Reactivation of hepatitis B virus in rheumatoid arthritis patients treated with biological disease-modifying antirheumatic drugs

Objective To examine the incidence of hepatitis B virus (HBV) reactivation in patients with rheumatoid arthritis (RA) receiving biological disease‐modifying antirheumatic drugs (DMARDs). Methods We retrospectively reviewed RA patients treated with biological DMARDs at our institution from July 2010 to December 2012. Patients with antibodies for hepatitis B core antigen and/or hepatitis B surface antigen were regarded as having prior HBV infection. Clinical data on these patients, including HBV‐DNA levels, were retrieved from the medical records. Results During the study period, 251 patients were administered various biological DMARDs. Six patients with a history of HBV vaccination and one patient with positive HBV surface antigen were excluded from the study. Fifty‐seven of the remaining 244 patients (23.4%) had prior HBV infection. These patients were followed for a median of 18 months (range: 2–27 months) and HBV‐DNA was examined a median of seven times (range: 2–27). HBV‐DNA was detected in three patients (5.3%), comprising two receiving tocilizumab and one receiving etanercept. However, HBV‐DNA levels were below the quantitation limit (