Active cancer as a risk factor for inappropriate VTE prophylaxis: Data from a single center study

Abstract Introduction: Hospitalized patients with cancer represent a high-risk group for venous thromboembolism (VTE) due to a hypercoagulable state, tumor-related vascular effects, and treatment-associated risks. Risk stratification in these patients is often challenging due to the presence of multiple comorbidities. This study aims to evaluate history of malignancy as a risk factor for inappropriate VTE prophylaxis in hospitalized patients. Methods: We conducted a retrospective review of electronic health records for all adult patients admitted to the inpatient medicine service between November and December 2023. Patients with active cancer—defined as malignancy under treatment or diagnosed within the prior six months—were identified for subgroup analysis. Collected variables included demographics, admission diagnoses, cancer history, and VTE risk factors. VTE risk was assessed using the Padua Prediction Score. Prophylaxis was deemed inappropriate if administered with a Padua score <4 without other indications, or in the presence of major contraindications. Descriptive statistics were used to compare prophylaxis patterns between patients with and without cancer. Results: Out of 1,574 hospitalized patients, 181 (11.5%) had active cancer. The median age of this subgroup was 76 years, with 53.0% male and 47.0% female. The most common admission diagnosis among cancer patients was urinary tract infection. The mean Padua score for this subgroup was 4.56, and the average length of hospital stay was 6.3 days. Of the 181 cancer patients, 139 (76.8%) received pharmacologic VTE prophylaxis. 41 patients (22.7%) received prophylaxis that was retrospectively deemed inappropriate based on criteria, often due to low cumulative risk, presence of contraindications, or misclassification of risk level. Conclusion: Patients with active cancer had a higher rate of inappropriate prophylaxis (22.7%) compared to the overall cohort (15.6%), suggesting that active cancer may independently contribute to overuse despite no formal indication. This pattern suggests a potential bias in clinical decision-making and highlights the importance of standardized risk stratification. Larger, multicenter studies are needed to develop risk assessment tools for patients with active malignancy.