Low Protein Nitrogen Appearance as a Surrogate of Low Dietary Protein Intake Is Associated with Higher All-Cause Mortality in Maintenance Hemodialysis Patients

• Published in: The Journal of nutrition Vol. 143; no. 7; pp. 1084 - 1092
• Main Authors: RAVEL, Vanessa A, MOLNAR, Miklos Z, KALANTAR-ZADEH, Kamyar, STREJA, Elani, JUN CHUL KIM, VICTOROFF, Alla, JENNIE JING, BENNER, Debbie, NORRIS, Keith C, KOVESDY, Csaba P, KOPPLE, Joel D
• Format: Journal Article
• Language: English
• Published: Bethesda, MD American Society for Nutrition 01.07.2013
• Subjects: Aged; Aged, 80 and over; Biological and medical sciences; Biomarkers - blood; Diet, Protein-Restricted; Dietary Proteins - administration & dosage; Feeding. Feeding behavior; Female; Follow-Up Studies; Fundamental and applied biological sciences. Psychology; Humans; Inflammation - pathology; Male; Middle Aged; Nitrogen - administration & dosage; Proportional Hazards Models; Prospective Studies; Renal Dialysis - mortality; Renal Insufficiency, Chronic - diet therapy; Renal Insufficiency, Chronic - mortality; Risk Factors; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Human; Maintenance hemodialysis; Nutrition; Food intake; Mortality; Nitrogen; Appearance; Protein; Feeding
• ISSN: 0022-3166; 1541-6100
• DOI: 10.3945/jn.112.169722

To determine the association between all-cause mortality and dietary protein intake in patients with chronic kidney disease, we performed a large-scale, 8-y prospective cohort study in 98,489 maintenance hemodialysis patients from a multicenter dialysis care provider. Compared with the reference level (60 to <70 g/d), low protein nitrogen appearance (PNA) levels [<30 g/d, HR: 1.40 (95% CI: 1.30, 1.50); 30 to <40 g/d, HR: 1.33 (95% CI: 1.28, 1.39)] was associated with higher all-cause mortality, and high PNA levels [≥110 g/d, HR: 0.92 (95% CI: 0.88, 0.97); 100 to <110 g/d, HR: 0.87 (95% CI: 0.82, 0.91)] were associated with lower all-cause mortality in all analyses. This association was also found in subanalyses performed among racial and hypoalbuminemic groups. Hence, using PNA as a surrogate for protein intake, a low daily dietary protein intake is associated with increased risk of death in all hemodialysis patients. Whether the association between dietary protein intake and survival is causal or a consequence of anorexia secondary to protein-energy-wasting/inflammation or other factors should be explored in interventional trials.