The relationship between the prognostic nutritional index and new-onset pneumonia in peritoneal dialysis patients

Purpose As an indicator of nutrition and immunity, the prognostic value of the prognostic nutritional index (PNI) has been confirmed in various diseases. However, the relationship between PNI and the incidence of pneumonia in peritoneal dialysis (PD) patients remains unknown. The purpose of this study was to investigate the relationship between PNI and new-onset pneumonia in patients undergoing PD. Methods Thousand two hundred and nighty eight patients were enrolled in this multicenter retrospective study from February 1, 2010, to February 28, 2020. A total of 899 patients were included in the final statistical analysis. The patients were stratified into two groups by PNI quartiles. The primary endpoint was a new-onset pneumonia event. Cox regression model analysis was used to explore the association between PNI and the first occurrence of pneumonia. Results During a mean follow-up of 41.43 months, 147 patients developed new-onset pneumonia. Kaplan–Meier survival curves showed a significant difference in the incidence of the first presentation of pneumonia between the two groups, that patients in the low PNI group had a higher risk of pneumonia ( P = 0.016). By adjusting for demographic parameters, comorbidities, and laboratory indicators, the Cox regression model showed that the high PNI group had less risk compared to the low PNI group (HR 0.479 95% CI 0.297–0.772, P = 0.003). There were no interactions in the subgroups as follows: diabetes, hypertension, age, and sex. Conclusions Low PNI levels were independently associated with the first occurrence of pneumonia in PD patients. PNI was an independent predictor of new-onset pneumonia in PD patients.