Assessing the Prognostic Performance of Pan Immune-Inflammation Value and Inflammatory Biomarkers in Critically Ill Patients with Community-Acquired Pneumonia

Community-acquired pneumonia (CAP) remains a major cause of morbidity and mortality, particularly among critically ill patients in intensive care units (ICUs). Although various clinical scoring systems are used for prognostic stratification, their limitations have prompted interest in novel biomarkers. The pan-immune-inflammation value (PIIV) is a recently proposed index assessing systemic inflammation and immune status. This study investigates the relationship between PIIV, traditional inflammatory markers, and mortality outcomes in ICU-admitted CAP patients. A total of 248 CAP patients were retrospectively analyzed. Demographic, clinical, and laboratory data were obtained from electronic medical records. Associations between these variables and 30-day mortality were evaluated. Univariate and multivariate logistic regression analyses identified independent mortality predictors, and Receiver Operating Characteristic (ROC) analysis assessed diagnostic performance. Among 248 patients, 156 (62.9%) died. PIIV, procalcitonin, lactate, and neutrophil-lymphocyte ratio (NLR) levels were significantly higher in non-survivors. Multivariable analysis identified PIIV (adjusted OR: 1.227; 95% CI: 1.097–1.372; p < 0.001), lactate (adjusted OR: 1.637; 95% CI: 1.290–2.077; p < 0.001), and procalcitonin (adjusted OR: 1.017; 95% CI: 1.002–1.033; p = 0.022), as independent predictors of 30-day mortality. ROC analysis showed optimal cut-off values: PIIV ≥1928.3 (54.5% sensitivity, 70.7% specificity), lactate ≥1.6 mmol/L (75.6% sensitivity), and procalcitonin ≥1.26 ng/mL (73.7% sensitivity, 61.9% specificity). PIIV is an independent prognostic indicator of mortality in CAP patients, reflecting systemic inflammation through multiple hematological parameters. It may capture complex immune-inflammatory dynamics and serve as a useful adjunctive biomarker alongside established markers.