OBJECTIVES

Risk of hepatitis B virus (HBV) reactivation has increased because of advances in immunosuppressive therapies. People having a previously-resolved HBV infection and those with serum HBs-antigen positivity are likely to develop liver injuries after the therapies. However, the risk of HBV reactivation for rheumatoid arthritis (RA) patients is still unclear. This study described a validity of detecting prHBV infection from administrative data by comparing with chart abstraction, and to determine an incidence of HBV reactivation during immunosuppressive therapy of Japanese RA patients.

METHODS

Adult patients who had been diagnosed with RA between 1 April 2011 and 31 March 2015 were extracted from the Medical Information Analysis (MIA) databank managed by the Clinical Research Center at the National Organization Hospitals (NHO) Headquarters. We also conducted chart abstraction in three hospitals to verify whether those patients actuary had records of prHBV infection, de novo hepatitis, and HBsAg carriers. A positive predictive value (PPV) of the algorithm of HBV-DNA testing with immunosuppressive therapy performed four times or more / year for the detection of prHBV infection from administrative data and an incidence rate of HBV reactivation among preHBV infections during immunosuppressive therapy for RA were calculated.

RESULTS

The PPV and its 95% confidence interval (CI) of administrative data for the identification of suspected prHBV infections was 85.8% (95% CI: 81.7% - 89.3%). The incidence rate of de novo hepatitis was 1.23 / 100 person-years.

CONCLUSIONS

The main concerns of epidemiological studies using administrative health data are lack of health information to identify true patients and the validity of recorded diagnoses and other information is critical. For HBV reactivation, monitoring data of serum HBV-DNA levels after immunosuppressive therapies were unavailable in the database and the chart review was useful approach. This validity study provided a good example to help our future HBV projects.