Cross-cultural adaptation and validation of the Japanese version of the Childhood Health Assessment Questionnaire (CHAQ)

To assess cross-cultural adaptation, and to validate the parent's version of a health-related quality-of-life instrument, the Childhood Health Assessment Questionnaire (CHAQ) was investigated after its translation into Japanese. A total of 132 subjects were enrolled: 63 patients with juvenile idiopathic arthritis (JIA) (34 systemic and 29 polyarticular) and 69 healthy children. The CHAQ distinguished clinically between healthy subjects and the two JIA subtypes of patients. The average disability index (DI) scores for systemic JIA (sJIA) and polyarticular JIA (pJIA) patients and healthy subjects were 1.5, 1.2, and 0.0, respectively. All variables in the questionnaire were shown to be significant (P < 0.001). Patients with pJIA showed better correlation than those with sJIA. Significant correlation was seen in the polyarticular group with CRP, ESR, parents' VAS, the number of joints with pain, and the number of active joints. However, there was even a negative correlation between DI and parent's assessment of overall well-being for the sJIA group. The Japanese version of the CHAQ was a reliable and valid tool for the functional assessment of children with pJIA. Functional ability, as assessed by the CHAQ, may not be the main consideration of sJIA patients' parents when assessing their child's status.     

Correlation between juvenile idiopathic arthritis activity and damage measures in early, advanced, and longstanding disease

OBJECTIVE: To compare the correlation between juvenile idiopathic arthritis (JIA) measures of disease activity and damage in patients with early and late disease. METHODS: Three cohorts of patients with JIA disease duration < or =1 year (early disease, n = 70), 5-9.9 years (advanced disease, n = 114), and > or =10 years (longstanding disease, n = 39) were studied. Measures included physician's global assessment of overall disease activity (MD global), parent's global assessment of the child's well-being (parent global) and pain (parent pain), joint counts, Childhood Health Assessment Questionnaire (CHAQ), erythrocyte sedimentation rate, C-reactive protein level, and Poznanski score of radiographic damage. RESULTS: In all cohorts, the MD global assessment was generally well correlated with the other variables, except the Poznanski score. The parent global assessment was correlated strongly with the parent pain assessment and moderately with the CHAQ irrespective of disease duration. Correlations between the CHAQ and the joint counts were low in early disease, moderate in advanced disease, and high to moderate in longstanding disease. Correlation between the CHAQ and the Poznanski score was low in early and advanced disease and moderate in longstanding disease. The Poznanski score was highly correlated with the number of joints with restricted motion in longstanding disease. CONCLUSION: We found important differences in the level of correlation between JIA measures of activity and damage in patients with different lengths of disease duration. These findings have important implications for clinical trials because they indicate that the responsiveness of some variables and their correlation with other variables change as disease duration changes.     

Proxy-reported health-related quality of life of patients with juvenile idiopathic arthritis: the Pediatric Rheumatology International Trials Organization multinational quality of life cohort study

OBJECTIVE: To investigate the proxy-reported health-related quality of life (HRQOL) and its determinants in patients with juvenile idiopathic arthritis (JIA). METHODS: In this multinational, multicenter, cross-sectional study, HRQOL of patients with JIA was assessed through the Child Health Questionnaire (CHQ) and was compared with that of healthy children of similar age from the same geographic area. Potential determinants of HRQOL included demographic data, physician's and parent's global assessments, measures of joint inflammation, Childhood Health Assessment Questionnaire (CHAQ), and erythrocyte sedimentation rate. RESULTS: A total of 6,639 participants (3,324 with JIA and 3,315 healthy) were enrolled from 32 countries. The mean +/- SD physical and psychosocial summary scores of the CHQ were significantly lower in patients with JIA than in healthy children (physical: 44.5 +/- 10.6 versus 54.6 +/- 4.0, P < 0.0001; psychosocial: 47.6 +/- 8.7 versus 51.9 +/- 7.5, P < 0.0001), with the physical well-being domain being most impaired. Patients with persistent oligoarthritis had better HRQOL compared with other subtypes, whereas HRQOL was similar across patients with systemic arthritis, polyarthritis, and extended oligoarthritis. A CHAQ score >1 and a pain intensity rating >3.4 cm on a 10-cm visual analog scale were the strongest determinants of poorer HRQOL in the physical and psychosocial domains, respectively. CONCLUSION: We found that patients with JIA have a significant impairment of their HRQOL compared with healthy peers, particularly in the physical domain. Physical well-being was mostly affected by the level of functional impairment, whereas the intensity of pain had the greatest influence on psychosocial health.     

