Two-thirds of NHS patients at risk of blood clots do not get preventative treatments, a study suggests.
Some hospital patients are at higher risk of clots
Researchers looked at 1,062 patients at two English teaching hospitals and found only a third of eligible patients got any treatment - despite guidelines.
They warn in the Journal of the Royal Society of Medicine that there must be greater awareness of the risks and preventative treatments made available.
DVT contributes to around 10% of deaths among hospital patients each year.
DVTs occur in the leg veins. These clots can break off and lodge in the small vessels in the lung.
If this occurs the condition is called a pulmonary embolism, which is fatal in about a third of cases without treatment.
DVTs are a common manifestation of venous thromboembolism (VTE).
VTE can be caused by surgery. But it is also the most preventable cause of mortality in medical patients staying in hospital.
Experts in the field advise that, to prevent clots occurring, patients can either be given heparin, a blood-thinning treatment, or surgical stockings.
The researchers looked at medical inpatients in two major English teaching hospitals.
They assessed 862 patients of which 89% were found to have moderate and high risk of developing VTE.
Of these, 71% did not receive any form of prophylaxis.
Of the 29% who did, expert guidelines about what kind of preventative treatment patients should receive were implemented correctly in only 4% of moderate and high-risk patients.
The researchers then made presentations to doctors from the medical specialties at the hospitals to improve their understanding of the experts' recommendations.
Six months later, the researchers went back to the hospitals to see what had changed.
They evaluated the care of 200 patients, and found the use of preventative, or prophylactic, treatments had increased very slightly, to 31%. However, all those patients were now receiving the right treatment.
The Commons Health Committee raised concerns over clot prevention for NHS patients in March of this year.
The government then announced its drugs and treatments watchdog, the National Institute for Health and Clinical Excellence, was drawing up official guidance on the issue, due out in 2007.
But lead researcher Dr Abdul Shlebak of St Mary's Hospital, London - one of the hospitals which took part in the study - told the BBC News website that was too far away.
"There is a huge amount of information around about the subject now. 2007 is too long to wait for official guidance."
"Clinicians and policymakers need to act on these findings if we are to reduce the incidence of VTE and prevent fatalities in hospitals."
The researchers are calling for measures including a DVT "tick sheet" attached to drug charts to be compiled for all patients on admission and greater understanding of DVT in medical and nursing education
They also want dedicated teams charged with the task of raising awareness and auditing the use of preventative treatments to be established.
Dr David Keeling, who advised the Commons Health Committee on behalf of the Royal College of Physicians, said: "The expert guidelines were published last year, and are very comprehensive.
"The information is out there."
He said that, in addition to the NICE guidance, a specialist committee of the British Society of Haematology was also drawing up guidelines, which should be available within months.
A spokesman for the Department of Health said: "We take this issue very seriously. Patients are already getting a good variety of treatments for VTE but we recognise that more needs to be done.
"There is a great deal of knowledge about how to prevent and treat VTE.
"The challenge is to ensure that the NHS is aware of and implements this good practice."