Early renal functional changes in children with insulin-dependent diabetes mellitus--their relation to metabolic control.

This is the first part of a study dealing with the predicted effect of early renal function changes on later development of diabetic nephropathy. Renal function was studied by the clearance method in 128 children with insulin dependent diabetes mellitus after 0, 2, 5 and 10 years duration of the disease. The glomerular filtration rate (GFR) and filtration fraction were significantly increased after 0-5 years, but after 10 years the GFR did not differ from that of controls, which finding might indicate an earlier onset of diabetic nephropathy in children. Renal plasma flow did not differ significantly from that of controls. Increased fractional sodium excretion in cases of recent onset might indicate inadequate adaptation of the proximal tubules to the increased filtered load or to inadequate insulin therapy. An inverse correlation was found between GFR and metabolic control as evaluated clinically and by glucosylated haemoglobin concentration, i.e., poor metabolic control corresponded with high glomerular filtration rates.