Multicenter Hospital Drug Utilization Study on the Prophylaxis of Venous Thromboembolism

1 Thromboembolic disease (TED) is an important cause of in-hospital morbidity and mortality. Although different prophylactic approaches have been shown to be effective and cost-effective, surveys have suggested that they are underused. The aim of this study was to estimate the prevalence of use of TED prophylaxis in our hospitals.2 All patients admitted on a specified day to the Internal Medicine and General Surgery wards of seven Spanish university hospitals were included in the study. They were identified cross-sectionally and followed up until discharge or for 15 days. Information about the following variables was collected: risk factors for venous thromboembolism, prophylactic measures used (if any), contraindications to the use of each specific drug or other prophylactic measure, and dosage schedule of the drug used, if any.3 Nine hundred and thirty-nine patients (53% men) were studied. The most common risk factors for venous thromboembolism were: age greater than or equal to 40 years (802; 85%), major surgery (298; 32%), immobilization greater than or equal to 6 days (285; 30%), obesity (241; 26%), and cancer (202; 22%).4 Prophylactic measures were used in 320 patients (34%). Of these, 297 (93%) received heparin, mainly as low molecular weight heparins (248, 78%); physical measures were rarely used.5 Five hundred and eighty-three patients (62%) fulfilled criteria for moderate or high risk of venous thromboembolism; only 275 (47%) of them received any form of prophylaxis.6 In a multivariate analysis the following variables were associated with the use of prophylaxis: hospital centre (adjusted odds ratios, 1.7 to 23.3, compared with reference hospital), history of venous thrombosis, major surgery, congestive heart failure, inflammatory bowel disease, age, immobilization, dehydration, and obesity.7 Contraindications to the use of anticoagulant or antiplatelet drugs were present in 234 patients (25%), but no relationship to the use of heparin was found. Of the patients treated with heparin who underwent major surgery, only 55 (36%) had received a preoperative dose.8 Although prophylaxis of TED was associated with certain risk factors, it was highly underused in moderate and high risk patients. Wide interhospital variability in the use of prophylaxis was recorded; this variability persisted after adjusting for differences in the prevalence of risk factors and for the presence of contraindications in each centre. Low molecular weight heparins are replacing conventional unfractionated heparin for this indication.