Juvenile idiopathic arthritis: parent-child discrepancy on reports of pain and disability

OBJECTIVE: To examine the incidence and nature of disagreements about pain and functional disability between parents and their children with juvenile idiopathic arthritis (JIA) and to identify demographic and psychosocial predictors of parent-child disagreement about pain and functional disability. METHODS: Participants comprised 63 children 8-16 years of age (mean 12.36 +/- 2.61) and their parents, followed as part of a longitudinal study of pain in children. During routine rheumatology clinic visits, children and their parents completed validated measures of pain, depressive symptoms, and functional disability. RESULTS: Parents and children often disagreed as to the frequency and intensity of pain and to the degree of disability caused by arthritis. Child depressive symptoms (p < 0.01) and parental perceptions of child limitations (p < 0.02) predicted parent-child disagreement about the frequency of the child's pain. Parental perceptions of child limitations also predicted parent-child disagreement about the child's level of functional disability (p < 0.04). Those children who estimated their level of disability to be different than their parents' rating also were more depressed compared to children who agreed with their parents about their level of disability (p < 0.01). CONCLUSION: Discrepancy between parent and child reports of pain and disability in children with JIA is common. Findings suggest that such disagreements in reporting of pain and functional disability by parents and their children with JIA are associated with underlying depressive symptoms in children.     

Validity of the childhood health assessment questionnaire is independent of age in juvenile idiopathic arthritis

OBJECTIVE: To determine whether the Childhood Health Assessment Questionnaire (CHAQ) is valid for the comparison of different age subgroups and for longitudinal studies in juvenile idiopathic arthritis (JIA). METHODS: A CHAQ was administered to 306 children with JIA. Rasch analyses were used to compare the difficulty of each of the 30 items of the questionnaire for children of 2 age groups (> or =10 years old and <10 years old). RESULTS: Independent of the physical disability level assessed by the Rasch model, 8 of the 30 items (27%) of the CHAQ were rated significantly different in the 2 age groups. Despite this age-related variation in item difficulty, the impact on the CHAQ disability index using its original scoring system remained low (about 0.25 points on a scale of 0-3). CONCLUSION: The difficulty of 8 of 30 items of the CHAQ depends on the respondent's age. Nevertheless, the design of the CHAQ and its scoring system remove most of the expected physical development bias.     

The clinical meaning of functional outcome scores in children with juvenile arthritis

OBJECTIVE: The Childhood Health Assessment Questionnaire (CHAQ) is the most widely used measure of function in childhood arthritis and yields a score of 0 (no disability) to 3 (very severe disability). This study ascertained the cutoff levels for CHAQ scores that represent no, mild, moderate, and severe disability, to determine the minimal clinically important change in scores and to determine whether the minimal important change in scores is similar for parent-reported assessments and the self-assessments provided by their older children. METHODS: One hundred thirty-six parents of children with arthritis were interviewed. They were asked to complete the CHAQ by assessing their child's functional status under 3 categories: current health, a hypothetical small improvement, and a hypothetical small worsening. They also completed a categorical scale of subjective disability. Those children who were > or = 10 years old also completed the CHAQ interview separately. RESULTS: The pediatric patients had mostly no, mild, or moderate disability. For those children rated as having no disability, the median CHAQ score was 0. The median CHAQ scores corresponding to mild, mild-to-moderate, and moderate disability were 0.13, 0.63, and 1.75, respectively. The minimal clinically important improvement was a reduction in score of 0.13. The minimal clinically important deterioration was a median change in score of 0.75. This discrepancy may be due to the ceiling effect seen with the CHAQ. There were no significant differences when the children assessed themselves. CONCLUSION: Clinicians, as well as researchers setting protocols, should aim for a mimimum improvement of 0.13 in the CHAQ score when treating pediatric patients with arthritis.     

