title: Dietary sodium intake in a multiethnic Asian population of healthy participants and chronic kidney disease patients.
abstract: BACKGROUND
  Clinical practice guidelines recommend using creatinine-based equations to estimate glomerular filtration rates (GFRs). While these equations were formulated for Caucasian-American populations and have adjustment coefficients for African-American populations, they are not validated for other ethnicities. The Chronic Kidney Disease-Epidemiology Collaborative Group (CKD-EPI) recently developed a new equation that uses both creatinine and cystatin C. We aimed to assess the accuracy of this equation in estimating the GFRs of participants (healthy and with chronic kidney disease [CKD]) from a multiethnic Asian population.
  
  
  METHODS
  Serum samples from the Asian Kidney Disease Study and the Singapore Kidney Function Study were used. GFR was measured using plasma clearance of 99mTc-DTPA. GFR was estimated using the CKD-EPI equations. The performance of GFR estimation equations were examined using median and interquartile range values, and the percentage difference from the measured GFR.
  
  
  RESULTS
  The study comprised 335 participants (69.3% with CKD; 38.5% Chinese, 29.6% Malays, 23.6% Indians, 8.3% others), with a mean age of 53.5 ± 15.1 years. Mean standardised serum creatinine was 127 ± 86 μmol/L, while mean standardised serum cystatin C and mean measured GFR were 1.43 ± 0.74 mg/L and 67 ± 33 mL/min/1.73 m2, respectively. The creatinine-cystatin C CKD-EPI equation performed the best, with an estimated GFR of 67 ± 35 mL/min/1.73 m2.
  
  
  CONCLUSIONS
  The new creatinine-cystatin C equation estimated GFR with little bias, and had increased precision and accuracy in our multiethnic Asian population. This two-biomarker equation may increase the accuracy of population studies on CKD, without the need to consider ethnicity.
authors: Department of Medicine, Yong Loo Lin School of Medicine, National University of Singapore, 1E Kent Ridge Road, Level 10 NUHS Tower Block, Singapore 119228. mdctbw@nus.edu.sg.
authors: Boon Wee
authors: BW
authors: Teo
authors: Soumita
authors: S
authors: Bagchi
authors: Hui
authors: H
authors: Xu
authors: Qi Chun
authors: QC
authors: Toh
authors: Jialiang
authors: J
authors: Li
authors: Evan J C
authors: EJ
authors: Lee
mesh_terms: D000328:Adult; D000368:Aged; D015992:Body Mass Index; D002681:China / Q000208:ethnology; D005260:Female; D064368:Healthy Volunteers; D006785:Hospitals, University; D006801:Humans; D006973:Hypertension / Q000453:epidemiology; D007194:India / Q000208:ethnology; D016014:Linear Models; D008296:Malaysia / Q000208:ethnology; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D051436:Renal Insufficiency, Chronic / Q000208:ethnology / Q000652:urine*; D012982:Sodium, Dietary / Q000652:urine*
chemical_list: D012982:Sodium, Dietary
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