Ong MS, Ringold S, Kimura Y, et al. - Through analyzing data on patients with polyarticular juvenile idiopathic arthritis (JIA) partaking in the Start Time Optimization of Biologics in Polyarticular JIA (STOP-JIA) study (n = 400) and a comparator cohort (n = 248) from the Childhood Arthritis and Rheumatology Research Alliance Registry, the authors discovered that starting biologic disease-modifying antirheumatic drugs (bDMARDs) within 3 months of baseline assessment is linked to more rapid achievement of inactive disease in patients with untreated polyarticular JIA. Such findings highlight the value of illness trajectory analysis as a strategy for measuring therapy efficacy.

• Within 3 months of baseline evaluation, 198 participants (49.5%) got bDMARDs in the STOP-JIA study.

• Latent class trajectory modeling analysis identified 3 latent classes representing 3 distinct illness trajectories, each with a slow, moderate, or rapid improvement in disease activity over time.

• Participants on the rapid improvement trajectory achieved inactive disease within 6 months of starting the study.

• After adjusting for demographic characteristics, clinical attributes, and baseline disease activity, the odds of being in the rapid improvement trajectory vs the slow improvement trajectory were 3.6 times higher for those treated with bDMARDs ≤ 3 months from baseline compared with individuals who started bDMARDs > 3 months after baseline.

• Shorter disease duration at the first rheumatology visit approached statistical significance as a predictor of a favourable trajectory in the absence of bDMARD treatment.