Growing up and moving on in rheumatology: parents as proxies of adolescents with juvenile idiopathic arthritis

OBJECTIVE: To examine agreement about physical health, functional ability, and health-related quality of life (HRQOL) between adolescents with juvenile idiopathic arthritis (JIA) and their parents. METHODS: The study group comprised 303 adolescent-parent dyads who completed individual questionnaires, including the Childhood Health Assessment Questionnaire with visual analog scales for pain and general well-being, and the Juvenile Arthritis Quality of Life Questionnaire. Agreement was determined using the Bland and Altman method. RESULTS: Approximately half of the adolescent-parent dyads showed clinically acceptable agreement for pain, general well-being, functional disability, and HRQOL. Where discrepancies occurred, there were similar numbers of parental overestimation and underestimation, with the exception that parents rated functional ability worse than did adolescents. Parents were also consistent with respect to overestimation or underestimation, irrespective of the health domain in question. Agreement was associated with better disease-related outcome variables, but was not significantly influenced by demographic factors. Agreement between adolescents and parents was dependent on the level of disease outcome and the health domain under scrutiny, and was less for moderate disease outcomes (as compared with mild or severe) and less visible phenomena (e.g., pain, global well-being). CONCLUSION: There is a wide variation in agreement between adolescents with JIA and their parents that is dependent on which health-related variable is under scrutiny. Proxy report is likely to be valid for adolescents with JIA at either the mild or severe end of the spectrum and/or for the visible manifestations of the disease. Consideration of both adolescent and parent-proxy reports is therefore important in future research.     

Cross cultural adaptation and validation of the Arabic version of the Childhood Health Assessment Questionnaire for measuring functional status in children with juvenile idiopathic arthritis

OBJECTIVE: To cross culturally adapt the American-English version of the Childhood Health Assessment Questionnaire (CHAQ) and to evaluate the validity and reliability of the modified translated version on children with juvenile idiopathic arthritis (JIA). METHODS: A cohort of 62 children suffering from JIA (32 Egyptian, 30 Saudi Arabian) were recruited and asked to participate in the study. Two questions had been changed to suit the Arabic culture and to tackle some aspects that are more typical of the Arabic culture. After modification, translation and back translation of the questionnaire, it was administered to the selected patients as well as their parents and tested for internal consistency, reliability and construct validity by correlating the yield of the questionnaire with other disease activity parameters. The questionnaire was administered again after a one-week interval for evaluation of the reliability of this test. The modified questions were tested for their loyalty to the principal component and their correlation with that of the other unchanged items was compared. RESULTS: CHAQ proved to be valid in clinically discriminating between healthy subjects and patients with different patterns of JIA. Test-retest showed strong reliability with a high percentage of agreement and high kappa values. Internal consistency showed a high value for the standardized Cronbach's alpha (0.951), and this value did not show any significant change when any one of the items was eliminated. The modified questionnaire showed a strong and significant validity when its results were correlated with disease activity parameters. CONCLUSION: The Arabic CHAQ is a reliable and valid instrument that can be administered to Arabic children suffering from JIA and to their parents, to evaluate the patients' functional disability. Its measurement properties were comparable to versions in other languages.     

The relationship between health-related quality of life, pain and coping strategies in juvenile idiopathic arthritis

OBJECTIVES: To investigate the relationship between health-related quality of life (HRQL), experience of pain and pain coping strategies in children with juvenile idiopathic arthritis (JIA). To compare reports describing these variables obtained from children and their parents. METHODS: Participants were 59 children aged 8 to 18 yr with JIA and their parents. Parents and children completed the PedsQL generic core scales and arthritis module, the visual analogue scale of the Varni-Thompson Pediatric Pain Questionnaire, and the Waldron/Varni Pediatric Pain Coping Inventory. Parents rated children's functional disability using the Childhood Health Assessment Questionnaire. RESULTS: Parents reported significantly lower scores (indicating worse HRQL) than children on five of the eight PedsQL scales rating children's HRQL. Parents and children reported a significant negative relationship between pain levels and the PedsQL scores assessing children's physical, emotional and social functioning. They also reported a significant negative relationship between scores on several pain coping scales and scores on the PedsQL scales. However, the pattern of these relationships varied for reports from parents and children. CONCLUSIONS: Pain intensity and pain coping strategies have a significant and independent relationship with several domains that comprise the HRQL of children with JIA. However, parents and children have differing perceptions of the nature of these relationships. The differences emphasize the importance of clinicians obtaining information about children's HRQL, pain levels and pain coping strategies from both parents and children.     

