Table 2.

Discounted mean per person lifetime costs (2005 US$), life expectancy, and incremental cost-effectiveness of different strategies with 5% prevalence of non-nucleoside reverse transcriptase inhibitor resistance in the population.

Treatment strategya	Discounted mean per person cost (2005 US$)	Discounted life expectancy (years)	Cost-effectiveness ($/year of life saved)
no ART (co-trimoxazole prophylaxis alone)	1090	2.78	–
Two sequential regimens of ART
Boosted PI-based regimen then NNRTI-based regimen	4970	6.71	Dominatedc
NNRTI-based regimen then boosted PI-based regimenb	5210	7.30	910

ART, antiretroviral therapy; NNRTI, non-nucleoside reverse transcriptase inhibitor; PI, protease inhibitor.

^aAll strategies with ART included co-trimoxazole prophylaxis starting at an observed CD4 cell count < 500/μl and contained two nucleoside reverse transcriptase inhibitors. ART was switched when the observed CD4 cell count fell to below 50% of the peak or at the development of one severe, late-stage opportunistic infection and was stopped when the observed CD4 cell count fell to 90% of peak or at the development of one severe, late-stage opportunistic infection.

^bOverall mean survival is greatest with this strategy, requiring the longest duration of therapy, and leading to the highest overall cost.

^cThough per person costs are less, this strategy has a higher cost-effectiveness ratio ($987/year of life saved) than the ‘NNRTI + 2NRTI →PI + 2NRTI’ strategy. By convention, such strategies are ‘dominated’ and cost-effectiveness ratios are not reported [8,37].