Prevalence of cryptococcal antigenuria at initial HIV diagnosis in KwaZulu-Natal

Objectives: The World Health Organization (WHO) recommends screening HIV-infected people for cryptococcal antigens to identify cryptococcosis, a major cause of AIDS-related deaths. As the burden of cryptococcosis is unknown in South Africa's KwaZulu-Natal province, we assessed the cryptococcal antigenuria prevalence among newly diagnosed HIV-infected adults there.

Methods: We conducted a cross-sectional study of newly diagnosed HIV-infected adults who received voluntary HIV testing in an out-patient clinic. Participants provided a urine specimen in a sterile container, and we performed testing with a WHO-endorsed rapid cryptococcal antigen lateral flow assay (Immy Inc., Norman, OK, USA) per the manufacturer's specifications. We assessed cryptococcal antigenuria prevalence among participants with CD4 counts < 200 cells/μL, and stratified results by CD4 count categories.

Results: Among 432 participants, the mean (± standard deviation) age was 36.1 ± 9.9 years and 172 (40%) were female. The overall estimated prevalence of cryptococcal antigenuria was 9.0% [95% confidence interval (CI) 6.5-12.1%]. CD4 counts were available for 319 participants (74%); the median CD4 count was 75 cells/μL [interquartile range (IQR) 34-129 cells/μL]. Participants with a negative cryptococcal antigenuria screening test had a median CD4 count of 79 cells/μL (IQR 36-129 cells/μL), while participants with a positive cryptococcal test had a median CD4 count of 41 cells/μL (IQR 10-112 cells/μL). The estimated prevalence of cryptococcal antigenuria among participants with CD4 counts < 50 cells/μL was 12.5% (95% CI 7.0-20.1%), which was significantly higher than that among participants with CD4 counts of 50-200 cells/μL (4.8%; 95% CI 2.3-8.7%).

Conclusions: Nearly 1 in 10 newly diagnosed HIV-infected adults with CD4 counts < 200 cells/μL in KwaZulu-Natal had evidence of cryptococcal antigenuria. Point-of-care CD4 count testing and cryptococcal antigen screening may rapidly identify cryptococcosis at the time of HIV diagnosis.