Factors Associated with ICU Admission and In-Hospital Mortality in a Decade of HIV/AIDS Admissions to a Tertiary Hospital at the Epicenter of the Brazilian Epidemic (2015-2024)

<title>Abstract</title> <p> Background: South Brazil experiences disproportionately high HIV/AIDS morbidity and mortality. To characterize the regional epidemic profile, we evaluated HIV hospitalizations over time. Methods: In a retrospective cohort of adults hospitalized with HIV between 2015–2024 to a tertiary institution in Porto Alegre, data extracted from institutional records was analyzed for hospitalization outcomes. Severe outcomes (SO) were defined as critical care admission or in-hospital mortality. Results: Among 5218 infectious disease hospitalizations, 3596 were due to HIV (69%), encompassing 2376 participants; 1555 (65%) met WHO stage III/IV criteria for advanced HIV disease (AHD). Most patients were white (65%), male (53%), urban (65%). Among AHD participants, 77% had not completed high school. From 2015 to 2024, median age of patients increased from 41 to 44 years (p &lt; 0.001). Declines in new HIV diagnoses following admission (p = 0.017) and AHD admissions (p = 0.015) occurred over time; new HIV diagnoses in AHD patients remained unchanged (p = 0.107). AHD case fatality rate of 11% remained stable (p = 0.287). Tuberculosis was the most prevalent reason for admission (21%, n = 488) followed by bacterial pneumonia (14%, n = 312) in AHD patients. Bacterial pneumonia was leading cause of admission in non-AHD patients (12%, n = 151). OIs and nosocomial infections were implicated in over half of in-hospital mortalities. Factors associated with SO were sepsis, pneumocystis pneumonia, nosocomial infections, non-opportunistic malignancy, tuberculosis, new HIV diagnoses and/or CD4 &lt; 50 cells/mm ³ . Conclusion: In south Brazil, late HIV diagnoses and barriers to care appear to drive mortality. Targeted efforts to diagnose and engage patients in care earlier are warranted to prevent severe outcomes. </p>