Plasma ultrafiltrable magnesium in insulin dependent diabetics.

Plasma ultrafiltrable (MgUF) and total magnesium concentrations were measured in 60 insulin dependent diabetics and compared with values in an age matched control group. Although the diabetic patients had lower plasma albumin concentrations (p less than 0.05), both ultrafiltrable and total magnesium concentrations were significantly decreased by 6.8% and 7.6%, respectively, compared with those of the controls (p less than 0.001). In the diabetic group MgUF varied inversely with fasting plasma glucose (r = -0.269, p less than 0.05). In 14 patients with significant hypomagnesaemia, fasting plasma glucose concentration was higher (p less than 0.01) and the diabetes was of shorter duration (p less than 0.05) than in 46 patients with an MgUF in the control range. The fasting urinary magnesium creatinine ratio was greater in the diabetic patients (p less than 0.05). Patients with retinopathy did not have lower plasma magnesium values than those without retinopathy.