Effectiveness and cost effectiveness of early and late prevention of HIV/AIDS progression with antiretrovirals or antibiotics in Southern African adults

As HIV/AIDS drugs are becoming more widely available in Southern Africa, we compared the effectiveness and cost effectiveness of different treatment options, using a Markov Monte Carlo simulation model based on published estimates of disease progression, treatment effectiveness and health care costs. Cost and outcome values were discounted. Quality of life was considered. Acceptability curves summarized uncertainties. Sensitivity analyses tested assumptions. Results showed that triple antiretroviral therapy (ARV) plus antibiotics would prolong life by 6.7 undiscounted years if provided ‘late’ (CD4 = 200 cells/µl) and by 9.8 years if provided ‘early’ (CD4 = 350 cells/µl). The incremental undiscounted costs per year of life gained, compared to no preventive therapy, were $17 for isoniazid plus cotrimoxazole started late, $244 for both antibiotics started early, $2454 for ARV plus antibiotics started late and $2784 for ARV plus both antibiotics started early. The discounted incremental costs per quality adjusted life year (QALY) gained were, respectively, $29 saving, $254, $4937 and $3057. Late ARV plus both antibiotics was the strategy most likely to be cost effective if society was willing to pay more than $2000 per life year gained. Cost-effectiveness estimates were sensitive to discounting and assumed treatment costs but were less sensitive to assumed treatment effectiveness.