Adherence to tuberculosis infection treatment and its impact on prevention of tuberculosis reactivation: A retrospective cohort study from Taiwan

BACKGROUND: Treatment for tuberculosis infection (TBI) is often discontinued owing to adverse drug effects. The impact of treatment completion on TB reactivation remains poorly understood. METHODS: We conducted a retrospective analysis of 1432 patients at one medical centre in Taiwan from 2016 to 2021. Patients with TBI were divided into three groups: non-initiation (N), incomplete treatment (IC), and complete treatment (C). Those exposure to TB but without TBI formed a control group. TB reactivation was analysed using multivariable Cox regression models, with follow-up for up to three years. RESULTS: The overall TB reactivation rate was 2.3 % (34/1432), ranging from 6.1 % in the TBI (N) group (n = 378), 2.1 % in the TBI (IC) group (n = 330), 0.5 % in the TBI (C) group (n = 430), and 0.7 % in the control group (n = 294). TBI treatment was independently associated with a reduced risk of TB reactivation. The adjusted hazard ratio (aHR) for TBI (IC) versus TBI (N) was 0.32 (95 % CI 0.12-0.85, p = 0.022), and for TBI (C) versus TBI (N), the aHR was 0.05 (95 % CI 0.01-0.29, p < 0.001). Each 10 % increase in treatment adherence rate resulted in a 23 % reduction in the risk of TB reactivation (aHR 0.77, 95 % CI 0.67-0.88, p < 0.001). CONCLUSIONS: TBI treatment, prescribed to 67 % and completed by 38 % of patients, significantly reduces TB reactivation risk, especially with high adherence. Enhancing adherence, particularly among elderly patients and those with comorbidities, is crucial for improving the effectiveness of TBI treatment.