The Thai version of the Juvenile Arthritis Multidimensional Assessment Report (JAMAR)

The Juvenile Arthritis Multidimensional Assessment Report (JAMAR) is a new parent/patient-reported outcome measure that enables a thorough assessment of the disease status in children with juvenile idiopathic arthritis (JIA). We report the results of the cross-cultural adaptation and validation of the parent and patient versions of the JAMAR in the Thai language. The reading comprehension of the questionnaire was tested in ten JIA parents and patients. Each participating centre was asked to collect demographic, clinical data and the JAMAR in 100 consecutive JIA patients or all consecutive patients seen in a 6-month period and to administer the JAMAR to 100 healthy children and their parents. The statistical validation phase explored descriptive statistics and the psychometric issues of the JAMAR: the three Likert assumptions, floor/ceiling effects, internal consistency, Cronbach’s alpha, interscale correlations, test–retest reliability, and construct validity (convergent and discriminant validity). A total of 104 JIA patients (45.2% systemic JIA, 10.6% oligoarticular, 9.6% RF negative polyarthritis, 34.6% other categories) and 102 healthy children, were enrolled in one paediatric rheumatology centre. Notably, none of the enrolled JIA patients is affected with psoriatic arthritis or undifferentiated arthritis. The JAMAR components discriminated well healthy subjects from JIA patients. All JAMAR components revealed satisfactory psychometric performances. In conclusion, the Thai version of the JAMAR is a valid tool for the assessment of children with JIA and is suitable for use both in routine clinical practice and clinical research.

The local members of the Paediatric Rheumatology International Trials Organisation (PRINTO) participating in the project are listed in the dedicated tables no. 2 and 3 of "https ://doi. org/10.1007/s0029 6-018-3944-1 / Cross-cultural adaptation and psychometric evaluation of the Juvenile Arthritis Multidimensional Assessment Report (JAMAR) in 54 languages across 52 countries: review of the general methodology".

Introduction
The aim of the present study was to cross-culturally adapt and validate the Thai parent, child/adult version of the Juvenile Arthritis Multidimensional Assessment Report (JAMAR) [1] in patients with juvenile idiopathic arthritis (JIA). The JAMAR assesses the most relevant parent/ patient-reported outcomes in JIA, including overall wellbeing, functional status, health-related quality of life (HRQoL), pain, morning stiffness, disease activity/status/ course, articular and extra-articular involvement, drugrelated side effects/compliance and satisfaction with illness outcome.
This project was part of a larger multinational study conducted by the Paediatric Rheumatology International Trials Organisation (PRINTO) [2] aimed to evaluate the epidemiology, outcome and treatment of childhood arthritis (EPOCA) in different geographic areas [3].
We report herein the results of the cross-cultural adaptation and validation of the parent and patient versions of the JAMAR in the Thai language.

Materials and methods
The methodology employed has been described in detail in the introductory paper of the supplement [4]. In brief, it was a cross-sectional study of JIA children, classified according to the ILAR criteria [5,6] and enrolled from June 2015 to November 2015. Children were recruited after Ethics Committee approval and consent from at least one parent.

The JAMAR
The JAMAR [1] includes the following 15 sections.
1. Assessment of physical function (PF) using 15-items in which the ability of the child to perform each task is scored as follows: 0 = without difficulty, 1 = with some difficulty, 2 = with much difficulty, 3 = unable to do and not applicable if it was not possible to answer the question or the patient was unable to perform the task due to their young age or to reasons other than JIA. The total PF score ranges from 0 to 45 and has three components: PF-lower limbs (PF-LL); PF-hand and wrist (PF-HW) and PF-upper segment (PF-US) each scoring from 0 to 15 [7]. Higher scores indicating higher degree of disability [8][9][10]. 2. Rating of the intensity of the patient's pain on a 21-numbered circle Visual Analogue Scale (VAS) [11].
3. Assessment of the presence of joint pain or swelling (present/absent for each joint). 4. Assessment of morning stiffness (present/absent). 5. Assessment of extra-articular symptoms (fever and rash) (present/absent). 6. Rating of the level of disease activity on a 21-circle VAS. 7. Rating of disease status at the time of the visit (categorical scale). 8. Rating of disease course from previous visit (categorical scale). 9. Checklist of the medications the patient is taking (list of choices). 10. Checklist of side effects of medications. 11. Report of difficulties with medication administration (list of items). 12. Report of school/university/work problems caused by the disease (list of items). 13. Assessment of HRQoL, through the physical health (PhH), and psychosocial health (PsH) subscales (five items each) and a total score. The four-point Likert response, referring to the prior month, are 'never' (score = 0), 'sometimes' (score = 1), 'most of the time' (score = 2) and 'all the time' (score = 3). A 'not assessable' column was included in the parent version of the questionnaire to designate questions that cannot be answered because of developmental immaturity. The total HRQoL score ranges from 0 to 30, with higher scores indicating worse HRQoL.
14. Rating of the patient's overall well-being on a 21-numbered circle VAS. 15. A question about satisfaction with the outcome of the illness (yes/no) [15].
The JAMAR is available in three versions, one for parent proxy-report (child's age 2-18), one for child self-report, with the suggested age range of 7-18 years, and one for adults.

