Comparison of serum cystatin C, serum creatinine, measured GFR, and estimated GFR to assess the risk of kidney failure in American Indians with diabetic nephropathy.
BACKGROUND
We compared values of baseline serum cystatin C (SCysC), serum creatinine (SCr), and measured glomerular filtration rate (mGFR) for predicting end-stage renal disease (ESRD) in patients with type 2 diabetes and elevated albuminuria.


METHODS
Observational longitudinal study.


METHODS
Pima Indians with type 2 diabetes and elevated albumin-creatinine ratio (ACR ≥30 mg/g).


METHODS
Baseline SCysC, SCr, and mGFR.


METHODS
Individuals were followed up from their first examination with diabetes and ACR ≥30 mg/g until December 2010, onset of ESRD, or death, whichever came first. Incidence rates adjusted for age and sex were computed by Mantel-Haenszel stratification. The abilities of SCysC, SCr, and mGFR values to predict ESRD were compared with receiver operating characteristic curves.


RESULTS
Of 234 Pima Indians with a mean age of 42.8 years who were followed up for a median of 10.7 (range, 0.6-21.3) years, 68 (29%) developed ESRD. The incidence of ESRD was significantly higher in patients in the lowest versus highest tertile of 1/SCysC (incidence rate ratio, 2.43; 95% CI, 1.31-4.50). By contrast, mGFR and 1/SCr had J-shaped associations with ESRD. In unadjusted analyses, 1/SCysC had the highest area under the receiver operating characteristic curve (AUROC; 0.719 ± 0.035) and mGFR had the lowest (0.585 ± 0.042; P < 0.001); the AUROC for 1/SCr was intermediate (0.672 ± 0.040; P = 0.1 and P = 0.03 vs 1/SCysC and mGFR, respectively). In analyses adjusted for age, sex, diabetes duration, height, weight, hemoglobin A1c level, and ACR, 1/SCysC had the highest AUROC (0.845 ± 0.026). Models with mGFR or 1/SCr alone had similar AUROCs (P = 0.9) and both were lower than the model with 1/SCysC alone (P = 0.02 and P = 0.03, respectively).


CONCLUSIONS
The predictive values of the filtration markers are limited to the extent that their precision is based on a single measurement.


CONCLUSIONS
SCysC level was a better predictor of ESRD than mGFR or SCr level in Pima Indians with type 2 diabetes and elevated albuminuria.
Centers for Disease Control and Prevention, Atlanta, GA, USA.
Meda E
ME
Pavkov
William C
WC
Knowler
Robert L
RL
Hanson
Desmond E
DE
Williams
Kevin V
KV
Lemley
Bryan D
BD
Myers
Robert G
RG
Nelson
D000328:Adult; D000419:Albuminuria / Q000097:blood / Q000175:diagnosis / Q000208:ethnology; D001130:Arizona / Q000208:ethnology; D015415:Biomarkers / Q000097:blood; D003404:Creatinine / Q000097:blood*; D055316:Cystatin C / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000175:diagnosis / Q000208:ethnology; D003928:Diabetic Nephropathies / Q000097:blood* / Q000175:diagnosis / Q000208:ethnology; D005260:Female; D005500:Follow-Up Studies; D005919:Glomerular Filtration Rate / Q000502:physiology*; D006801:Humans; D007198:Indians, North American / Q000208:ethnology; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D051437:Renal Insufficiency / Q000097:blood / Q000175:diagnosis* / Q000208:ethnology; D012307:Risk Factors
D015415:Biomarkers; C525030:CST3 protein, human; D055316:Cystatin C; D003404:Creatinine