Protein Nutrition Index as a Function of Patient Survival Rate in Peritoneal Dialysis

Abstract

Background/Aims: Protein-energy wasting (PEW) is a well-known risk factor of long-term survival in peritoneal dialysis (PD) patients. Serum albumin is a measure of visceral protein, lean body mass is a measure of somatic protein stores and normalized protein nitrogen appearance is a measure of daily protein intake. A protein nutrition index (PNI) that combined these 3 factors was designed and tested as a function of survival in PD patients. Methods: We enrolled 552 PD patients for this study. Demographic, biochemical, nutritional markers, comorbidity and dialysis-related data were obtained. The PNI was calculated. All patients were followed up to investigate the risks for mortality. Results: Patients with probable PEW/low-average nutrition were older and had lower serum creatinine (Cr) and blood urea nitrogen, lower adequacy data and higher D4/P4 Cr compared with patients with high-average/good nutrition. 108 patients (19.6%) died during the observational period. By multivariate analysis, we found only age, comorbidity index and PNI (relative risk = 0.84, confidence interval: 0.76–0.93, p = 0.001) to be independent predictors of mortality. Conclusion: The PNI at the start of PD is associated with all-cause mortality, and each increase by a score of 1 in PNI leads to a 16% decrease in the risk of mortality. Predialysis evaluation of this scoring system is recommended for further research in order to improve outcomes in PD patients.