Prevalence of renal failure and use of antithrombotic prophylaxis among medical inpatients at increased risk of venous thromboembolic events.

Background: Evidence-based guidelines recommend the use of antithrombotic prophylaxis in medical patients at risk of venous thromboembolism (VTE). Low molecular weight heparins (LMWHs) are usually preferred to unfractionated heparin. However, when prophylactic doses of LMWH are administered, patients with renal failure (RF) are exposed to the risk of excessive accumulation, and thus to an increased risk of bleeding. We aimed to assess the prevalence of RF among medical inpatients at increased risk of VTE and the use and dosage of antithrombotic prophylaxis in these patients.

Methods: In a cross sectional study carried out at three different hospitals, information on all medical inpatients was collected. Patients were defined at increased risk of VTE according to the American College of Chest Physicians guidelines. Data on the proportion of patients with renal RF, on the use and dosage of antithrombotic prophylaxis, and on the presence of contraindications to antithrombotic therapy were ascertained.

Results: 439 hospital charts were examined; 158 patients (36.0%) were defined at increased risk of VTE and had no contraindications to antithrombotic treatment. Thromboprophylaxis was prescribed to 61.4% of these patients. Eighty (50.7%) of them also had moderate or severe RF. There was no difference in the rate of prescription nor in the doses of antithrombotic prophylaxis between patients with and without RF (p=0.81 and p=0.94, respectively).

Conclusions: RF is frequently present in medical patients at risk of VTE. A considerable proportion of these patients may not receive the optimal type or dose of antithrombotic prophylaxis.