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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/µL to ≤200 cells/µL. CrAg screening at CD4 ≤100 cells/µL is cost-effective; however, the cost-effectiveness of screening patients with CD4 101-200 cells/µL 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/µL. 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/µL, 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/µL was estimated to have a modest impact, involve additional costs, and be less cost-effective than screening populations with CD4 counts ≤100 cells/µL. Additional CrAg screening costs must be considered against other health system priorities.
RESUMO
PURPOSE OF REVIEW: The role of the CD4 cell count in the management of people living with HIV is once again changing, most notably with a shift away from using CD4 assays to decide when to start antiretroviral therapy (ART). This article reflects on the past, current and future role of CD4 cell count testing in HIV programmes, and the implications for clinicians, programme managers and diagnostics manufacturers. RECENT FINDINGS: Following the results of recent randomized trials demonstrating the clinical and public health benefits of starting ART as soon as possible after HIV diagnosis is confirmed, CD4 cell count is no longer recommended as a way to decide when to initiate ART. For patients stable on ART, CD4 cell counts are no longer needed to monitor the response to treatment where HIV viral load testing is available. Nevertheless CD4 remains the best measurement of a patient's immune and clinical status, the risk of opportunistic infections, and supports diagnostic decision-making, particularly for patients with advanced HIV disease. SUMMARY: As countries revise guidelines to provide ART to all people living with HIV and continue to scale up access to viral load, strategic choices will need to be made regarding future investments in CD4 cell count and the appropriate use for clinical disease management.