DOES EVIDENCE EXIST THAT CORRECTION OF METABOLIC ACIDOSIS IMPROVES BONE MINERAL METABOLISM IN CHRONIC UREMIA?
In a well designed study by Lefebvre et al, 21 patients on hemodialysis were randomly allocated to treatment with either a conventional dialysate bicarbonate concentration (33 mmol/liter) or dialysis with an additional supplementation of bicarbonate to elevate predialysis serum-HCO3 to 24 mmol/liter for 18 months59. Progression of sHPT was documented by increased plasma PTH and bone histology in patients treated with the conventional solution, while there was no further progression of histological and serological findings in the patients with eubicarbonatemia. Furthermore, in patients with a suppressed bone formation rate at baseline, serum osteocalcin levels as a marker for increased osteoblast activity increased in the high bicarbonate group, but remained low in the control group treated with the conventional dialysate. Metabolic acidosis may further alter the sensitivity of the parathyroids to calcium, as pointed out recently by Graham and coworkers60. Performing dynamic studies of