Relationship between functional ability and physical fitness in juvenile idiopathic arthritis patients

OBJECTIVE: To determine the relationship between aerobic and anaerobic physical fitness and functional ability in children with juvenile idiopathic arthritis (JIA). METHODS: Eighteen children with JIA (age 7 to 14 yr., 3 male/15 female) performed a maximal aerobic exercise test and a Wingate anaerobic exercise test. Functional ability was concurrently assessed using the Childhood Health Assessment Questionnaire (CHAQ). RESULTS: A low relationship between aerobic fitness and functional ability was found (r = 0.0 to 0.4, p > 0.05, except for eating r = 0.46, p < 0.05). The correlations between anaerobic physical fitness and functional ability in JIA patients were strong (r = 0.5 to 0.75, p < 0.05). This indicated a good relationship between anaerobic fitness and functional ability. CONCLUSION: The strong association between anaerobic physical fitness and functional ability showed the importance of anaerobic physical fitness for children with JIA.     

The relationship between impairments in joint function and disabilities in independent function in children with systemic juvenile idiopathic arthritis

OBJECTIVE: Knowledge about the impact of joint impairment on functional ability is needed in planning care and setting treatment goals in children with juvenile idiopathic arthritis (JIA). We investigated the relationship between joint impairments and upper and lower limb function. METHODS: Twenty-one children with systemic JIA with an average age of 9.2 years and a mean disease duration of 4.8 years participated in this study. Joint impairments were assessed by the following variables: joint counts on swollen (JCS) and tender (JCT) joints and the loss of joint motion as determined by the Joint Alignment and Motion scale (JAM). Functional performance and functional ability were determined by the Juvenile Arthritis Functional Assessment Scale (JAFAS) and Childhood Health Assessment Questionnaire (CHAQ), respectively. The relationship between impairments and functional disabilities was studied at the level of (1) the complete instruments, (2) upper and lower limb function separately, and (3) the individual joints and items. RESULTS: Regarding complete instruments, the Spearman rank correlation between functional disabilities and loss of joint motion was moderate to good (JAM/CHAQ rs = 0.66, JAM/JAFAS rs = 0.77). A fair correlation was found between functional disabilities and the joint count on swollen joints (JCS/CHAQ rs = 0.45, JCS/JAFAS rs = 0.52), but no significant relationship was found with the number of tender joints (JCT/CHAQ rs = 0.02, p > 0.05, and JCT/JAFAS rs = 0.14, p > 0.05). At the extremity level (upper and lower limb function), the relationship between functional disabilities and the loss of joint motion appeared to be stronger in the leg than in the arm. At the level of the individual joints and questionnaire items, loss of joint motion in hip or shoulder joint appeared to be the most important factor in predicting limitation in leg or arm function. CONCLUSION: Our study shows that with respect to joint impairments, loss of joint motion is the strongest indicator of functional disability in children with systemic JIA. Loss of joint motion has a greater effect on lower limb function.     

Clinical responsiveness of self‐report functional assessment measures for children with juvenile idiopathic arthritis undergoing intraarticular corticosteroid injections

Objective

The Childhood Health Assessment Questionnaire (CHAQ), Juvenile Arthritis Functional Assessment Report (JAFAR), and Juvenile Arthritis Functional Status Index (JASI) are widely used functional measures for juvenile idiopathic arthritis (JIA) that differ in content, format, and completion time. We compared the responsiveness and child‐parent agreement of the JAFAR, CHAQ, and JASI in a prospective, multicenter study.

Methods

Children and adolescents from 5 rheumatology centers were enrolled. Subjects were about to undergo therapy (intraarticular corticosteroid injections [IAS] and methotrexate or hip surgery (MTX/hip]) expected to produce a functional improvement. All subjects were studied before the intervention and at 6 weeks and 6 months posttreatment. At each study visit, the 3 measures were administered in randomized, balanced order to both parents and children.

