S3407 Testing Patterns and Prevalence of Latent Tuberculosis Co-Infection Among Patients With Chronic Hepatitis B Virus Infection

Introduction: Chronic hepatitis B virus (HBV) and latent tuberculosis infection (LTBI) are preventable diseases that disproportionately affect ethnic minorities. Although HBV is known to increase risks of drug-induced liver injury (DILI) among patients receiving LTBI treatment, few studies have characterized testing patterns and prevalence of LTBI among HBV patients. We evaluated testing patterns and prevalence of LTBI among chronic HBV patients using a large national clinical laboratory database. Methods: We retrospectively evaluated Quest Diagnostics clinical laboratory data from 2016-2020. Chronic HBV was identified by any combination of two positive results of HBV surface antigen, HBV e antigen, or HBV DNA, at least 6 months apart. LTBI was identified as having a positive QuantiFERON or T-SPOT® test without evidence of active TB infection. Diagnostic testing patterns and prevalence of LTBI among chronic HBV patients were stratified by age, sex, and race/ethnicity. Comparisons between groups utilized chi-square testing with two-tailed p < 0.05 indicating statistical significance. Results: From 2016-2020, 17,635,261 individuals were tested for HBV, among which overall prevalence of chronic HBV was 0.51% (95% CI 0.50-0.51). Among 89,259 chronic HBV patients, 9,503 (10.6%) were tested for LTBI overall; 5.9% had testing for LTBI within 3 months of chronic HBV diagnosis, 6.9% within 6 months, and 8.0% within 1 year. Compared to non-Hispanic whites, Hispanics and African Americans were more likely to be tested for LTBI (Table). Among chronic HBV patients who received LTBI testing, prevalence of LTBI (indicating HBV-LTBI co-infection) was more than twice the prevalence of LTBI in patients without chronic HBV (19.6% vs 7.3%, p < 0.01). HBV-LTBI co-infection prevalence was similar in women vs men, but increased with older age (from 7.2% in age < 18y to 29.5% in age > 70y, Cochran-Armitage test for trend, p < 0.01), and was significantly higher in Asians (22.8%, p < 0.001) and Hispanics (20.7%, P = 0.03) compared to non-Hispanic whites (18.4%). Conclusion: Despite a LTBI prevalence of 19.6% among chronic HBV patients, less than 11% of HBV patients were tested for LTBI. This is alarming given that underlying HBV is associated with higher risks of DILI in patients treated for LTBI. Early identification of HBV-LTBI co-infection can help guide clinicians to modify both HBV and LTBI treatment approaches to reduce the risks of DILI, leading to improved patient outcomes.Table 1.: Proportion of Chronic HBV Patients Tested for LTBI and Prevalence of HBV-LTBI Co-Infection.