The role of serum calcium on carbohydrate metabolism in severely uraemic patients.

In 25 severely uraemic patients, the relation of serum calcium levels and oral glucose tolerance test (GTT) was studied. Seventeen of the 25 patients, who had a creatinine clearance of 6.16 +/- 1.24 ml . l-1 and a low serum calcium (6.53 +/- 0.35 mg%), had abnormal oral GTT, while from the other 8 patients, who had a creatinine clearance of 6.73 +/- 1.05 ml . l-1 and a normal serum calcium (8.75 +/- 0.60 mg%), only 4 had abnormal oral GTT. In 6 out of 17 patients, the low serum calcium (6.50 +/- 0.34 mg%) was normalized (8.85 +/- 0.54 mg%) by giving calcium gluconate in normal saline intravenously for two days. Subsequently to the calcium treatment, in four of these six patients the oral GTT changed to normal. The insulinogenic index showed increased secretion of insulin in the four patients whose oral GTT was normalized. These findings led us to the conclusion that low serum calcium is one of the contributing factors in the development of abnormal GTT in severely uraemic patients.