Objective: To evaluate the association of the admission Prognostic Nutritional Index (PNI) with concomitant pulmonary infection and in-hospital mortality in hospitalized lung cancer patients. Methods: In this retrospective cohort study, 417 lung cancer patients admitted between December 2022 and November 2023 were categorized into those with (n=218) and without (n=199) concomitant pulmonary infection based on clinical, radiological, and microbiological evidence within 48 hours of admission. The PNI and other inflammatory indices, including the systemic immune-inflammation index (SII), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), and monocyte-to-lymphocyte ratio (MLR), were calculated from admission laboratory data. Multivariable logistic regression adjusted for age, sex, cancer stage, chronic obstructive pulmonary disease (COPD), etc. and receiver operating characteristic (ROC) analyses were used. Results: Patients with concomitant pulmonary infection had significantly lower PNI (median: 45.03 vs. 47.25, P < 0.001) and higher SII (median: 724.00 vs. 448.00, P < 0.001) compared to those without infection. Lower PNI (aOR: 0.964, 95% CI: 0.942– 0.986) and higher SII (aOR: 1.001, 95% CI: 1.000– 1.001) were independently associated with concomitant infection. Among infected patients, non-survivors had significantly lower PNI (mean: 39.85 vs. 46.67, P < 0.001) and higher MLR (median: 0.50 vs. 0.32, P < 0.001) compared to survivors. Lower PNI (aOR: 0.854, 95% CI: 0.796– 0.916) and higher MLR (aOR: 1.377, 95% CI: 1.026– 1.849) were independently associated with in-hospital mortality. The combination of PNI and MLR achieved an AUC of 0.806 (95% CI: 0.747– 0.857) for mortality discrimination. Conclusion: Admission PNI is significantly associated with concomitant pulmonary infection and independently associated with in-hospital mortality in infected lung cancer patients. Combining PNI with SII or MLR may enhance risk stratification and nutritional-immunological assessment in this vulnerable population. Keywords: lung cancer, pulmonary infection, prognostic nutritional index, nutritional status, inflammation, in-hospital mortality
Wang et al. (2026) studied this question.