Objective We started an information technology (IT) system that encodes the medical treatment status of hepatitis B virrus (HBV) with a 9-digit number, automatically checks for inappropriate situations occurring due to immunosuppression and chemotherapy that do not comply with the flowchart of the hepatitis B countermeasure guideline, and promotes correct HBV medical treatment in our hospital. We conducted a prospective study of HBV reactivation using this system. Methods Among 21,607 cases that were managed using this system, 1,206 patients who were HBs antigen-negative, HBc antibody- and/or HBs antibody-positive and in whom HBV DNA quantification was performed two times or more were examined for the occurrence of HBV reactivation. The study population included: malignant lymphoma patients using rituximab (n=40), patients with malignant tumors using anticancer agents (n=546), patients treated with steroids (n=274), rheumatoid arthritis (RA) patients (n=144), patients using immunosuppressants/biologics (n=26), and patients undergoing hepatitis C direct acting antiviral (DAA) treatment (n=176). Results HBV reactivation was observed in 27 cases undergoing treatment with the following agents: rituximab (n=6), anticancer agents (n=8), steroids (n=10), anti-RA agents (n=1), and hepatitis C DAA (n=2). Among the 40 patients who were using rituximab, 6 (18.2%) showed a high rate of reactivation. In 10 in which HBV reactivation occurred at a median of 10 (range, 4-32) months after steroid administration, 6 occurred after the 7th month, and 1 patient showed HBs antigen positivity and severe hepatitis. Conclusion Continuing of the operation of an automatic check system using coded medical information to check for the reactivation enabled this prospective study of HBV reactivation. Careful attention should be paid to patients using steroids, as well as malignant lymphoma patients who are treated with rituximab. The results of the present study suggest that the present IT encoding system would be useful for preventing HBV reactivation.
Keywords: HBV reactivation; immunosuppression/chemotherapy; medical information coding; rituximab; steroids.