Asian multicenter trials on urinary type IV collagen in patients with diabetic nephropathy

To investigate the changes of renal type IV collagen turnover in diabetic n ephropathy, urinary type IV collagen was measured by a highly sensitive one -step sandwich enzyme immunoassay (EIA). Urinary samples were obtained from 698 diabetic patients and 191 healthy adults. Among the patients, 264 had urinary albumin levels of less than 29 mg/g.creatine (Cr) (Stage I: normoal buminuric stage), 169 had microalbuminuria from 30 to 299 mg/g.Cr (Stage II : microalbuminuric stage), 84 patients had macroalbuminuria of more than 30 0 mg/g.Cr and serum Cr of less than 1.1 mg/dl (Stage IIIA: macroalbuminuric stage without renal dysfunction), 97 had macroalbuminuria of more than 300 mg/g.Cr and serum Cr of more than 1.2 mg/dl (Stage IIIB: macroalbuminuric stage with renal dysfunction), and 84 had renal failure (Stage IV). The lev els of urinary type IV collagen in Stages II, IIIA, IIIB, and IV were signi ficantly higher than those in Stage I (P < 0.0001). The level of urinary ty pe IV collagen in Stage I (5.00 +/- 0.23 mug/g Cr; mean +/- SE) was also hi gher than that in normal adults (3.44 +/- 0.11 mug/ g.Cr; mean +/- SE). The se levels increased gradually due to progression of the clinical stage of d iabetic nephropathy. It appears that the levels of urinary type IV collagen can be a useful marker for detecting renal injuries in diabetes according to our Asian multicenter trials. (C) 2001 Wiley-Liss, Inc.