Joint inflammation tends to recur in the same joints during the rheumatoid arthritis disease course

Objectives We investigated whether local joint swelling recurs in the same joints over time in patients with rheumatoid arthritis (RA) who are treated to target. Methods Patients with newly diagnosed RA participating in the Behandel-Strategieen, treatment strategies (BeSt) study (n=508) were followed for median 10 years while receiving Disease Activity Score (DAS) <= 2.4 steered treatment. Every 3 months 68 joints were assessed for the presence of swelling. We evaluated whether baseline local joint swelling was predictive for swelling in the same joint during follow-up using a multilevel mixed-effect logistic regression model. Different strategies were used to account for missing data. A permutation test was performed to assess if joint swelling was better predicted by baseline swelling of the joint itself than by baseline swelling of randomly selected other joints. Results In 46% of the joints that were swollen at baseline, joint swelling later recurred at least once during follow-up. Joint swelling at baseline was statistically significantly associated with swelling in the same joint during follow-up (OR 2.37, 95% CI 2.30 to 2.43, p<0.001), and also specifically with recurrent swelling in the same joint (OR 1.73, 95% CI 1.37 to 1.59, p<0.001). Local joint swelling was better predicted by baseline swelling of that particular joint than by baseline swelling of other joints (p<0.001). Conclusion Joint swelling tends to recur locally in the joints swollen at RA onset. This suggests that local factors influence the manifestation of joint inflammation over time.

Automated summary

In patients with rheumatoid arthritis, baseline joint swelling was significantly associated with swelling in the same joint during follow-up, and it was found to better predict local joint swelling compared to baseline swelling in other joints. This suggests that local factors play a role in the recurrence of joint swelling over time.