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 Universitário Clementino Fraga Filho (Rio de Janeiro, Brazil).

Patients: Thirty CKD patients undergoing conservative treatment were divided according to plasma HCO(3)(-) values into acidotic (HCO(3)(-) 22 mM, n = 15).

Main Outcome Measure: Biochemical, nutritional, and anthropometric parameters and PRAL were measured.

Results: The mean of plasma HCO(3)(-) 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 HCO(3)(-) 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.