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Rheumatol IntDOI 10.1007/s00296-014-2950-1

ORIgInal aRtIcle

Determinants of health‑related quality of life impairment in Egyptian children and adolescents with juvenile idiopathic arthritis: Sharkia Governorate

Amal B. Abdul‑Sattar · Enass A. Elewa · Eman El‑Dessoky El‑Shahawy · Eman H. Waly

Received: 13 July 2013 / accepted: 17 January 2014 © Springer-Verlag Berlin Heidelberg 2014

given to JIa patients who stop going to school and who has low socioeconomic status.

Keywords Juvenile idiopathic arthritis · Health-related quality of life impairment · Determinants

Introduction

Juvenile idiopathic arthritis (JIa) is the most common arthropathy of childhood, with an estimated prevalence between 7 and 400 for every 100,000 children [1]. In Sharkia governorate, egypt, prevalence of JIa is 3.43 per 100,000 [2]. JIa is a heterogeneous, multifactorial autoim-mune disease characterized by persistent joint inflamma-tion, which manifests as swelling, pain and limitation of movement [3]. Depending upon the severity and extent of disease involvement, children often experience significant pain and disability, which impede the execution of ordinary activities [4]. as children reach adulthood, they face possi-ble continuing disease activity, medication-associated mor-bidity, lifelong disability and an increased risk of emotional and social dysfunctioning [5]. It has also been established that children with JIa report lower health-related quality of life (HRQOl) as compared to their healthy peers [6–11]. Instruments used to measure HRQOl can be condition spe-cific that address aspects related to a specific condition and can be used to compare data from children and adolescents with the same chronic medical condition [12]. Pediatric HRQOl instruments must be sensitive to cognitive devel-opment and can include both child self-reports and parent proxy-reports [13], whereas other studies have shown that self-reporting appears to be more reliable for evaluating HRQOl [14, 15]. Few studies focused on risk factors for HRQOl impairment in children with JIa. Determinants

Abstract the aim of this study was to identify the pos-sible determinants of impaired health-related quality of life (HRQOl) in egyptian children and adolescents with juvenile idiopathic arthritis (JIa). Fifty-eight consecutive patients of JIa aged from 8 to 18 years underwent assess-ment of socio-economic and demographic characteris-tics; HRQOl using Pediatric Quality of life Inventory 4.0 generic core Scale, disease activity using the Juve-nile arthritis Disease activity Score based on 27 joints (JaDaS-27), functional ability using the childhood health assessment questionnaire (cHaQ), pain score on visual analog scale and psychological symptoms using the chil-dren’s Depression Inventory (cDI) score. Multivariate modeling was applied to determine the factors that asso-ciated with HRQOl impairment. a total of 55 % of the patients (32 of 58) had impaired HRQOl (<78.6). In multi-ple regression analyses, high cHaQ scores (OR 6.0, 95 % cI 2.0–17.5, P = 0.001), pain (OR 3.1, 95 % cI 1.9–6.3, P = 0.01), stop going to school (OR 3.9, 95 % cI 2.0–7.3, P = 0.01), low socioeconomic status (OR 2.3, 95 % cI 1.09–4.7, P = 0.04) and high psychological symptoms (OR 4.2, 95 % cI 2.0–12.6, P = 0.001) were determinants for HRQOl impairment. HRQOl impairment is a significant problem in egyptian children and adolescents with JIa. these findings underscore the critical need for monitor-ing of HRQOl in these patients. More attention should be

a. B. abdul-Sattar · e. a. elewa · e. e.-D. el-Shahawy (*) Department of Rheumatology and Rehabilitation, University of Zagazig, Sharkia, egypte-mail: aymony_s@yahoo.com; eman_d@zu.edu.eg

e. H. Waly Department of community Medicine and Public Health, Faculty of Medicine, University of Zagazig, Sharkia, egypt

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that had been identified for impaired HRQOl are polyar-ticular arthritis or extended oligoarthritis [16], short dis-ease duration [17], pain [14, 18], disabilities and increased disease severity [10]. In this study, we aimed to study the health-related quality of life among children and adoles-cents with JIa and to identify factors that may be associ-ated with impaired HRQOl.

