RENAL HEMODYNAMIC-CHANGES IN RESPONSE TO MODERATE HYPERGLYCEMIA IN TYPE-1 (INSULIN-DEPENDENT) DIABETES-MELLITUS

The prevailing blood‐glucose level has been found to influence renal haemodynamics in type 1 (insulin‐dependent) diabetes mellitus. In a group of 48 type 1 diabetic patients with normal serum creatinine (< 120 μmol 1−1) and without persistent proteinuria, no relationship was present between blood glucose, corrected to near normoglycaemia (6·8 [6·2 to 7·3] mmol 1−1 (median [95% confidence interval]), and glomerular filtration rate (GFR), effective renal plasma flow (ERPF) determined with 125I‐iothalamate and 131I‐hippuran respectively. GFR tended to increase (2 [‐1 to +4] ml min−1 1·73 m−2, 0·05 < P < 0·10) and ERPF did not change after a blood glucose rise of 7·9 (7·0 to 8·9) mmol 1−1, achieved by an intravenous glucose load in 31 patients. The individual changes in GFR and ERPF were correlated (r = 0·60, P < 0·005). The changes in GFR were inversely related to baseline blood glucose (r = −0·45, P < 0·02), but not to baseline GFR. GFR increased (3·5 [0 to +12] ml min−1 1·73 m−2, P < 0·01) if baseline blood glucose was ·6·8 mmol 1−1 (n = 16) but ERPF did not. Achievement of near normoglycaemia before measurement of kidney function in type 1 diabetes appears to reduce the influence of variation in glycaemia on renal haemodynamics and thus would improve comparison between and within individuals. Moderate hyperglycaemia can cause a small rise in the glomerular filtration rate. 1990 European Society for Clinical Investigation