Impact of csDMARDs adherence on clinical remission in patients with new-onset inflammatory arthritis: a prospective cohort study from the ELECTRA database

BACKGROUND: Major improvements in the management of rheumatoid arthritis (RA) have made clinical remission an achievable and desirable goal but, despite the relevance gained by a profound disease suppression, many patients with RA still miss clinical remission due to several factors influencing disease activity, including treatment adherence. OBJECTIVE: To evaluate the effect of adherence to conventional synthetic disease-modifying anti-rheumatic drugs (csDMARDs) on the achievement of clinical remission in a cohort of patients with new-onset inflammatory arthritis. STUDY DESIGN: A prospective cohort study was conducted using the ELECTRA database, which consists of clinical data from patients followed at the IRCCS Policlinico San Matteo Foundation (Pavia, Italy), linked to regional administrative healthcare databases. METHODS: We enrolled patients with new-onset active disease between January 2006 and December 2013 and followed them until their first clinical remission or end of follow-up (December 2015). To assess the association of csDMARD adherence with clinical remission, we estimated the csDMARD proportion of days covered (PDC) during follow-up. PDC was added to the main clinical adjustment covariates as a time-dependent variable in a proportional hazard Cox regression model. RESULTS: The cohort included 324 patients with a mean (SD) age of 58 (13.9) and predominantly female (74.5%). A total of 219 patients (67.6%) achieved clinical remission during follow-up and 85 (26.2%) in the first 6 months (early clinical remission). Cox regression models showed that a 10% increment of PDC increased the probability of achieving clinical remission by 10% (p < 0.001) and the probability of early clinical remission by 21% (p = 0.03). CONCLUSION: Patients at disease onset with higher adherence to csDMARDs were more likely to achieve clinical remission and early clinical remission. Our study highlighted the importance of close monitoring of patients to increase their likelihood of following therapeutic indications and achieving favorable disease outcomes, such as lower disability.