Venous Thromboembolism (VTE) Risk Scoring in Ambulatory Surgical Patients

• Activity Number: 489 - Multiplicity: Methods and Applications
• Type: Contributed
• Date/Time: Thursday, August 6, 2020 : 10:00 AM to 2:00 PM
• Sponsor: Biopharmaceutical Section
• Author(s): In-Lu Liu* and Yi-Lin Wu and Stacy J Park and Michael K. Gould
• Companies: Kaiser Permanente and Kaiser Permanente and Kaiser Permanente and Kaiser Permanente
• Keywords: risk model; risk score; multiple logistic regression analysis; Hosmer and Lemeshow Goodness-of-Fit

Abstract

This study aimed to develop a risk score for VTE in patients undergoing ambulatory surgery. We conducted a retrospective, observational study of patients who underwent 50,835 common ambulatory procedures between 2016-2017 within a large, integrated healthcare system. We identified potential patient- and procedure-specific VTE risk factors based on clinical judgment. During the 90-day post-surgical period, we observed 151 VTE cases (0.3%). Using multiple logistic regression analysis, we identified eight major risk factors: prior VTE, cancer, immobility, thrombophilia, hypoalbuminemia, general anesthesia and operation duration >90 minutes. A score was generated for each risk factor based on the size of its estimates relative to the smallest exponentiated parameter estimate. Individual risk factor scores were summed to generate a cumulative score which was then used to classify patients at very low, low, medium, or high VTE risk. The risk scoring system demonstrated fair to good accuracy to predict VTE outcomes (C = 0.73) with good model fit (Hosmer-Lemeshow test, P = .999). The model provides a simple method to assess VTE risks in ambulatory surgical patients.