Cardiovascular risk in post-myocardial infarction patients: nationwide real world data demonstrate the importance of a long-term perspective

AIMS: Long-term disease progression following myocardial infarction (MI) is not well understood. We examined the risk of subsequent cardiovascular events in patients discharged after MI in Sweden. METHODS AND RESULTS: This was a retrospective, cohort study linking morbidity, mortality, and medication data from Swedish national registries. Of 108 315 patients admitted to hospital with a primary MI between 1 July 2006 and 30 June 2011 (index MI), 97 254 (89.8%) were alive 1 week after discharge and included in this study. The primary composite endpoint of risk for non-fatal MI, non-fatal stroke, or cardiovascular death was estimated for the first 365 days post-index MI and Day 366 to study completion. Risk and risk factors were assessed by Kaplan-Meier analysis and Cox proportional hazards modelling, respectively. Composite endpoint risk was 18.3% during the first 365 days post-index MI. Age [60-69 vs. <60 years: HR (95% CI): 1.37 (1.30-1.45); 70-79 vs. <60 years: 2.13 (2.03-2.24); >80 vs. <60 years: 3.96 (3.78-4.15)], prior MI [1.44 (1.40-1.49)], stroke [1.49 (1.44-1.54)], diabetes [1.37 (1.34-1.40)], heart failure [1.57 (1.53-1.62)] and no index MI revascularisation [1.88 (1.83-1.93)] were each independently associated with a higher risk of ischaemic events or death. For patients without a combined endpoint event during the first 365 days, composite endpoint risk was 20.0% in the following 36 months. CONCLUSIONS: Risk of cardiovascular events appeared high beyond the first year post-MI, indicating a need for prolonged surveillance, particularly in patients with additional risk factors.