Influence of Seasons on the Management and Outcomes of Pulmonary Embolism

BACKGROUND: There are limited data on seasonal variations and outcomes in pulmonary embolism (PE). AIMS: To understand the seasonal variations in PE outcomes. METHODS: All adult (³18 years) non-elective admissions with a primary diagnosis of PE were identified using the National Inpatient Sample (2016-2022) and assessed by the season of admission-spring (March-May), summer (June-August), fall (September-November), and winter (December-February). The primary outcome was in-hospital mortality across the seasons. Secondary outcomes included total hospitalization costs, hospital length of stay, and discharge disposition. RESULTS: During the 7-year period, 1,278,754 PE admissions were identified. Spring, summer, fall, and winter had 24.1%, 25.0%, 25.3%, and 25.6% admissions, respectively (p < 0.001). The baseline and in-hospital characteristics were comparable across cohorts with no significant clinical differences noted. Mechanical thrombectomy rates were highest in fall (spring 2.5%, summer 3.0%, fall 3.5%, winter 2.7%, p < 0.001), whereas systemic thrombolysis (spring 2.9%, summer 3.0%, fall 2.9%, winter 3.1%, p = 0.04) was highest in the summer. Use of other therapies were comparable. There was no statistical difference in adjusted in-hospital mortality rates among seasons. There were slight variations in hospitalization costs, length of stay, and discharge dispositions across the four cohorts but were not clinically relevant. CONCLUSION: In this study, there was no significant seasonal variation in in-hospital mortality from PE.