5. Cost, cost-saving potential, and cost-effectiveness of AZT therapy for pregnant women

While anti-retroviral therapy appears prohibitively expensive in many regions, therapy for HIV infected pregnant women over a relatively very short time-period may be more affordable. It may also be cost-effective: in the USA, treating pregnant women with AZT has been shown to reduce maternal-child transmission from a rate of 25.5% to 8.3% (Connor et al, 1994).

In the USA, treatment consisted of 500mg AZT per day on an out-patient basis, starting treatment between weeks 14 and 34 of gestation and continuing until the onset of labour. During labour, a loading dose of 2mg/kg was given, followed by continuous infusion of 1mg/kg of bodyweight per hour during delivery. In the final phase, new-born infants were treated orally with AZT syrup at 2mg/kg bodyweight every six hours, beginning 8 to 12 hours after birth and continuing for six weeks. The cost for such treatment per pregnant woman has been estimated at US$ 895 for drugs and US$ 150 for laboratory tests, US$ 1 045 in total (Mauskopf et al, 1996). In addition, there are costs associated with testing and counselling all pregnant women, since this is necessary for identification of pregnant women who should receive the AZT treatment. This was estimated to cost US$ 60 for a women testing negative and US$ 163 for those who test positive. On the assumption of a prevalence rate among pregnant women of 1.71%, testing would on average cost US$ 61.8 per pregnant woman. AZT treatment for HIV+ pregnant women would on average cost US$ 79.6 per pregnant woman. With around 4 million births per year (World Development Report, 1993), this equates to an annual cost of approximately US$ 318 million or US$ 0.3 billion. In the context of health expenditures in the region of US$ 690 billion per year, this appears affordable. For other high income countries with usually lower prevalence rates than those found in the USA, such treatment also appears affordable.

In poorer countries with higher prevalence rates, these costs appear very high. For example, in Uganda there are an estimated 884 000 births per year (World Development Report, 1993). Drug costs alone would be US$ 79.1 millions, even assuming only 10% of women were HIV+. Total health expenditure in 1990 was only US$ 95 millions (ibid.). It is therefore not surprising that the one published article concerning AZT for pregnant women in Sub-Saharan Africa has concluded that the treatment regimen used in the USA trial is too expensive for developing countries (Mansergh et al, 1996). Instead, a shorter regimen, of as yet unproven efficacy, has been suggested to be more realistic. Trials currently underway in Thailand and sub-Saharan Africa will, when completed, demonstrate whether shorter and cheaper regimens are as effective.

In the USA, it has been suggested that AZT therapy for pregnant women is not only affordable but also cost-saving, due to averted paediatric HIV/AIDS treatment costs, which are very large (Mauskopf et al, 1996; Gorsky et al, 1996). In the first study, a child infected by its mother was estimated to incur HIV/AIDS-related health care costs of US$ 98 915. In developing countries, paediatric HIV/AIDS costs are much lower and are unlikely to offset the costs associated with AZT therapy - even when the indirect costs associated with lost productivity are considered (Mansergh et al, 1996). Furthermore, even assuming a less costly treatment regimen than the one shown to be effective in the USA, and making assumptions concerning its likely effectiveness, the cost/HIV infection averted in the baseline analysis was US$ 1 115 (ibid). The authors commented that "This figure would be considered highly cost-effective from a developed country perspective; in a developing country setting in which health care expenditures are much more limited, one might question the cost-effectiveness of this program". Again, more definitive answers concerning the cost-effectiveness of AZT therapy in developing countries will be available when trials now underway in Thailand and Sub-Saharan Africa are completed.