Infections, particularly sepsis, are a global health threat and a leading cause of mortality among elderly patients (≥ 60 years) in intensive care units (ICUs). The variable immune responses in this vulnerable population warrant deeper investigation. This multicenter prospective study included elderly patients with infections admitted to the ICUs of four hospitals between May 2023 and October 2024. Patients were classified into sepsis and non-sepsis infection groups based on a ≥2-point increase in Sequential Organ Failure Assessment (SOFA) score. Baseline immune and inflammatory markers were compared between groups. Logistic regression analyses were used to assess associations with mortality. Subgroup analyses were conducted by sex, age, infection site, and pathogen type. Among 1,152 elderly patients with infections in the ICUs, 640 with sepsis were older (70.0 vs.72.0 years), were predominantly male (55.3% vs. 68.1%), and had more comorbidities, all P 1, all P 1), decreased T cells (OR 0.05). Sex differences included higher levels of innate immune markers in males and elevated adaptive immune indicators in females. With age, patients showed reduced T cell counts and increased inflammatory markers (procalcitonin and C-reactive protein). Patients aged > 80 years exhibited marked lymphopenia, lower CD4+ T cell counts (β 1, P 1, P < 0.05) compared with bacterial infections, whereas viral infections showed reduced T cell subsets and cytokine levels (IL6, IL8, IL17; β < 1, P < 0.05). Elderly patients in the ICU, especially those with sepsis, exhibit immune imbalances of hyperinflammation and immunosuppression, varying with age, sex, pathogen type, and infection site. These findings highlight the potential role of immune phenotyping in guiding treatment decisions in this patient population.
Ju et al. (Wed,) studied this question.