Laboratory-reflex cryptococcal antigen screening is associated with a survival benefit in Tanzania

Abstract

Background: Cryptococcal antigen (CrAg) screening in persons with advanced HIV/AIDS is recommended to prevent death. Implementing CrAg screening only in outpatients may underestimate the true CrAg prevalence and decrease its potential impact. Our previous 12-month survival/retention in CrAg-positive persons not treated with fluconazole was 0%. Methods: HIV testing was offered to all antiretroviral therapy– naive outpatients and hospitalized patients in Ifakara, Tanzania, followed by laboratory-reflex CrAg screening for CD4 ,150 cells/ mL. CrAg-positive individuals were offered lumbar punctures, and antifungals were tailored to the presence/absence of meningitis. We assessed the impact on survival and retention-in-care using multivariate Cox-regression models. Results: We screened 560 individuals for CrAg. The median CD4 count was 61 cells/mL (interquartile range 26–103). CrAg prevalence was 6.1% (34/560) among individuals with CD4 #150 and 7.5% among #100 cells/mL. CrAg prevalence was 2.3-fold higher among hospitalized participants than in outpatients (12% vs 5.3%, P = 0.02). We performed lumbar punctures in 94% (32/34), and 31% (10/34) had cryptococcal meningitis. Mortality did not differ significantly between treated CrAg-positive without meningitis and CrAg-negative individuals (7.3 vs 5.4 deaths per 100 person-years, respectively, P = 0.25). Independent predictors of 6-month death/lost to follow-up were low CD4, cryptococcal meningitis (adjusted hazard ratio 2.76, 95% confidence interval: 1.31 to 5.82), and no antiretroviral therapy initiation (adjusted hazard ratio 3.12, 95% confidence interval: 2.16 to 4.50). Conclusions: Implementing laboratory-reflex CrAg screening among outpatients and hospitalized individuals resulted in a rapid detection of cryptococcosis and a survival benefit. These results provide a model of a feasible, effective, and scalable CrAg screening and treatment strategy integrated into routine care in sub-Saharan Africa.