Results

A total of 92 subjects (mean age 12.8 years) were enrolled in the study, 74 of which were in the IAS group. The responsiveness of all 3 measures was moderate to strong. The standardized response mean at 6 weeks for the IAS group on the JAFAR, CHAQ, and JASI was 0.41 (95% confidence interval [95% CI] 0.18, 0.64), 0.70 (95% CI 0.47, 0.93), and 0.36 (95% CI 0.13, 0.59), respectively. The CHAQ was somewhat more responsive to change at 6 weeks (IAS group: relative efficiency 0.34 [JAFAR], 0.27 [JASI]), but less responsive at 6 months (MTX/hip group: relative efficiency 5.1 [JAFAR], 3.9 [JASI]). All 3 questionnaires showed acceptable parent‐child agreement, and overall, there were few differences between the 3 questionnaires.

Conclusion

The functional outcome measures currently used for JIA are all adequately responsive for use in trials or in the clinic setting. The choice of which measure to use should therefore be based on the time available for completion, the intended clinical/research use, and the depth of content required.

     

Responsiveness of clinical measures in children with oligoarticular juvenile chronic arthritis.

OBJECTIVE: To compare the relative responsiveness of outcome measures in children with oligoarticular course juvenile chronic arthritis (JCA). METHODS: Twenty-six consecutive children with JCA and < or =4 joints involved were assessed at admission and after 3 months of followup. Outcome measures included physician and parent global assessments, functional ability as measured by the Childhood Health Assessment Questionnaire (CHAQ), articular variables, and laboratory indicators of systemic inflammation. Responsiveness was calculated with the standardized response median, the effect size, and the Guyatt method. RESULTS: The physician global assessment of disease activity, the active joint count, the global articular severity score, and the number and score of swollen joints proved consistently more responsive with either responsiveness measure used. The parent global assessment of the child's well being, the scores of joints with pain/tenderness and limited range of motion, and the number of joints with limited range of motion showed intermediate responsiveness. The CHAQ, morning stiffness, and laboratory indicators of systemic inflammation were the least responsive measures. CONCLUSION: The subjective estimation of disease activity by the physician and the articular variables were the more responsive outcome measures in children with oligoarticular JCA. The assessment of functional ability as measured by the CHAQ showed a poor sensitivity to clinical change in this subset of patients with JCA.     

Comparison between children with juvenile idiopathic arthritis and their parents concerning perceived treatment adherence

OBJECTIVE: Adherence to treatment in juvenile idiopathic arthritis (JIA) may be associated with better outcomes. Clinicians must be aware of possible divergence between parents and children regarding adherence, in order to gain a better understanding of adherence and factors associated with it. The objective was to determine the level of agreement between children with JIA and their parents concerning perception of the child's adherence to the treatment regimen (for both medications and exercises). METHODS: Fifty patients and their parents, who attended the JIA clinic at the Montreal Children's Hospital, completed the Child Adherence Report Questionnaire and the Parent Adherence Report Questionnaire. Paired t-tests were used to compare parents' and children's scores for adherence questions and agreements were analyzed by intraclass correlation coefficients (ICCs). RESULTS: Parents reported that their children showed more negative reactions to taking medication and doing exercises, more helpfulness from the medication, and more difficulty to carry out the exercise program than their children reported. ICCs (95% confidence interval) for medications and exercises were, respectively, 0.32 (0.04, 0.56) and 0.77 (0.61, 0.87) for overall adherence, 0.33 (0.05, 0.57) and 0.39 (0.09, 0.62) for perceived difficulty to following treatment, and 0.37 (0.09, 0.60) and 0.45 (0.17, 0.67) for how often children had negative reactions following treatment. Levels of agreement for perceived helpfulness of treatments were quite low. CONCLUSION: Agreement between parents and children concerning adherence was at best moderate, and generally better for the exercise program than for prescribed medications.     

