HOLLYWOOD, FLA. – The relative risk of thromboembolic events is greater in inpatient inflammatory bowel disease patients than in the general population, but prophylactic treatment is still not standard, according to a speaker at a conference on inflammatory bowel diseases.
"It’s a relatively rare problem, only about 1 to 1.5 percent," said Dr. Athos Bousvaros, of Boston Children’s Hospital. "So, why worry about it so much? Because it really is a major source of morbidity in the IBD population. It usually happens in the sick patients, the ones at risk for strokes; and it usually happens at the worst time, when you’re thinking about colectomy."
However, Dr. Bousvaros said only about a third of IBD patients at risk for a thromboembolic event are given prophylactic treatment in the inpatient setting, especially in severe colitis, and it is generally recommended.
Although pharmacologic prophylaxis is included in the American College of Gastroenterology guidelines, Dr. Bousvaros cited a recent study that found only 35% of gastroenterologists in the United States actually do so (J. Clin. Gastroenterol. 2013;47:e1-e6).
"In the inpatient setting, especially in severe colitis, [prophylaxis] is generally recommended," Dr. Bousvaros said. "It is included in the AGA [American Gastroenterological Association] physician performance measure set." In the outpatient setting, data do not support it, he said.
Relative risk high
While the absolute risk is low, the relative risk of a venous thromboembolic event is six times greater in IBD, particularly in patients aged 20 years or less, said Dr. Bousvaros, citing a cohort study that used Danish administrative data (Gut 2011;60:937-43). "It’s mainly patients with flares, and mainly those with colitis, either Crohn’s or severe ulcerative colitis," Dr. Bousvaros said.
In a prospective study of about 2,800 IBD patients (mean age, 42 years) recruited over 2.5 years, matched with non-IBD controls, and followed for several years, about 4% developed de novo venous thromboembolism (Gastroenterol. 2010;139:779-787.e1). Dr. Bousvaros emphasized that IBD was an independent risk factor for VTE recurrence in the study. "They were typically treated with long-standing prophylaxis. And if any anticoagulation was involved, the risk of recurrence was high," he said at the meeting, which was sponsored by the Crohn’s & Colitis Foundation of America.
Overall, the relative risk for VTE was found by a just-published meta-analysis of more than 200,000 IBD patients to be 2.4 for deep vein thrombosis, 2.5 for pulmonary embolism, 1.3 for ischemic heart disease, and 3.4 for mesenteric ischemia (J. Crohns Colitis 2013 Oct 29 [doi: 10.1016/j.crohns.2013.09.021]). Dr. Bousvaros said the investigators did not find an increased risk for arterial thromboembolic events in IBD, but that VTEs "were highly significant in this population."
Patients with IBD should be considered high risk for VTE if they are being treated in hospital for severe colitis and have a personal or family history of thrombosis, have known thrombophilia, have been taking oral contraceptives, have a history of smoking, are obese, or have had a PICC line.
"Any of those makes you a particularly high-risk patient," Dr. Bousvaros said.
Dr. Bousvaros disclosed he has consulting relationships with Cubist, Dyax, and Millennium.