Histoplasmosis screening using urinary antigen detection in people living with HIV in Southern Brazil

Histoplasmosis is a life-threatening opportunistic infection in individuals with advanced HIV disease, particularly in endemic regions such as Latin America. Early diagnosis is crucial for reducing mortality but remains underdiagnosed due to non-specific clinical presentations and limited diagnostic access. This study evaluates the impact of systematic histoplasmosis screening over 18 months (March 2021-September 2022) using the Histoplasma urinary antigen detection test in people living with HIV (PLHIV) receiving outpatient care or hospitalized at a reference center in Southern Brazil. A retrospective analysis was conducted on PLHIV screened with the Clarus® Histoplasma GM enzyme immunoassay (HGM-EIA, IMMY, USA). Inclusion criteria comprised a recent HIV diagnosis (≤ 30 days), poor adherence to or abandonment of antiretroviral therapy (>90 days), CD4 + count < 200 cells/mm³, or clinical/radiological findings suggestive of histoplasmosis. Clinical, laboratory, and treatment data were assessed, along with 90-day outcomes. Among 287 PLHIV screened, Histoplasma antigen was detected in 9.1% (26/287), including 19.6% of hospitalized patients and 6.4% of outpatients. Overall mortality was 24%, with a higher rate among inpatients (27.3%). Fever, neurological impairment, and lung opacification were more frequent in hospitalized cases. Amphotericin B deoxycholate was more commonly administered to inpatients (63.6% vs. 25%). Mortality at 90 days was significantly higher in patients with a histoplasmosis case-fatality score ≥ 5 (66.7% vs. 33.3%, P = .016). Systematic screening enhances early detection of histoplasmosis, facilitating timely treatment and reducing hospitalizations and mortality.