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.