People with inflammatory bowel disease (IBD) are at far greater risk of developing life-threatening blood clots than previously thought, a British study has shown.
IBD has been known to predispose sufferers to blood clots (thromboembolism) for some time. Clots in the leg veins have a mortality rate of six per cent, rising to as much as 20 per cent if the embolism is in the lungs.
Previous research has suggested that most patients who develop thromboembolism do so when their IBD is 'active', i.e. has flared up and they are three times more likely to have a blood clot than non-sufferers.
This has led to the use of anti-clotting drugs as standard care for patients with active IBD who are admitted to hospital.
The new research at University of Nottingham was conducted to determine what the blood-clotting risk is to patients with IBD who manage their flare-ups outside the hospital environment, with medical care from primary care sources like their GP.
For the study, the researchers used the UK General Practice Research Database from November 1987 to July 2001 to compare patients with IBD with controls without the disease.
They concluded that non-hospitalised sufferers with active IBD were 16 times more likely to develop a blood clot than the general population.
"Inflammatory bowel disease was associated with a roughly three-fold increase in the risk of venous thromboembolism. Compared with the general population while ambulatory, the risk of venous thromboembolism was increased about 16-fold for non-hospitalised patients with active inflammatory bowel disease," Dr Matthew Grainge, Lecturer in the University's Department of Community Health Sciences said.
"Despite the low absolute risks during non-hospitalised periods, these results suggest that active inflammatory bowel disease in ambulatory patients might be a far greater risk factor for venous thromboembolism than previously recognised," he added.
The study has been published in the Lancet.