Introduction

The aim of the present study was to cross-culturally adapt and validate the Chilean Spanish 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 well-being, functional status, health related quality of life (HRQoL), pain, morning stiffness, disease activity/status/course, articular and extra-articular involvement, drug-related 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 Chilean Spanish 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] enrolled from November 2011 to October 2013. 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. 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 3 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. 2.

    Rating of the intensity of the patient’s pain on a 21-numbered circle visual analogue scale (VAS) [11].

  3. 3.

    Assessment of the presence of joint pain or swelling (present/absent for each joint).

  4. 4.

    Assessment of morning stiffness (present/absent).

  5. 5.

    Assessment of extra-articular symptoms (fever and rash) (present/absent).

  6. 6.

    Rating of the level of disease activity on a 21-circle VAS.

  7. 7.

    Rating of disease status at the time of the visit (categorical scale).

  8. 8.

    Rating of disease course from previous visit (categorical scale).

  9. 9.

    Checklist of the medications the patient is taking (list of choices).

  10. 10.

    Checklist of side effects of medications.

  11. 11.

    Report of difficulties with medication administration (list of items).

  12. 12.

    Report of school/university/work problems caused by the disease (list of items).

  13. 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. A separate score for PhH and PsH (range 0–15) can be calculated [12,13,14].

  14. 14.

    Rating of the patient’s overall well-being on a 21-numbered circle VAS.

  15. 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); and construct validity in its two components: the convergent or external validity which examines the correlation of the JAMAR sub-scales 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 Chilean Spanish parent and patient versions of the JAMAR are available upon request to PRINTO.

Results

Cross-cultural adaptation

The Chilean Spanish JAMAR was fully cross-culturally adapted from the standard English version with 2 forward and 2 backward translations with a concordance for 118/123 (95.9%) translations lines for the parent version and 113/120 (94.2%) lines for the child version. Of the 123 lines in the parent version of the JAMAR, 117 (95.12%) were understood by at least 80% of the 10 parents tested (median 100%; range 60–100%). In the patient version of the JAMAR, 103/120 (85.8%) lines were understood by at least 80% of the children (median 100%; range 50–100%). Lines 64, 65, 68, 69, 88, and 114 of the parent version of the JAMAR and lines 4, 5, 10, 50, 55, 62–70, 94, 107, 111 of the child version were modified according to parent patients suggestions.

Demographic and clinical characteristics of the subjects

A total of 49 JIA patients were enrolled at the paediatric rheumatology centre of the Hospital Dr. Exequiel Gonzalez Cortes in Santiago. At the study unit, it was possible to enroll only 70 healthy children as a control cohort.

In the 49 JIA subjects, the JIA categories were 12.2% with systemic arthritis, 24.5% with oligoarthritis, 22.5% with RF negative polyarthritis, 2.0% with RF positive polyarthritis, 8.2% with enthesitis related arthritis and 30.6% with undifferentiated arthritis (Table 1). Notably, none of the enrolled JIA patients is affected with psoriatic arthritis.

Table 1 Descriptive statistics (medians, 1st and 3rd quartiles or absolute frequencies and %) for the 49 JIA patients
Full size table

All the 119 subjects had the parent version of the JAMAR completed by a parent (49 from parents of JIA patients and 70 from parents of healthy children). The JAMAR was completed by 102/119 (85.7%) mothers and 17/119 (14.3%) fathers. The child version of the JAMAR was completed by all the 70 children aged 7.0 or older.

Discriminant validity

The JAMAR results are presented in Table 1, including the scores [median (1st–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 of findings, unless otherwise specified.

Table 2 Main psychometric characteristics between the parent and child version of the JAMAR
Full size table

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 HRQoL. All response choices were used for the different HRQoL items, whereas a reduced number of response choices was used for PF items 11 and 13.

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% (0–0%) for the PF and 1% (0–1%) for the HRQoL items.

Floor and ceiling effect

The median floor effect was 44.9% (38.8–67.3%) for the PF items, 22.4% (22.4–28.6%) for the HRQoL PhH items, and 22.4% (18.4–26.5%) for the HRQoL PsH items. The median ceiling effect was 10.2% (6.1–14.3%) for the PF items, 16.3% (16.3–20.4%) for the HRQoL PhH items, and 14.3% (14.3–14.3%) for the HRQoL PsH items. The median floor effect was 24.5% for the pain VAS, 30.6% for the disease activity VAS and 16.3% for the well-being VAS. The median ceiling effect was 0% for the pain VAS, 0% for the disease activity VAS and 4.1% for the well-being VAS.

Equal items–scale correlations (second Likert assumption)

Pearson items–scale correlations corrected for overlap were roughly equivalent for items within a scale for 93% of the PF items, with the exception of PF item 15, and for 100% of the HRQoL items, with the exception of HRQoL items 1 and 5.

Items internal consistency (third Likert assumption)

Pearson items–scale correlations were ≥ 0.4 for 100% of items of the PF and 100% of items of the HRQoL.

Cronbach’s alpha internal consistency

Cronbach’s alpha was 0.96 for PF-LL, 0.97 for PF-HW, 0.89 for PF-US. Cronbach’s alpha was 0.96 for HRQoL-PhH and 0.90 for HRQoL-PsH.

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 for all the items (except for PF item 13).

Test–retest reliability

Reliability was assessed in 10 JIA patients, by re-administering both versions (parent and child) of the JAMAR after a median of 7 days (7–8 days). The intraclass correlation coefficients (ICC) for the PF total score showed a substantial reproducibility (ICC 0.68). The ICC for the HRQoL PhH showed an almost perfect reproducibility (ICC 0.85) while the ICC for the HRQoL PsH showed a substantial reproducibility (ICC 0.78).

Convergent validity

The Spearman correlation of the PF total score with the JIA core set of outcome variables ranged from 0.7 to 0.9 (median 0.8). The PF total score best correlation was observed with the parent assessment of pain (r = 0.9, p < 0.001). For the HRQoL, the median correlation of the PhH with the JIA core set of outcome variables ranged from 0.6 to 0.9 (median 0.7), whereas for the PsH ranged from 0.5 to 0.7 (median 0.6). The PhH showed the best correlation with the parent’s assessment of disease activity (r = 0.9, p < 0.001) and the PsH with the parent global assessment of well-being (r = 0.8, p < 0.001). The median correlations between the pain VAS, the well-being VAS, and the disease activity VAS and the physician-centred and laboratory measures were 0.8 (0.6–0.8), 0.7 (0.6–0.8), 0.7 (0.6–0.8), respectively.

Discussion

In this study, the Chilean Spanish version of the JAMAR was cross-culturally adapted from the original standard English version with two forward and two backward translations. According to the results of the validation analysis, the Chilean Spanish 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 and the overall internal consistency was excellent for all the domains.

In the external validity evaluation, the Spearman’s correlations of the PF and HRQoL scores with JIA core set parameters ranged were 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 Chilean Spanish 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.