Influence of Seasons on the Management and Outcomes of Pulmonary Embolism

There are limited data on seasonal variations and outcomes in pulmonary embolism (PE).

To understand the seasonal variations in PE outcomes.

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.

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.

In this study, there was no significant seasonal variation in in-hospital mortality from PE.