Serum ascorbic acid and protein calorie malnutrition in continuous ambulatory peritoneal dialysis patients

Protein calorie malnutrition (PCM) is a major predictor of morbidity and mortality in continuous ambulatory peritoneal dialysis (CAPD) patients. Oxidative stress has been implicated as a contributory cause. The relative lack of ascorbic acid, a plasma antioxidant, has been reported in CAPD patients. We therefore examined the correlation between serum ascorbic acid (SAA) and parameters of PCM in a cross-sectional study of 50 clinically stable adult CAPD patients. The mean age of the study group was 61 +/- 11 years; 48% of the patients were male; and 64% had diabetes. The parameters assessed were SAA, serum albumin (S Alb), body mass index (BMI), subjective global assessment (SGA), and lean body mass (LBM). The results (mean +/- standard deviation) were: SAA, 9.44 +/- 8.79 mg/L; S Alb, 31.6 +/- 4.9 g/L; BMI, 24.4 +/- 3.4; LBM, 0.66 +/- 0.14 kg/kg body weight; SGA, 9 of 50 were considered mildly-to-moderately malnourished (the rest were well-nourished). A significant correlation (p < 0.001) was found between SAA and S Alb only with SAA < or = 9 mg/L. No correlation was seen between SAA (at any level) and BMI or LBM. The SAA was not significantly different between the groups as graded by SGA. The data suggest that the mechanisms for low serum albumin in these patients may be related to the role of ascorbic acid as a plasma antioxidant.