Economic analysis of initial HIV treatment. Efavirenz- versus indinavir-containing triple therapy

To compare the clinical and economic outcomes associated with triple therapy containing efavirenz or indinavir and 2 nucleoside reverse transcriptase inhibitors (NRTIs; zidovudine and lamivudine) in HIV-positive patients. An economic model based on viral load and CD4+ cell counts to predict long term outcomes such as progression to AIDS and AIDS-related death was developed and then analysed using data from a randomised clinical trial. Cost estimates from the healthcare system perspective were based on data from 6 state, all-payor databases, the AIDS Cost and Services Utilisation Study, and other literature. Analyses were carried out for time horizons between 5 and 15 years. HIV-positive patients with limited exposure to NRTIs. Initial regimens consisted of efavirenz or indinavir, each combined with 2 NRTIs. A maximum of 2 switches to other regimens was permitted. The efavirenz-containing triple therapy regimen was predicted to prolong survival at a savings of up to 10,923 US dollars (1998 values) relative to initial therapy with the indinavir-containing regimen. Patients who receive efavirenz are expected to have 11% greater survival at 5 years and fewer treatment failures (28 vs 52%, at 2 years). Overall, the economic and health benefits predicted for the efavirenz-containing regimen were robust to reasonable variation in key parameters. The superior clinical trial outcomes for efavirenz-containing regimens should translate into substantial economic and health benefits.