Background Rheumatoid arthritis (RA) patients have increased mortality due to cardiovascular disease (CVD). Case fatality after an acute myocardial infarction (AMI) has been reported to be increased. Whether the prognosis after AMI has changed over time in RA is unknown.
Objectives To study the one-year mortality after a first AMI in RA versus non-RA patients during the time period 1998–2013. To identify time trends in mortality, co-morbidities and secondary preventive treatments and to explore any characteristics associated with mortality.
Methods We identified all patients with a first time AMI in the Swedish Register of Information and Knowledge about Swedish Heart Intensive Care Admissions (RIKS-HIA) between 1998–2013. We used the National Patient Register (NPR) to identify AMI patients with RA (RA defined as ≥2 visits to a Rheumatology or Internal Medicine department with a diagnosis of RA). In total 245376 AMI patients were identified, 4268 of them had RA. To study trends over time, the study period was divided into five consecutive time periods. Multivariate Cox regression analysis was used to identify variables associated with mortality.
Results The one-year mortality in RA patients was stable and lower compared to non-RA patients during the first time periods but thereafter increased above the non-RA patients. In non-RA patients, mortality decreased over time and stabilised during the last time period (Figure). In RA patients the mean age at admission increased from 69 to 73 years, whilst in non-RA patients it was unchanged, 71 years. Atrial fibrillation (AF) was initially more common in non-RA patients but the prevalence decreased over time (from 19.2% to 17.5%). In RA patients, AF increased over time from 15.6% to 21.4%. The prevalence of congestive heart failure (CHF) during hospitalisation decreased markedly more in non-RA (from 41.5% to 22.7%) than in RA patients (from 36.0% to 29.2%). The most important secondary preventive treatments were similar in RA and non-RA patients. In a multivariate Cox model including data from the last time period, 2011–2013, age, CHF during hospitalisation, ST-elevation AMI (STEMI), AF, prior diabetes mellitus, a diagnosis of RA and oral anticoagulation were significantly associated with higher one-year mortality (Table).
Conclusions The marked decrease in one-year mortality after AMI seen over time in non-RA patients was not applicable in RA patients. Our finding might to some extent be explained by an increased age at AMI onset and unfavourable trends for AF and CHF in RA. However, RA per se was significantly associated with a worse prognosis during the last years of the study period. Secondary preventive treatment was similar in RA and non-RA patients. Further analyses including RA treatments are necessary to gain further insight into reasons behind the discrepant prognosis in RA vs. non-RA patients.
Disclosure of Interest None declared