Detection of substantial numbers of latent tuberculosis and positive hepatitis B serology results in rheumatology patients preparing to receive intensified immunosuppressive therapy in a low-prevalence country: why screening still matters.

Introduction /objectives: International guidelines recommend screening for latent tuberculosis infection (LTBI) and chronic viral hepatitis infections before initiating intensified immunosuppressive therapy. We assessed the prevalence of positive screening tests for LTBI, hepatitis B virus (HBV), and hepatitis C virus (HCV) in patients screened at a large rheumatology outpatient center in Germany.

Method: This retrospective cohort study used electronic health records from adult rheumatology patients. The presence of LTBI was evaluated by chest X-rays, patient medical history/self-report, and QuantiFERON®-TB Gold Plus (QFT) interferon-gamma release assays. Antibodies to HBV core antigen (anti-HBc) and HCV were used to assess HBV and HCV, respectively. Statistically significant associations were evaluated by Fisher exact tests.

Results: Of 697 screened patients with a rheumatological condition (61.3% female, mean age 60.0 years), 132 (18.9%) patients were positive for LTBI (99 [14.2%]), anti-HBc (39 [5.6%]), or anti-HCV (3 [0.4%]). Nine patients had more than one positive result; different infections were not significantly associated. QFT detected the most LTBI cases (59.5%) followed by patient report/history (42.4%) and chest X-rays (17.2%). Although most patients (83.8%) were positive on only one test, associations among LTBI tests were statistically significant. Biologic disease-modifying antirheumatic drug (bDMARD) use was lower in patients with a positive LTBI screening result compared with all screened patients (73.7% vs 86.4%) and targeted synthetic DMARD (tsDMARD) use was higher (10.1% vs 5.9%).

Conclusions: Almost one-fifth of rheumatology patients preparing to initiate intensified immunosuppressive therapy have positive results on screening tests for LTBI or show evidence of exposure to HBV or HCV. These findings support the need for careful screening, even in "low-prevalence" countries.