Mortality among high risk patients with acute myocardial infarction admitted to U.S. teaching-intensive hospitals in July: A retrospective observational study

Abstract BACKGROUND: Studies of whether inpatient mortality in US teaching hospitals rises in July as a result of organizational disruption and relative inexperience of new physicians (July effect) find small and mixed results, perhaps because study populations primarily include low-risk inpatients whosemortality outcomes are unlikely to exhibit a July effect. METHODS AND RESULTS: Using the US Nationwide Inpatient sample, we estimated difference-in-difference models of mortality, percutaneous coronary intervention rates, and bleeding complication rates, for high- and low-risk patients with acute myocardial infarction admitted to 98 teaching-intensive and 1353 non-teaching-intensive hospitals during May and July 2002 to 2008. Amongpatients in the top quartile of predicted acute myocardial infarction mortality (high risk), adjustedmortality was lower in May than July in teaching-intensive hospitals (18.8% in May, 22.7% in July, P