Study design and participants

all JIa patients aged from 8 to 18 years, residing in Sharkia governorate and diagnosed according to the International league against Rheumatism (IlaR) classification [19], were consecutively recruited from in and outpatient clinics of rheumatology department, faculty of medicine, Zagazig University hospitals in this cross-sectional study between October 2010 and October 2012. Most pediatric patients in our setting receive health assistance close to their area of residence through the primary heath care centers within the national Health Insurance Program that provide more than 90 % of pediatric primary health care. So, the patients from health insurance hospitals were also recruited.

exclusion criteria: Patients younger than 8 years, patients less than 1 year of diagnosis and patients with a chronic disease, in addition to JIa, which would influence the child’s function, were excluded from this study.

Written informed consent was obtained from parents, and verbal assent was obtained from all children and adolescents for their study participation. the study approved by the local ethical committee of Zagazig University hospitals.

Method for data collection

the medical records were reviewed to collect data about: age of onset of disease, disease subtype at presentation according to the IlaR classification (systemic arthritis, oligoarticular arthritis, polyarthritis with rheumatoid factor, polyarthritis without rheumatoid factor, psoriatic arthritis, enthesitis-related arthritis and undifferentiated arthritis) [19], routine blood results, current and prior use of medi-cations for JIa treatment, as well as the duration of use of each medication. Subjects were only considered to be on methotrexate or a biologic drug if the duration of use was ≥2 months.

Demographic and socioeconomic

the parents completed the form that included child’s gen-der, age, residency and school grade, and they completed the questionnaire that measures the socioeconomic status of children and adolescents during the same visit of the clinical assessment of the patients. the socioeconomic

status was assessed using the socioeconomic status scale for health research in egypt, which is scoring system, based on seven domains (education and cultural, occupa-tion, family, family possessions, economic, home sanita-tion and health care) with a total score of 84. Higher score indicating better SeS. Socioeconomic level to be classified into very low, low, middle and high levels depending on the quartiles of the score calculated. this socioeconomic status scale has adequate factor reliability and validity [20].

Health-related quality of life

Health-related quality of life was assessed in patients using Pediatric Quality of life Inventory 4.0 generic core Scales (PedsQl 4.0), which is child self-report and parent proxy-report formats and has well-established reliability and validity in children with both acute and chronic health con-ditions. each scale uses a likert five-point scale to ask the child or caregiver how much of a problem each item has been over the past month (0 = never a problem, 1 = almost never a problem, 2 = sometimes a problem, 3 = often a problem and 4 = almost always a problem). Items are reverse-scored and linearly transformed to a 0–100 scale (0 = 100, 1 = 75, 2 = 50, 3 = 25 and 4 = 0), so that higher scores indicate better HRQOl [21]. the PedsQl 4.0 generic core Scale has four subscales: physical function-ing, emotional functioning, social functioning and school functioning. all scales demonstrate high reliability [22]. In this study, we used the arabic version. Reliability and validity data for the arabic version are comparable to those provided for the original instrument [23]. We used the self-reported forms of age 8–12 years and 13–18 years as the self-reporting appears to be more reliable as compared to proxy-report for evaluating HRQOl [14, 15], and the chil-dren as young as 6 years can reliably and validly self-report their HRQOl status if the questionnaire is age and cogni-tive appropriate [24]. Suboptimal (Impaired) HRQOl was defined as a PedsQl 4.0 total mean scale score <78.6 [10].

Disease activity

By using the Juvenile arthritis Disease activity Score based on 27 joints (JaDaS-27) that included the follow-ing four measures: physician global assessment of disease activity, measured on a 10-cm visual analog scale (VaS) where 0 = no activity and 10 = maximum activity; par-ent/patient global assessment of well-being, measured on a 10-cm VaS where 0 = very well and 10 = very poor; count of joints with active disease; and erythrocyte sedi-mentation rate. the JaDaS-27 was calculated as the sim-ple linear sum of the scores of its 4 components, which yields a global score of 0–57: 0 = no disease activity and 57 = maximum disease activity [25].

