24 Absence of a weekend effect on 30 day mortality among 3757 patients with acute myocardial infarction

ObjectivesSeveral publications have demonstrated increased 30 day mortality in patients admitted on Saturdays or Sundays compared with weekdays. We sought to determine whether this was true for two different cohorts of patients admitted with acute myocardial infarction (MI).Methods and resultsThirty-day mortality data were obtained for 3757 patients who had been admitted to the Belfast HSC Trust with acute myocardial infarction between 2009 and 2015. They were subdivided into those presenting with ST elevation MI (STEMI, n = 2240) and non-ST elevation MI (NSTEMI, n = 1517). Day of admission was evenly spread across the week among all patients and among those who died within 30 days (Figure 1). Overall, 30 day mortality was 5.32% (6.25% among patients with STEMI and 3.96% in patients with NSTEMI). We observed no difference in 30 day mortality between those admitted at weekends and those admitted on weekdays (Table 1). The Cox Proportional Hazards model constructed hazard ratios for 30 day mortality associated with each day of admission compared with Wednesday. Following adjustment for covariates (age, gender and type of infarction), there was no significant excess hazard for any day of the week compared with Wednesday (Table 2).Abstract 24 Figure 1Abstract 24 Table 130 day mortality among 3757 patients admitted with acute myocardial infarction, by day of admission and type of myocardial infarctionAdmitted Mon–Fri(30-day mortality)Admitted Sat–Sun(30-day mortality)Chi2 P value STEMI (n = 2240)101/1591 (6.35%)39/649 (6.00%)0.0680.423NSTEMI (n = 1517)46/1131 (4.10%)14/386 (3.63%)0.1470.417Abstract 24 Table 2Cox proportional hazard ratios (95% confidence intervals) comparing 30 day mortality hazard associated with each day of admission compared with Wednesday, among 3757 patients admitted with acute myocardial infarction (MI), following adjustment for type of infarction, age and gender30 day mortality Patients with MI (n = 3757)Sun vs WedMon vs WedTues vs WedThurs vs WedFri vs WedSat vs Wed 0.997 (0.722, 1.375)1.001 (0.735, 1.362)0.856 (0.616, 1.188)0.880 (0.634, 1.220)0.962 (0.701, 1.319)0.883 (0.640, 1.139)ConclusionsWe observed no evidence of an excess 30 day mortality associated with weekend admission. The data suggest that not all patients admitted as emergencies at weekends are exposed to excess mortality risk. Further work is needed to repeat this analysis on a larger, national cohort.