Cost effectiveness of diagnostic monitoring on HIV care in resource poor settings

Background: Although the number of HIV infected people receiving Highly Active Anti-Retroviral Therapy (HAART) has soared in recent years, relatively little attention has been paid to disease management in resource-poor settings.

Methods: We compared the incremental lifetime costs and benefits of three different strategies for managing HAART therapy: a symptom-based strategy, a CD4-based strategy, and a CD4 plus viral load strategy for starting and switching regimens. We used published data from the Cape Town AIDS Cohort and constructed a microsimulation of HIV disease. For the base case, we estimated the cost of a CD4 cytometer to be about $35,000, a throughput of 30 specimens per day, and a cost per test of $15.

Results: Use of CD4 counts to guide treatment was highly effective and cost-effective. Compared to a symptom-based approach, starting treatment at a threshold of 350 cells/ml and monitoring CD4 and viral load every 3 months had an incremental cost-effectiveness ratio of about $1,100 per life year gained. Strategies where treatment was started at a threshold of 200 cells/ml and diagnostic tests were performed every 3 months were less effective and more expensive. Lifetime testing costs varied by about $500 per patient between the most expensive diagnostic equipment and the least costly equipment. Using viral load in addition to CD4 was substantially more expensive than using CD4 alone and produced only modest incremental health benefit.

Conclusion: Using diagnostic monitoring for management of HAART therapy in resource-poor regions provides substantial health benefit with a modest investment in resources.