Incidence of and Risk Factors for Tuberculosis Among Patients Treated for Hepatitis C: a Population-based Cohort Study.

BACKGROUND: There is limited evidence on factors affecting tuberculosis (TB) disease development among patients treated for hepatitis C virus (HCV) infection. This study aimed to estimate the incidence of and risk factors for TB disease among patients treated within a national hepatitis C elimination program. METHODS: We conducted a cohort study using nationwide electronic TB and HCV databases. The study population included adults who completed HCV treatment between April 2015 and December 2022. We calculated TB disease incidence rate (IR) per 100 000 person-years (PY) with 95% confidence intervals (CIs) overall and by subgroups: advanced liver fibrosis (fibroscan ≥ F3 or FIB-4 > 3.25), diabetes mellitus (DM) (fasting glucose level≥7 mmol/l or self-reported diabetes), and low body mass index (BMI < 18.5). Poisson regression was used to estimate adjusted incidence rate ratio (aIRR) and 95% CIs. RESULTS: Among 75 693 individuals who completed treatment for hepatitis C, 544 new TB cases were identified over a median follow-up period of 69 months, corresponding to an IR of 136 per 100 000 PY (95% CI: 125, 148). Individuals with DM had a 53% higher incidence of TB (aIRR = 1.53; 95% CI: 1.09, 2.07) compared to those without. Underweight individuals (BMI < 18.5) had a higher incidence of TB compared with those of normal weight (aIRR 2.8; 95% CI: 1.67, 4.41). Advanced liver fibrosis was not significantly associated with TB disease (aIRR = .95, 95% CI: 0.72, 1.24). CONCLUSIONS: Individuals successfully treated for hepatitis C experienced high incidence of TB disease. Our findings suggest hepatitis C care programs may reduce TB risk by including DM screening and nutritional assessments.