2004; Magni-Manzoni et al., 2005). 2.2.2. Setting and patients This study was undertaken between January and December, 2005, in the same setting as outlined in Study 1. A convenience sampling method was used. Eligibility inclusion criteria included adolescents: (a) between the ages of 9 and 18 years, (b) diagnosed with JIA by a rheumatologist, (c) scheduled to receive intraarticular steroid joint injection(s), and (d) able to speak and read English. The same exclusion criteria as outlined above for Study 1 were used. 2.2.3. Measures 2.2.3.1. e-OuchÓ multidimensional electronic pain diary. The multidimensional electronic pain diary has been described above under Study 1.

2.2.4. Procedures Similar study procedures were utilized as outlined for Study 1 with few differences. Participants were asked to start their diary 1 week (7 days) prior to their scheduled joint injection. The investigator met with each participant before the scheduled procedure to collect data using the same measures used in Study 1. The investigator recorded the joints injected and then asked the participant to continue to complete daily pain assessments for the next 2 weeks following the joint injection. 2.2.5. Statistical analyses Based on previous studies (Brostro¨m et al., 2004; MagniManzoni et al., 2005), we calculated that to achieve 80% power to detect an effect size of .45 when the F test was used to test the time factor at p = .01 and the actual standard deviation among the means was 0.29 (NCSS, 1998), the required sample size was 25 (Mueller and Barton, 1989). Data were analyzed using the same approach outlined in Study 1. RM-ANOVA was performed to evaluate Hypothesis 1 following the same procedure as outlined in Study 1. To test Hypothesis 2, within-person effect sizes were calculated as the change in the participant’s average weekly e-OuchÓ pain and symptom scores divided by the standard deviation of the participant’s baseline score in Week 1 (Kazis et al., 1989; Liang et al., 2002). Effect size was designated as small (0.20), medium (0.50), and large (0.80) in magnitude of change (Cohen, 1992). In addition, median effect sizes were calculated given that the pain indices were not normally distributed (Kazis et al., 1989; Liang et al., 2002). Similar to Study 1, compliance was calculated by examining the observed and expected number of diary entries completed overall for each sample. Compliance was 100% when data were entered by participants three times a day for 21 days (63 entries). Data from the e-OuchÓ Evaluation Questionnaire were used to examine adolescents’ likes and dislikes of the electronic pain diary.

3. Results 3.1. Study 1 3.1.1. Demographic and illness characteristics of the sample A total of 76 adolescents consented to participate yielding an acceptance rate of 71% (n = 76/107) of eligible adolescents. Twelve adolescents refused to participate due to time constraints or feeling overwhelmed; while 19 adolescents were not approached for various reasons (e.g., participated in Study 2, missed in clinic). All of the participants were recruited from the main rheumatology clinic. The mean age of the adolescents was 13.4 years (SD = 2.5; range: 9– 17 years) and the majority of participants were female (77.6%). The sample was equal in terms of public and high school (51.4%) attendance. The illness characteristics of the sample are outlined in Table 1.

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Table 1 Illness characteristics of study participants Characteristic

n (%)

Study 1 (N = 76) M (SD)

JIA diagnosis Systemic Oligoarthritis Polyarthritis (RF ) Polyarthritis (RF+) Psoriatic arthritis Enthesitis-related arthritis Other Duration of illness (years) Disease severity (100-mm VAS) Total number of active joints Number of medications used Medications used NSAIDs Methotrexate Prednisone Enbrel Remicade Arava Acetaminophen

n (%) Mdn (IQR)

10 (13.2) 11 (14.5) 32 (42.1) 5 (6.6) 8 (10.5) 8 (10.5) 2 (2.6)

Study 2 (N = 36) M (SD)

Mdn (IQR)

5.5 (4.0) 28.6 (21.2) 4.0 (3.9) 1.4 (0.8)

4.0 (2.1, 8.2) 25.5 (10.3, 42.5) 3.0 (1.0, 5.0) 1.0 (1.0, 2.0)

4 (11.1) 14 (38.9) 9 (25.0) 1 (2.8) 2 (5.6) 4 (11.1) 2 (5.6) 4.5 (4.3) 31.3 (26.6) 8.8 (11.1) 1.5 (0.9)

