Cost-effectiveness of antiretroviral regimens in the World Health Organization's treatment guidelines: a South African analysis.

OBJECTIVE

the World Health Organization (WHO) recently changed its first-line antiretroviral treatment guidelines in resource-limited settings. The cost-effectiveness of the new guidelines is unknown.

DESIGN

comparative effectiveness and cost-effectiveness analysis using a model of HIV disease progression and treatment.

METHODS

using a simulation of HIV disease and treatment in South Africa, we compared the life expectancy, quality-adjusted life expectancy, lifetime costs, and cost-effectiveness of five initial regimens. Four are currently recommended by the WHO: tenofovir/lamivudine/efavirenz; tenofovir/lamivudine/nevirapine; zidovudine/lamivudine/efavirenz; and zidovudine/lamivudine/nevirapine. The fifth is the most common regimen in current use: stavudine/lamivudine/nevirapine. Virologic suppression and toxicities determine regimen effectiveness and cost-effectiveness.

RESULTS

choice of first-line regimen is associated with a difference of nearly 12 months of quality-adjusted life expectancy, from 135.2 months (tenofovir/lamivudine/efavirenz) to 123.7 months (stavudine/lamivudine/nevirapine). Stavudine/lamivudine/nevirapine is more costly and less effective than zidovudine/lamivudine/nevirapine. Initiating treatment with a regimen containing tenofovir/lamivudine/nevirapine is associated with an incremental cost-effectiveness ratio of $1045 per quality-adjusted life year compared with zidovudine/lamivudine/nevirapine. Using tenofovir/lamivudine/efavirenz was associated with the highest survival, fewest opportunistic diseases, lowest rate of regimen substitution, and an incremental cost-effectiveness ratio of $5949 per quality-adjusted life year gained compared with tenofovir/lamivudine/nevirapine. Zidovudine/lamivudine/efavirenz was more costly and less effective than tenofovir/lamivudine/nevirapine. Results were sensitive to the rates of toxicities and the disutility associated with each toxicity.

CONCLUSION

among the options recommended by WHO, we estimate only three should be considered under normal circumstances. Choice among those depends on available resources and willingness to pay. Stavudine/lamivudine/nevirapine is associated with the poorest quality-adjusted survival and higher costs than zidovudine/lamivudine/nevirapine.