Incremental cost-effectiveness of two zidovudine regimens to prevent perinatal HIV transmission in the United States

Background. Recently concluded clinical trials in Thailand have demonstrated that a short course of zidovudine therapy administered to human immunodeficiency virus-infected women during late pregnancy and labor can substantially reduce the likelihood of perinatal transmission of HIV. This regimen is both less expensive and less effective than the full course of therapy recommended for use in the United States by the U.S. Public Health Service (PHS). The objective of the current study is to estimate the incremental cost-effectiveness of the full-course zidovudine regimen in comparison to the short-course regimen that was tested in Thailand and to determine conditions under which the PHS-recommended regimen produces a net savings in societal resource utilization, relative to the shorter regimen. Methods. We used standard methods of incremental cost-effectiveness analysis and derived cost and effectiveness estimates from published studies. The main outcome measure is the incremental cost-effectiveness ratio, which is the additional cost per additional case of perinatal HIV infection averted by the full course of therapy. Results. Full-course zidovudine therapy costs an additional $21,337 per additional case of HIV infection averted, relative to the shorter regimen; this is much less than the cost of treating a case of pediatric HIV infection. Conclusions. Economic and clinical findings both favor full-course zidovudine therapy over short-course therapy to prevent perinatal transmission of HIV in the United States. (C) 2000 American Health Foundation and Academic Press.