[Rationalization of risk factors for venous thromboembolism in medical inpatients. A prospective study]

In terms of preventive management of venous thromboembolism in medical inpatients, very large differences may be observed. Rationalization of behaviour requires the evaluation of simple and logical parameters, which takes into account both patient safety and economic considerations.

The aim of this study was to evaluate a preventive scheme including the rationalization of the indications and the use of low molecular weight heparin.

Epidemiologic investigation.

Patients hospitalized in five medical departments in the Hospital Center of Nantes, France.

The risk of venous thromboembolism was rated as high, intermediate and low. Patients with high or intermediate risk were eligible for prevention therapy (table I).

The main criterion was the occurrence during hospital stay of deep or superficial venous thrombosis of the lower limbs, pulmonary embolism, or unexplained sudden death. The screening was based on clinical features double-checked by venous doppler ultrasonography of the lower limbs and/or ventilation-perfusion lung scanning.

24,497 patients were eligible (table II), 15% were considered at risk and treated with Nadroparin, 6% had the same risk profile but were not treated and 14. 7% had low risk and no prevention. No bleeding event was reported. The incidence of venous thromboembolism was 0.75%, 1.7% and 0.14% respectively (p <0.01) (table III). This efficacy does not appear to depend on body weight or the existence of multiple risk factors observed (table IV and V).

This analysis of risk factors separates two populations with rates of incidence dramatically and significantly different. The prevention of venous thromboembolism by fixed dose of low molecular weight heparin remains justified since it reduces the risk of venous thromboembolism by a factor of 2.5.