Epidemiology of recurrent myocardial infarction in the reperfusion era

Abstract Introduction During the past decades, the incidence, management, and outcomes of myocardial infarction (MI) have improved considerably.(1-4) However, the characteristics and outcomes of patients who experience a recurrent MI are sparsely described. Purpose This study aimed to analyse the epidemiology and temporal trends of recurrent MI during the reperfusion era. Methods A nationwide registry-based cohort study was conducted, including all hospital admissions for recurrent MI in Denmark during 2000 to 2020. Descriptive statistics were used to analyse changes in patient characteristics and management. Survival analyses, taking competing risks into account when relevant, and multivariable Cox proportional hazards models adjusted for sex, age, comorbidities, and pre-recurrent MI pharmaceutical treatment were used to analyse the outcomes of interest: all-cause mortality, hospitalisation for heart failure (HHF), and additional recurrent MI. Results A total of n=55,722 admissions for recurrent MI between 2000 and 2020 were included. Median age at admission was 73 years, 68.0% were male, and 32.9% were patients with a 3rd or more recurrent MI. Between 2000-02 (n=9,490) and 2018-20 (n=5,520), patients admitted with a recurrent MI had an increased prevalence of comorbidities such as diabetes, chronic kidney disease, and cancer (Condensed Table 1). Likewise, the use of guideline directed management at the time of recurrent MI increased during the study period: percutaneous coronary intervention (PCI) from 12.8% to 47.2%, coronary angiography (CAG) from 21.8% to 68.0%, statins from 30.5% to 74.2%, and adenosine diphosphate (ADP) receptor inhibitors from 8.2% to 41.8%. Statistically significant linear calendar time trends were observed for all three outcomes (Figure 1). Between 2000-02 and 2018-20 (Figure 2), the absolute 1-year risk of mortality declined from 31.6% to 16.0% (adjusted hazard ratio [aHR]: 0.46 [95% CI: 0.43-0.50]). The absolute 1-year risk of an additional recurrent MI declined from 13.9% to 6.2% (aHR: 0.38 [0.34-0.43]). The absolute 1-year risk of HHF increased from 8.8% in 2000-02 to 10.5% in 2009-11 (aHR: 1.09 [0.99-1.21]), before declining to 7.4% in the final calendar year period (aHR: 0.75 [0.66-0.84]). Interpretation and conclusion Despite remarkable advances in the management and outcomes of patients experiencing recurrent MI during the reperfusion era, this remains a vulnerable, high-risk population. Special attention is warranted regarding the optimization of guideline directed care and prevention of heart failure following a recurrent MI.Figure 1Figure 2 & Condensed Table 1