Implementation of point-of-care testing and prevalence of cryptococcal antigenaemia among patients with advanced HIV disease in Mumbai, India.

Abstract

To describe the implementation of screening for cryptococcal antigenaemia by point-of-care (POC) serum cryptococcal antigen (CrAg) lateral flow assay, measure the prevalence and factors associated with serum cryptococcal antigenaemia in the routine programmatic setting. Cross-sectional study. Seventeen publicly funded antiretroviral therapy (ART) centres in Mumbai, India. Serum CrAg screening was offered to all adolescents (>10 years of age) and adults with advanced HIV disease (AHD) (CD4 <200 cells/mm³ or with WHO clinical stage III/IV) regardless of symptoms of cryptococcal meningitis. The primary outcome was to describe the implementation of serum CrAg screening and secondary outcome was to measure the prevalence of serum cryptococcal antigenaemia and its risk factors. A total of 2715 patients with AHD were tested for serum CrAg by POC assay. Of these, 25 (0.9%) had a CrAg positive result. Among CrAg-positive patients, only one had symptoms. Serum CrAg positivity was 3.6% (6/169) and 1.6% (6/520) among those presenting with CD4 <100 cells/mm³ in the treatment naïve and treatment experienced group, respectively. On multivariable analysis, CD4 count <100 cells/mm³ (OR: 2.3, 95% CI 1.01 to 5.3; p=0.05) and people living with HIV who were treatment naïve (OR: 2.5, 95% CI 1.04 to 6.0; p=0.04) were significantly associated with a positive serum CrAg result. Lumbar puncture was obtained in 20/25 patients within 4 days (range: 1-4 days) of positive serum CrAg result and one person was confirmed to have meningitis. All serum CrAg-positive patients who had a negative cerebrospinal fluid CrAg were offered pre-emptive therapy. Implementation of a POC CrAg assay was possible with existing ART centre staff. Initiation of pre-emptive therapy and management of cryptococcal antigenaemia are operationally feasible at ART centres. The Indian National AIDS Control Programme may consider reflexive CrAg screening of all AHD patients with CD4 <100 cells/mm³.