Clinical Significance of Serum and Urinary Cystatin-C Levels in Diabetic Patients

Abstract

Serum cystatin-C (SCys-C) levels have recently been reported to reflect renal function better than serum creatinine (SCre) levels, and urinary Cys-C (UCys-C) levels have been reported to indicate tubular impairment. We measured the SCys-C and SCre levels of 640 type 2 diabetes patients and found that the SCre levels were elevated in patients with proteinuria who had a decreased glomerular filtration rate (GFR), and the SCys-C levels were significantly elevated in patients with microalbuminuria. Although the UCys-C levels were not correlated with the urinary creatinine (UCre) levels, the UCys-C/UCre ratio (UCCR) tended to be increased in the patients with microalbuminuria, and it was significantly increased in patients with proteinuria and in patients with end-stage renal disease/hemodialysis.
These findings suggest that SCys-C and UCys-C determinations are helpful in diagnosing the early stage of diabetic nephropathy and identifying tubular impairment.