50 (65.8) 30 (39.5) 17 (22.4) 11 (14.5) 7 (9.2) 0 (0) 2 (2.6)

3.1.2. Characteristics of pain ratings on the multidimensional electronic pain diary On average, participants reported mild pain intensity (M = 21.7, SD = 20.1), unpleasantness (M = 19.8, SD = 19.5), and interference (M = 13.4, SD = 15.2) over the course of the 2-week study period. During this 2-week period, 7 (9.2%) adolescents experienced no pain; while 13 (17.1%) reported pain on every entry. In terms of interference with HRQL, pain had the most interference with walking and had the least impact on relationships with friends and family. Participants typically reported mild stiffness (M = 24.4, SD = 23.2) and mild to moderate levels of fatigue (M = 36.6, SD = 24.1). On average, participants perceived that they had a fairly high ability to control their pain (M = 72.5, SD = 24.7). There were no significant differences between males and females or between 9–12 versus 13– 18 year olds in these pain and symptom indices. 3.1.3. Changes in pain indices within and across days Pain fluctuated within and across days. The main effect of time of day for pain interference (F[2, 774] = 7.06, p < .01), stiffness (F[2, 774] = 40.93 p < .01) and fatigue (F[2, 774] = 33.08, p < .01) was significant. Adolescents reported significantly higher levels of pain interference and stiffness in the morning compared to the afternoon and evenings, and significantly higher levels of fatigue in the morning and evening compared to the afternoon. The main effect of Week was significant for pain intensity (F[1, 775] = 13.28, p < .01), unpleasantness (F[1, 774] = 7.36, p < .01), and interference (F[1, 774] = 9.79, p < .01) ratings as well as for stiffness ratings (F[1, 774] = 10.34, p < .01). Adolescents

2.6 (1.4, 7.2) 25.3 (7.0, 46.6) 3.0 (2.0, 12.0) 1.0 (1.0, 2.0) 28 (77.8) 8 (22.2) 4 (11.1) 1 (2.8) 1 (2.8) 3 (8.3) 0 (0)

reported significantly higher levels of pain intensity, unpleasantness, and interference as well as stiffness during Week 1 compared to Week 2. All other main and interaction effects were non-significant. Participants were asked at the end of the study to think about their pain over the last 7 days and to compare it to the week before in terms of whether they thought their pain had changed. While 34% of participants felt their pain was unchanged; 44.2% thought it was ‘‘a little’’ or ‘‘much better’’ and 14.5% perceived their pain to be ‘‘a little’’ or ‘‘much worse’’. It is important to note that 30 (39.5%) participants had changes in their medications during their clinic appointment (e.g., increased dose, addition of a new medication, or change in route such as PO to subcutaneous). However, change in medication did not explain the decrease in pain between Week 1 and 2 (Sign Rank Test, p = .08). Furthermore, both the e-OuchÓ and recalled pain scores reflected this significant decrease in pain across the weeks. Given the unexpected decrease in pain found on both measures, we explored whether age, gender, or disease severity could explain this change in scores. We found a gender difference in the change reported from Week 1 to 2 on the electronic diary. Males had a significant decrease in pain (Fisher’s exact test p = .005) from Week 1 to 2; whereas females demonstrated little to no change in pain scores. However, none of these factors accounted for the change in pain scores on the recalled pain diary. 3.1.4. Construct validity of the multidimensional electronic pain diary 3.1.4.1. Correlations between pain ratings on multidimensional electronic pain diary and other theoretically

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Table 2 Correlations between average pain intensity, unpleasantness, and interference ratings on e-OuchÓ and RPI RPI

e-OuchÓ Week 1 (n = 71) M (SD)

M (SD) Average intensity Average unpleasantness Average interference

28.2 (22.7) 24.4 (24.9) 13.6 (17.3)

Week 2 (n = 70)

Average intensity

Average unpleasantness

Average interference

21.7 (20.1) .55* .49* .56*

19.8 (19.5) .61* .58* .66*

13.4 (15.2) .59* .54* .77*

M (SD)

22.5 (22.3) 20.6 (23.4) 13.6 (18.2)

