Objective: To examine the associations of total protein intake (TPI) and dietary protein intake (DPI) with baseline nutrition and subsequent mortality.
Design: Retrospective analysis of incident dialysis patients.
Setting: National cohort from The United States Renal Data System data.
Patients: Incident dialysis patients (n = 5,059) with blood urea nitrogen (BUN) and urea clearances reported on form 2728.
Methods: TPI was calculated from BUN and urea clearance. DPI was defined as TPI divided by weight. Urinary creatinine (UCr) calculated from creatinine clearance and serum creatinine was used as a marker of muscle mass. The associations of TPI and DPI with each of serum albumin < or = 3.3 g/dL (50th percentile), UCr < or = 0.56 g/d (25th percentile), body mass index < 18.5, and death were examined.
Results: Compared with patients in the highest quartile of TPI (> 60.2 g/d), those in the lowest quartile (< or = 32.4 g/d) had 1.89-fold higher odds (P < .001) of low serum albumin, 10.22-fold higher odds (P < .001) of low UCr, and 3.83-fold higher odds (P < .001) of low body mass index in multivariable logistic regression models, and an 18% increase (P < .001) in hazard of death. Compared with patients with DPI > 1.2 g/kg/d, those with DPI < 0.8 g/kg/d had nonsignificantly higher odds of low serum albumin, 2.38-fold higher odds (P < .001) of low UCr, and 0.44-fold lower odds (P < .001) of low body mass index, and a 15% (P = .04) decrease in hazard of death.
Conclusions: Higher TPI is associated with better nutrition at baseline and subsequent survival. Normalization of TPI by body weight provides contradictory information on nutritional status as well as survival.