- OBJECTIVES: We evaluated the quality of randomized clinical trials (RCTs) of therapy for juvenile idiopathic arthritis (JIA) using an individual component approach and assessed temporal changes. METHODS: A systematic review of the literature was performed to identify all RCTs involving exclusively JIA patients. Two investigators independently assessed the identified articles for six quality indicators: generation of allocation sequence, allocation concealment, masking, intention-to-treat (ITT) analysis, dropout rates and clearly stated primary outcome. RESULTS: Fifty-two RCTs involving JIA patients were assessed. Generation of allocation sequence was unclear in 79% of the studies. Reporting of allocation concealment was adequate in only one-third of the studies. Masking was adequate in 73%, inadequate in 19% and unclear in 8% of the reports. ITT analysis was employed in 37% of the reports. Per-protocol analysis was used in 40% and in 23% the method was unclear. Most of the reports (67%) had dropout rates < or = 20%. About half of the reports (n = 25) failed to show a significant effect of the experimental treatment. No significant associations were found between the study results and quality indicators. With the exception of adequate masking and dropout rate, all quality indicators showed a trend of improvement over the decades. CONCLUSIONS: The quality of RCTs in JIA based on the selected indicators was poor. Although there were some positive changes over time, the reporting and methodological quality of trials should be improved. New, more powerful and acceptable RCT designs should be developed in this patient population.