Average intensity

Average unpleasantness

Average interference

19.0 (22.5) .76* .72* .59*

17.9 (22.2) .76* .72* .63*

11.6 (15.3) .77* .74* .84*

Note. *p < .01.

the multidimensional electronic pain diary and scores from illness severity and disease activity indices were low and not significant, demonstrating the discriminant validity of the multidimensional electronic pain diary. These analyses support that the multidimensional electronic pain diary has evidence of construct validity.

relevant constructs. The means, standard deviations, and correlations for average weekly pain intensity, unpleasantness, and interference ratings from the multidimensional electronic pain diary and recalled pain intensity, unpleasantness, and interference ratings from the RPI are outlined in Table 2. All of the correlations were statistically significant (p < .01) with r P .49. As predicted, correlations between average weekly pain intensity, unpleasantness, and pain interference ratings on the real-time electronic pain VAS and scores from: (a) recalled average weekly pain intensity, unpleasantness, and interference paper VAS ratings were positive in direction and moderate to high in magnitude demonstrating convergent validity of the multidimensional electronic pain diary. The means, standard deviations, and correlations for scores on PedsQL Generic Inventory, PedsQL Arthritis Module, and the Pain Coping Questionnaire and dimensions of the electronic pain diary are outlined in Tables 3–5, respectively. As predicted, correlations between average weekly pain intensity, unpleasantness, and interference VAS scores on the electronic pain diary and scores from overall HQOL (r = .39 to .64), diseasespecific HRQL (r = .18 to .58), and emotion-focused pain coping (r = .24 to .48) were low to moderate in magnitude, demonstrating the discriminant validity of the multidimensional electronic pain diary. The means and standard deviations for disease activity indices and correlations with the dimensions on the electronic pain diary are outlined in Table 6. None of the correlations were statistically significant. As predicted, correlations between average weekly pain intensity, unpleasantness, and interference VAS scores on

3.1.4.2. Relationship between pain intensity, unpleasantness, and interference ratings. There was a strong positive correlation between average weekly pain intensity and unpleasantness (r = .73, [CI = .67, .78]), pain intensity and interference (r = .71, [CI = .66, .76]), and unpleasantness and interference (r = .74, [CI = .69, .78]) ratings. As predicted, average weekly pain unpleasantness and interference scores on the multidimensional electronic pain diary were higher in adolescents with higher average weekly pain intensity ratings than in adolescents with lower average weekly pain intensity ratings. 3.1.5. Accuracy of the multidimensional electronic pain diary and recalled pain inventory ratings Accuracy was defined in terms of errors marking the VAS or in ordering of pain ratings. No e-OuchÓ diary entries contained errors. Furthermore, during the diary demonstration adolescents correctly classified the standardized vignettes according to the degree of pain intensity (i.e., ‘‘mild’’ or ‘‘severe’’), unpleasantness (‘‘not at all bothersome’’ or ‘‘very bothersome’’) and interference (‘‘minimal interference’’ to ‘‘interferes greatly’’) as predetermined by a panel of experts. However, participants made two types of errors when completing the RPI including: (a) how they marked the VAS and (b) ordering of least, average and worst pain intensity, unpleasantness and inter-

Table 3 Correlations between average pain intensity, unpleasantness and interference ratings on e-OuchÓ and PedsQL Generic Inventory PedsQL Generic Inventory (0–100)

M

SD

e-OuchÓ Week 1 (n = 71) Average intensity

Physical health summary score Psychosocial health summary score Total scale score Note. *p < .01.

66.7 75.1 73.4

24.9 19.7 19.7

.51* .39* .44*

Average unpleasantness .55 .45* .50*

Week 2 (n = 70) Average interference .60* .50* .55*

Average intensity .52* .43* .47*

Average unpleasantness .54* .49* .53*

Average interference .63* .60* .64*

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Table 4 Correlations between average pain intensity, unpleasantness and interference ratings on e-OuchÓ and PedsQL Arthritis Module PedsQL Arthritis Module (0–100)

M

SD

e-OuchÓ Week 1 (n = 72) Average intensity

Pain and Hurt summary score Daily Activities summary score Treatment summary score Worry summary score Communication summary score Total scale score

