Time to Occurrence Based on Risk Stratification of Hospital-Acquired Venous Thromboembolism: A Retrospective Observational Cohort Study.

Background: In-hospital venous thromboembolism (VTE) causes significant morbidity and mortality in hospitalized patients. The objective of our study is to determine the time to in-hospital VTE based on baseline risk stratification. Methods: All adult patients admitted to a 900-bed academic tertiary referral hospital who developed a VTE during hospital admission from September 1, 2011, to June 30, 2015, were retrospectively analyzed. Patients were excluded if they were younger than 18 years or if the VTE was present on admission. Results: The cohort included 400 patients, 224 (56%) males, median age 66 years. The median time to VTE was 8 days. Significant differences in time to VTE existed between the risk groups. Conclusion: Time to VTE in a broad hospitalized patient population differs based on admission risk group. This finding highlights the importance of performing risk assessment upon admission and subsequently with clinical changes to assess increases in risk scores.