In this study the relationship between values of serum cystatin C or serum creatinine and prognostic stages of type II diabetic nephropathy was determined. Blood samples from 87 patients with type II diabetes were obtained from Nephrology Department, Zagazig University Hospitals, Zagazig, Egypt.
Patients were categorized into five stages as follows: stage I, stage II, stage IIIa, stage IIIb, and stage IV according to the concentration of albumin in their 24 hours urines.
The values of both serum cystatin C and creatinine were measured. It was found that, the mean levels of serum cystatin C in stage IIIb, were significantly higher than those in stages I or II (p < 0.00001/ p < 0.0005 respectively).
The mean values of serum cystatin C in stages III, and IV were also significantly higher than those in stage I (p < 0.00001).
However, the mean values of serum creatinine in stage IIIa, were not significantly higher than those in stages I or II. The values of serum creatinine in stages III, and IV were significantly higher than those in stage I (p < 0.00001).
The Receiver Operating Characteristic (ROC) plot indicated that, serum cystatin C may be superior to serum creatinine for detecting impaired glomerular filtration rate (GFR).
It appears that the values of serum cystatin C may be of value in predicting prognostic stages of patients with type II diabetic nephropathy.