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Pain assessment

By completing a 100-mm VaS for the evaluation of pain (where 0 = no pain and 100 = very severe pain) by the patients, the VaS has been established and widely used as a reliable and valid measure of pain intensity with children.

Functional ability

Functional ability was assessed using the self-report form (age 8–18 years) of childhood health assessment ques-tionnaire (cHaQ) [26], which describes the child’s usual activities in eight domains over the past week. It includes dressing, getting up, eating, walking, with or without aids or assistive devices, hygiene, reaching overhead objects, grip and activities. each question is scored from 0 to 3 (0 = no difficulty, 1 = some difficulty, 2 = much difficulty and 3 = unable to do). the score for each of the eight func-tional areas was averaged to calculate the disability index. the arabic form of cHaQ was used in this study [27].

Depressive symptoms

Participants completed the children’s Depression Inventory (cDI). the cDI is a 27-item self-report inventory of child-hood depression that taps a variety of depressive symptoms. Items assess negative mood, interpersonal difficulties, nega-tive self-esteem, ineffectiveness and anhedonia in children aged 7–17 years. each item offers respondents three alter-natives scored 0, 1 or 2, and accordingly, raw scores range from 0 to 54 and then convert raw scores to t-scores. Higher scores indicate higher levels of depressive symptoms [28]. the cDI has adequate factor reliability and validity [29]. the cDI was translated and normalized for arab children by gharib [30]. Reliability and validity data for the arabic version are comparable to those provided for the original instrument. For this study, we considered t-Score ≥70 clini-cally significant score as in previous study [31].

Statistical analyses

after data collection, data were coded, entered and analyzed using SPSS (Statistical Package for Social Science) version 19. Descriptive statistics were performed. chi-square tests for categorical variables and unpaired t tests for continu-ous variables were used. all variables were dichotomized to make interpretation more explicit. a multiple logistic regression model was built up to identify factors associ-ated with impaired HRQOl (PedsQl 4.0 total mean scale score <78.6). associations between potential confounding variables (socio-economic, demographic and clinical) and impaired HRQOl were first examined in univariate logistic

Table 1 Demographic, socioeconomic and clinical characteristics

PedsQL pediatric quality of life, JIADAS Juvenile arthritis Disease activity Score, CHAQ childhood health assessment questionnaire, CDI children’s Depression Inventory

Variables

age, years, median (range) 9.1 (7–17)

Sex [n (%)]

Females 41 (70.7)

Males 17 (29.3)

Residency [n (%)]

Rural 39 (67.2)

Urban 19 (32.8)

Disease duration, years, median (range) 4.7 (1–10)

Schooling status [n (%)]

continue 46 (79.3)

Stop 12 (20.7)

Socioeconomic status [n (%)]

Very low 19 (32.8)

low 21(36.2)

Moderate 12 (20.7)

High 6 (7)

Subtypes of JIa [n (%)]

Systemic 13 (22.4)

Oligoarthritis 28 (48.3)

Polyarthritis 17 (29.3)

HRQOl (PedsQl total score), mean (SD)

children (8–12 years) 70.39 (19.02)

adolescents (13–18 years) 71.27 (14.09)

Pain, VaS score, median (range) 40 (20–80)

JIaDaS-27, median (range) 19.2 (6–25.4)

cHaQ score, median (range) 0.7 (0–1.8)

cDI total t-score, median (range) 57 (35–86)

Medications [n (%)]

Patients who were receiving corticosteroid 31 (53.4)

Patients who were receiving methotrexate 27 (46.5)

Patients who were receiving sulfasalazine 7 (12)

Patients who were receiving Prednisone >1 mg/kg/day 22 (38)

Table 2 HRQOl subscales (self-report) in JIa patients

the results are presented as mean ± SD

HRQOl subscales children (n = 26)(Mean ± SD)

adolescents (n = 32)(Mean ± SD)

Physical health 66.11 ± 18.2 68.98 ± 20.34

emotional functioning 73.80 ± 20.02 70.60 ± 22.81

Social functioning 68.19 ± 21.01 78.72 ± 17.18

Schooling functioning 71.80 ± 18.70 66.81 ± 18.17

total score 70.39 ± 19.02 71.27 ± 14.09

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regression analyses. then, the variables that had a significant association with impaired HRQOl were included in the mul-tiple regression models as independent variables. the results are presented as odds ratios (ORs) with 95 % confidence intervals (cIs). a P value <0.05 was considered significant.

