Risk factors for inpatient venous thromboembolism despite thromboprophylaxis

Introduction Venous thromboembolism (VTE) is the most common preventable cause of morbidity and mortality in the hospital. Adequate thromboprophylaxis has reduced the rate of hospital-acquired VTE substantially; however, some inpatients still develop VTE even when they are prescribed thromboprophylaxis. Predictors associated with thromboprophylaxis failure are unclear. In this study, we aimed to identify risk factors for inpatient VTE despite thromboprophylaxis. Materials and methods We conducted a case-control study to identify independent predictors for inpatient VTE. Among patients discharged from the BJC HealthCare system between January 2010 and May 2011, we matched 94 cases who developed in-hospital VTE while taking thromboprophylaxis to 272 controls who did not develop VTE. Matching was done by hospital, patient age, month and year of discharge. We used multivariate conditional logistic regression to develop a VTE prediction model. Results We identified five independent risk factors for in-hospital VTE despite thromboprophylaxis: hospitalization for cranial surgery, intensive care unit admission, admission leukocyte count > 13,000/mm³, presence of an indwelling central venous catheter, and admission from a long-term care facility. Conclusions We identified five risk factors associated with the development of VTE despite thromboprophylaxis in the hospital setting. By recognizing these high-risk patients, clinicians can prescribe aggressive VTE prophylaxis judiciously and remain vigilant for signs or symptoms of VTE.