Children with Enthesitis Have Worse Quality of Life, Function, and Pain, Irrespective of Their Juvenile Arthritis Category

OBJECTIVE:To estimate the impact of enthesitis on patient-reported outcomes in children with juvenile idiopathic arthritis (JIA), irrespective of JIA category. METHODS:Children enrolled in the Research in Arthritis in Canadian Children Emphasizing Outcomes cohort were studied. Entheseal tenderness by physician examination in 33 defined locations, Juvenile Arthritis Quality of Life Questionnaire (JAQQ), Quality of My Life (QoML) Questionnaire, Childhood Health Assessment Questionnaire (C-HAQ), and a pain visual analog scale were completed at enrollment, every 6 months for 2 years, and then yearly up to 5 years. Analyses consisted of descriptive statistics, linear mixed models for longitudinal data, and analysis of covariance. RESULTS:Among 1,371 patients followed for a median of 35.3 months (interquartile range 22.1, 49.2), 214 (16%) had enthesitis, of whom 137 (64%) were classified as having enthesitis-related arthritis. After adjusting for JIA category and covariates, children with enthesitis reported higher JAQQ (mean raw score 2.71 versus 2.16, adjusted difference 0.41 points; 95% confidence interval [95% CI] 0.22, 0.59), higher C-HAQ (0.47 versus 0.31, adjusted difference 0.14 points; 95% CI 0.07, 0.22), higher pain (3.01 versus 1.68, adjusted difference 0.94 points; 95% CI 0.64, 1.25), and lower QoML (7.02 versus 8.23, adjusted difference -0.80 points; 95% CI -1.09, -0.51) scores than children without enthesitis. These differences persisted up to 5 years. CONCLUSION:Children with enthesitis, regardless of JIA category, report worse patient-reported outcomes than those without enthesitis. Thus, enthesitis should be assessed in all children with JIA.