Results

the number of the eligible patients was 64, while the num-ber of the patients who completed the questionnaires and were included in this study was 58.

Table 3 Univariate analyses of factors associated with impaired HRQOl

Values are the number (percentage)

OR odds ratio, CI confidence interval, PedsQL pediatric quality of life, JIADAS Juvenile arthritis Disease activity Score, CHAQ childhood health assessment questionnaire, CDI children’s Depression Inventory

Variables Patients with poor HRQOl (n = 32), n (%) OR (95 % cI) P value

age

child < 11 years (n = 26) 14 (53.8) 0.73 (0.5–1.4) 0.21

adolescent ≥ 11 years (n = 32) 18 (56.25)

gender

Female (n = 41) 22 (53.7) 0.83 (0.4–1.7) 0.83

Male (n = 17) 10 (58.8)

Residency

Rural (n = 39) 24 (61.5) 2.4 (1.3–7.2) 0.03

Urban (n = 19) 8 (42.1)

Schooling status

continue (n = 46) 22 (46.8) 3.2 (1.4–7.4) 0.01

Stop (12) 10 (83.3)

Socioeconomic status

Very low and low (n = 40) 26 (65.0) 2.3 (1.5–4.7) 0.02

Moderate and high (n = 18) 6 (33.3)

Subtype of JIa

Oligoarthritis (n = 28) 15 (53.6) 0.83 (0.3–2.4) 0.69

Other subtypes (n = 30) 17 (56.6)

Disease duration

<4.7 (n = 22) 12 (54.5) 0.9 (0.8–2.3) 0.85

≥4.7 (n = 36) 20 (55.5)

JIaDaS-27

<19.2 (n = 38) 16 (42.1) 2.1 (1–4.1) 0.02

≥19.2 (n= 20) 16 (80)

cHaQ score

no difficulty (0) (n = 35) 15 (42.8) 2.4(1.5–6.8) 0.01

Difficulty(>0) (n = 23) 17 (73.9)

cDI total t-score

<70 (n = 37) 16 (43.2) 2.5 (1.7–5.9) 0.02

≥70 (n = 21) 16 (76.2)

Pain score (0–100 VaS)

<30 (n = 40) 17 (42.5) 2.1 (1.4–3.3) 0.01

≥30 (n = 18) 15 (83.3)

Prednisone > 1 mg/kg/day

Yes (n = 22) 18 (77.3) 2.8 (1.2–4.5) 0.01

no (n = 36) 14 (38.8)

Table 4 Factors associated with impaired HRQOl by multiple logis-tic regressions

OR odds ratio, CI confidence interval, CHAQ childhood health assessment questionnaire, SES socioeconomic status, CDI children’s Depression Inventory

Variables Odds ratio (OR) 95 % confidence interval (cI)

P value

cHaQ score 6.0 2.0–17.5 0.001

low-very low SeS 2.3 1.9–4.7 0.04

Pain score 3.1 1.9–6.3 0.01

Stopped schooling 3.9 2.0–7.3 0.01

cDI total t-score 4.2 2.0–12.6 0.001

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as anticipated, suboptimal HRQOl was reported by 55 % of the sample (32 of 58). the median age of the patients was 9.1 (7–18) years; the median disease dura-tion was 4.7 (1–10) years, and the majority were female (71 %) and live in rural region (67 %). they were further characterized as 13 systemic-onset, 28 oligoarticular (11 persistent and 17 extended), 17 polyarticular (5 RF posi-tive and 12 RF negative). none of our patients had pso-riasis- or enthesitis-related arthritis. Median JaDaS-27 was 19.2 (6–25.4), median cHaQ was 0.7 (0–1.8), and median cDI total t-score was 57 (35–86). More than half of our patients (53 %) were receiving steroid, 46.5 % were receiving methotrexate, and 12 % were receiving sulfasala-zine. However, no patients received any biological therapy (table 1).

