Taking ART to Scale: Determinants of the Cost and Cost-Effectiveness of Antiretroviral Therapy in 45 Clinical Sites in Zambia

Kara K Wools-Kaloustian,Elliot Marseille,Mead Over,James G Kahn,Mark J Giganti,Lloyd Mulenga,Angela Chisembele-Taylor,Jeffrey S A Stringer,Albert Mwango

doi:10.1371/journal.pone.0051993

Abstract

BackgroundWe estimated the unit costs and cost-effectiveness of a government ART program in 45 sites in Zambia supported by the Centre for Infectious Disease Research Zambia (CIDRZ).MethodsWe estimated per person-year costs at the facility level, and support costs incurred above the facility level and used multiple regression to estimate variation in these costs. To estimate ART effectiveness, we compared mortality in this Zambian population to that of a cohort of rural Ugandan HIV patients receiving co-trimoxazole (CTX) prophylaxis. We used micro-costing techniques to estimate incremental unit costs, and calculated cost-effectiveness ratios with a computer model which projected results to 10 years.ResultsThe program cost $69.7 million for 125,436 person-years of ART, or $556 per ART-year. Compared to CTX prophylaxis alone, the program averted 33.3 deaths or 244.5 disability adjusted life-years (DALYs) per 100 person-years of ART. In the base-case analysis, the net cost per DALY averted was $833 compared to CTX alone. More than two-thirds of the variation in average incremental total and on-site cost per patient-year of treatment is explained by eight determinants, including the complexity of the patient-case load, the degree of adherence among the patients, and institutional characteristics including, experience, scale, scope, setting and sector.Conclusions and SignificanceThe 45 sites exhibited substantial variation in unit costs and cost-effectiveness and are in the mid-range of cost-effectiveness when compared to other ART programs studied in southern Africa. Early treatment initiation, large scale, and hospital setting, are associated with statistically significantly lower costs, while others (rural location, private sector) are associated with shifting cost from on- to off-site. This study shows that ART programs can be significantly less costly or more cost-effective when they exploit economies of scale and scope, and initiate patients at higher CD4 counts.

Highlights

Zambia is among the countries most severely affected by the HIV/AIDS epidemic
[1] Provision of free treatment started in April 2004, with support from the Global Fund to Fight AIDS, Tuberculosis and Malaria which in 2004 committed $254 million over 5 years; and from the President’s Emergency Fund for AIDS Relief (PEPFAR)
The bar was raised for what constitutes ‘‘Universal access’’ in November, 2009, when new World Health Organization (WHO) guidelines were released recommending an increase in the CD4 threshold for starting antiretroviral therapy (ART) from,200 cells/uL to,350 cells/uL

Summary

Introduction

Zambia is among the countries most severely affected by the HIV/AIDS epidemic. Prevalence among adults was between 14.3 and 16.4% in 2007. [1] Provision of free treatment started in April 2004, with support from the Global Fund to Fight AIDS, Tuberculosis and Malaria which in 2004 committed $254 million over 5 years; and from the President’s Emergency Fund for AIDS Relief (PEPFAR). 330,000 people in Zambia needing antiretroviral therapy (ART) were receiving it, and a third of all health facilities in the country were able to offer treatment. The bar was raised for what constitutes ‘‘Universal access’’ in November, 2009, when new World Health Organization (WHO) guidelines were released recommending an increase in the CD4 threshold for starting ART from ,200 cells/uL to ,350 cells/uL. This change, once adopted by countries, will instantly double the number of people eligible for therapy. We estimated the unit costs and cost-effectiveness of a government ART program in 45 sites in Zambia supported by the Centre for Infectious Disease Research Zambia (CIDRZ)

Methods

Results

Discussion

Conclusion