L-Shaped Association of 24-Hour Urine Output with 3-Month and 1-Year All-Cause Mortality in Patients with Acute Pulmonary Embolism: A Retrospective Cohort Study.

Aim: To explore the prognostic value of the first 24-h urine output (UO) after admission in patients with acute pulmonary embolism (APE) in the intensive-care unit (ICU) for short- and long-term all-cause mortality risk.

Methods: This retrospective cohort study used the MIMIC-IV database. Patients with APE were divided into 4 teams (T1-T4) by their first 24-h UO after admission: T1 (UO ≤ 400 ml), T2 (400＜UO ≤ 800 ml ), T3 (800＜UO ≤ 2500 ml), and T4 (UO＞2500 ml). The primary endpoints were the three-month and one-year all-cause mortality rates. The relationship between UO and mortality was assessed using Kaplan-Meier survival curves and Cox proportional hazards models.

Results: This study included 2012 patients with APE, of whom 50.75% were female. Compared to the T3 group, patients in the T1 and T2 groups had higher all-cause mortality rates. Kaplan-Meier survival curves showed that patients in the T1 and T2 groups had a higher risk of death, while those in the T4 group seemed to have a lower risk of death (P＜0.001). The results remained stable in all three adjusted models and subgroup analyses. A restricted cubic spline analysis (RCS) revealed that the risk of all-cause mortality gradually decreased with an increase in UO, showing an "L"-shaped relationship. A UO of ＜1283 ml increased the risk of death in patients. Subgroup analysis indicated that the first 24-h UO was associated with 3-month and 1-year all-cause mortality rates in most subgroups of patients.

Conclusions: The first 24-h UO after admission is an important indicator for the prognosis of APE patients. A lower 24-h UO is strongly related to a higher risk of short-term and long-term all-cause mortality in ICU patients with APE.