Rheumatoid arthritis and risk of myocardial infarction: A nationwide cohort study

AIMS: We investigated the risk of MI by RA status and seropositivity and performed exploratory analysis of biologic DMARD (bDMARD) and targeted synthetic DMARD (tsDMARD) use. METHODS AND RESULTS: This retrospective cohort study used the Korean National Health Insurance System database. Patients aged ≥ 40 years newly diagnosed with RA (n = 36,377) were matched 1:3 with non-RA controls (n = 109,131). Fine and Gray subdistribution hazard models estimated subdistribution hazard ratios (sHR) for MI risk by RA status, seropositivity, bDMARD, and tsDMARD use. During a mean follow-up of 5.6 ± 2.3 years, 1201 MI events in non-RA, 738 in RA, 186 in seronegative RA (SNRA), 552 in seropositive RA (SPRA), 64 with bDMARD use, and 4 with tsDMARD use were identified. Patients with RA had a 1.8-fold increased MI risk compared to non-RA (sHR: 1.84, 95% CI: 1.67-2.01). SNRA and SPRA showed similar risks (sHR: 1.74, 95% CI: 1.49-2.04, and sHR: 1.87, 95% CI: 1.69-2.07, respectively). MI risk remained elevated both with and without bDMARD use (sHR: 2.34, 95% CI: 2.05-2.67; sHR: 1.81, 95% CI: 1.72-1.91, respectively). Non-use of tsDMARDs was associated with increased MI risk (sHR: 1.86, 95% CI: 1.77-1.96), whereas tsDMARD use was not significantly associated with MI (sHR: 1.43, 95% CI: 0.90-2.28). CONCLUSIONS: RA was associated with increased MI risk irrespective of seropositivity status. Exploratory analyses suggested that tsDMARD users did not exhibit increased MI risk, although the small number of events warrants large-scale prospective studies.