53.3 88.3 32.1 57.3 68.3 68.7

.51* .24 .39* .45* .18 .45*

24.8 18.9 18.5 30.3 27.3 18.9

Week 2 (n = 71)

Average unpleasantness .55* .29 .43* .47* .24 .50*

Average interference .49* .38* .41* .47* .26 .51*

Average intensity

Average unpleasantness

.51* .31* .44* .48* .24 .52*

.54* .33* .49* .50* .25 .55*

Average interference .50 * .46* .50* .51* .27 .58*

Note. *p < .01.

ference ratings for the past week (e.g., worst < average, average > worst, least > average or worst). While adolescents were instructed to mark a straight line through the VAS, only seven (9.2%) participants correctly marked the VAS. Eighty-one percent of the participants used other markings such as an X; using a double line, thick line or dot; changing or scratching out score; placing ratings beyond anchors; and writing on the VAS. The second type of errors related to the participants’ ordering of least, average, and worst pain intensity, unpleasantness, and interference ratings for the past week. Seventy-seven percent of the participants made errors in ordering these aspects of their recalled pain. Minor errors (defined as 65 mm difference on VAS) were made by 23/74 (31.1%); major errors (defined as >5 mm difference on VAS) were made by 34/74 (45.9%). A two-way contingency table analysis was used to evaluate whether there was a difference in category of error by sex. Category of error and sex were not found to be significantly related at the .01 level (p = .40, Fisher’s exact test). There was also no statistically significant difference in age between those with no errors or minor errors (M = 13.6 years, SD = 2.4) and those with major errors (M = 13.1 years, SD = 2.6) using Wilcoxon Rank–Sum Test (T= 1213.5; p = .51). Recalled average weekly pain intensity was significantly different between those with minor (M = 15.8, SD = 17.3) and major errors (M = 41.4, SD = 20.5) using Wilcoxon Rank–Sum Test (T = 1730.5, p < .01). On average, adolescents who made major errors tended to have higher levels of recalled average weekly pain than those who made less severe errors.

3.2. Study 2 3.2.1. Demographic and illness characteristics of the sample A total of 36 adolescents consented to participate yielding an acceptance rate of 33.3% (38/114) of eligible adolescents. Four adolescents refused to participate (i.e., due to time commitment or feeling overwhelmed), 72 adolescents were not approached for various reasons (i.e., recruited in Study 1 or pilot study, lived too far away, or missed in clinic); while 2 participants were lost to follow-up (i.e., NPO instructions not followed so injections were cancelled and one adolescent refused to have injections). All but two of the participants were recruited from the main rheumatology clinic. The mean age of the sample in Study 2 was 12.6 years (SD = 2.4; range: 8–17 years), and the majority were female (66.7%) and in public school (63.9%). The illness characteristics of the sample are outlined in Table 1. 3.2.2. Characteristics of pain ratings on the multidimensional electronic pain diary On average, participants reported mild levels of pain intensity (M = 20.5, SD = 18.1), unpleasantness (M = 20.6, SD = 20.9), and interference (M = 14.5, SD = 17.5), as well as mild levels of stiffness (M = 25.2, SD = 22.9) and fatigue (M = 29.8, SD = 20.0) prior to the joint injection. Three adolescents reported no pain prior to or following the joint injections. There were no significant differences between males and females or between 9–12 versus 13–18 year

Table 5 Correlations between average pain intensity, unpleasantness and interference ratings on e-OuchÓ and Pain Coping Questionnaire (PCQ) PCQ (0–5)

M

SD

e-OuchÓ Week 1 (n = 72) Average intensity

Approach Distraction Emotion-focused avoidance Note. *p < .01.

