Association of Rheumatoid Arthritis and Hepatitis B Infection: A Nationwide Nested Case-Control Study From 1999 to 2009 in Taiwan.

Rheumatoid arthritis (RA) is a disorder with altered immunologic function and increased risks of infection, while the association between HBV and RA remains largely unknown.To determine the prevalence and risk of HBV infection in patients with RA, 2 cohort datasets were sourced from Taiwan's National Health Insurance Research Database to capture National Health Insurance claims data between 1999 and 2009. One set was a specially requested RA subject's dataset extracted from the whole 23 million beneficiaries, and a total of 38,969 aged ≧18 years RA subjects were identified (RA cohort). The other one was a randomly selected 1 million patients' longitudinal dataset, and from which an additional 701,476 aged ≧18 years non-RA subjects were identified (non-RA cohort). An epidemiological approach was used to compare the prevalence and risk for HBV infection between RA and non-RA subjects.During the followed interval between 1999 and 2009, 3260 in RA cohort and 63,588 in non-RA cohort had a diagnosis of HBV infection. The annual age- and sex-standardized prevalence of HBV infection in the RA cohort was generally higher than that in the non-RA cohort. The RA patients had a higher HBV period prevalence than did the non-RA subjects (RA vs. non-RA = 69.9 vs. 60.1 cases per 1000 subjects). Compared with the non-RA cohort, the RA cohort had an increased risk of HBV infection after adjustment for potential prognostic factors (1.13, 95% CIs: 1.08-1.17).RA patients are characterized by an increased risk of HBV infection than non-RA subjects.