Cross-cultural adaptation and validation
The process of cross-cultural adaptation was conducted according to international guidelines with 2-3 forward and backward translations. In those countries for which the translation of JAMAR had been already cross-cultural adapted in a similar language (i.e. Spanish in South American countries), only the probe technique was performed. Reading comprehension and understanding of the translated questionnaires were tested in a probe sample of ten JIA parents and ten patients.
Each participating centre was asked to collect demographic, clinical data and the JAMAR in 100 consecutive JIA patients or all consecutive patients seen in a 6-month period and to administer the JAMAR to 100 healthy children and their parents.
The statistical validation phase explored the descriptive statistics and the psychometric issues [16]. In particular, we evaluated the following validity components: the first Likert assumption (mean and standard deviation [SD] equivalence); the second Likert assumption or equal items-scale correlations (Pearson r all items within a scale should contribute equally to the total score); third Likert assumption (item internal consistency or linearity for which each item of a scale should be linearly related to the total score that is 90% of the items should have Pearson r ≥ 0.4); floor/ceiling effects (frequency of items at lower and higher extremes of the scales, respectively); internal consistency, measured by the Cronbach's alpha, interscale correlation (the correlation between two scales should be lower than their reliability coefficients, as measured by Cronbach's alpha); test-retest reliability or intra-class correlation coefficient (reproducibility of the JAMAR repeated after 1 or 2 weeks); and construct validity in its two components: the convergent or external validity which examines the correlation of the JAMAR subscales with the six JIA core set variables, with the addition of the parent assessment of disease activity and pain by the Spearman's correlation coefficients (r) [17] and the discriminant validity, which assesses whether the JAMAR discriminates between the different JIA categories and healthy children [18].
Quantitative data were reported as medians with 1st and 3rd quartiles and categorical data as absolute frequencies and percentages.
The complete Thai parent and patient versions of the JAMAR are available upon request to PRINTO.

Cross-cultural adaptation
The Thai JAMAR was fully cross-culturally adapted with two forward and two backward translations. The concordance rate between the original standard English version of the JAMAR and the two back-translations was 68.3% (84/123 lines) for the parent version and 70.8% (85/120 lines) for the child version.
Of the 123 lines in the patient version of the JAMAR, 119 (97%) lines were understood by at least 80% of the ten parents tested (median = 100%; range 60-100%). Of the 120 lines in the patient version of the JAMAR, 116 (97%) lines were understood by at least 80% of the children (median = 100%; range 40-100%). Lines 47, 60, 111, and 114 of the parent version of the JAMAR and lines 45, 58, 108, and 111 of the child version of the JAMAR were modified considering to parents' and patients' suggestions.

Demographic and clinical characteristics of the subjects
A total of 104 JIA patients and 102 healthy children (total of 206 subjects), were enrolled at the paediatric rheumatology clinic in Ramathibodi Hospital.
In the 104 JIA subjects, the JIA categories were 45.2% with systemic JIA, 10.6% with oligoarthritis, 9.6% with RF negative polyarthritis, 10.6% with RF positive polyarthritis and 24.0% with enthesitis related arthritis. Notably, none of the enrolled JIA patients is affected with psoriatic arthritis or undifferentiated arthritis (Table 1).
A total of 188/206 (91.3%) subjects had the parent version of the JAMAR completed by a parent (87 from parents of JIA patients and 101 from parents of healthy children). The JAMAR was completed by 168/188 (89.4%) mothers and 20/188 (10.6%) fathers. The child version of the JAMAR was completed by 141/206 (68.4%) children age 5.1 or older. Also patients younger than 7 year old, capable to assess their personal condition and able to read and write, were asked to fill in the patient version of the questionnaire.

Discriminant validity
The JAMAR results are presented in Table 1, including the scores [median (1 st -3rd quartile)] obtained for the PF, the PhH, the PsH subscales and total score of the HRQoL scales. The JAMAR components discriminated well between healthy subjects and JIA patients.
In summary, the JAMAR revealed that JIA patients had a greater level of disability and pain, as well as a lower HRQoL than their healthy peers.

