Association of age and gender with risk for non-ST-elevation myocardial infarction

Abstract

Background: Age and gender associated risks for non-ST-elevation myocardial infarction (NSTEMI) at the population level are largely uncharacterized. Design: Nationwide, population (26,724,165 person-years) based eight-year registry-study in Finland. Methods: Gender- and age-associated frequency and incidence of NSTEMI were studied using a nationwide, population based registry of hospital admissions in patients aged ≥30 years during 2001-2008. Patients with NSTEMI as primary (88%), secondary (10%) or tertiary (2%) discharge diagnosis were included. Data was collected nationwide from all 22 hospitals with a coronary angiolaboratory. Results: The study period included 48,584 NSTEMI admissions of which 55.3% (95% confidence interval (CI) 54.6-56.0%) were of men and 44.7% (CI 44.1-45.3%) were of women, with age-adjusted relative risk of 1.86 (CI 1.60-2.16, p<0.0001) for male gender. Female patients were significantly older than males (77.8 SD 10.2 vs. 70.2 SD 11.9 years, p<0.0001). Standardized incidence rate of NSTEMI was 20.6 (CI 20.4-20.8)/10,000 person-years overall, 28.7 (CI 28.3-29.0)/10,000 in men and 15.0 (CI 14.7-15.2)/10,000 in women. Men had a 2.36-fold (CI 2.23-2.49; p<0.0001) age-adjusted relative risk for NSTEMI compared with women, with highest risk difference in population under 40 years of age (relative risk 4.48; CI 3.10-6.48, p<0.0001). Incidence increased with age by an estimated genderadjusted increase rate of 61% (CI 59-62%; p<0.0001) per five-year increase in age. Conclusions: Men have a 2.4-fold overall risk for NSTEMI compared with women, with highest relative risk in young adults. Incidence rate of non-ST-elevation myocardial infarction increases by an estimated 61% per five-year increase in age.