Cost and enrollment implications of targeting different source population for an HIV treatment program

Background: Rapid scale-up of antiretroviral therapy (ART) is a worldwide priority, and ambitious targets for numbers on ART have been set. Antenatal clinics (ANCs) and tuberculosis (TB) clinics have been targeted as entry points into HIV care. Methods: We developed a conditional probability model to evaluate the effects of ANC and TB clinic populations on ART program enrollment. Results: To start 1 individual on ART, 3 TB patients have to be screened at a crude program cost of US $36 per patient initiated on therapy. By contrast, 48 ANC patients have to be screened at a cost of US $214 per patient on therapy. In an incremental analysis in which ANC HIV testing was bome by a program to prevent mother-to-child transmission, recruitment efficiency increased (8 screened per patient starting ART) and cost decreased (US $114 per patient on therapy). Absolute numbers starting ART, however, remained fixed. If all 60,000 ANC patients seen yearly in the Lusaka District were screened, 1247 would start ART. Approaching the district's 35,000 annual TB patients would generate 11,947 patients on ART. Conclusion: In areas with high HIV prevalence, targeting chronically ill populations for HIV treatment may have significant short-term benefits in cost savings and recruitment efficiency.