The cost effectiveness of antiretroviral regimens for the treatment of HIV/AIDS

Objective: To estimate survival, the number of life-years gained and cost effectiveness of antiretroviral therapy (ART) regimens, denoted as ERA-I [zidovudine + (didanosine or zalcitabine)]; ERA-II [stavudine + (didanosine or zalcitabine) or lamivudine + (zidovudine or didanosine or zalcitabine or stavudine)]; and ERA-III [2 nucleoside reverse transcriptase inhibitors + (1 protease inhibitor or 1 non-nucleoside reverse transcriptase inhibitor)]. Design: Modelling of drug cost, cost of opportunistic diseases and survival of HIV-positive men and women in the province of British Columbia who were first prescribed any ART between October 1992 and June 1996. A 'reference cohort' was modelled upon individuals in a longitudinal cohort of homosexual men followed since 1982. Perspective and setting: Third-party payer perspective in British Columbia, Canada. Patients: All HIV-positive men and women aged greater than or equal to 18 years with CD4+ counts less than or equal to 350 cells/mu L who were enrolled in the province-wide drug treatment programme. Main outcome measures: Annual costs, survival and cost-effectiveness ratios of successive ART regimens. Results: Total costs [1997 Canadian dollars ($Can)] at 12 months under ERA-I, -II and -III were $Can4897, $Can6620 and $Can11 914, respectively. Survival at 12 months under ERA-I, -II and -III was 89.6%, 91.0% and 97.6%, respectively. The annual incremental cost (estimated by the total incremental cost at 12 months) between ERA-II and ERA-I was $Can1723. The incremental cost-effectiveness ratios between ERA-III and ERA-I, and between ERA-III and ERA-II were SCan58 806 and $Can46 971 per life-year gained, respectively. Conclusion: We found the cost effectiveness of ERA-III ART regimens well within the range of currently funded therapies for the treatment of other chronic diseases.