Objectives: Limited information suggests the existence of a high prevalence of hepatitis B (HBV) and C virus (HCV) infection in inflammatory bowel disease (IBD). This knowledge is relevant because the viruses may reactivate under immunosuppressive therapy. The objectives of this study are to assess the prevalence of HBV and HCV infection in IBD, in a nationwide study, and to evaluate associated risk factors.

Methods: This cross-sectional multicenter study included 2,076 IBD patients, consecutively recruited in 17 Spanish hospitals. Factors related to IBD (severity, invasive procedures, etc.) and to infection (transfusions, drug abuse, etc.) were registered. Independent risk factors for viral infection were evaluated using logistic regression analysis.

Results: Present and/or past HBV and HCV infection was found in 9.7% of patients of both ulcerative colitis (UC) and Crohn's disease (CD) (UC: HBsAg 0.8%, anti-HBc 8%, anti-HCV 1.3%; CD: HBsAg 0.6%, anti-HBc 7.1%, anti-HCV 2.3 %). Effective vaccination (anti-HBs, without anti-HBc) was present in 12% of patients. In multivariate analysis, age (odds ratio (OR) 1.04; 95% confidence interval (CI) 1.02-1.06; P=0.000), family history of hepatitis (OR 2.48; 95% CI 1.3-4.74; P=0.006) and moderate-to-severe IBD disease (OR 2.5; 95% CI 1.02-6.15; P=0.046) were significantly related to HBV, whereas transfusions (OR 2.66; 95% CI 1.2-5.87; P=0.015) and antibiotic use (OR 2.66; 95% CI 1.1-6.3; P=0.03) were significantly related to HCV. The significance for transfusions was lost if they were administered after 1991, when HCV markers became mandatory in blood banks.

Conclusions: Prevalence of HBV and HCV infection in IBD is similar to that of the general population of reference and lower than that in previously published series. This fact, in addition to the lack of association with invasive procedures, suggests the existence of adequate preventive measures in centers attending to these patients. The low percentage of effective vaccination makes it mandatory to intensify B virus vaccination in IBD.