Methotrexate (MTX) has been associated with reduced risk for cardiovascular disease (CVD) events among patients with rheumatoid arthritis (RA) not exposed to biologic disease-modifying antirheumatic drugs (bDMARDs). The effect of concomitant MTX on CVD risk among RA patients initiating bDMARDs remains unknown.
A retrospective cohort study was conducted to assess the effect of MTX on CVD risk using 2006-2015 Medicare claims data for patients with RA initiating bDMARD. The main exposure was current use of MTX, updated in a time-varying fashion. The primary outcome was a composite of incident myocardial infarction (MI), stroke, and fatal CVD. Secondary outcomes were each event that comprised the primary outcome. Incidence rates (IR) and 95% CI were calculated using Poisson regression. Associations between MTX and risk of CVD were assessed using Cox regression.
A total of 88,255 bDMARD initiations and 1861 CVD events were included in this study. Mean age was 64.6 (12.3) years, 84.0% were female, and 68.2% were non-Hispanic White. The crude IRs (95% CI) for CVD were 17.9 (16.9-18.8) and 12.1 (11.1-13.2) per 1000 patient-years among MTX unexposed and exposed, respectively. The multivariable adjusted HR (95% CI) for CVD events associated with MTX was 0.76 (0.68-0.85). Multivariable adjusted HRs were 0.78 (0.66-0.91), 0.74 (0.62-0.88), 0.77 (0.68-0.86), and 0.82 (0.73-0.93) for MI, stroke, MI or stroke, and a composite CVD outcome, respectively. Results were robust in sensitivity and subgroup analyses.
Among patients with RA receiving biologics, concomitant MTX use was associated with a 24% lower risk for CVD events.