2.6 3.1 2.0

0.9 0.9 0.9

.06 .10 .24

Average unpleasantness .08 .10 .34*

Week 2 (n = 71) Average interference .13 .08 .31*

Average intensity .16 .12 .41*

Average unpleasantness .14 .12 .48*

Average interference .19 .10 .46*

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Table 6 Correlations between average pain intensity, unpleasantness and interference ratings on e-OuchÓ and physician rated disease activity indices Disease activity indices

M

SD

e-OuchÓ Study 1 – Week 1(n = 76)

Illness severity (0–100 mm) Total active joints (0–58)

31.7 9.0

26.8 11.2

Study 1 – Week 2 (n = 76)

Average intensity

Average unpleasantness

Average interference

Average intensity

Average unpleasantness

Average interference

.14 .06

.14 .08

.19 .04

.18 .02

.20 .04

.27 .04

olds in these pain indices. Changes in pain indices (intensity, unpleasantness, interference) and other symptoms across the 3-week study period are addressed below under ability of the measure to detect changes following joint injections. 3.2.3. Ability of the multidimensional electronic pain diary to detect changes following joint injections using RM-ANOVA The main effect of Week was significant (F[2, 70] = 12.41, p < .01) for pain intensity with significantly higher ratings of pain in Week 1 compared to Week 3 (F[1, 70] = 23.59, p < .01) and Week 2 compared to Week 3 (F[1, 70] = 11.49, p = < .01). There was no difference in pain intensity ratings between Week 1 and Week 2. There was a significant main effect of Week (F[2, 70] = 12.42, p < .01) for pain unpleasantness with significantly higher ratings of pain unpleasantness in Week 1 compared to Week 3 (F[1, 70] = 31.29, p < .01) and Week 2 compared to Week 3 (F[1, 70] = 18.94, p < .01). Similarly, there was a significant main effect of Week for pain interference ratings (F[2, 70] = 17.17, p < .01) with significantly higher ratings of pain interference in Week 1 compared to Week 3 (F[1, 70] = 31.41, p < .01) and Week 2 compared to Week 3 (F[1, 70] = 18.36, p < .01). As predicted, pain intensity, unpleasantness and interference ratings were significantly lower following joint injections compared to pre-treatment. Changes in stiffness, fatigue, and perceived ability to control pain were also examined using RM-ANOVA. There was a significant main effect of Week for stiffness (F[2, 70] = 9.58, p < .01) with significantly higher ratings of stiffness in Week 1 compared to Week 3 (F[1, 70] = 17.26, p < .01) and Week 2 compared to Week 3 (F[1, 70] = 10.70, p < .01). The week main effects for tiredness and control were non-significant. Adolescents reported significantly less stiffness following joint injections compared to pre-treatment; however there were no significant differences in level of fatigue or perceived ability to control pain across time. 3.2.4. Ability of the multidimensional electronic pain diary to detect changes following joint injections using effect sizes The descriptive statistics for the effect sizes are outlined in Table 7. All of the median effect sizes for the

pain indices (0.22–0.33) and other symptoms (0.06– 0.24) from Week 1 to 2 were less than 0.40. The effect sizes for the pain dimensions were in the predicted range of low to moderate. The median effect sizes for the pain indices (0.52–0.70) and other symptoms (0.26–0.60) from Week 1 to 3 were between 0.26 and 0.70. As predicted, the effect sizes for the pain dimensions were in the moderate to high range at the second week postinjection. The highest effect sizes were found for pain intensity ratings at both the first and second week post-injection. These findings provide evidence that the multidimensional electronic pain diary is able to detect changes in pain intensity, unpleasantness, and interference, and other symptoms in adolescents undergoing intra-articular joint injections. 3.3. Feasibility of the multidimensional electronic pain diary in Study 1 and 2 3.3.1. Compliance Overall compliance with the 2- and 3-week study protocols was 78% and 73%, respectively. On average, compliance was not significantly different during the week compared to the weekend in either study. Compliance was significantly higher in Week 1 (88%) compared to Week 2 (73%) in Study 1 and Weeks 1 and 2 (77%) compared to Week 3 (67%) in Study 2 (p < .01). Compliance at anytime of the day was significantly different from compliance at any other time of day (p < .01). Compliance was highest in the morning (Study 1 = 84%; Study 2 = 77%) and lowest after school (Study 1 = 73%; Study 2 = 67%). Compliance was not affected by age, sex, or technical difficulties. 3.3.2. Acceptability (likes and dislikes) The majority of adolescents in both studies found it easy to remember to complete the diary three times a day. Most adolescents liked the way the diary looked and found it quick and easy to complete. They also found that the diary was easy to use to rate their pain. The majority of adolescents found that the diary was not overly bothersome to complete three times a day for the 2- and 3-week study periods and that it interfered minimally with activities and friends. Half of the participants were willing to use the diary again for at least 2 weeks; while the other half were willing to use it for a longer period of time.