Ratings of health-related quality of life (PedsQl 4.0) that were reported by children (8–12 years) and adolescents (13–18 years) are shown in table 2. across the four generic HRQl domains, both the child age group (8–12 years) and the adolescent age group (13–18 years) reported low HRQOl; the lowest HRQl scores that reported by chil-dren were in the areas of physical and social functioning. However, the lowest HRQl scores that reported by adoles-cents were in the areas of physical and school functioning (table 3).

In univariate analysis, impaired HRQOl was signifi-cantly associated with living in rural region, low socioeco-nomic status, stop going to school, high cHaQ scores, high pain score, disease activity, using of prednisone >1 mg/kg/day and greater psychological symptoms (based on cDI total t-score).

In multiple regression analyses, high cHaQ scores (OR 6.0, 95 % cI 2.0–17.5, P = 0.001), greater psychological symptoms (OR: 4.2, 95 % cI: 2.0-12.6, P = 0.001), stop going to school (OR 3.9, 95 % cI 2.0–7.3, P = 0.01), low socioeconomic status (OR 2.3, 95 % cI 1.09–4.7, P = 0.04) and pain (OR 3.1, 95 % cI 1.9–6.3, P = 0.01) were associated independently with impaired HRQOl (table 4).

Discussion

to the best of our knowledge, this is the first study about HRQOl impairment, based on self-reported PedsQl 4.0 generic core Scales in egyptian children and adolescents with JIa. In this cross-sectional study, we assessed the fre-quency of impaired HRQOl, as well as we examined the association between impaired HRQOl and a comprehen-sive set of variables in a representative sample of egyptian children and adolescents with JIa.

Our main finding was that more than half of the studied sample (55 %) have been found to experience suboptimal

HRQOl, defined as PedsQl 4.0 total scale score <78.6. Our result was comparable to that described in australian [18], Sweden [32], Italian [33] and Dutch children [34].

In the current study, we found that JIa subtype was not a determinant for impaired HRQOl. In contrast to our finding, previous studies demonstrated that the patients with persistent oligoarthritis had better HRQOl compared with other subtypes, whereas HRQOl was similar across patients with systemic arthritis, polyarthritis and extended oligoarthritis [7, 35]. another study found that JIa has sub-stantial adverse impact on HRQOl of patients, principally adolescents with polyarticular and systemic subtypes [6].

Similar to previous studies [6, 7, 9–11, 34–36], func-tional disability (high cHaQ scores) was significant deter-minant for impaired HRQOl in our current study. another study found that individualized training programs may sig-nificantly improve the physical ability of the adolescent and therefore positively influence a child’s HRQOl [37].

In consistent with our finding, previous studies [6, 7, 10, 11, 18, 34–36] found that the pain was a significant pre-dictor of lower HRQOl in JIa. also, lovell et al. [38] reported that the relief of pain and pain management are important factors to deal with in the care of children with JIa.

Similar to what was reported in previous studies [17, 39], we also showed that higher score of psychologi-cal symptoms, as measured by cDI, was a determinant of impaired HRQOl in this study. Recent study [36] found that adolescents with JIa and low HRQOl at baseline reported better HRQOl after psychological intervention.

In our study, another important determinant of impaired HRQOl appeared to be stopping go to school. Haverman et al. [34] found that children who reported more school absence in the 3 months prior to the consultation showed lower HRQOl and more impaired school functioning than those children with less school absence.

Regarding the influence of socioeconomic status on HRQOl in the present study, we found that low socioeco-nomic status was associated with impaired HRQOl. this could be explained by the fact that the risk factors associ-ated with low socioeconomic may directly or indirectly affect not only family HRQOl but also HRQOl of chil-dren [40]. Previous study demonstrated that higher car-egiver perceived economic hardship was associated with worse HRQOl in children with JIa [41]. a study on chil-dren with type 1 diabetes mellitus suggested that low and middle socioeconomic status of families in children with type 1 diabetes mellitus is associated with lower generic HRQOl as compared to control children with similar soci-oeconomic status of families [42].

