Prognosis and treatment in patients admitted with acute myocardial infarction on weekends and weekdays from 1997 to 2009

Abstract

Background: Less invasive treatment and poorer outcomes have been shown among patients admitted with acute myocardial infarction (AMI) on weekends compared to weekdays.

Objectives: To investigate the 'weekend-effect' on mortality in patients with AMI.

Methods: Using nationwide registers we identified 92,164 patients aged 30-90 years who were admitted to a Danish hospital with a first AMI from 1997 to 2009. Patients were stratified according to weekday- or weekend admissions and four time-periods to investigate for temporal changes. All-cause mortality at 2, 7, 30, and 365 days was investigated using proportional hazards Cox regression.

Results: Mortality rates were higher on weekends within seven days of admission in 1997-99 (absolute difference ranging from 0.8 to 1.1%). Weekend-weekday hazard-ratios were 1.13 (1.03-1.23) at day 2 and 1.10 (1.01-1.18) at day 7. There were no significant differences in 2000-09 and estimates suggested an attenuation of the initial 'weekend-effect'. Overall, the use of coronary angiography (34.9% vs. 72.3%) and percutaneous coronary intervention (6.6% vs. 51.0%) within 30 days increased, as did the use of statins (49.9% vs. 80.1%.) and clopidogrel (26.7% vs. 72.7%). The cumulative mortality decreased during the study period from 5.4% to 2.5% at day of admission, from 19.5% to 11.0% at day 30 and from 28.0% to 19.0% at day 365 (all tests for trend p<0.0001).

Conclusions: No persistent 'weekend-effect' on mortality was present in patients with AMI in 1997-2009. Overall, mortality rates have decreased concomitantly with an increased use of current guideline-recommended invasive and medical therapy.

Keywords: CAPTIM; Comparison of primary Angioplasty and Prehospital Fibrinolysis in Acute Myocardial Infarction; Coronary intervention; DANAMI-2; Danish Trial in Acute Myocardial Infarction-2; FRISC-II; Fast Revascularisation during InStability in Coronary artery disease II; MONICA; Monitoring Trends and Determinants in Cardiovascular Disease project; Mortality; Myocardial infarction; PRAGUE 1 and 2; Primary Angioplasty Versus Fibrinolysis in Acute Myocardial Infarction 1 and 2; RITA-3; Secondary prevention; TACTICS-TIMI 18; Treat Angina with Aggrastat and determine Cost of Therapy with an Invasive or Conservative Strategy-Thrombolysis In Myocardial Infarction 18; Trends; the third Randomized Intervention Trial of unstable Angina.