Different types of proteinuria in diabetes mellitus

Urinary protein concentration and urinary protein pattern as determined by sodium dodecyl sulphate polyacrylamide gel electrophoresis, were investigated in 53 type 1 diabetic children and in 56 (41 type 1 and 15 type 2) diabetic adults. Reversible tubular proteinuria was found in 26 diabetic children with hyperglycaemic ketoacidosis. Among the patients, 43 exhibited physiological, 31 fixed tubular and nine glomerular type proteinuria. The prevalence of retinopathy and neuropathy in the different patient groups has also been evaluated. Urinary protein concentration appeared to be above the usual reference values during hyperglycaemic ketoacidosis, and was normalized with the successful control of metabolism. In the other three groups, urinary protein concentration was increased only in the case of glomerular type proteinuria. It is suggested that the above classification characterizes the development of diabetic nephropathy, progressing from reversible tubulointerstitial dysfunction through fixed tubulointerstitial dysfunction to glomerulopathy.