Table 2. Characteristics of the Study Population.
| All subjects | Age<60 | Age≥60 | |
| Age(years) | 54(41–65) | 45(34–53) | 69(64–75) |
| Gender | |||
| Male | 478(60.70) | 298(59.60) | 180(62.5) |
| Female | 310(39.30) | 202(40.40) | 108(37.5) |
| Weight(kg) | 65(55–69) | 65(55–68) | 65(56–70) |
| Height(m) | 1.69(1.60–1.70) | 1.70(1.60–1.70) | 1.68(1.60–1.70) |
| BSA(m2) | 1.74(1.57–1.79) | 1.73(1.56–1.78) | 1.75(1.60–1.79) |
| BMI(kg/m2) | 22.49(21.48–24.49) | 22.49(21.48–24.22) | 22.49(21.48–24.89) |
| BUN(mmol/L) | 5.75(4.52–7.54) | 5.33(4.17–6.78) | 6.74(5.29–9.22) |
| Scr(mg/L) | 0.94(0.74–1.22) | 0.85(0.68–1.06) | 1.09(0.88–1.51) |
| Scys(mg/L) | 1.09(0.92–1.43) | 0.98(0.84–1.20) | 1.34(1.10–1.93) |
| rGFR(mL/min/1.73 m2) | 76.35(59.03–92.50) | 85.35(70.83–100.45) | 62.85(46.35–74.85) |
| GFR category | |||
| ≥60 mL/min/1.73 m2 | 584(74.11) | 425(85.00) | 159(55.21) |
| <60 mL/min/1.73 m2 | 204(28.59) | 75(15.00) | 129(44.79) |
| eGFR(mL/min/1.73 m2) | |||
| C-MDRD | 87.27(62.91–111.25) | 99.39(75.78–123.62) | 66.35(45.24–85.99) |
| MacIsaac | 73.99(54.88–89.50) | 82.58(66.33–96.75) | 58.30(40.50–73.80) |
| Ma | 84.82(58.92–107.25) | 96.61(76.16–116.41) | 63.31(41.15–80.31) |
| CKD-EPI2009Scr | 83.57(58.90–102.16) | 95.82(76.18–110.28) | 61.22(41.19–78.68) |
| CKD-EPI2012cys | 67.75(45.62–90.63) | 81.71(61.19–99.22) | 47.57(30.45–64.65) |
| CKD-EPI2012Scr-cys | 75.80(51.41–94.67) | 88.00(69.42–103.28) | 54.06(34.45–70.38) |
| Comorbid conditions | |||
| Nephritis | 46(5.84) | 28(5.60) | 18(6.25) |
| Kidney neoplasm | 221(28.04) | 132(26.40) | 89(30.90) |
| Hematological disease | 111(14.09) | 101(20.20) | 10(3.47) |
| Hypertension | 162(20.56) | 70(14.00) | 92(31.94) |
| Coronary heart disease | 35(4.44) | 7(1.40) | 28(9.72) |
| Diabetic mellitus | 84(10.66) | 26(5.20) | 58(20.14) |
Note: Values for continuous variables expressed as median (inter-quartile range); values for categorical values expressed as number (percentage). Conversion factors for units: serum creatinine in mg/dL to µmol/L, ×88.4.
Abbreviations: BSA: body surface aera; BMI: body mass index; Scr: serum creatinine; Scys: serum cystatin C; rGFR: reference glomerular filtration rate (using the 99mTc-DTPA renal dynamic imaging method); eGFR: estimated glomerular filtration rate; C-MDRD: the Chinese modified Modification of Diet in Renal Disease equation; CKD-EPI: Chronic Kidney Disease Epidemiology Collaboration; CKD-EPI2009Scr: serum creatinine–based CKD-EPI equation which was developed in 2009; CKD-EPI2012cys: cystatin C–based CKD-EPI equation which was newly developed in 2012; CKD-EPI2012Scr-cys: serum creatinine– and cystatin C–based CKD-EPI equation which was newly developed in 2012.