[Detection of Histoplasma capsulatum antigen in urine as a prognostic tool in patients with advanced HIV infection].

Introduction: The main objective of this study was to evaluate the association between the baseline level of Histoplasma capsulatum urinary antigen (AgU) and the severity of histoplasmosis in the context of HIV, as well as its utility for treatment monitoring. Secondary objectives included determining the appropriate cutoff point for AgU detection for the diagnosis of proven histoplasmosis.

Materials and methods: The study was an analytical, retrospective cohort study in adults diagnosed with HIV, with at least one determination of AgU using ELISA. Sociodemographic, clinical, and laboratory variables were collected. Statistical analysis was performed using R-project® software.

Results: A total of 452 individuals with AgU were included from March 2018 to July 2022, with 42 (9.3%) positive results (25 proven histoplasmosis and 17 probable cases). An statistically significant correlation was found between the baseline concentration of AgU and positive cultures. However, the utility of AgU as a followup tool could not be evaluated. The optimal cutoff point for detecting proven histoplasmosis was an AgU value ≥2.2 ng/mL (specificity: 96.3% and sensitivity: 100%).

Discussion: Further studies are needed to evaluate the utility of AgU as a tool for monitoring antifungal treatment. A value of AgU ≥2.2 ng/mL could potentially correspond to a diagnosis of proven histoplasmosis.