Cost-effectiveness of cryptococcal antigen screening at CD4 counts of 101-200 cells/L in Botswana

Abstract

Background: Cryptococcal antigen (CrAg) screening in individuals with advanced HIV reduces cryptococcal meningitis (CM) cases and deaths. The World Health Organization recently recommended increasing screening thresholds from CD4 ≤100 cells/L to ≤200 cells/L. CrAg screening at CD4 ≤100 cells/L is cost-effective; however, the cost-effectiveness of screening patients with CD4 101-200 cells/L requires evaluation. Methods: Using a decision analytic model with Botswana-specific cost and clinical estimates, we evaluated CrAg screening and treatment among individuals with CD4 counts of 101-200 cells/L. We estimated the number of CM cases and deaths nationally and treatment costs without screening. For screening we modeled the number of CrAg tests performed, number of CrAg-positive patients identified, proportion started on pre-emptive fluconazole, CM cases and deaths. Screening and treatment costs were estimated and cost per death averted or disability-adjusted life year (DALY) saved compared with no screening. Results: Without screening, we estimated 142 CM cases and 85 deaths annually among individuals with CD4 101-200 cells/L, with treatment costs of 368,982. With CrAg screening, an estimated 33,036 CrAg tests are performed, and 48 deaths avoided (1,017 DALYs saved). While CrAg screening costs an additional 155,601, overall treatment costs fall by 39,600 (preemptive and hospital-based CM treatment), yielding a net increase of 116,001. Compared to no screening, high coverage of CrAg screening and pre-emptive treatment for CrAg-positive individuals in this population avoids one death for 2440 and 114 per DALY saved. In sensitivity analyses assuming a higher proportion of antiretroviral therapy (ART)-naïve patients (75% versus 15%), cost per death averted was 1472; 69 per DALY saved. Conclusions: CrAg screening for individuals with CD4 101-200 cells/L was estimated to have a modest impact, involve additional costs, and be less cost-effective than screening populations with CD4 counts ≤100 cells/L. Additional CrAg screening costs must be considered against other health system priorities.