Utilization of rheumatoid arthritis medications (Q14-01)

Guidelines for treatment of rheumatoid arthritis (RA) recommend the use of conventional synthetic DMARDs (csDMARD) as concomitant therapy with biologic disease modifying antirheumatic drugs (bDMARD) after failure of csDMARD treatment alone. Concomitant csDMARD therapy is thought to decrease the risk of discontinuation of bDMARDs, however the literature is inconsistent.

Incretin-based drugs are popular therapies for the treatment of type 2 diabetes.

CNODES undertook a retrospective cohort study using administrative health databases with 20,221 new users of bDMARDs from 5 Canadian provinces (Alberta, Manitoba, Ontario, Quebec and Sakstachewan) as well as the US IBM® MarketScan® Databases (MScan) between Jan 1, 2007 and March 30, 2014. Exposure to concomitant csDMARD was compared to non-csDMARD exposure. The outcomes were discontinuation of bDMARD therapy, switching of bDMARDs, and percentage change in dose of bDMARD compared to the initial dose. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated and pooled across sites using meta-analysis. The change in dosage was analyzed using linear regression.

Approximately 76% of the patients were women. Concomitant use of csDMARD therapy was not significantly associated with a reduced discontinuation of bDMARD treatment (HR 0.90; 95% CI: 0.79 to 1.02). Furthermore it was not significantly associated with a reduced switching of bDMARDs (HR 0.95; 95% CI: 0.80 to 1.11).

There was no clear evidence that RA patients on bDMARDs were less likely to discontinue or switch bDMARDs if they received concomitant csDMARD therapy.

• This large, international, multi-centre retrospective cohort study provides key data regarding the impact of the concomitant use of csDMARD in rheumatoid arthritis patients using bDMARDs.
• These data can assist in informing physicians prescribing these medications along with other evidence and patient preferences, while bearing in mind the important limitations of the administrative claims data used in our analysis.