The evidence that pharmacological thromboprophylaxis can reduce the rate of venous thromboembolism by 60-65% is compelling.1 2 3 Last month the United Kingdom's National Institute for Health and Clinical Excellence (NICE) published guidelines on venous thromboembolism in patients having surgical procedures,4 which are summarised in this week's BMJ.5 The risks to surgical patients, particularly those undergoing orthopaedic procedures, are well known, but most people who develop venous thromboembolism in hospital are medical patients.

The prevention of venous thromboembolism in adult patients in hospital was the main challenge to patient safety in 2001, according to a technical assessment by the Agency for Healthcare Research and Quality in the United States.6 In 2005, the UK government's Health Select Committee reported that venous thromboembolism caused more than 25 000 potentially preventable deaths a year, and probably half of these deaths resulted from admission to hospital.7

Despite all …