Protein malnutrition and hypoalbuminemia as predictors of vascular events and mortality in ESRD

Background It is proposed that chronic inflammation is common to the pathogenesis of malnutrition and vascular disease, both frequently observed in patients with end-stage renal disease. However, previous studies were unable to differentiate between true protein malnutrition and hypoalbuminemia. Methods: This study was undertaken to determine the associations between malnutrition, measured by total-body nitrogen (TBN), and albumin, a marker of both nutritional status and chronic inflammation, with mortality and morbidity. One hundred nine patients starting dialysis therapy underwent nutritional assessment (TBN level and anthropometric measurements), vascular risk assessment (hypertension, hypercholesterolemia, diabetes mellitus, and smoking status), and serum albumin measurement. Subsequent patient mortality and new vascular events were recorded. Results: Survival was associated independently with both TBN (hazard ratio [HR], 1.6; 95% confidence interval [CI], 1.1 to 2.5; P = 0.02 for every 10% decrease in nitrogen index) and serum albumin levels (HR, 1.1; 95% CI, 1.0 to 1.2; P = 0.004 for every 0.1-g/dL (1-g/L) decrease in serum albumin level) adjusted for other variables. Only low serum albumin level predicted subsequent vascular morbidity (HR, 2.2; 95% CI, 1.0 to 4.9; P = 0.049), as did increasing age (HR, 2.0; 95% CI, 1.4 to 3.0; P = 0.0004 for every 10-year increase in age) adjusted for other important risk factors. Conclusion: This study dissociates the effect of protein malnutrition and hypoalbuminemia on morbidity and mortality in patients starting dialysis therapy. Protein malnutrition and hypoalbuminemia are independently predictive of mortality, whereas hypoalbuminemia is predictive of vascular morbidity. The study supports the hypothesis that hypoalbuminemia is pathogenically associated with vascular disease, but dissociates this effect from protein malnutrition.