Surprisingly, disease activity was not a predictor for lower HRQOl in the present study. Previous study found that children with no, or very mild, clinical JIa symptoms

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have been found to experience suboptimal HRQOl [10]. On the other hand, previous studies reported that higher disease activity was associated with worse HRQOl in chil-dren with JIa [6, 7, 9, 41].

Our study showed that living in rural regions associ-ated with lower HRQOl in the univariate analyses. We explained that association by the fact that the egyptian rural regions have poor medical services and less expert pediatric rheumatologist. thus, children with JIa have to travel to urban regions asking for medical advices. Other-wise, the disease may be diagnosed lately or misdiagnosed. However, in the multivariate analyses, the living in rural region was not a determinant for impaired HRQOl.

In our study, age, sex, duration of disease and treatment were not associated with HRQOl impairment. Similar to our results, previous studies [6, 7, 43] found that age and sex did not influence HRQOl. Haverman et al. [34] found that receiving medication was not a predictor of impaired HRQOl.

Similar to previous study [7] and in contrast to other study [17], disease duration was not associated with impaired HRQOl in this study.

limitations of this study must be taken in account. First, the study sample was small. Second, the cross-sectional design limits the ability to determine temporal relationships between risk factors and HRQOl. So, further longitudinal studies with a larger sample necessary to confirm the find-ing of this study. Despite the methodological limitations of this study, this study has two strengths. First, it could support the few studies concerning the determinants of HRQOl impairment in children and adolescents with JIa. Second, this study is the first study performed, based on self-reported PedsQl 4.0 generic core Scales, in egyptian children and adolescents with JIa. Despite the limitations, this study found that the impaired HRQOl is significantly high in egyptian children and adolescents with JIa. low functional ability, self-reported pain, high depressive symp-toms, stop going to school and low socioeconomic status are determinants for impaired HRQOl in children and ado-lescents with JIa. Improving of HRQOl should focus on interventions to relive pain, to improve physical function and to alleviate depressive symptoms. Other risk factors that may influence HRQOl in patients with JIa need to be investigated in future studies.

References

1. Olson Jc (2003) Juvenile idiopathic arthritis: an update. WMJ 102:45–50

2. abou el-Soud aM, el-naajjar aR, el-Shahawy ee et al. (2013) Prevalence of juvenile Idiopathic arthritis in Sharkia governorate, egypt: epidemiological study. Rheumatol Int 33(9):2315–2322

3. Weiss Je, llowite nt (2005) Juvenile idiopathic arthritis. Pediatr clin north am 52(2):413–442

4. Schanberg l, anthony K, gil K, Maurin e (2003) Daily pain and symptoms in children with polyarticular arthritis. arthritis Rheum 48:1390–1397

5. Moorthy ln, Peterson Mg, Hassett al, lehman tJ (2010) Burden of childhood-onset arthritis. Pediatr Rheumatol Online J 8:20

6. amine B, Rostom S, Benbouazza K, abouqal R, Hajjaj-Hassouni n (2009) Health related quality of life survey about children and adolescents with juvenile idiopathic arthritis. Rheumatol Int 29(3):275–279

7. Shaw Kl, Southwood tR, Duffy cM, McDonagh Je (2006) Health-related quality of life in adolescents with juvenile idi-opathic arthritis. arthritis Rheum 55(2):199–207

8. norrby U, nordholm l, andersson-gäre B, Fasth a (2006) Health-related quality of life in children diagnosed with asthma, diabetes, juvenile chronic arthritis or short stature. acta Paediatr 95(4):450–456

9. Ringold S, Wallace ca, Rivara FP (2009) Health-related qual-ity of life, physical function, fatigue, and disease activity in chil-dren with established polyarticular juvenile idiopathic arthritis. J Rheumatol 36(6):1330–1336

