Creation and Validation of a Simple Venous Thromboembolism Risk Scoring Tool for Thermally Injured Patients

Abstract

Venous thromboembolism (VTE) has been identified as a major patient safety issue. The authors report their use of the National Burn Repository (NBR) to create and validate a weighted risk scoring system for VTE. Adult patients with thermal injury from the NBR admitted between 1995 and 2009 were included. Independent variables were either known or could be derived at the time of admission, including TBSA burned, inhalation injury, gender, and age. The dependent variable was VTE, a composite variable of patients with deep venous thrombosis, and pulmonary embolus. The dataset was split into working and validation sets using a random number generator. Multivariable logistic regression identified independent predictors. β-coefficients for independent predictors were used to generate a weighted risk score. The NBR contained 22,618 patients who met inclusion criteria. The working and validation sets were not statistically different for demographics or risk factors. In the working set, the presence of inhalation injury and increased TBSA were independent predictors of VTE. Adjusted β-coefficients were used to generate a weighted risk score, which showed excellent discrimination for VTE in both the working (c-statistic 0.774) and the validation (c-statistic 0.750) sets. As risk score increased, a linear increase in observed VTE rate was demonstrated in both working and validation sets. The authors have created and validated a simple risk score model to predict VTE risk in thermally injured patients using the NBR. The model is based on risk factors that are easily identified during initial patient contact.