Joint damage progression in patients with rheumatoid arthritis in clinical remission: do biologics perform better than synthetic antirheumatic drugs?

Abstract

Randomized controlled studies have demonstrated protective advantages of biologic therapies over the synthetic disease-modifying antirheumatic drugs (DMARD) in slowing joint damage progression in patients with rheumatoid arthritis (RA). This effect appears to be largely independent of the clinical disease control. We measured the rate of radiographic progression in patients with RA in clinical remission treated with synthetic versus biologic DMARD. This is an observational cohort study of patients with RA in clinical remission, nested within the Swiss Clinical Quality Management in Rheumatoid Arthritis (SCQM-RA) Registry. The primary study outcome was the rate of radiographic progression (Ratingen erosion score), and a secondary outcome was functional disability [Health Assessment Questionnaire-Disability Index (HAQ-DI)] progression. We compared the rate of progression between synthetic and biologic DMARD using a multivariate regression model for longitudinal data, adjusting for potential confounders. A total of 2055 patients in the SCQM-RA registry were in remission at least once from 1999 to 2012 and met the study inclusion criteria. Baseline characteristics of patients in remission receiving synthetic and biologic DMARD were not significantly different in terms of prognostic factors for joint damage progression. During followup, erosion progression differed significantly between the 2 groups [1.4% (95% CI: 1.1-1.6) vs 0.9% (95% CI: 0.5-1.2) of progression over 3 years, respectively, p < 0.001], with less damage progression in patients treated with biologic DMARD than with synthetic DMARD. This difference remained significant after adjusting for confounding factors. The evolution of the HAQ-DI score was also statistically better in the biologic group (p < 0.001). This observational study confirms that the rate of structural damage progression in clinical remission is decreased taking biologics compared to synthetic DMARD. However, while the difference is statistically significant it is probably not relevant from a clinical perspective.