Kidney function in newly diagnosed Type 2 (non-insulin-dependent) diabetic patients, before and during treatment

Summary Glomerular filtration rate, kidney volume, and urinary albumin excretion rate were studied in otherwise healthy newly diagnosed Type 2 (non-insulin-dependent) diabetic patients, untreated at diagnosis, after short-term treatment and after 3 months treatment. In 10 patients (Group A) glomerular filtration rate (measured by the plasma clearance of 51-Cr-EDTA) decreased from the time of diagnosis 106.2±14.6 ml·min^–1·1.73m^2–1 (mean±SD) to 95.9±13.7 ml·min^–1·1.73m^2–1 after 3 months treatment (p=0.049). At the same time, mean plasma glucose was reduced from 13.3±3.2 mmol/l to 6.5±1.1 mmol/l. The fall in mean plasma glucose was correlated to the reduction in glomerular filtration rate, r=0.76, p=0.011. Kidney volume as measured by ultrasonic scanning was reduced from 264.0±33.7 ml/l.73m² to 210.8±23.8 ml/l.73 m² (p<0.005). The relative decline in urinary albumin excretion rate was correlated to the fall in glomerular filtration rate, r=0.69, p=0.026. In 15 patients (Group B) 24-h urine collections were made during 9.5±3.2 days, urinary albumin excretion rate fell from the first to the last day in hospital from 14.0×/÷3.0 g/min (geometric mean ×/÷ tolerance factor) to 7.0×/÷2.7 g/min p=0.015. The relative decline was correlated to the change in mean plasma glucose, r=0.65, p=0.032.Thus, kidney function in Type 2 diabetic patients is influenced by metabolic control, although to a lesser extent than is seen in Type 1 (insulin-dependent) diabetic patients with comparable glycaemic control. Urinary albumin excretion is reduced by improvement in glycaemic control, to which it is significantly correlated. Long-term consequences of reduction in urinary albumin excretion on the development of diabetic nephropathy and on survival remains to be elucidated.