The Effect of Correction of Metabolic Acidosis on Calcium and Protein Metabolism in Patients on Hemodialysis

Acid-base balance can be improved in the patient on hemodialysis by increasing the dialysate bicarbonate. One hundred and forty-three adult patients undergoing hemodialysis at a university hospital dialysis center were studied for two consecutive months. After the regular dialysis treatment of 35 mEq/L of dialysate bicarbonate for one month, the experimental group (n = 110 patients) received an increase in their dialysate bicarbonate to 38 mEq/L. The control group (n = 33) was given their regular dialysis treatment of 35 mEq/L of dialysate bicarbonate for the entire two month study period. Monthly serum bicarbonate levels were compared in the experimental group and in the control group. Metabolic acidosis was corrected postdialysis in the experimental group as evidenced by improved levels of bicarbonate; midweek predialysis serum bicarbonate levels increased from 20.2 ± 0.3 (Mean ± SEM) to 21.2 ± 0.3 (p = 0.02), and midweek postdialysis serum bicarbonate levels increased from 27.1 ± 0.3 (Mean ± SEM) to 28.8 ± 0.3 (p = 0.000). In the experimental group the serum calcium levels increased from 8.3 ± 0.1 (Mean ± SEM) to 8.6 ± 0.1 (p = 0.04) despite a decrease in the dialysate calcium (30 to 2.8 mEq/L). No changes in the dialysate calcium or serum calcium occurred in the control group during the two month period. Improved serum calcium levels may reflect changes occurring in bone metabolism. No changes were detectable in protein metabolism after monthly analysis of the caloric and dietary protein intakes. KT/V. and protein catabolic rate during this short evaluation period.