Microalbuminuria following exercise, an early sign of diabetic nephropathy

Microalbuminuria after physical exercise is characteristic for the preclinical stage of diabetic nephropathy, permitting an early diagnosis of this severe complication of diabetes mellitus. In 24 patients with type I diabetes, 11 women and 13 men free of clinical and biological signs of renal damage, the presence of microalbuminuria has been investigated by radial immunodiffusion in the urines collected between 3 and 7 hrs in the morning, as well as after a 20-min rest following a moderate exercise of 75 watts during 20 min at the ergometric bicycle. The patients were distributed into four groups, according to the age of disease, and microalbuminuria was expressed in micrograms/min. Compared with the mean values recorded in normal subjects by the same method (6.8 micrograms/min), the level of microalbuminuria has been significantly higher in the cases evaluating since more than two years, in keeping with the time elapsed after onset, and particularly following exercise. No relationship could be established between the quality of metabolic control of diabetes and the levels of microalbuminuria after exercise.