Treatments and in-hospital mortality in acute myocardial infarction patients with rheumatoid arthritis: a nationwide retrospective cohort study in Japan

No previous study has examined the differences in treatments and outcomes after acute myocardial infarction (AMI) between patients with and without rheumatoid arthritis (RA) in a setting where coronary reperfusion therapy was readily available. This study aimed to examine whether coexisting RA affected likelihood of receiving coronary reperfusion therapy and in-hospital mortality among AMI patients in a Japanese nationwide setting where coronary reperfusion therapy was readily available. Using the Diagnosis Procedure Combination database, we retrospectively identified patients admitted with AMI between 2010 and 2014 and created a matched-pair cohort of patients with and without RA based on age, sex, hospital, and admission year at a maximum ratio of 1:5. We performed multivariable logistic regression analyses for associations of RA with likelihood of coronary reperfusion therapy and 30-day in-hospital mortality. There were no significant differences between the RA group (n = 938) and non-RA group (n = 3839) in the proportions of patients receiving coronary reperfusion therapy (on the day of admission 75.8% vs. 77.2%, P = 0.364; during hospitalization 87.1% vs. 87.3%, P = 0.913) and 30-day in-hospital mortality (5.9% vs. 5.9%, P = 1.000). Multivariable logistic regression analyses showed that RA was not significantly associated with either likelihood of receiving coronary reperfusion therapy during hospitalization (odds ratio 1.02; 95% confidence interval 0.82-1.27; P = 0.837) or 30-day in-hospital mortality (odds ratio 1.16; 95% confidence interval 0.81-1.65; P = 0.419). Coexisting RA did not affect likelihood of receiving coronary reperfusion therapy or in-hospital mortality among AMI patients in a setting where reperfusion therapy was readily available.