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289

Table 7 Sensitivity of e-OuchÓ electronic pain diary indices in detecting change in adolescents following joint injections Variable (0–100)

n

Median value (IQR) at baseline

Intensity Unpleasantness Interference Stiffness Tiredness Control

34 33 33 34 34 28

13.6 12.4 8.4 17.1 27.9 68.4

(7.3, 29.7) (5.1, 35.4) (1.8, 20.1) (8.5, 40.8) (14.6, 43.5) (41.0, 89.8)

Median change (IQR) Time 1 2.5 1.3 0.7 2.1 2.8 2.8

( ( ( ( ( (

10.9, 4.4) 10.5, 4.9) 5.2, 2.0) 9.4, 1.3) 11.8, 6.3) 11.8, 6.1)

4. Discussion To our knowledge, this is the first study to evaluate the validity of an RTDC electronic diary approach using VAS (e-OuchÓ) to record pain intensity, unpleasantness, and pain’s interference with activities of daily living in adolescents with JIA. The e-OuchÓ pain diary has evidence of construct validity and is able to detect changes in pain ratings in adolescents undergoing joint injections. Completion of three pain ratings per day using an electronic format on a handheld PDA in a home setting is feasible and highly acceptable in the pediatric population. Establishing construct validity is one of the most difficult and challenging tasks of instrument development. Construct validity is an on-going process of learning more about the construct, making predictions about individuals based on their scores from that measure, and then testing them (Streiner and Norman, 2005). The moderate to strong positive correlations between VAS pain ratings on the e-OuchÓ and recalled diaries support the convergent validity of the e-OuchÓ. No researchers have compared average weekly recalled pain in children to average pain recorded using an RTDC approach. However, Stone et al. (2000, 2003b) in two different studies found that average weekly momentary reports correlated highly (r = .72–.75) with recalled pain ratings over the previous week. Conversely, low correlations between measures of disease activity and pain in children with JIA demonstrate divergent validity of the measure. Similarly, other researchers have found disease severity to have low correlations with pain intensity levels (Hagglund et al., 1995; Varni et al., 1996). Taken together, these findings provide support of the construct validity of the e-OuchÓ diary. The e-OuchÓ measure was able to detect changes in pain in adolescents undergoing joint injections. While multiple researchers have evaluated the efficacy of intra-articular joint injections in children (See, 1998), only two researchers used pain as a clinical outcome measure (Brostro¨m et al., 2004; Magni-Manzoni et al., 2005). In both studies, participants had significantly less pain following the joint injection and Magni-Manzoni et al. (2005) found a moderate effect size for parent reported pain on a 100-mm VAS. Therefore, pain in

Effect size Time 1 0.33 0.22 0.23 0.24 0.24 0.06

Median change (IQR) Time 2 7.3 5.9 2.6 8.1 4.7 6.2

( ( ( ( ( (

17.3, 1.4) 12.4, 1.4) 9.2, 2.0) 16.6, 0.5) 17.4, 3.2) 17.4, 3.2)

Effect size Time 2 0.71 0.64 0.52 0.60 0.26 0.26

children with JIA may be useful as a clinical outcome measure in trials of intra-articular steroid injections. Limited empirical evidence exists regarding the relationship between pain intensity, and pain unpleasantness and interference in children with arthritis over time. We found that within-adolescents, increases in pain intensity were associated with increases in pain’s unpleasantness and interference with aspects of everyday life. Similarly, several researchers have found that children reported higher levels of activity limitations on days when they had increases in pain (Schanberg et al., 2003; Palermo et al., 2004). These findings highlight the importance of aggressively treating pain to reduce its unpleasantness and impact on HRQL. The e-OuchÓ diary could enable researchers to obtain more detailed information about the relationships between pain intensity and pain’s unpleasantness and interference with activities of daily living in children with arthritis. While routine use of RTDC approaches in everyday clinical practice might not be realistic at the present time; they could be useful for monitoring symptoms and response to treatment(s) in adolescents at high risk for impaired physical and psychological functioning due to uncontrolled pain. Children with JIA also showed considerable variability in their pain within and across days using the e-OuchÓ diary. While pain intensity, unpleasantness, and interference appeared to be higher in the morning, significant differences were only found for interference. The higher level of pain interference in the morning reported by participants is most likely due to morning function-limiting stiffness (Schanberg et al., 1997). The few longitudinal studies that have been conducted show that pain varies across days in children with arthritis (Schanberg et al., 1997, 2003; Sa¨llfors et al., 2003; Palermo et al., 2004). However, most of these studies used end-of-day diaries which prohibited the ability to examine how pain varies within days. The ability of the electronic diary to capture changes within days provides evidence of the incremental validity of this measure over recalled diaries. Surprisingly, we found that pain significantly decreased during the second week of Study 1. One possible explanation is that having adolescents monitor their pain several times a day could have been an un-

