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 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.