Long-Term Survival Among Patients With Myocardial Infarction Before Age 50 Compared With the General Population: A Danish Nationwide Cohort Study

Background The long-term prognosis for young myocardial infarction (MI) survivors remains poorly understood. Methods and Results We conducted a nationwide population-based cohort study using prospectively collected medical data from all hospitals in Denmark during 1980 to 2009. We examined 30-year cause-specific death rates among 21693 MI patients <50 years versus 216930 sex- and age-matched people from the general population. We calculated mortality rate ratios (MRRs) based on Cox regression. Between 1980 to 1989 and 2000 to 2009, MI mortality declined from 12.5% to 3.2% within 30 days, 5.1% to 1.6% within 31 to 365 days, and 24.2% to 8.9% within 1 to 10 years. Compared with the general population, the MRR adjusted for sex, age, and cardiovascular and noncardiovascular comorbidity decreased 4.5-fold within 30 days (from 468 to 97), 3-fold within 31 to 365 days (from 11.32 to 3.70), and 2.5-fold within 1 to 10 years (from 4.77 to 1.89). The remaining 1.89-fold increased mortality rate among 1-year survivors in 2000 to 2009 corresponded to 6 additional deaths each year per 1000 patients compared with the general population. Long-term causes of death were primarily because of cardiovascular and chronic pulmonary diseases. The excess 10-year MRR among 1-year survivors was consistent within MI subtypes, did not differ substantially between comorbidity categories, but was higher for women than men (3-fold versus 1.7-fold). Conclusions The long-term mortality rate after MI before age 50 has decreased remarkably over the last 3 decades, but remains increased relative to the general population, mainly because of deaths from ischemic heart disease and other smoking-related diseases.