Outcomes of gastrointestinal malignancies in HIV: The impact of opportunistic and non-opportunistic infections.

Abstract

e16350 Background: Gastrointestinal (GI) malignancies are a major source of cancer-related mortality. Human immunodeficiency virus (HIV) patients face an inordinate cancer burden, and in the antiretroviral therapy (ART) era, non-AIDS-defining GI malignancies account for many HIV hospitalizations. Opportunistic infections (OIs) may represent an overlooked driver of adverse inpatient outcomes. While ART has reduced the incidence of OIs such as cytomegalovirus, hospitalized patients with HIV may still develop OIs or non-OIs, defined as “community-acquired” pathogens. The impact of infection phenotype on inpatient outcomes across individual GI cancer sites remains poorly characterized. Methods: We conducted a retrospective cohort study using the National Inpatient Sample (2018–2021) of adults hospitalized with GI malignancies. HIV status, infection phenotype (OI, non-OI, or none), and cancer site were defined using ICD-10. The primary outcome was in-hospital mortality; secondary outcomes included mechanical ventilation (MV), shock, length of stay (LOS), and non-home discharge. Survey-weighted multivariable regression adjusted for demographics, socioeconomic factors, payer, cancer site, and year. Exploratory subgroup analyses among HIV-positive patients evaluated individual OIs. Results: Infection phenotype was the significant driver of mortality with OIs 3.2 times and non-OIs 5.1 times more likely (p < .0001) but not HIV status (p = 0.64). Mortality varied by cancer site, with increased odds across most sites except rectal. Infection phenotype demonstrated site-specific heterogeneity: OIs were associated with increased mortality among colon, rectosigmoid, and rectal cancers (all p < .012), while non-OIs were associated among esophageal, hepatobiliary, pancreatic, rectal, and other digestive cancers (all p < .024). OIs were associated with increased odds of shock and MV, whereas HIV status and non-OIs were associated with lower odds (all p < .0001). Both OIs and non-OIs were associated with increased LOS and non-home discharge (p < .0001). Subgroup analyses of individual OIs were not statistically significant. Conclusions: Among hospitalizations with GI malignancies, infection phenotype, not HIV status, was the primary driver of mortality and critical illness. Both OIs and non-OIs conferred substantial risk, with non-OIs demonstrating equal or greater associations with adverse outcomes, highlighting the importance of these infections. Infection-associated risk varied by GI cancer site, suggesting site-specific vulnerability to infectious complications. This nationally representative analysis provides one of the first comprehensive evaluations of HIV status, infection phenotype, and GI-cancer site locations emphasizing the need for early recognition and targeted management of infectious complications to improve inpatient outcomes in this population.