Early Prophylactic-Dose Thromboprophylaxis and 30-Day Mortality in Solid Tumor Patients Hospitalized for COVID-19: A Multicenter Retrospective Cohort Study.

ObjectivePatients with solid tumors are at increased risk of venous thromboembolism (VTE), and COVID-19 infection may further enhance thrombotic risk. Although prophylactic-dose thromboprophylaxis is recommended for hospitalized patients with COVID-19 when bleeding risk is acceptable, its clinical impact among patients with solid tumors remains uncertain.MethodsWe conducted a multicenter retrospective cohort study across three tertiary hospitals in China from December 2022 to January 2023. Adult patients with solid tumors hospitalized for laboratory-confirmed COVID-19 were included. Patients receiving prophylactic-dose thromboprophylaxis within 24 hours of admission were classified as the early cohort, whereas those initiating prophylaxis after 24 hours or receiving no prophylaxis were classified as the non-early cohort. The primary outcome was 30-day mortality. Secondary outcomes included thrombotic events, bleeding events, and 60-day mortality. Multivariable Cox regression, inverse probability of treatment weighting (IPTW) analyses, multiple imputation, and sensitivity analyses were performed.ResultsAmong 431 patients, 86 were classified into the early cohort and 345 into the non-early cohort. Early prophylactic-dose thromboprophylaxis was not significantly associated with 30-day mortality (adjusted HR=1.468, 95% CI 0.840-2.567, P=0.173) or 60-day mortality (adjusted HR=1.386, 95% CI 0.798-2.408, P=0.241). IPTW-adjusted analyses and sensitivity analyses yielded consistent results. No significant associations were observed between early thromboprophylaxis and thrombotic or bleeding events.ConclusionsIn this multicenter cohort of patients with solid tumors hospitalized for COVID-19, early prophylactic-dose thromboprophylaxis was not clearly associated with improved 30-day or 60-day mortality. Further prospective studies are needed to identify patients who may benefit from optimized thromboprophylaxis strategies.