Objectives: To assess tenofovir + lamivudine + efavirenz versus zidovudine + lamivudine + efavirenz in treatment-naive patients using a cost-effectiveness analysis.
Methods: A decision tree was designed. Effectiveness was estimated from clinical trials. Viral load and CD4 cells count were chosen as endpoints for health outcome. Both healthcare and treatment costs were considered, and univariate sensitivity tests were performed.
Results: The regimen including tenofovir would have a yearly cost of 10,116.61 Euros when effective, and of 12,140.40 Euros in case of therapeutic failure. The regimen including zidovudine would have a yearly cost of 7,470.36 Euros when effective, and of 8,964.90 Euros in case of therapeutic failure. The cost of switching to the regimen with tenofovir represents 14,765.86 Euros per year per additional patient with non-detectable viral load. After 3 years, the expected yearly cost is 8,765.83 Euros for the regimen including tenofovir versus 8,894.36 Euros for the regimen including zidovudine.
Conclusion: The regimen including zidovudine is less costly in the short run when compared to the regimen including tenofovir. Both regimens become financially similar when extending the study horizon.