[Long-term survival of patients with acute myocardial infarction in Iceland]

Abstract

Introduction: Despite the decreasing incidence rate of acute coronary syndromes worldwide, the incidence of NSTEMI (Non- ST elevation myocardial infarction) has increased relative to STEMI (ST elevation myocardial infarction). The aim of this study was to compare long-term survival rates of NSTEMI and STEMI patients and to explore the effects of risk factors on survival.

Material and methods: All patients hospitaized for acute myocardial infarction at Landspitali University Hospital during the calendar year of 2006 were included in the study. Information about risk factors was obtained using electronic medical records. The primary endpoint was all cause mortality, the secondary endpoint was defined as death or myocardial infartion. Patients were followed up to January 1st 2015.

Results: Among 447 patients diagnosed with acute myocardial infarction in Iceland in 2006, 280 patients were diagnosed with NSTEMI (I21.4) and 167 with STEMI (I21, I21.9). NSTEMI and STEMI incidence rates per 100.000 inhabitants in Iceland were 91.3 and 55.9, respectively. The mean age of NSTEMI patients was 73.0 years, women were on average 8.4 years older than men. The mean age of STEMI patients was 65.3 years, women were on average 7.3 years older than men. The five-year survival rate for NSTEMI patients was 51%, 42% among women and 57% among men. The five-year survival rate for STEMI patients was 77%, 68% among women and 80% among men. Five year age-adjusted survival rates were higher for STEMI than NSTEMI (logrank: p <0.01).

Conclusion: The incidence of NSTEMI was higher than that of STEMI in Iceland in 2006. The worse prognosis of women as compared to men was due to the higher mean age of women. Overall, long-term survival of NSTEMI patients was worse than that of STEMI patients even after adjustment for difference in age.

Keywords: Non ST elevation myocardial infarction; ST elevation myocardial infarction; acute myocardial infarction; long term survival; prognosis.