Summary
Objectives: The rifampicin and isoniazid (RIF-INH) testing provides simultaneous detection of RIF-INH resistance, yet its economic implications in Indonesia have not been evaluated. This study assessed the economic impact of implementing RIF-INH testing compared with rifampicin-only (RIF-only) testing.
Methods: An economic evaluation was conducted using a decision-tree model simulating diagnostic and treatment pathways for 1,670,317 adults with presumptive pulmonary tuberculosis (TB). All TB subtypes were modeled through the first treatment cycle, capturing treatment success, treatment failure, death, and loss to follow-up (LTFU). The second cycle was limited to downstream consequences of isoniazid-resistant tuberculosis (Hr-TB) arising from the first cycle.
Results: RIF-INH testing was projected to increase first-cycle direct medical costs by 8.1% while improving treatment success by 5.9%. Although first-cycle direct non-medical costs were 24.3% higher, second-cycle Hr-TB-related direct medical and non-medical costs were projected to be 57.3% and 61.0% lower, respectively, than with RIF-only testing. Probabilistic uncertainty analysis consistently showed lower downstream Hr-TB costs, whereas differences in first-cycle and total model costs remained uncertain.
Conclusions: RIF-INH testing requires higher upfront costs but may reduce downstream Hr-TB-related costs. However, the overall total cost difference remains uncertain after accounting for parameter uncertainty.
