Hepatitis B Screening in Patients on Immunusuppressive Therapies for the Treatment of Inflammatory Bowel Disease
INTRODUCTION: Potent immunosuppressive therapies that are available for treatment of severe inflammatory bowel disorders has meant that strategies need to be implemented prior to initiation of therapy to reduce the risks of reactivating a number of latent infections. This includes screening fortuberculosis as well as hepatitis B viral infection. We reviewed the current recommendations for hepatitis B screening and performed an audit of our practice at our tertiary referral institution.
MATERIALS AND METHODS: Literature search was done using Medline. A retrospective audit was undertaken at Concord Repatriation General Hospital. The files of 166 patients who have attended the inflammatory bowel disease clinic were reviewed, electronic hospital results (Powerchart) and results from private laboratories were sought and recorded. Analysis was stratified according to biological monotherapy (infliximab, adalimumab, clinical trial drugs), immunomodulatormonotherapy (thiopurine, methotrexate, cyclosporine) or combination therapy. Chi Square and logistical regression statistics were performed.
RESULTS: Of the 166 consecutive patients, 8 (4.82%) were on biological monotherapy, 83 (50.0%) on combination biological and immunomodulators, 54 (32.5%) on immunomodulator alone and 21 (12.7%) on neither. Documented HBsAg screening was performed on 25.0%, 65.1% and 53.7% of patients respectively (Yates p value=0.14). In 86 patients (51.8%),hepatitis B surface antibody (HBsAb) test results were not documented or not done, 24 (14.4%) serologically immune (HBsAb>10) and 56 (33.7%) serologically not immune (HBsAb<10). Only 17.6% of patients undergoing treatment with biologics were serologically immune and in 49.5% of these patients, HBsAb levels were either not done or not documented. Hepatitis B core antibody screening was documented in 13.2% of patients receiving biologics. One patient was hepatitis B surface antigen positive with an undetectable HBV DNA level. The HBV seroprevalence rates were 0%, 0%, and 1.9% for biological monotherapy, combination therapy and immunomodulator monotherapy respectively. No patients were on anti-viral therapy for HBV at any time. Significant predictors of screening included combination biological and immunomodulator therapy (p=0.008, odds ratio [OR] 4.0, 95% CI: 1.43 to 11.32), and male sex (p=0.041, OR 2.0, 95% CI: 1.03-3.73). There were no cases of acute HBV hepatitis or reactivation in patients undergoing immunosuppressive therapies for the duration of the study.
CONCLUSION: Reactivation of latent hepatitis B following immunosuppression can be life threatening and is well documented. Consensus statements have been developed that recommend screening for HBV following several case reports of adverse events. We report on the audit of our tertiary referral clinic where the screening rates remain suboptimal. This retrospective study identified that combination immunosuppressive therapy predicted for highest HBV screening compliance, confirming awareness of guidelines. Overall, screening and documentation of serological immunity status need to be improved but there have been no adverse HBV events in our cohort. Strategies have now been implemented as part of the pre-therapy work up of patients undergoing immunosuppressive therapy, to ensure that those that may require antivirals will have cover. Ongoing education remains a priority.