10. Seid M, Opipari l, Huang B, Brunner HI, lovell DJ (2009) Disease control and health-related quality of life in juvenile idi-opathic arthritis. arthritis Rheum 61(3):393–399

11. gutierrez-Suarez R, Pistorio a, cespedes ca, norambuena X, Flato B, Rumba I et al (2007) Health-related quality of life of patients with juvenile idiopathic arthritis coming from 3 differ-ent geographic areas: the PRIntO multinational quality of life cohort study. Rheumatology (Oxford) 46(2):314–320

12. Baars R, atherton c, Koopman H, Bullinger M, Power M (2005) group D. the european DISaBKIDS project: development of seven condition-specific modules to measure health related qual-ity of life in children and adolescents. Health Qual life Outcome 3:70

13. Simeoni M, Schmidt S, Muehlan H, Debensason D, Bullinger M, group D (2007) Field testing of a european quality of life instru-ment for children and adolescents with chronic conditions: the 37-item DISaBKIDS chronic generic Module. Qual life Res 16(5):881–893

14. Brunner HI, Klein-gitelman MS, Miller MJ, trombley M, Bald-win n, Kress a et al (2004) Health of children with chronic arthritis: relationship of different measures and the quality of par-ent proxy reporting. arthritis Rheum 51:763–773

15. Varni JW, Burwinkle tM, lane MM (2005) Health-related qual-ity of life measurement in pediatric clinical practice: an appraisal and precept for future research and application. Health Qual life Outcomes 3:34

16. arkela-Kautiainen M, Haapasaari J, Kautiainen H, Vilkkumaa I, Malkia e, leirisalo-Repo M (2005) Favourable social function-ing and health related quality of life of patients with JIa in early adulthood. ann Rheum Dis 64:875–880

17. Muller-godeffroy e, lehmann H, Kuster RM, thyen U (2005) Quality of life and psychosocial adaptation in children and ado-lescents with juvenile idiopathic arthritis and reactive arthritis. Z Rheumatol 64(3):177–187

18. Sawyer Mg, Whitham Jn, Roberton DM, taplin Je, Varni JW, Baghurst Pa (2004) the relationship between health-related quality of life, pain and coping strategies in juvenile idiopathic arthritis. Rheumatology (Oxford) 43:325–330

19. Petty Re, South Wood tR, Manners P et al (2004) International league of associations for rheumatology. International league of associations for rheumatology classification of juvenile idi-opathic arthritis: second revision, edmonton, 2001. J Rheumatol 31:390–392

Rheumatol Int

1 3

20. el-gilany a, el-Wehady a, el-Wasify M (2012) Updating and validation of the socioeconomic status scale for health research in egypt. east mediterr Health J 18(9):962–968

21. Varni JW, Seid M, Knight tS, Uzark K, Szer IS (2002) the PedsQl 4.0 generic core scales: sensitivity, responsiveness, and impact on clinical decision maker. J Behav Med 25:175–193

22. Varni JW, Burwinkle tM, Seid M, Skarr D (2003) the PedsQl™ 4.0 as a pediatric population health measure: feasibility, reliabil-ity, and validity. ambul Pediatr 3:329–341

23. arabiat D, elliott B, Draper P, al Jabery M (2011) cross-cultural validation of the Pediatric Quality of life Inventory™ 4.0 (Ped-sQl™) generic core scale into arabic language. Scand J caring Sci 25(4):828–833

24. Varni JW, limbers ca, Burwinkle tM (2007) How young can children reliably and validly self-report their health-related qual-ity of life? an analysis of 8.591 children across age subgroups with the PedsQl 4.0 generic core Scales. Health Qual life Out-comes 5:1

25. consolaro a, Ruperto n, Bazso a et al (2009) Pediatric Rheu-matology International trials Organisation. Development and validation of a composite disease activity score for juvenile idi-opathic arthritis. arthritis Rheum 61:658–666

26. Singh g, athreya BH, Fries JF, goldsmith DP (1994) Measure-ment of health status in children with juvenile rheumatoid arthri-tis. arthritis Rheum 37:1761–1769

