Effects of correction of metabolic acidosis on blood urea and bone metabolism in patients with mild to moderate chronic kidney disease: a prospective randomized single blind controlled trial.

BACKGROUND: There are no controlled trials on the efficacy of oral bicarbonate therapy in patients with mild to moderate chronic kidney disease (CKD). This prospective randomized controlled study was done to evaluate the effects of correction of metabolic acidosis on renal functions and bone metabolism in this group of patients.

PATIENTS AND METHODS: Forty patients were randomized to treatment with oral bicarbonate or placebo for a period of 3 months. Investigations at baseline included venous pH, bicarbonate, renal functions, serum iPTH, and bone radiology. The treatment group (Group B) received daily oral sodium bicarbonate therapy at a dose of 1.2 mEq/kg of body weight. Their venous blood pH and bicarbonate levels were estimated weekly to keep blood pH near 7.36 and bicarbonate at 22-26 mEq/L by adjusting the dose of sodium bicarbonate. At the end of 3 months, all the tests were repeated in both groups.

RESULTS: After oral bicarbonate therapy (OBT), there was a significant decline in the rise of blood urea level in Group B associated with a sense of well-being in 50% patients. The rise in parathormone (PTH) was six times the baseline value in Group A and only 1.5 times baseline value in Group B, although not statistically significant. There was no significant change in total calcium, phosphorus, alkaline phosphatase, creatinine, total protein, or albumin levels.

CONCLUSION: Correction of metabolic acidosis in patients with moderate CKD attenuates the rise in blood urea and PTH, which might prevent the deleterious long-term consequences of secondary hyperparathyroidism.