Brief Report: Geographical Variation in Prevalence of Cryptococcal Antigenemia Among HIV-Infected, Treatment-Naive Patients in Nigeria: A Multicenter Cross-Sectional Study.

Abstract

Worldwide, HIV-associated cryptococcal meningitis affects approximately 1 million persons and causes 600,000 deaths each year mostly in sub-Saharan Africa. Limited data exist on cryptococcal meningitis and antigenemia in Nigeria, and most studies are geographically restricted. We determined the prevalence of cryptococcal antigenemia (CrAg) among HIV-infected, treatment-naive individuals in Nigeria. This was a retrospective, cross-sectional study across 4 geographic regions in Nigeria. We performed CrAg testing using a lateral flow immunoassay on archived whole-blood samples collected from HIV-infected participants at US President's Emergency Plan for AIDS Relief (PEPFAR)-supported sites selected to represent the major geographical and ethnic diversity in Nigeria. Eligible samples were collected from consenting patients (>15 years) naive to antiretroviral therapy with CD4 count less than 200 cells per cubic millimeter and were stored in an -80°C freezer. A total of 2752 stored blood samples were retrospectively screened for CrAg. Most of the samples were from participants aged 30-44 years (57.6%), and 1570 (57.1%) were from women. The prevalence of CrAg positivity in specimens with CD4 <200 cells per cubic millimeter was 2.3% (95% confidence interval: 1.8% to 3.0%) and varied significantly across the 4 regions (P < 0.001). At 4.4% (3.2% to 5.9%), the South East contained the highest prevalence. The significant regional variation in CrAg prevalence found in Nigeria should be taken into consideration as plans are made to integrate routine screening into clinical care for HIV-infected patients.