27. Rostom S, amine B, Bensabbah R, chkirat B, abouqal R, Haj-jaj-Hassouni n (2010) Psychometric properties evaluation of the childhood health assessment questionnaire (cHaQ) in Moroccan juvenile idiopathic arthritis. Rheumatol Int 30(7):879–885

28. Kovacs M (1981) Rating scales to assess depression in school-age children. acta Paedopsychiatr 46:305–315

29. Saylor c, Finch a, Spirito a, Bennett B (1984) the children’s Depression Inventory: a systematic evaluation psychometric properties. J consult clin Psychol 52:955–967

30. gharib (1995) the children Depression Inventory cDI. Dar el-nahda: cairo, Second

31. logan De, Simons le, Kaczynski KJ (2009) School functioning in adolescents with chronic pain: the role of depressive symptoms in school impairment. J Pediatr Psychol 34(8):882–892

32. cespedes-cruz a, gutierrez-Suarez R, Pistorio a, Ravelli a, loy a, Murray KJ et al (2008) Methotrexate improves the health-related quality of life of children with juvenile idiopathic arthri-tis. ann Rheum Dis 67:309–314

33. lundberg V, lindh V, eriksson c, Petersen S, eurenius e (2012) Health-related quality of life in girls and boys with juvenile idi-opathic arthritis: self- and parental reports in a cross-sectional study. Pediatr Rheumatol 10(1):33

34. Hagerman l, grootenhuis Ma, van den Berg JM, van Veenendaal M, Dolman KM, Swart JF, Kujjpers tw, van Rossum Ma (2012) Predictors of health-related quality of life in children and ado-lescents with juvenile idiopathic arthritis: results from a Web-based survey. arthritis care Res (Hoboken) 64(5):694–703. doi:10.1002/acr.21609.23

35. Oliveira S, Ravelli a, Pistorio a et al (2007) Proxy-reported health-related quality of life of patients with juvenile idiopathic arthritis: the Pediatric Rheumatology International trials Organi-zation multinational quality of life cohort study. arthritis Rheum 57(1):35–43

36. Fuchs ce, Van geelen SM, Hermans HJ, Van Putte eM, Van geel R, Sinnema g, Kuis W (2013) Psychological intervention for adolescents with juvenile idiopathic arthritis: for whom and when? J Rheumatol 40(4):528–534

37. Van Brussel M, lelieveld Ot, van der net J, engelbert RH, Helders PJ, takken t (2007) aerobic and anaerobic exercise capacity in children with juvenile idiopathic arthritis. arthritis Rheum 57:891–897

38. lovell DJ, Passo MH, Beukelman t, Bowyer Sl, gottlieb BS, Henrickson M et al (2011) Measuring process of arthritis care: a proposed set of quality measures for the process of care in juve-nile idiopathic arthritis. arthritis care Res (Hoboken) 63:10–16

39. Stevanovic D, Susic g (2013) Health-related quality of life and emotional problems in juvenile idiopathic arthritis. Qual life Res 22(3):607–612

40. tahirovic e, Begic H, Sutovic a, tahirovic H (2010) Impact of the family socioeconomic status on health related quality of life in children operated on for congenital heart defects. acta Med croatica 64(1):9–16

41. toupin april K, cavallo S, eharmann Feldman D, ni a (2012) the associations among economic hardship, caregiver psycho-logical distress, disease activity, and health-related quality of life in children with juvenile idiopathic arthritis. Qual life Res 21(7):1185–1191

42. tahirovic e, toromanovic a, tahirovic e, Begic H (2013) Impact of socioeconomic status on health-related quality of life in chil-dren with type 1 diabetes mellitus in Bosnia and Herze-govina. Minervia Pediatr 65(2):207–212

43. Petersen c, nordmeyer S, Muller-godeffroy e, Foeldvari I, Kuster RM, Bullinger M (2008) Health-related quality of life in children and adolescents with juvenile idiopathic arthritis: which role do age sex and medical parameters play? Klin Padiatr 220(4):259–265