Cost-Effectiveness of Serum Cryptococcal Antigen Screening to Prevent Deaths among HIV-Infected Persons with a CD4+ Cell Count ≤100 Cells/mL Who Start HIV Therapy in Resource-Limited Settings

Background. Cryptococcal meningitis (CM) remains a common AIDS-defining illness in Africa and Asia. Subclinical cryptococcal antigenemia is frequently unmasked with antiretroviral therapy (ART). We sought to define the cost-effectiveness of serum cryptococcal antigen (CRAG) screening to identify persons with subclinical cryptococcosis and the efficacy of preemptive fluconazole therapy. Methods. There were 609 ART-naive adults with AIDS who started ART in Kampala, Uganda, and who had a serum CRAG prospectively measured during 2004-2006. The number needed to test and treat with a positive CRAG was assessed for >= 30-month outcomes. Results. In the overall cohort, 50 persons (8.2%) were serum CRAG positive when starting ART. Of 295 people with a CD4(+) cell count <= 100 cells/mu L and without prior CM, 26 (8.8%; 95% confidence interval [CI], 5.8%-12.6%) were CRAG positive, of whom 21 were promptly treated with fluconazole (200-400 mg) for 2-4 weeks. Clinical CM developed in 3 fluconazole-treated persons, and 30-month survival was 71% (95% CI, 48%-89%). In the 5 CRAG-positive persons with a CD4(+) cell count <= 100 cells/mu L treated with ART but not fluconazole, all died within 2 months of ART initiation. The number needed to test and treat with CRAG screening and fluconazole to prevent 1 CM case is 11.3 (95% CI, 7.9-17.1) at costs of $190 (95% CI, $132-$287). The number needed to test and treat to save 1 life is 15.9 (95% CI, 11.1-24.0) at costs of $266 (95% CI, $185-$402). The cost per disability-adjusted life year saved is $21 (95% CI, $15-$32). Conclusions. Integrating CRAG screening into HIV care, specifically targeting people with severe immunosuppression (CD4(+) cell count similar to 100 cells/mL) should be implemented in treatment programs in resource-limited settings. ART alone is insufficient treatment for CRAG-positive persons.