Exploring the effect of weekend admissions to hospital on health outcomes of inpatients with acute myocardial infarction in Shanxi, China: a longitudinal study

Abstract

BackgroundPrevious studies have identified a so-called weekend effect—ie, higher mortality for inpatients admitted to hospital on a weekend than on a weekday. However, the effect for acute myocardial infarction-related admissions to hospital and other health outcomes are unclear. We therefore aimed to investigate the weekend effect on adverse outcomes in inpatients with acute myocardial infarction in China. MethodsWe did a longitudinal study of 31 tertiary hospitals in Shanxi, China. We included inpatients with acute myocardial infarction who were aged 18 years or more. These eligible participants were identified from the front pages of inpatients' medical records, and we classified them into two groups: ST-elevation myocardial infarction (STEMI) and non-ST-elevation myocardial infarction (NSTEMI). The primary measures were the associations between weekend admission and in-hospital mortality, hospital-acquired infection, and extended length of stay (defined as length of stay >75 percentile). We used multivariate logistic regression models with clustered robust variance estimator to determine these associations. FindingsBetween Sept 1, 2013, and Oct 31, 2017, a total of 42 671 inpatients with acute myocardial infarction were identified (28 731 inpatients in the STEMI group and 13 940 in the NSTEMI group), and 11 294 (26·5%) inpatients were admitted to hospitals during the weekend. The crude in-hospital mortality was 1·83% (weekend 2·20% vs weekday 1·69%; p<0·0001), hospital-acquired infection was 4·99% (weekend 5·29% vs weekday 4·88%; p<0·0001), and extended length of stay was 23·58% (weekend 26·23% vs weekday 22·63%; p<0·0001). After controlling for demographics, comorbidities, and hospital characteristics, patients admitted to hospitals on weekends were significantly more likely to have an extended length of stay for both STEMI (odds ratio [OR] 1·22, 95% CI 1·13–1·30]) and NSTEMI (1·19, 1·10–1·28) groups than those admitted to hospitals on weekdays. There were no significant differences in in-hospital mortality (STEMI group: OR 1·10 [95% CI 0·87–1·39]; NSTEMI group: 1·08 [0·84–1·41]) and hospital-acquired infection (STEMI group: 0·95 [0·79–1·15]; NSTEMI group: 0·92 [0·63–1·32]) between weekend and weekday admissions. InterpretationFor patients admitted to hospital for acute myocardial infarction, weekend admission is associated with a higher risk of extended length of stay than weekday admission, but not for in-hospital mortality and hospital-acquired infection. More efforts are needed to reduce the disparities of extended length of stay and improve patient safety and quality of care for weekend admissions. FundingNational Natural Science Foundation of China Grant (71473099).