BackgroundThe prognostic impact of previous depression on myocardial infarction survival remains poorly understood.AimsTo examine the association between depression and all-cause mortality following myocardial infarction.MethodUsing Danish medical registries, we conducted a nationwide population-based cohort study. We included all patients with first-time myocardial infarction (1995-2014) and identified previous depression as either a depression diagnosis or use of antidepressants. We used Cox regression to compute adjusted mortality rate ratios (aMRRs) with 95% confidence intervals.ResultsWe identified 170 771 patients with first-time myocardial infarction. Patients with myocardial infarction and a previous depression diagnosis had higher 19-year mortality risks (87% v. 78%). The overall aMRR was 1.11 (95% CI 1.07-1.15) increasing to 1.22 (95% CI 1.17-1.27) when including use of antidepressants in the depression definition.ConclusionsA history of depression was associated with a moderately increased all-cause mortality following myocardial infarction.