Minimal clinically important differences of the childhood health assessment questionnaire

OBJECTIVE: The Childhood Health Assessment Questionnaire (CHAQ) is a commonly used measure of disability and physical function for children with juvenile rheumatoid arthritis (JRA), whose scores range between 0 (no disability) and 3 (very severe disability), with a smallest potential difference in the CHAQ score of individuals at 0.125. We estimated minimal clinically important differences (MCID) of the CHAQ for worsening and improvement that were actually experienced by children with JRA using patient, parent, and clinical perspectives. METHODS: Changes in CHAQ scores were calculated for parent (n = 92) and patient ratings (children age > or = 8 yrs only; n = 67) between subsequent clinic visits. Changes in patient well being and disease activity and the occurrence of flare or important improvement between visits served as external standards for the MCID. MCID were defined as the median changes of the CHAQ scores of individual patients who had a minimal important improvement or worsening between visits. RESULTS: The median change in CHAQ scores of patients who rated themselves or were rated by others as unchanged was often 0. Depending on the external standard used, the MCID for improvement of the CHAQ was -0.188 at most, while the MCID for worsening was at most +0.125. CONCLUSION: The MCID of the CHAQ for both improvement and worsening are often at or close to the level of the smallest potential difference, suggesting that the CHAQ is relatively insensitive to important short term changes in children with JRA. This may warrant a change in the calculation of the global CHAQ score, or the development of more sensitive functional measures.     

Measuring health status in early juvenile idiopathic arthritis: determinants and responsiveness of the child health questionnaire

OBJECTIVE: To assess the determinants and responsiveness of the Norwegian version of the Child Health Questionnaire (CHQ) in patients with early juvenile idiopathic arthritis (JIA) and to compare health status in patients and controls. METHODS: A total of 116 children (median age 8.4 yrs) with JIA and < 2.5 years of disease duration (median 11.0 mo) were examined by a pediatric rheumatologist and reassessed after a median of 10.0 months. Physical and psychosocial health were assessed by means of the CHQ, which provides summary scores for physical and psychosocial health, the Childhood Health Assessment Questionnaire (CHAQ), and the Child Behavior Checklist (CBCL, n = 32). Matched controls (n = 116), randomly selected from the general population, completed the CHQ at baseline. RESULTS: The patients with JIA had poorer physical health and slightly impaired psychosocial health compared with the controls [41.2 +/- 13.6 vs 55.2 +/- 7.3 (p < 0.001) and 51.0 +/- 7.5 vs 54.1 +/- 5.7 (p = 0.002), respectively]. The most important determinants of the CHQ physical summary score were the child's pain, morning stiffness, the CHAQ disability index, erythrocyte sedimentation rate (ESR), overall well-being, and physician's global assessment of disease activity. The psychosocial summary score correlated with the CBCL level of internalizing, externalizing, and total behavior problems. The standardized response mean for the physical summary score was large (0.96) for those who improved, and moderate (-0.60) for those who became worse. CONCLUSION: The CHQ discriminated between patients with early JIA and controls. The most important determinants of the CHQ physical summary score were the child's pain, morning stiffness, CHAQ, ESR, overall well-being, and physician's global assessment of disease activity. The CHQ was sensitive to clinical changes in children with JIA.     

Psychometric properties evaluation of the childhood health assessment questionnaire (CHAQ) in Moroccan juvenile idiopathic arthritis

The objective of this study is to develop and validate a Moroccan version of the childhood health assessment questionnaire (CHAQ), a disability measure for children suffering from juvenile idiopathic arthritis. The CHAQ has been validated in a cross-sectional study in 60 JIA, classified into systemic (33%), polyarticular (38%), extended oligoarticular (6.4%), and persistent oligoarticular (21.6%) subtypes. The CHAQ was tested for reliability and construct validity by correlating the yield of the questionnaire with other disease activity parameters. Disability index was significantly different among the four JIA subtypes. CHAQ proved to be valid in clinically discriminating between healthy subjects and patients with different patterns of JIA. The convergent validity was demonstrated by strong correlations of the disability score with the JIA score set of variables. In conclusion, the Moroccan version of the CHAQ has good psychometric properties. This validated version of the Moroccan CHAQ should help to individual follow-up of children suffering from JIA.     

Measuring the function of children with juvenile arthritis.

