‘July effect’ in management and outcomes of patients admitted with pulmonary embolism in the United States, 2016 to 2021

This study sought to assess the outcomes of pulmonary embolism (PE) admissions at teaching and nonteaching hospitals in the month of July, when new trainees begin their training in the United States. During 2016-2021, adult (≥18 years) nonelective admissions with PE, admitted to urban teaching hospitals in the months of May and July, were identified using the National Inpatient Sample and compared to nonteaching admissions. Outcomes of interest included in-hospital mortality, complications, variations in management, total hospitalization costs, and hospitalization duration. From January 1, 2016, to December 31, 2021, 164,244 PE admissions were identified in May and July to teaching (76.5%) and nonteaching (23.5%) hospitals. The May and July cohorts had comparable baseline characteristics at both teaching and nonteaching hospitals. The rates of organ failure, noncardiac and cardiac organ support, cardiogenic shock, and cardiac arrest were comparable across all four cohorts. Use of systemic thrombolysis (3.8% vs 3.1%; P = 0.002) and catheter-directed therapies (4.1% vs 3.8%; P = 0.05) were higher in the teaching hospitals in July than in May, but there were no differences in nonteaching hospitals. The cohorts of teaching (3.0% vs 3.3%, P = 0.30) and nonteaching hospitals (2.7% vs 2.2%, P = 0.15) had comparable adjusted in-hospital mortality in May and July. Hospitalization duration, total hospitalization costs, and discharge disposition were comparable in all four cohorts. In this large 6-year US analysis, there were no differences in the outcomes of PE admissions to teaching and nonteaching hospitals in the months of May and July, arguing against the 'July effect.'