Background Rheumatoid arthritis (RA) treatment may differ according to hepatitis B state and consequently bring about different outcome of arthritis. Only a small number of studies have addressed the differences in disease characteristics and treatment patterns of RA in relation to hepatitis B state. However, it has not yet been elucidated whether hepatitis B affects treatment outcome such as disease activity.

Objectives We investigated possible differences in change of arthritis activity between RA patients according to concomitant hepatitis B virus (HBV) infection.

Methods A retrospective analysis of 40 hepatitis B surface antigen (HBsAg)-positive RA patients and 112 HBsAg-negative RA patients was conducted. The longitudinal relationship between HBsAg-positivity and RA activity/medication use was analyzed using generalized estimating equations in regression models.

Results There were no significant differences in group for baseline characteristics. In regression analysis, RA activity-related outcomes showed follow-up time-dependent improvement during study period. We observed significant interaction between time and HBsAg-positivity for disease activity score in 28 joints with 3 variables (DAS28–3; P =0.026), that means decreases in DAS28–3 with time influenced by HBsAg-positivity. But this interaction did not remain significant after adjustment. For tender joints, erythrocyte sedimentation rate, and C-reactive protein levels, there were no interaction between time and HBsAg-positivity, while swollen joints showed significant interaction (P =0.017). The time-association and group differences were not observed in alanine aminotransferase (ALT) level. Over all visits, HBsAg-positive patients were less likely to receive methotrexate (OR 0.09 [95% CI 0.04–0.19], P <0.0001) and more likely to receive sulfasalazine (OR 3.67 [95% CI 1.94–6.95], P <0.0001). In HBsAg-positive RA patients, initial hepatitis B state was related to use of DMARDs, especially methotrexate (P =0.040). Hepatitis reactivation occurred in 4 patients (10%) in HBsAg-positive RA patients. Among the patients who experienced HBV reactivation, only one patient had received previous antiviral treatment at baseline, but the patient exhibited lower adherence to drug. All patients who experienced HBV reactivation showed positive HBV DNA at baseline. There were no cases of hepatic failure or death.

Conclusions There were no significant differences over time in DAS28–3, tender joints, inflammatory markers, according to HBsAg-positivity, while swollen joints showed significant difference over time. ALT level did not showed time-association and group differences. HBsAg-positive RA patients were less likely to receive methotrexate and more likely to receive sulfasalazine.

Disclosure of Interest None declared