Prognostic Nutritional Index, Circulating Bacterial and Viral DNA, and Neurocognitive Vulnerability in Geriatric Inpatients: A Cross-Sectional Study

Background/Objectives: Impaired immunonutritional status is common among hospitalized older adults and may contribute to adverse outcomes through alterations in gut–brain axis pathways involving immune, microbial, and inflammatory mechanisms. The Prognostic Nutritional Index (PNI), a composite marker based on serum albumin and lymphocyte count, may identify patients with altered immunonutritional status and increased clinical vulnerability. This cross-sectional study investigated whether PNI-defined immunonutritional impairment is associated with bacterial and viral DNAemia, inflammation, and neurocognitive conditions in 1016 geriatric patients from the Report-AGE cohort.

Methods

Participants were stratified according to PNI into low- and high-PNI groups. Blood bacterial DNA (BB-DNA), Torque teno virus (TTV), herpes simplex virus (HSV-1), varicella-zoster virus (VZV), leukocyte telomere length (LTL), inflammatory and neurodegeneration-related biomarkers were evaluated. Multivariable logistic regression models were used to assess the associations of BB-DNA and PNI with cognitive impairment and interRAI-derived neurocognitive conditions.