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intentional feedback intervention and thus might have resulted in changes in their appraisals of, or even their attempts to manage their pain. To date, only a few studies have examined reactive effects in diary research and they have not shown the hypothesized effects (increased pain) in chronic pain patients (von Baeyer, 1994; Cruise et al., 1996; Stone et al., 2003a; Aaron et al., 2005). However, this change was evident in both the electronic and recalled pain diaries. There are a host of other factors that might account for this change including random fluctuations and regression to the mean (Aaron et al., 2005), as well as a natural resolution in the arthritis flare. Participants may have also had other alterations in medications or treatments (e.g., exercise, splints) which were not recorded. Finally, males, in particular, may have learned to avoid the recording of long diaries by denying their pain during Week 2. Future research is required to (a) rule out reactive effects in children using RTDC and recalled approaches and (b) confirm the sensitivity of the electronic pain diary. Accuracy of diaries is crucial as incorrect values may make participant’s data unusable or invalid (Stone and Shiffman, 1994). All e-OuchÓ diary entries contained no errors. However, adolescents made errors in the ordering of their recalled least, average, and worst pain ratings, as well as errors in marking the paper VASs. Little empirical evidence exists on the accuracy of electronic diaries used by children. Palermo et al. (2004) compared the accuracy of electronic (e) and paper (p) diaries used by children with JIA and headaches. They found no errors of omission in the e-diary group; while only 51% of the diaries in the p-diary group had no errors. Other researchers have found that paper diaries contain numerous out-of-range or illegible data (with rates as high as 80%), which in turn limits their usefulness in clinical research (Gendreau et al., 2003). Other technology-enabled approaches, such as webbased applications of the diary, are also worth exploring to determine their reliability, validity, and feasibility in pediatric chronic pain populations. It would be important to compare PDA and web-based approaches to determine their relative advantages and disadvantages in clinical trials with children. In addition, as electronic diary technology evolves any comparison of electronic and paper (with audible prompts using programmable wrist watches) pain diaries need to be evaluated in light of diverging technological capabilities and include costbenefit analyses (Tennen et al., 2006). The major strength of this study was its use of an RTDC approach to determine the construct validity and feasibility of a newly developed multidimensional electronic pain diary using VAS in adolescents with arthritis. However, momentary reports are dependent on the sampling strategy. Therefore, we might have missed important fluctuations in pain levels with the signal-contingent approach using pre-specified

times (Stone and Shiffman, 1994). Having random prompts at more frequent intervals, a stratified random sampling protocol or event-signaling (pain P4/ 10) might have reduced this potential bias (Stone et al., 2004; Williams et al., 2004). Therefore, our results are limited to the particular fixed-time, within-day sampling protocol that was used, and therefore we cannot generalize these findings to other sampling protocols. While studies incorporating RTDC approaches are becoming more common, the analyses of these data present a challenge and require statistical techniques unfamiliar to many researchers. Some researchers argue that multilevel mixed-effects models are the most advantageous to use as they control for between-person effects when assessing the effects of within-person factors, treat participants as random factors, and control for autocorrelation between reports (Schwartz and Stone, 1998). A RM-ANOVA approach was used in these studies as the momentary data had been aggregated to the subject level and a balanced design was achieved by employing a block design. Despite high compliance, another study limitation was that 22% of the data were missing. We explored various options for replacing the missing data; however, from a clinical perspective the difference was so small that the advantage of weighting was unsupported. Therefore, the average weekly electronic pain ratings may have been a biased estimate due to the amount of missing data. Chronic pain is a significant problem for adolescents with JIA and has a negative impact on all aspects of HRQL. Current methods for evaluating pain in children with arthritis suffer from methodological problems. Therefore, electronic diary formats should be considered as a promising alternative format for obtaining prospective diary data on pain and other symptoms and their impact on functioning in children in clinical and research practice. Establishing psychometrically sound and feasible approaches to measurement is crucial for understanding the day-to-day variability of chronic pain, selecting and evaluating a broad range of treatment interventions, enhancing patient outcomes and decreasing suffering in children. The e-ouchÓ diary could serve as a template for measurement of pain and other symptoms in a wide variety of pediatric chronic illnesses. Conflict of interest statement We declare that we have no conflict of interest.

