Trends and Outcomes of Interhospital Transfer for High-Risk Acute Pulmonary Embolism: A Nationwide Analysis

Background: Data on outcomes of patients with high-risk acute pulmonary embolism (PE) transferred from other hospitals are scarce. Methods: We queried the Nationwide Readmissions Database for admissions who were ≥18 years old, and with a primary discharge diagnosis of acute high-risk PE between the years 2016 and 2019. The main outcome of interest was the difference in all-cause in-hospital mortality between patients admitted directly to small/medium hospitals; patients admitted directly to large hospitals; and patients transferred to large hospitals. Results: Among 11,341 weighted hospitalizations with high-risk PE, 631 (5.6%) patients were transferred to large hospitals. There was no significant change in the rates of transfer during the study period. Transferred patients were younger and had a higher prevalence of comorbidities. They were more likely to present with saddle PE and cor pulmonale and were more likely to receive advanced therapies. In-hospital mortality was not different between patients transferred to large hospitals and those admitted directly to large hospitals (adjusted odd ratio [OR] 1.11, 95% confidence interval [CI] 0.81, 1.54) as well as between patients transferred to large hospitals and those admitted directly to small/medium hospitals (aOR 1.28, 95% CI 0.92, 1.76). The rates of major bleeding and cardiac arrest were higher among transferred patients. Admissions for transferred patients were associated with higher cost and longer length of stay. Conclusion: Transferred patients with high-risk PE were more likely to receive advanced therapies. There was no difference in-hospital mortality rates compared with patients admitted directly to the large or small/medium hospitals.