Long-term mortality, cardiovascular events, and bleeding in stable patients 1 year after myocardial infarction: a Danish nationwide study

Abstract

Aims: Outcomes after myocardial infarction (MI) improved during recent decades alongside better risk factor management and implementation of guideline-recommended treatments. However, it is unknown whether this applies to stable patients who are event-free 1 year after MI.

Methods and results: Using nationwide Danish registries, we included all patients with first-time MI during 2000-17 who survived 1 year free from bleeding and cardiovascular events (n = 82 108, median age 64 years, 68.2% male). Follow-up started 1 year after MI and continued through January 2022. Crude risks of mortality, cardiovascular events, and bleeding were estimated in consecutive 3-year periods. Standardized risks were calculated with respect to the distribution of age, sex, comorbidities, and treatments in the latter period. Guideline-recommended treatment use increased during the study period: e.g. statins (68.6-92.5%) and percutaneous coronary intervention (23.9-68.2%). The crude 5-year risks of outcomes decreased (all P-trend <0.001): Mortality, 18.6% (95% confidence interval [CI]: 17.9-19.2) to 12.5% (CI: 11.9-13.1); Recurrent MI, 7.5% (CI: 7.1-8.0) to 5.5% (CI: 5.1-6.0); Bleeding, 3.9% (CI: 3.6-4.3) to 2.7% (CI: 2.4-3.0). Crude 5-year risk of mortality in 2015-17 was as low as 2.6% for patients aged <60 years. Use of guideline-recommended treatments was associated with improved outcomes: After standardization for changes in treatments, 5-year risk of mortality in 2000-02 was 15.5% (CI: 14.9-16.2).

Conclusions: For patients who were event-free 1 year after MI, the long-term risks of mortality, cardiovascular events, and bleeding decreased significantly, along with an improved use of guideline-recommended treatments between 2000 and 2017. In the most recent period, 1 year after MI, the risk of additional events was lower than previously reported.

Keywords: Guidelines; Registry; long-term risk; myocardial infarction stable; outcomes.

Structured Graphical Abstract

Overview of the study design and the main findings. MI, myocardial infarction.

Figure 1

Flowchart of the study population selection, exclusions, and follow-up. Abbreviations: MI, myocardial infarction; HF, heart failure.

Figure 2

Crude risk curves with 95% confidence intervals for mortality, recurrent myocardial infarction, hospitalization for heart failure, ischaemic stroke, and hospitalization for bleeding according to calendar period in patients with event-free survival 1 year after myocardial infarction.

Figure 3

Redemption of prescriptions for guideline-recommended pharmacological treatments according to calendar period between index MI and study inclusion (1 year after index MI). Shown are the relative frequencies for prescription redemptions categorized according to specific periods: from 0 to 12 months after index MI, from 0 to 6 months after index MI, and from 6 to 12 months after index MI. Abbreviations: MI, myocardial infarction; ADP, adenosine diphosphate; RAS, renin-angiotensin system.

Figure 4

Crude and standardized 5-year risks of (A) mortality, (B) recurrent myocardial infarction, hospitalization for heart failure, ischaemic stroke, and hospitalization for bleeding according to calendar period. Standardization was performed with the 2015–17 population as reference and is interpreted as the predicted 5-year risk had the patients in each calendar period had the same distribution of sex, age, comorbidities, and guideline-recommended treatments as the 2015–17 reference population.

Figure 5

Absolute 5-year risks of mortality, recurrent myocardial infarction, hospitalization for heart failure, ischaemic stroke, and hospitalization for bleeding stratified according to age and sex. *P-trend <0.001, ^†P-trend =0.031, ‡P-trend =0.038.