Is cystatin C a useful marker in the detection of diabetic kidney disease?
OBJECTIVE
To evaluate cystatin C as a marker of diabetic kidney disease in normoalbuminuric diabetic patients without chronic kidney disease (CKD).


METHODS
A cross- sectional study was carried out comprising 243 hypertensive patients, 61 of them with type 2 diabetes, presenting normoalbuminuria and an estimated glomerular filtration rate (eGFR) >or=60 ml/min/1.73 m(2). Renal function assessment included determinations of serum creatinine and cystatin C levels, microalbuminuria, as well as eGFR through Cockcroft-Gault and Modification of Diet in Renal Disease equations.


RESULTS
Diabetic patients presented higher cystatin C levels than nondiabetic patients (0.95 +/- 0.19 vs. 0.89 +/- 0.17 mg/l; p < 0.05). In the binary logistic regression, the presence of diabetes and metabolic syndrome was significantly associated with elevated cystatin C levels. Diabetic patients also presented a slightly greater albuminuria (6.72 +/- 4.43 vs. 5.07 +/- 3.59 microg/min; p < 0.05).


CONCLUSIONS
Our results suggest that elevated cystatin C levels in diabetic patients may identify a certain degree of renal dysfunction even when albuminuria and eGFR do not mirror CKD. Longitudinal studies with direct GFR measures need to be done in order to confirm the value of cystatin C as an indicative of worse renal outcomes in the diabetic population.
Borges
Rodolfo L
RL
Division of Endocrinology, Federal University of São Paulo, São Paulo, Brazil. endorodolfo @ uol.com.br
Hirota
Andréa H
AH
Quinto
Beata M R
BM
Ribeiro
Arthur B
AB
Zanella
Maria T
MT
Batista
Marcelo C
MC
D015415:Biomarkers / Q000097:blood; D001938:Brazil / Q000453:epidemiology; D055316:Cystatin C / Q000097:blood*; D003928:Diabetic Nephropathies / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology*; D003936:Diagnosis, Computer-Assisted / Q000379:methods*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D015995:Prevalence; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
D015415:Biomarkers; D055316:Cystatin C