Abstract
OBJECTIVE: This study aimed to investigate the association between prognostic nutritional index (PNI) and mortality risk in Chinese patients with pneumonia. METHODS: This retrospective cohort study was conducted using a multicenter hospital database of adult patients with pneumonia in China. We analyzed data from 635 patients diagnosed with pneumonia at six secondary and tertiary academic hospitals in China between 1 January 2013 and 31 December 2019. Cox regression analysis was used to compare the mortality rates across the PNI tertiles. Restricted cubic spline (RCS) models, Kaplan-Meier survival analysis and Subgroup Analysis were used to explore the association between PNI and the clinical outcomes of these pneumonia patients. RESULTS: A total of 635 patients were included. In the fully adjusted model, each 1-unit increase in PNI was associated with a 5.0% reduction in 30-day mortality risk (HR = 0.950, 95% CI: 0.929-0.972, p < 0.001) and a 4.5% reduction in 90-day mortality risk (HR = 0.955, 95% CI: 0.934-0.975, p < 0.001). Compared with the lowest PNI tertile (Tertile 1), patients in the highest tertile (Tertile 3) had a 64.5% lower risk of 30-day mortality (HR = 0.335, 95% CI: 0.212-0.594, p < 0.0001) and a 60.6% lower risk of 90-day mortality (HR = 0.394, 95% CI: 0.247-0.627, p < 0.0001). Restricted cubic spline (RCS) analysis further illustrated a consistent inverse relationship between PNI and mortality risk. Additionally, Kaplan-Meier survival curves indicated significantly lower cumulative mortality with higher PNI values. CONCLUSION: Our investigation identified a significant association between poorer PNI scores and higher mortality in Chinese patients with pneumonia.