Effects of oral base therapy on serum ionized calcium, phosphorus and parathyroid hormone in chronic hemodialysis patients.

The purpose of this study was to evaluate the effects of oral base therapy on selected chemical parameters in chronic hemodialysis patients. Oral base supplements were administered to 20 acidotic chronic hemodialysis patients for one month. Serum bicarbonate levels rose from 18.6 +/- 2.9 to 22.5 +/- 4.0 mEq/L (p less than 0.0005) and pH rose from 7.35 +/- 0.03 to 7.39 +/- 0.04 (p less than 0.0005). Serum ionized calcium levels fell from 5.03 +/- 0.37 to 4.83 +/- 0.34 mg/dL (1.25 +/- 0.09 to 1.21 +/- 0.08 mmol/L) (p less than 0.01), while intact parathyroid hormone (PTH) levels rose from 547 +/- 697 to 619 +/- 776 pg/mL (p less than 0.05). Base therapy did not result in significant changes in serum levels of total calcium, phosphorus, alkaline phosphatase, urea nitrogen, creatinine, total protein, albumin or potassium. If empiric therapy with exogenous base is given to dialysis patients, ionized calcium levels should be closely monitored since changes in calcium supplement or vitamin D therapy may be required to maintain ionized calcium and parathyroid hormone values at the pre-treatment levels.