OBJECTIVES

Loss of hepatitis B virus (HBV) surface antibody (anti-HBs) occurs before HBV reactivation. To elucidate risk factors for loss of hepatitis B virus (HBV) surface antibody (anti-HBs) in patients with rheumatic diseases and HBV surface-antigen negative/anti-HBs positive (HBsAg−/anti-HBs+) serostatus during biologic disease-modifying anti-rheumatic drug (DMARD) treatment.

METHODS

This nested case-control study prospectively enrolled patients with rheumatoid arthritis, ankylosing spondylitis, psoriatic arthritis/psoriasis, and juvenile idiopathic arthritis, who were treated with biologic DMARDs from January 2013 to September 2017. The analytic sample included patients with HBsAg−/anti-HBs+ serostatus. Anti-HBs titers were monitored, and cases defined as anti-HBs <10 mIU/mL during follow-up. Cases were matched one-to-all with controls with anti-HBs ≥10 mIU/mL on the same event date and equivalent duration of biologic DMARDs treatment. Between-group characteristics were compared and risk factors for anti-HBs loss elucidated by conditional logistic regression analyses.

RESULTS

Among 189 enrolled patients, 15 cases were matched with 211 controls. Risk factors associated with anti-HBs loss in multivariate analysis were low baseline anti-HBs titer (adjusted risk ratio = 0.96, 95% CI 0.93–0.99) and chronic kidney disease (adjusted risk ratio = 26.25, 95% CI 1.85–372.35). All cases had baseline anti-HBs titer <100 mIU/mL, and none developed HBV reactivation upon losing anti-HBs.

CONCLUSIONS

Chronic kidney disease and low baseline anti-HBs titer and are independent risk factors associated with loss of anti-HBs in patients with HBsAg−/anti-HBs+ serostatus who receive biologic DMARDs to treat rheumatic diseases.