Cystatin C and cystatin glomerular filtration rate as markers of early renal disease in Asian Indian subjects with glucose intolerance (CURES-32).
BACKGROUND
The aim of this study was to assess cystatin C (cys-C) as a marker of early diabetic nephropathy and cystatin glomerular filtration rate (cys-GFR) in Asian Indians.


METHODS
Five groups of subjects were studied: Group 1, normal glucose tolerance (NGT) and normoalbuminuria (n = 43); group 2, impaired glucose tolerance (IGT) and normoalbuminuria (n = 44); group 3, type 2 diabetes (T2DM) with neither microalbuminuria nor retinopathy (n = 40); group 4, T2DM with microalbuminuria but without diabetic retinopathy (n = 40); and group 5, T2DM with microalbuminuria and any degree of diabetic retinopathy (DR) (n = 42). Subjects were recruited from the Chennai Urban Rural Epidemiology Study (CURES). Microalbumin concentration was assessed in the urine sample by immunoturbidometric assay. cys-C concentrations were measured in serum by a high-sensitivity particle-enhancing nephlometric assay. cys-GFR was calculated by the formula (86.7/cys-C) - 4.2.


RESULTS
cys-C levels were highest in group 5 (1.75 +/- 0.12 mg/L) followed by group 4 (1.30 +/- 0.08 mg/L), group 3 (0.98 +/- 0.04 mg/L), group 2 (0.89 +/- 0.03 mg/L), and group 1 (0.79 +/- 0.18 mg/L, P < 0.001). cys-GFR levels were in reverse order going from highest in group 1, followed by groups 2, 3, 4, and 5. cys-C levels were correlated with age, fasting plasma glucose, glycosylated hemoglobin, microalbuminuria, and serum cholesterol.


CONCLUSIONS
cys-C levels increase and cys-GFR levels decrease with increasing severity of glucose intolerance and are highest and lowest, respectively, in type 2 diabetes mellitus (T2DM) subjects with microalbuminuria and retinopathy. In T2DM subjects, cys-C and cys-GFR appear to be useful markers of early renal damage.
Madras Diabetes Research Foundation, Kallam Anji Reddy Centre, Siruseri, India.
J
J
Surendar
S
S
Anuradha
Berty
B
Ashley
M
M
Balasubramanyam
V
V
Aravindhan
M
M
Rema
V
V
Mohan
D000328:Adult; D000419:Albuminuria / Q000097:blood / Q000208:ethnology / Q000209:etiology / Q000503:physiopathology; D044466:Asian People / Q000706:statistics & numerical data; D015415:Biomarkers / Q000097:blood; D001786:Blood Glucose / Q000378:metabolism; D002784:Cholesterol / Q000097:blood; D055316:Cystatin C / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000150:complications* / Q000208:ethnology / Q000503:physiopathology; D003928:Diabetic Nephropathies / Q000097:blood / Q000208:ethnology / Q000209:etiology* / Q000503:physiopathology; D003930:Diabetic Retinopathy / Q000097:blood / Q000208:ethnology / Q000209:etiology / Q000503:physiopathology; D042241:Early Diagnosis; D005919:Glomerular Filtration Rate; D018149:Glucose Intolerance / Q000097:blood / Q000150:complications* / Q000208:ethnology / Q000503:physiopathology; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007194:India / Q000453:epidemiology; D008875:Middle Aged; D008954:Models, Biological; D011237:Predictive Value of Tests; D012720:Severity of Illness Index; D015854:Up-Regulation
D015415:Biomarkers; D001786:Blood Glucose; D002784:Cholesterol; D055316:Cystatin C; D006442:Glycated Hemoglobin; C525030:CST3 protein, human; C517652:hemoglobin A1c protein, human