Risk of early recurrence and mortality in high-risk myocardial infarction patients: A population-based linked data study

Abstract

BackgroundSurvival during the early period following myocardial infarction (MI) has significantly improved although there are limited data on cardiovascular recurrence during this period. MethodsWe identified all emergency hospitalisations for MI from November 1, 2011 to October 31, 2016 in Western Australia from a linked hospitalisation/mortality dataset. Patients were included if they survived >3 days, had no acute kidney injury, and had ≥1 of: ≥65 years, prior MI, diabetes or peripheral arterial disease. Outcomes were major adverse cardiovascular events (MACE, a composite of CVD death, recurrent MI or stroke), cardiovascular disease (CVD) death, all-cause mortality, recurrent MI and stroke. Cumulative risks at 90-days and 1-year were estimated from Kaplan-Meier analyses and predictors of each outcome from multivariable Cox regression models. ResultsThere were 8024 high-risk MI patients identified (males 61.8%). Median age was 73.7 years (IQR 66.3–82.2). Half of the risk of MACE occurred in the first 90-days post-MI (6.6% vs 12.6% at 1-year) and was underpinned by risk of recurrent MI. Risk was generally higher in women than men (MACE: 6.0% males, 7.7% females, p = 0.0025; CVD mortality: 1.7% males, 3.7% females; all-cause mortality: 2.8% males, 5.6% females, p < 0.0001). Independent predictors of 90-day MACE were increasing age, heart failure history, hypertension and prior stroke. Female sex was not associated with a higher rate of any of the outcomes after multivariable adjustment. ConclusionHalf of cardiovascular events in the year following an MI occur within 90-days, demonstrating that reductions in MI burden could be achieved by further targeted intervention in the early period following an MI.