Resident University of Maryland, Baltimore VA Medical Center Baltimore, Maryland, United States
Objective: Venous thromboembolism (VTE) is a preventable complication of hospitalization. VTE risk-assessment models (RAMs) including the Caprini and Padua RAMs quantify VTE risk based on demographic and clinical characteristics. Both RAMs have performed well in selected high-risk cohorts with relatively small sample sizes but few studies have evaluated the RAMs in large, unselected cohorts. We assessed the ability of both RAMs to predict VTE in a large, nationwide, diverse cohort of surgical and nonsurgical patients.
Methods: We analyzed consecutive first hospital admissions of 1,252,460 unique patients to 1,283 VA facilities nationwide between January-2016 and December-2021. Caprini and Padua scores were calculated using data from VINCI (VA Informatics and Computing Infrastructure), the electronic medical record repository of the entire VA system.We first assessed the ability of the two RAMs to predict VTE within 30, 60 and 90-days after admission. We then compared the predictive ability of the two RAMs in surgical and nonsurgical patients by comparing the areas under their respective receiver operating characteristic (ROC) curves (AUC).
Results: 1,252,460 hospitalized patients were analyzed; 26.6% (n=333,286) where surgical patients and 73.4% (n= 948,728) were nonsurgical. Caprini scores ranged from 0-28 (median: 4, IQR: 3-6); Padua scores ranged from 0-13 (1, 1-3); higher scores were associated with higher VTE rates.35,557 patients developed VTE within 90 days of admission (2.88%, Table 1). The ability of both RAMs to predict VTE within 90 days of admission was low (AUC 0.56 and 0.59 respectively). The predictive ability of both RAMs was similar within 30, 60 and 90 days of admission. Both RAMs performed marginally better in non-surgical compared to surgical patients (Caprini AUCs: 0.59 vs 0.54, p=0.001; Padua AUCs: 0.60 vs 0.56, p=0.001, Figure 1).
Conclusions: In the largest validation study performed to date, increasing Caprini and Padua RAM scores are associated with increasing VTE rates. Both RAMs have low ability to predict VTE at 30, 60 or 90 days after admission in an unselected population of surgical and non-surgical patients. Both RAMs are marginally better at predicting VTE risk in non-surgical populations. Studies are needed to improve the predictive ability of existing VTE RAMs before they can be applied to the general hospital population.