Relationships among glomerular filtration rate, albuminuria, and autonomic nerve function in insulin-dependent and non-insulin-dependent diabetes mellitus

The associations among autonomic neuropathy, urinary albumin excretion, and glomerular filtration rate (GFR) measured with Cr-51-EDTA and iohexol clearance were studied in 41 patients with insulin-dependent diabetes mellitus (IDDM) and 15 patients with non-insulin-dependent diabetes mellitus (NIDDM). The study showed that increased urinary albumin excretion was more common in NIDDM than in IDDM. In contrast with IDDM, albuminuria in NIDDM was not related to GFR. Autonomic neuropathy was common in IDDM as well as in NIDDM, and also in patients without nephropathy, but was not connected with hyperfiltration. Low brake index, an ortostatic autonomic index, was associated with nephropathy in NIDDM. Iohexol, a non-ionic contrast medium, was found to be a useful alternative to Cr-51-EDTA for determination of GFR. Moreover, comparison between conventional four-sample plasma clearance and single-sample clearance showed a close correlation. Accordingly, assessment of GFR using a single plasma sample provides reliable results even at high GFR values. (C) Elsevier Science Inc., 1997.