Evidence that even "normal" albuminuria may denote incipient GFR reduction in patients with type 2 diabetes mellitus.
OBJECTIVE
In patients with diabetes and microalbuminuria, small changes of GFR could have been missed, due to the lack of sensitive methodology for GFR determination in clinical practice (creatinine based calculations). Therefore we explored the relation of the degree of albumin excretion with Cystatin C, which has been recently proved to be a better marker of GFR, compared to serum creatinine.


METHODS
We studied 179 patients with type 2 diabetes, in whom renal function and microalbuminuria were evaluated.


RESULTS
In patients with normal renal function, GFR/MDRD>or=60 ml/min/1.73 m(2), (n=79), urinary albumin concentration (UAC) was significantly correlated with Cystatin C, both in patients with normoalbuminuria (r=0.547, p<0.023) or microalbuminuria (r=0.305, p<0.035), while it was not correlated either with serum creatinine or calculated creatinine clearance. In patients with GFR/MDRD<60 ml/min/1.73 m(2), (n=100), UAC was significantly correlated with Cystatin C, also both in patients with normoalbuminuria (r=0.536, p<0.032) or microalbuminuria (r=0.340, p<0.016), while it was significantly correlated with serum creatinine and calculated creatinine clearance only in those with microalbuminuria.


CONCLUSIONS
Subtle changes in renal function, as judged by Cystatin C concentration, may parallel the degree of albuminuria, even in the normoalbuminuric stage. This finding needs further confirmation by more appropriate methodology in prospective follow up studies.
Kravaritou
M
M
Diabetes Center, 2nd Department of Internal Medicine, National University of Athens, Hippokration General Hospital, 114, Vas Sofias av., Athens 115 27, Greece.
Thanopoulou
A
A
Karamanos
B
B
Kofinis
A
A
Noutsou
M
M
Spanou
E
E
Varsou
A
A
Archimandritis
A
A
D000368:Aged; D000419:Albuminuria / Q000097:blood*; D003404:Creatinine / Q000097:blood / Q000652:urine; D003924:Diabetes Mellitus, Type 2 / Q000097:blood* / Q000652:urine; D003928:Diabetic Nephropathies / Q000097:blood* / Q000652:urine; D005260:Female; D005919:Glomerular Filtration Rate; D006442:Glycated Hemoglobin / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000097:blood; D007677:Kidney Function Tests; D008297:Male; D012016:Reference Values; D012044:Regression Analysis
D003404:Creatinine; D006442:Glycated Hemoglobin; D007328:Insulin