Assessing one-year risk of heart failure following first time myocardial infarction and subsequent five-year mortality risk: a nationwide study of 34,401 patients

Abstract Introduction A comprehensive understanding of the post-myocardial infarction (MI) trajectory leading to heart failure (HF) and its profound impact on long-term mortality is imperative for effective secondary prevention and risk assessment. Methods We conducted a registry-based nationwide cohort study of all Danish patients with a first MI during 2014 to 2020. Excluding patients with prior HF, individuals were followed for one year post-MI, assessing HF incidence through hospital admissions and visits to elective HF ambulatory clinics. Among those who survived one year, long-term mortality 1-6 years post-index MI was assessed using landmark analysis and Cox proportional hazards models adjusting for age, gender and comorbidities and hazard. Patients were categorized into three groups: not HF, referred for elective HF outpatient follow-up, and acute admission for HF. Results Among 34,301 individuals with a first MI and surviving the first year (median age 67.5, and 66.9 % male), 3.3 % were admitted acute for HF while 11.2 % had an elective HF outpatient follow-up within one year of the MI event (see Figure 1a). We observed a significant association between acute HF admissions post-MI and increased five-year mortality risk (hazard ratio [HR] 1.63, 95% confidence interval [CI] 1.40-1.90, p-value <0.001, see Figure 1b) (absolute 5-year risk: 18.4 %). In contrast, the five-year mortality risk for patients with elective outpatient HF follow-up was comparable to that of individuals without HF (HR 1.06 [0.94-1.19], p-value 0.34) (absolute 5-year risk: 9.6 vs 8.5 %). Conclusion Our findings suggest that acute admission for HF after a first time MI occur in 3.3 % of the patients with a subsequent significantly increased mortality risk compared to patients that do not develop clinical HF. Admission for HF in patients with a first time MI should be considered as a relatively rare but fatal complication.