Factors affecting the efficacy of intraarticular corticosteroid injection of knees in juvenile idiopathic arthritis

Objective. To determine in a prospective analysis whether baseline demographic, clinical, and laboratory variables predict the outcome of intraarticular corticosteroid (IAC) injection of the knees in children with juvenile idiopathic arthritis (JIA). Methods. We studied consecutive patients who met the criteria for the diagnosis of JIA and received their initial injection of triamcinolone hexacetonide in one or both knees. Predictor variables included sex, age, age at onset of JIA, onset subtype, disease duration, drug therapy at the time of IAC injection, physician and parent global assessment of disease status, Childhood Health Assessment Questionnaire disability index, erythrocyte sedimentation rate (ESR), C-reactive protein, involvement of other joints besides knees, amount of fluid aspirated, and dose of IAC injected. The primary outcome measure was persistence of complete clinical response at 6 months, i.e., no evidence of synovitis clinically. Results. Ninety-four patients were available for analysis. At 6 months after the IAC injection, 65 (69%) patients showed a sustained complete clinical response, whereas 29 (31%) had had a recurrence of joint inflammation. Univariate statistical analyses showed that patients who had a sustained clinical response had a significantly higher ESR than those who did not (p = 0.023). The ESR was the only variable that remained in the best-fit model from multivariate logistic regression analysis (OR 2.61, p = 0.049). Conclusion. Our findings indicate that patients with JIA who have a higher ESR are more likely to benefit from IAC injection of the knees.