Inflammation and dietary protein intake exert competing effects on serum albumin and creatinine in hemodialysis patients.
BACKGROUND
Cross-sectional studies have shown an inverse correlation between serum C-reactive protein (CRP) and serum albumin concentration in hemodialysis patients. The net effects of inflammation and dietary protein intake on nutritional markers over time are unknown.


METHODS
To explore the effects of CRP and normalized protein catabolic rate (nPCR) on serum albumin and creatinine, we analyzed six consecutive months of laboratory data from 364 hemodialysis patients, using a multivariable Mixed model with conservative biases.


RESULTS
The overall trend over time in serum albumin was slightly positive (0.039 g/dL/month) and in serum creatinine slightly negative (-0.052 mg/dL/month). With increasing CRP, serum albumin declined significantly (-0.124 g/dL/month per unit increase in log CRP, adjusted for age, gender, race, diabetes, and nPCR, P < 0.0001). Serum albumin increased with increasing nPCR (0.021 g/dL/month per 0.1 g/kg/day, P < 0.0001). The effect of CRP on albumin was attenuated in African Americans and at a higher nPCR. Corresponding values for creatinine mirrored those for albumin. With increasing CRP, creatinine declined significantly [-0.142 mg/dL/month per unit increase in log CRP, adjusted for age, gender, race, diabetes (time since initiation of dialysis; vintage), Kt/V, and nPCR, P = 0.002]. Serum creatinine increased with increasing nPCR (0.183 mg/dL/month per g/kg/day, P < 0.0001).


CONCLUSIONS
Proxies of inflammation and dietary protein intake exert competing effects on serum albumin and creatinine in hemodialysis patients. These data provide a rationale for prospective testing of dietary protein supplementation in hemodialysis patients with biochemical evidence of ongoing inflammation and "malnutrition."
Kaysen
G A
GA
Division of Nephrology, University of California, Davis, USA. gakaysen@ucdavis.edu
Chertow
G M
GM
Adhikarla
R
R
Young
B
B
Ronco
C
C
Levin
N W
NW
D000328:Adult; D000368:Aged; D002097:C-Reactive Protein / Q000378:metabolism; D015331:Cohort Studies; D003404:Creatinine / Q000097:blood*; D003430:Cross-Sectional Studies; D004044:Dietary Proteins / Q000494:pharmacology*; D005260:Female; D006760:Hospitalization; D006801:Humans; D007249:Inflammation / Q000097:blood*; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D009026:Mortality; D011379:Prognosis; D011506:Proteins / Q000378:metabolism; D006435:Renal Dialysis; D012709:Serum Albumin / Q000032:analysis*
D004044:Dietary Proteins; D011506:Proteins; D012709:Serum Albumin; D002097:C-Reactive Protein; D003404:Creatinine