We compared values of baseline serum cystatin C (SCysC), serum creatinine (SCr), and measured GFR (mGFR) for predicting end-stage renal disease (ESRD) in patients with type 2 diabetes and elevated albuminuria.
Observational longitudinal study.
Setting & Participants
Pima Indians with type 2 diabetes and elevated albumin/creatinine ratio (ACR ≥ 30 mg/g).
Baseline SCysC, SCr, and mGFR.
Outcomes & Measurements
Individuals were followed from their first diabetic examination with 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 to predict ESRD were compared with receiver operating characteristic curves.
Of 234 Pima Indians with a mean age of 42.8 years who were followed for a median of 10.7 (range, 0.6–21.3) years, 68 (29%) developed ESRD. The incidence of ESRD was significantly higher among patients in the lowest vs. 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 the lowest (0.585±0.042; P<0.001); the AUROC for 1/SCr was intermediate (0.672±0.040; P of 0.1 and 0.03 vs 1/SCysC and mGFR, respectively). In analyses adjusted for age, sex, diabetes duration, height, weight, hemoglobin A1c, and ACR, 1/SCysC had the highest AUROC (0.845±0.026). Models with mGFR or 1/SCr alone had similar AUROCs (0.815±0.028) and both were lower than the model with 1/SCysC alone (P=0.02 and P=0.03, respectively).
The predictive values of the filtration markers are limited to the extent that their precision is based on a single measurement.
SCysC was a better predictor of ESRD than mGFR or SCr in Pima Indians with type 2 diabetes and elevated albuminuria.