Rheumatoid arthritis may influence the outcome after an acute myocardial infarction. We aimed to compare trends in one-year mortality, co-morbidities and treatments after a first acute myocardial infarction in patients with rheumatoid arthritis versus non-rheumatoid arthritis patients during 1998-2013. Furthermore, we wanted to identify characteristics associated with mortality.
Data for 245,377 patients with a first acute myocardial infarction were drawn from the Swedish Register of Information and Knowledge about Swedish Heart Intensive Care Admissions for 1998-2013. In total, 4268 patients were diagnosed with rheumatoid arthritis. Kaplan-Meier analysis was used to study mortality trends over time and multivariable Cox regression analysis was used to identify variables associated with mortality. The one-year mortality in rheumatoid arthritis patients was initially lower compared to non-rheumatoid arthritis patients (14.7% versus 19.7%) but thereafter increased above that in non-rheumatoid arthritis patients (17.1% versus 13.5%). In rheumatoid arthritis patients the mean age at admission and the prevalence of atrial fibrillation increased over time. Congestive heart failure decreased more in non-rheumatoid arthritis than in rheumatoid arthritis patients. Congestive heart failure, atrial fibrillation, kidney failure, rheumatoid arthritis, prior diabetes mellitus and hypertension were associated with significantly higher one-year mortality during the study period 1998-2013.
The decrease in one-year mortality after acute myocardial infarction in non-rheumatoid arthritis patients was not applicable to rheumatoid arthritis patients. This could partly be explained by an increased age at acute myocardial infarction onset and unfavourable trends with increased atrial fibrillation and congestive heart failure in rheumatoid arthritis. Rheumatoid arthritis 