Acknowledgments The authors thank all of the adolescents who enthusiastically agreed to participate in these studies. We also

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acknowledge PalmOne and Rogers Wireless, who donated Tungsten Ws for use in these studies and the Department of Anesthesia at The Hospital for Sick Children, who financially supported the software (MobileVB and VB) for the diaries. Funding is gratefully acknowledged from the University of Toronto Centre for the Study of Pain AstraZeneca Award. Jennifer Stinson’s doctoral work was supported by a Canadian Nurses Foundation/Hospital for Sick Children/Canadian Institutes of Health Research Doctoral Fellowship, Hospital for Sick Children Clinician Scientist Training Fellowship, Pain in Child Health CIHR Strategic Training Program, and funding from a Premier’s Research Excellence Award to Dr. Stevens. Drs. Feldman and McGrath hold Canada Research Chairs. Dr. Stevens holds the Signy Hildur Eaton Chair in Paediatric Nursing Research at the Hospital for Sick Children. We also thank the reviewers for their helpful comments on an earlier version of this manuscript. Contributors. All authors helped draft and review the manuscript. J.N. Stinson had full access to all of the data in the study and takes responsibility for the integrity of the data and the accuracy of the data analysis. J.N. Stinson, B.J. Stevens, B.M. Feldman, P.J. McGrath, and D. Streiner contributed to the design and conduct of the study. J.N. Stinson and B.J. Stevens developed the e-OuchÓ pain diary questionnaire. G. Petroz developed the software for the e-OuchÓ diary and provided technical support for the diary during the study. J.N. Stinson, G. Petroz, and N, Gill conducted the data collection and management. J.N. Stinson, A. Dupuis, and N. Gill undertook the statistical analysis. J.N. Stinson, B.J. Stevens, B.M. Feldman, P.J. McGrath, D. Streiner, and A. Dupuis interpreted the data. B. Stevens provided doctoral supervision for J.N. Stinson during this study. References Aaron LA, Turner JA, Mancl L, Brister H, Sawchuk CN. Electronic diary assessment of pain-related variables: is reactivity a problem? J Pain 2005;6:107–15. Beales JG, Keen JH, Holt PJL. The child’s perception of the disease and the experience of pain in juvenile chronic arthritis. J Rheumatol 1983;10:61–5. ˚ kerlind Y. Effect of joint Brostro¨m E, Hagelberg S, Haglund-A injections in children with juvenile idiopathic arthritis: evaluation by 3D-gait analysis. Acta Paediatr 2004;93:906–10. Cleeland CS. Brief Pain Inventory – Short Form. Houston, TX: The University of Texas M.D. Anderson Cancer Centre; 2003. Cohen J. A power primer. Psychol Bull 1992;112:155–9. Cruise CE, Broderick J, Porter L, Kaell A, Stone AA. Reactive effects of diary self-assessment in chronic pain patients. Pain 1996;67:253–8. Dworkin RH, Turk DC, Farrar JT, Haythornthwaite JA, Jensen MP, Katz N, et al. Core outcome measures for chronic pain clinical trials: IMMPACT recommendations. Pain 2005;11:9–19. Gendreau M, Hufford MR, Stone AA. Measuring clinical pain in chronic widespread pain: selected methodological issues. Best Pract Res Clin Rheumatol 2003;17:575–92.

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