Boosted-protease inhibitors (PIs) including lopinavir/ritonavir (LPV/r) and atazanavir/ritonavir (ATV/r) are recommended as the second-line antiretroviral therapy (ART) for those who failed or cannot tolerate the first-line therapy. According to the LASA study, in HIV-infected Thai adults with virologic suppression, the efficacy of ATV/r 200/100 mg was proved non-inferior to ATV/r 300/100 mg which is the current recommended dose. It also showed less side effects, resulting in less discontinuation rate and costs less to the patients. Thus, dose reduction in patients with well-suppressed viral load may result in better long-term safety profile and less treatment cost.

OBJECTIVES: The aim of this study was to perform an economic evaluation comparing ATV/r 200/100 mg with ATV/r 300/100 mg in Thai adults with virologic suppression.

METHODS: The cost-utility analysis was carried out using a Markov model implemented in Microsoft^®Excel worksheet to calculate Incremental cost-effectiveness ratio (ICER), applying results from the LASA study and literatures. The model’s time horizon reflected a patient’s lifetime, and including costs from payer’s perspective. Costs and health outcomes were discounted at 3% per year and presented in Thai Baht and Quality-adjusted life years (QALYs). One-way sensitivity analysis was performed to test the robustness of the results.

RESULTS: The results showed that costs of treating patient using ATV/r 200/100 mg is less than ATV/r 300/100 mg with total costs of US$171,311 (6.0 million Thai Baht) and US$ 187,479 (6.5 million Thai Baht) per patient for ATV/r 200/100 mg and ATV 300/100 mg, respectively. While patients using ATV/r 200/100 mg experienced a better outcome of 14.65 QALYs compare to 14.16 QALYs in patients using ATV/r 300/100 mg.

CONCLUSIONS: ATV/r 200/100 mg is cost-saving and more effective compared to ATV/r 300/100 mg.