Estimation of glomerular filtration rate using serum cystatin C in overweight and obese subjects.
BACKGROUND
Obesity and overweight are strong independent risk factors for chronic kidney disease (CKD). Using serum creatinine-based estimated glomerular filtration rate (eGFR) equations in these subjects may be inaccurate. On the other hand, cystatin C-based eGFR equations may overestimate CKD prevalence as recent findings suggest an association of cystatin C with obesity. The objective of this study was to assess the accuracy of a cystatin C-based eGFR equation compared to two creatinine -based eGFR equations in overweight and obese subjects.


METHODS
This was a prospective cross-sectional study which recruited healthy volunteers aged 18-55 years with a body mass index (BMI) > or = 23kg/m(2) (Asia Pacific Guidelines). Their renal profiles, serum cystatin C and 99m technetium diethylene triamine pentacetic acid (99)mTc-DTPA) scans were performed on the same day. The correlations and accuracy of the creatinine-based and cystatin C-based eGFR equations with the (99)mTc-DTPA GFR were determined.


RESULTS
One hundred and one subjects with a median age of 30.0 (27.0-43.5) years and mean BMI of 28.7 +/- 4.5 kg/m(2) were recruited. The cystatin C-based eGFR equation showed the best correlation with the (99)mTc-DTPA GFR (r = 0.526, p = 0.001) and was more accurate in measuring abnormal GFR compared to the creatinine-based eGFR equations.


CONCLUSIONS
Our study showed that the cystatin C-based eGFR equation was more accurate, sensitive and specific in overweight and obese subjects compared to the creatinine-based eGFR equations.
Faculty of Medicine, University Kebangsaan Malaysia.
M N Norli
MN
Marwyne
C Y
CY
Loo
A G
AG
Halim
K
K
Norella
T
T
Sulaiman
M I
MI
Zaleha
D000293:Adolescent; D000328:Adult; D003430:Cross-Sectional Studies; D055316:Cystatin C / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000503:physiopathology*; D050177:Overweight / Q000503:physiopathology*; D011446:Prospective Studies; D012372:ROC Curve
D055316:Cystatin C