Differences in rates of remission between rheumatoid factor positive and negative rheumatoid arthritis patients: experience from a resource-limited setting.

Background: Rheumatoid arthritis (RA) is an autoimmune disease of the joints with occasional involvement of extra-articular organs. Although rheumatoid factor (RF) is associated with more severe baseline disease severity and a higher incidence of extraarticular diseases, whether it predicts response to treatment in patients taking conventional disease-modifying antirheumatic drugs (DMARDs) is unclear as evidence has so far been conflicting.

Methods: A 3-year (January 2021 to December 2023) multicenter retrospective cohort study was done at 1 public and 4 private hospitals in Addis Ababa, Ethiopia. After categorizing eligible patients into RF-positive and RF-negative, they were retrospectively followed for 12 months. A disease activity score in 28 joints (DAS-28) score of less than 2.6 was used to define remission. The time-to-remission between the two groups was compared using the Kaplan-Meier survival function. In order to control for potential confounders, the Cox regression model was used to calculate adjusted hazard ratios (AHR).

Results: After screening a total of 676 patients, 207 were found to be eligible for the study. The median (interquartile range (IQR)) age at diagnosis was 46 (36 - 58) years, and 171 (82.6%) were female. At 12 months of follow-up, remission occurred in 39.4% of RF-positive patients and 60.0% of RF-negative patients (AHR, 0.57; 95% confidence interval (CI), (0.368-0.88; P = 0.012). The overall remission rate was 47.3%.

Conclusion: In this study, among patients taking conventional DMARDs, RF-negative RA patients achieved better remission rates compared to RF-positive patients. The study provides insight into the association between RF status and treatment outcome among RA patients in a resource-limited setting. Key Points • Our work adds to the existing body of knowledge regarding the relationship between RF positivity and response to treatment in patients with RA. It is also the first study to examine this association in a previously understudied population of Sub-Saharan Africa.