Use of calcium channel blockers and myocardial infarction in hypertensive patients with rheumatoid arthritis - A nationwide cohort study.

Background/purpose: Rheumatoid arthritis (RA) should be regarded as a high risk factor for myocardial infarction (MI). In addition to anti-hypertensive effect, calcium channel blockers (CCBs) were frequently used as anti-angina drugs in patients with MI. However, the association between CCBs and MI in RA remains unclear. We investigated whether CCBs could decrease incidence of myocardial infarction in patients with hypertension and RA.

Methods: We identified patients from the Registry for Catastrophic Illness, a nation-wide database encompassing almost all of the RA patients in Taiwan from 1995 to 2008. The primary endpoint was MI and the median duration of follow up was 3,050 days. Propensity score matching and Cox proportional hazards regression models were used to estimate hazard ratios for MI.

Results: Among 27,844 patients with hypertension, 17,317 (61.5%) subjects received CCBs (mean age = 58.8 years, 72.1% female). The incidence of MI significantly decreased in patients treated with CCBs (hazard ratio [HR] 0.560; 95% confidence interval [CI] 0.494-0.634). After propensity match, subjects receiving CCBs had significantly lower risk of MI (HR 0.637, 95% CI 0.549-0.740). The protective effect of CCBs therapy was significantly better in patients taking longer duration. Of note, the effect remained robust in subgroup analyses, including dihydropyridine CCBs (HR 0.550; 95% CI 0.466-0.650) and non-dihydropyridine CCBs (HR 0.674, 95% CI 0.588-0.773).

Conclusion: Therapy of CCBs is associated with a lower risk of MI among hypertensive patients with RA. Hence, the prescription of CCBs may be a compelling indication of BP lowering in RA population.