RESUMO

INTRODUCTION: Available evidence to identify factors independently associated with failed thromboprophylaxis (FT) in medical patients is insufficient. The present study seeks to evaluate in hospitalized patients, which clinical factors are associated with the development of FT. MATERIALS AND METHODS: A case-control study nested to a historical cohort, comparing patients who developed failed thromboprophylaxis (cases) with those who did not (controls). Univariate and multivariate regression analysis was performed to define the factors associated with FT. RESULTS: We selected 204 cases and 408 controls (52.4% men, median age 63 years). Medical patients were 78.4%. The most frequent thromboprophylaxis scheme was enoxaparin. In the failed thromboprophylaxis group, most of the embolic events corresponded to pulmonary embolism (53.4%). Among cases, BMI was higher (26.3 vs. 25 kg/m2, p < 0.001), as was the proportion of patients with leukocytosis > 13,000 (27% vs. 18.9%, p:0.22), and patients who required intensive care management (48% vs. 24.8%, p < 0.001). Factors independently associated with FT were BMI (OR1.04;95%CI 1.00-1.09, p:0.39), active cancer (OR:1.63;95%IC 1.03-2.57, p:0.04), leukocytosis (OR:1.64;95%CI 1.05-2.57, p:0.03) and ICU requirement (OR:3.67;95%CI 2.31-5.83, p < 0.001). CONCLUSION: Our study suggests that the failed thromboprophylaxis is associated with high BMI, active cancer, leukocytosis, and ICU requirement. Future studies should evaluate whether there is benefit in adjusting the thromboprophylaxis scheme in patients with one or more of these factors.