Psychometric issues
The main psychometric properties of both parent and child versions of the JAMAR are reported in Table 2. The following "Results" section refers mainly to the parent's version findings, unless otherwise specified.

Descriptive statistics (first Likert assumption)
There were no missing results for all JAMAR items, since data were collected through a web-based system that did not allow to skip answers and input of null values. The response pattern for both PF and HRQoL was positively skewed toward normal functional ability and normal Table 1 Descriptive statistics (medians, 1st 3rd quartiles or absolute frequencies and %) for the 104 JIA patients  HRQoL. A reduced number of response choices were used for the different HRQoL items except for items 2, 3 and 4, whereas a reduced number of response choices was used for all the PF items except for items 3 and 5. The mean and SD of the items within a scale were roughly equivalent for the PF and for the HRQoL items (data not shown). The median number of items marked as not applicable was 0% (0-1%) for the PF and 0% (0-1%) for the HRQoL.

Equal items-scale correlations (second Likert assumption)
Pearson items-scale correlations corrected for overlap were roughly equivalent for items within a scale for 67% of the PF items, with the exception of PF items 6, 10, 11, 14 and 15, and for 90% of the HRQoL items, with the exception of HRQoL item 1.

Items internal consistency (third Likert assumption)
Pearson items-scale correlations were ≥ 0.4 for 73% of items of the PF (except for PF items 10, 11, 14 and 15) and 70% of items of the HRQoL (except for HRQoL items 1, 7 and 9).

Interscale correlation
The Pearson correlation of each item of the PF and the HRQoL with all items included in the remaining scales of the questionnaires was lower than the Cronbach's alpha except for the PF items 12 and 13, and for the HRQoL item 4.

Test-retest reliability
Reliability was assessed in eight JIA patients, by re-administering both versions (parent and child) of the JAMAR after a median of 8 days (8-8 days). The intraclass correlation coefficients (ICC) for the PF total score showed an almost perfect reproducibility (ICC = 0.96). The ICC for the HRQoL PhH showed an almost perfect reproducibility (ICC = 0.95) while the ICC for the HRQoL PsH showed a poor reproducibility (ICC = 0.0).

Convergent validity
The Spearman's correlation of the PF total score with the JIA core set of outcome variables ranged from 0.3 to 0.5 (median = 0.4). The PF total score best correlation was observed with the parent assessment of pain (r = 0.5, p < 0.001). The correlation of the PF total score with the ESR was not significant (p = 0.17). For the HRQoL, the median correlation of the PhH with the JIA core set of outcome variables ranged from 0.2 to 0.7 (median = 0.6), whereas for the PsH ranged from 0.04 to 0.4 (median = 0.2). The PhH showed the best correlation with the parent's assessment of pain (r = 0.7, p < 0.001) and the PsH with the physician global assessment of well-being (r = 0.4, p = 0.0001). The median correlations between the pain VAS, the well-being VAS, and the disease activity VAS and the physician-centred and laboratory measures were 0.4 (0.3-0.5), 0.4 (0.2-0.5), 0.4 (0.3-0.4), respectively.

Discussion
In this study, the Thai version of the JAMAR was fully crossculturally adapted from the original standard English version with two forward and two backward translations. According to the results of the validation analysis, the Thai parent and patient versions of the JAMAR possess satisfactory psychometric properties. The disease-specific components of the questionnaire discriminated well between patients with JIA and healthy controls. Psychometric performances were good for all domains of the JAMAR with some exceptions: four PF items ("open and close a tap or open a previously open jar", "stretch out arms", "bend head back" and "bite a sandwich or an apple") and three HRQoL items ("have difficulty taking care", "feeling nervous or anxious" and "have difficulty concentrating or paying attention") showed a lower items internal consistency. Furthermore, the overall internal consistency for PF-US and for HRQoL-PsH subscales were questionable.
In the external validity evaluation, the Spearman's correlations of the PF and HRQoL scores with JIA core set parameters ranged from weak to strong.
The results obtained for the parent version of the JAMAR are very similar to those obtained for the child version, which suggests that children are equally reliable proxy reporters of their disease and health status as their parents. The JAMAR is aimed to evaluate the side effects of medications and school attendance, which are other dimensions of daily life that were not previously considered by other HRQoL tools. This may provide useful information for intervention and follow-up in health care. In conclusion, the Thai version of the JAMAR was found to have satisfactory psychometric properties and it is, thus, a reliable and valid tool for the multidimensional assessment of children with JIA.