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 betwe en serum C-reactive protein (CRP) and serum albumin concentration in hemodi alysis 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 rat e (nPCR) on serum albumin and creatinine, we analyzed six consecutive month s 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, di abetes, 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 albu min was attenuated in African Americans and at a higher nPCR. Corresponding values for creatinine mirrored those for albumin. With increasing CRP, cre atinine declined significantly [-0.142 mg/dL/month per unit increase in log CRP, adjusted for age, gender, race, diabetes (time since initiation of di alysis: vintage), Kt/V. and nPCR, P = 0.002]. Serum creatinine increased wi th increasing nPCR (0.183 mg/dL/month per g/kg/day, Pt 0.0001). Conclusions. Proxies of inflammation and dietary protein intake exert compe ting effects on serum albumin and creatinine in hemodialysis patients. Thes e data provide a rationale for prospective testing of dietary protein suppl ementation in hemodialysis patients with biochemical evidence of ongoing in flammation and "malnutrition.".