Background/Purpose: Rituximab is used to treat a variety of rheumatic diseases. In 2015, the American Gastroenterological Association (AGA) categorized rituximab as high-risk in terms of hepatitis B virus (HBV) reactivation. Specifically, patients that are hepatitis B surface antigen (HBsAg) negative and total hepatitis B core antibody (anti-HBc) positive or HBsAg and anti-HBc positive are at high risk of reactivation when receiving rituximab, and therefore, should receive antiviral prophylaxis. This study aims to evaluate rates of HBV screening prior to rituximab.

Methods: A retrospective chart review was conducted on 228 patients at a single tertiary center. Patients were included who had received rituximab for a rheumatologic indication, were seen by the rheumatology department, and received the first rituximab infusion between January 1, 2008 and February 28, 2019. Charts were reviewed for dates of HBsAg, anti-HBc, IgM antibody to hepatitis B core antigen (IgM anti-HBc), and hepatitis B surface antibody (anti-HBs) laboratory tests. If patients were found to be HBsAg or anti-HBc positive, charts were reviewed for any referral to hepatology or infectious disease specialties as well as for any antiviral prophylaxis initiation.

Results: Out of 228 patients meeting criteria, indications for rituximab varied, with the majority being rheumatoid arthritis (65 [28.5%]) and granulomatosis with polyangiitis (44 [19.3%]). One hundred ninety (83.3%) had HBsAg tested and 133 (58.3%) were tested for anti-HBc before first rituximab infusion. Out of these patients, all 190 were HBsAg negative and eight of the 133 tested for anti-HBc were positive. Six of these patients were referred to either infectious disease or hepatology and initiated on tenofovir or entecavir for antiviral prophylaxis. No action was taken on the remaining two patients with positive anti-HBc. An additional two patients were found to be anti-HBc positive after receiving rituximab and both were started on entecavir. No documented HBV reactivation occurred in any of the patients.

Conclusion: This chart review identified inadequate screening of HBV prior to the administration of rituximab. The majority of patients were properly screened for HBsAg; but only slightly more than half had testing for anti-HBc prior to first rituximab infusion. This study identifies areas to implement system changes to improve rates of HBV screening.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/screening-for-hepatitis-b-surface-antigen-and-core-antibody-prior-to-administration-of-rituximab-in-rheumatology-patients/