Influence of Renal Function and Diet on Acid-Base Status in Chronic Kidney Disease Patients

Objective: We investigated the influence of potential renal acid load (PRAL) and renal function on the degree of metabolic acidosis in patients with chronic kidney disease (CKD). Design: This was a cross-sectional study. Setting: This study was conducted at the Nephrology Outpatient Division of the Hospital Universitario Clementino Fraga Filho (Rio de Janeiro, Brazil). Patients: Thirty CKD patients undergoing conservative treatment were divided according to plasma HCO3- values into acidotic (HCO3- <= 22 mM, n = 15) and nonacidotic (HCO3- > 22 mM, n = 15). Main Outcome Measure: Biochemical, nutritional, and anthropometric parameters and PRAL were measured. Results: The mean of plasma HCO3- values was 17.7 +/- 2.8 mM in the acidotic group, and 25.1 +/- 2.2 mM in the nonacidotic group. There was no significant difference in mean PRAL values between the acidotic (9.8 +/- 6.4 mEq/ day) and nonacidotic (12.7 +/- 10.0 mEq/day) groups, but there was a significant correlation between plasma HCO3- and creatinine clearance (r = 0.78, P < .0001). Based on the receiver operating characteristic curve, the level of creatinine clearance to begin detection of acidosis was 31.8 mL/min, with a sensitivity and specificity of 86.7%. Conclusion: The acid-base status of this group of CKD patients undergoing conservative treatment was mainly determined by degree of renal insufficiency rather than diet. (C) 2009 by the National Kidney Foundation, Inc. All rights reserved.