Long-term prognosis after a first myocardial infarction: eight years follow up of the case-control study PAROKRANK.

Abstract

Objective. To explore long-term cardiovascular outcomes and mortality in patients after a first myocardial infarction (MI) compared with matched controls in a contemporary setting. Methods. During 2010-2014 the Swedish study PAROKRANK recruited 805 patients <75 years with a first MI and 805 age-, gender-, and area-matched controls. All study participants were followed until 31 December 2018, through linkage with the National Patient Registry and the Cause of Death Registry. The primary endpoint was the first of a composite of all-cause death, non-fatal MI, non-fatal stroke, and heart failure hospitalization. Event rates in cases and controls were calculated using a Cox regression model, subsequently adjusted for baseline smoking, education level, and marital status. Kaplan-Meier curves were computed and compared by log-rank test. Results. A total of 804 patients and 800 controls (mean age 62 years; women 19%) were followed for a mean of 6.2 (0.2-8.5) years. The total number of primary events was 211. Patients had a higher event rate than controls (log-rank test p < .0001). Adjusted hazard ratio (HR) for the primary outcome was 2.04 (95% CI 1.52-2.73). Mortality did not differ between patients (n = 38; 4.7%) and controls (n = 35; 4.4%). A total of 82.5% patients and 91.3% controls were event-free during the follow up. Conclusions. In this long-term follow up of a contemporary, case-control study, the risk for cardiovascular events was higher in patients with a previous first MI compared with their matched controls, while mortality did not differ. The access to high quality of care and cardiac rehabilitation might partly explain the low rates of adverse outcomes.