Trends in hospitalisation for acute myocardial infarction in Ireland, 1997-2008

Abstract

Objective: To study the temporal and gender trends in age-standardised hospitalisation rates, in-hospital mortality rates and indicators of health service use for acute myocardial infarction (AMI), and the sub-categories, ST elevation MI (STEMI) and non-ST elevation MI (NSTEMI), in Ireland, 1997-2008.

Design, setting, patients: Anonymised data from the hospital inpatient enquiry were studied for the ICD codes covering STEMI and NSTEMI in all 39 acute hospitals in Ireland over a 12-year period. Age standardisation (direct method) was used to study hospitalisation and in-hospital mortality rates. Joinpoint regression analysis was undertaken to identify significant inflection points in hospitalisation trends.

Main outcome measures: Age-standardised hospitalisation rates, in-hospital mortality and indicators of health service use (length of stay, bed days) for AMI, STEMI and NSTEMI patients.

Results: From 1997 to 2008, hospitalisation rates for AMI decreased by 27%, and by 68% for STEMI patients (test for trend p<0.001), and increased by 122% for NSTEMI, (test for trend p<0.001). The mean age of male STEMI patients decreased (p<0.01), while those for the remaining groupings of AMI and subcategories increased. The proportion of males increased significantly for STEMI and NSTEMI (p<0.001). In-hospital mortality decreased steadily (p=0.01 STEMI, p=0.02 NSTEMI), as did median length of stay.

Conclusions: The authors found a steady decrease in hospitalisation rates with AMI, and a shift away from STEMI towards rising rates of NSTEMI patients who are increasingly older. In an ageing population, and with increasing survival rates, surveillance of acute coronary syndrome and allied conditions is necessary to inform clinicians and policy makers.