Association between albumin-based nutritional inflammation indices and all-cause mortality in patients with severe pneumonia

Severe pneumonia is associated with high mortality rates. Nutritional and inflammatory status significantly impacts outcomes. While albumin-based indices have been demonstrated to predict outcomes in other diseases, their role in severe pneumonia remains underexplored. This study aimed to investigate the association between albumin-based nutritional inflammation indices and all-cause mortality in patients with severe pneumonia. A retrospective cohort study was conducted using data from the SCRIPT CarpeDiem Dataset. 488 critically ill patients with severe pneumonia (188 COVID-19, 250 bacterial, 50 other viral) requiring mechanical ventilation were included. Five albumin-based indices were calculated: Neutrophil-albumin ratio (NAR), Prognostic Nutritional Index (PNI), Advanced Lung Cancer Inflammation Index (ALI), Lymphocyte × albumin index (LA), and CRP-albumin-lymphocyte index (CALLY). The primary outcome was all-cause mortality. Associations were assessed using logistic regression (continuous and quartile-based) and restricted cubic spline (RCS) analyses, adjusting for confounders (age, gender, BMI, race). The overall mortality rate was 44.5% (n = 217). Logistic regression revealed higher NAR was associated with increased mortality risk (Continuous OR: 1.11, 95% CI: 1.03–1.20, p = 0.007; Q4 vs Q1 OR: 1.94, 95% CI: 1.17–3.23, p = 0.011). Higher PNI (Continuous OR: 0.93, 95% CI: 0.91–0.96, p < 0.001; Q4 vs Q1 OR: 0.23, 95% CI: 0.14–0.40, p < 0.001) and LA (Continuous OR: 0.99, 95% CI: 0.98–0.99, p < 0.001; Q4 vs Q1 OR: 0.33, 95% CI: 0.19–0.55, p < 0.001) were protective. Higher ALI and CALLY quartiles were also associated with reduced mortality (Q4 vs Q1 OR: 0.35, p < 0.001 and OR: 0.42, p < 0.001, respectively). RCS analyses confirmed significant non-linear associations for all indices (all overall p < 0.05). Albumin-based nutritional inflammation indices (NAR, PNI, ALI, LA, CALLY) are significantly associated with all-cause mortality in severe pneumonia patients. Elevated NAR is a risk factor, while higher PNI, ALI, LA, and CALLY are protective factors. These indices provide valuable prognostic information for risk stratification.