OBJECTIVE: Juvenile idiopathic arthritis (JIA) can affect a child's performance across a range of activities necessary to normal childhood development. Although there are now several available measures of disability in JIA, none have been validated for use with children in the UK. Consequently, a study was undertaken to compare and validate four such measures, together with a locally developed function test. METHODS: Fifty-three children between the ages of 5 and 16 yr were recruited into the study. The mean age was 10.4 yr and mean duration of disease 4 yr. Seventy per cent were female. RESULTS: Internal consistency was adequate in three of five measures. Four of five measures showed the expected associations between disease activity and function (P<0.05). The level of reliability was poor for tests that involved direct assessment by therapists. Most showed poor levels of unidimensionality. CONCLUSION: Until new measures become available, the CHAQ appears to be the current 'best buy' for measuring function in children with arthritis.     

Design and validation of a new scale to assess the functional ability in children with juvenile idiopathic arthritis (JIA)

OBJECTIVE: The assessment of the functional ability is one of the items of the core set to define improvements in patients with JIA, CHAQ being the most used scale already validated in 32 countries. The aim of this study was to design and validate a new scale named CAPFUN (capacidad funcional = functional ability) to assess functional ability in children with JIA. METHODS: This scale includes 20 items, 8 of upper limbs, 8 of lower limbs, 3 combined, and 1 of cervical spine, developed in two steps according with OMERACT. Each item is scored: 0 when it is impossible to be performed, 1 when it is performed incompletely or with difficulties, and 2 when it is well performed. Seventy three patients with JIA according to ILAR criteria were assessed: 25 boys (34.2%) and 48 girls (65.8%) whose aver-age age was 12.8 years (95% CI 11.8 - 13.8) and the time from disease onset was 5.02 years (95% CI 3.9 - 6.1). For validation purposes, it was applied to 91 healthy children and adolescents. In every patient, correlation with active joints count and functional class according to Steinbrocker was assessed and with CHAQ in 31 patients in this series. RESULTS: The CAPFUN index obtained in all healthy children was 2. Patients' media CAPFUN index was 1.54 (95%CI 1.38 - 1.68). The CAPFUN index for Steinbrocker's class I was 1.84 +/- 1.8; for class II 1.60 +/- 1.5 and for class III 0.91 +/- 1 (F 24.1 p < 0.001). CAPFUN showed significant correlation with CHAQ (Spearman coefficient -0.79 p < 0.001), with active joints count (Spearman coefficient -0.72 p < 0.001) and with Steinbrocker functional classes (Spearman coefficient -0.69 p < 0.001). This scale showed a good internal reliability (alpha coefficient equal to 0.94), its construct validity is demonstrated by its good correlation with Steinbrocker's scale and with CHAQ. CONCLUSION: CAPFUN is a new instrument in order to assess functional ability in children with JIA. This scale showed a good internal reliability. Construct validity is demonstrated by its high correlation with Steinbrocker's scale and with CHAQ. This study demonstrates the usefulness of CAPFUN for the assessment of functional ability in children with JIA.     

Relative responsiveness of condition specific and generic health status measures in juvenile idiopathic arthritis

OBJECTIVES: To compare the relative responsiveness of condition specific measures with that of a generic health status instrument for outcome assessment of intra-articular corticosteroid (IAC) injection in patients with juvenile idiopathic arthritis (JIA). METHODS: We examined 44 consecutive patients with oligoarticular JIA before an IAC injection and after 6 months. Condition specific measures included physician's and parent's global assessments, the Childhood Health Assessment Questionnaire (CHAQ), the articular indices, and laboratory indicators of systemic inflammation. The generic health status instrument was the Child Health Questionnaire (CHQ), which was divided into two parts: the physical score (PhS) and the psychosocial score (PsS). Responsiveness statistics were the standardised response mean, the effect size, and Guyatt's method. The discriminative ability of the clinical measures in distinguishing improved from non-improved patients was evaluated with the correlation and the receiver operating characteristic methods, using the physician's and the parent's judgements of the treatment outcome as external criteria. RESULTS: All responsiveness statistics and discriminative ability assessments consistently ranked the physician's global assessment of the disease activity as the most responsive measure. The CHQ-PhS revealed superior ability in detecting baseline versus 6 month change compared with the CHAQ and the CHQ-PsS; both summary scales of the CHQ revealed better discriminative ability than the CHAQ. CONCLUSIONS: The physician's global assessment of the disease activity proved the most responsive outcome measure in our patients with JIA. The relative evaluative properties of the generic health status instrument and the CHAQ should be further investigated.