Impact of time of admission on short- and long-term mortality in the Vienna STEMI registry

Abstract

Background: Several studies have shown contradictive findings regarding mortality and hospital admission time in patients presenting with ST-elevation myocardial infarction (STEMI). The aim of this study was to assess the impact of "on-" or "off-hour" admission on short- and long-term all-cause mortality of patients in the advanced Vienna STEMI network between 2003 and 2009.

Methods and results: In total, 2829 patients were included into this analysis. Patients were stratified according to admission time into "on-hour" admission (07:30 until 15:00h on weekdays) and "off-hour" admission (15:00-7:30h on weekdays and 24h on weekends). As endpoint of interest, all-cause mortality was investigated after 30days and 3years of follow-up, the latter for all patients and as Landmark analysis for survivors of the index event. Mean age was 60.5±13.3years, 2048 (72.4%) patients were male and 1260 (44.5%) patients presented with anterior wall infarction. 683 (24.1%) patients were admitted "on-hours", 2146 (75.9%) patients were admitted "off-hours". All-cause death occurred in 176 (6.2%) patients after a follow-up of 30days and in 337 (11.9%) patients after 3years. For short- and long-term all-cause mortality no significant differences could be detected between "on-" and "off-hour" admission in univariate and multivariate Cox proportional hazard analyses as well as for propensity score adjusted outcome analysis.

Conclusion: In the Vienna STEMI network, "on-" or "off-hour" admission had no impact on short- and long-term mortality for all-comers presenting with acute STEMI. Our findings confirm the imperative need for well-structured STEMI networks of care, as previous data repeatedly demonstrated increased adverse cardiovascular outcome for "off-hour" admission.

Keywords: Admission time; Mortality; ST-elevation myocardial infarction; STEMI network.