Relationship between time of day, day of week, timeliness of reperfusion, and in-hospital mortality for patients with acute ST-segment elevation myocardial infarction

Abstract

Context: Understanding how door-to-drug and door-to-balloon times vary by time of day and day of week can inform the design of interventions to improve the timeliness of reperfusion therapy. Objective: To determine the pattern of door-to-drug and door-to-balloon times by time of day and day of week and whether this pattern may affect mortality. Design, Setting, and Participants: Cohort study of 68 439 patients with ST-segment elevation myocardial infarction (STEMI) treated with fibrinolytic therapy and 33 647 treated with percutaneous coronary intervention (PCI) from 1999 through 2002. We classified patient hospital arrival period into regular hours (weekdays, 7 AM-5 PM) and off-hours (weekdays 5 PM-7 AM and weekends). Main Outcome Measures: Geometric mean door-to-drug time for fibrinolytic therapy and door-to-balloon time for PCI and all-cause in-hospital mortality. All outcomes were adjusted for patient and hospital characteristics. Results: Most fibrinolytic therapy (67.9%) and PCI patients (54.2%) were treated during off-hours. Door-to-drug times were slightly longer during off-hours (34.3 minutes) than regular hours (33.2 minutes; difference, 1.0 minute; 95% confidence interval [CI], 0.7-1.4; P