The Childhood Health Assessment Questionnaire (CHAQ) has been adapted from the Stanford Health Assessment Questionnaire for assessing functional ability in children. The present study aimed to determine the correlation between CHAQ and disease activity in juvenile idiopathic arthritis (JIA) during active and inactive disease.
JIA patients in the Pediatric Department, Ramathibodi Hospital, between January 2011 and December 2013, were included in the study. The CHAQ disability index (DI) and disease activity variables, including active and limited joint count, erythrocyte sedimentation rate, patient's global assessment (PtGA), physician's global assessment (PGA) and 27-joint Juvenile Arthritis Disease Activity Score (JADAS27), were collected from medical records for each patient over six visits. At each visit, each patient was classified as having either active or inactive disease. The correlations between CHAQ-DI and disease activity variables were analysed using Spearman's correlation.
The classification of 139 JIA patients consisted of enthesitis-related arthritis (30.9%), systemic JIA (28.1%), oligoarthritis (16.5%), rheumatoid factor (RF)-negative polyarthritis (15.1%), RF-positive polyarthritis (6.5%) and undifferentiated arthritis (2.9%). Out of 812 patient visits, 606 were in active disease and 206 were in inactive disease. RF-negative polyarthritis had the highest CHAQ-DI (0.39 ± 0.66), while oligoarthritis had the lowest (0.20 ± 0.32). There was a good correlation between CHAQ-DI and JADAS27, PGA and PtGA in all JIA subtypes (p < 0.05) during active disease, but a poor correlation between CHAQ-DI and disease activity variables during inactive disease.
CHAQ-DI had a good correlation with disease activity during active disease but a poor correlation during inactive disease. Therefore, CHAQ is only useful for assessing functional ability during active disease.