A retrospective review of the use of thromboprophylaxis in patients who subsequently developed a venous thromboembolism after discharge from hospital.

Thromboprophylaxis is highly effective, safe and cost-effective. However, data from international studies have shown that many at-risk hospitalised patients do not receive appropriate prophylaxis, leaving them at risk of venous thromboembolism (VTE) and its consequences. To assess whether patients readmitted with a VTE to the North Shore Hospital, Auckland, received appropriate thromboprophylaxis during their index admission. Discharge coding was used to identify all patients admitted for VTE-related events between 1 July 2005 to 30 June 2007. Further analysis identified those patients hospitalised for any cause in the 3 months prior to the VTE event. Data were collected on patient characteristics, risk factors for VTE and the thromboprophylaxis regimen prescribed. The seventh American College of Chest Physicians (ACCP) guidelines on the prevention of venous thromboembolism were used to assess VTE risk and to determine whether patients received appropriate prophylaxis. Of the 962 patients admitted with a VTE event, 243 (25%) had been hospitalised within the preceding 3 months. 108 patients were eligible for inclusion in the study; 58 were categorized as medical admissions and 50 as surgical. Using the ACCP-defined criteria, 29 (50%) medical and 38 (76%) surgical patients were identified as being at increased risk of VTE. Only one third of at-risk patients received ACCP-recommended prophylaxis during their index hospital admission. More surgical patients received recommended prophylaxis than medical patients, although this was not statistically significant (37% vs 24%, p=0.3, Fisher's exact test). A significant number of at-risk patients, who subsequently developed VTE after discharge from hospital, failed to receive appropriate thromboprophylaxis during their index admission. Implementing national and local strategies, to improve the use of thromboprophylaxis in hospitalised patients, may help to reduce the burden of VTE.