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Table 1 Baseline characteristics: All advanced CKD patients starting dialysis in Singapore in 2008–2011, by estimated glomerular filtration rate (eGFR) category at 1 dialysis

From: Timing of commencement of maintenance dialysis and mortality in young and older adults in Singapore

Variables

All

(N = 3286)

Missing N (%)

aLate start (n = 1709)

aIntermediate start

(n = 1359)

aEarly start

(n = 218)

Ç‚P value

Age at 1st dialysis (years, mean, SD)

  

60.1 (13.0)

62.9 (12.1)

64.2 (12.2)

<0.001

Age at 1st dialysis

     

<0.001

 18 to 54 years

919

 

568 (33.2)

309 (22.7)

42 (19.3)

 

 55 to 64 years

995

 

507 (29.7)

427 (31.4)

61 (28.0)

 

 ≥ 65 years

1372

 

634 (37.1)

623 (45.8)

115 (52.8)

 

Gender

      

 Male

1862

 

874 (51.1)

840 (61.8)

148 (67.9)

<0.001

Ethnicities

 

28 (0.9)

   

0.32

 Chinese

2122

 

1097 (64.6)

881 (65.4)

144 (67.6)

 

 Malay

873

 

477 (28.1)

341 (25.3)

55 (25.8)

 

 Indian

250

 

117 (6.9)

119 (8.8)

14 (6.6)

 

 Eurasia

13

 

7 (0.4)

6 (0.5)

0 (0.0)

 

Education

 

3 (0.1)

    

 No/Primary

2223

 

1130 (66.2)

934 (68.7)

159 (73.3)

0.072

 Secondary

806

 

443 (26.0)

314 (23.1)

49 (22.6)

 

 Post-secondary

254

 

134 (7.9)

111 (8.2)

9 (4.2)

 

Smoking

 

57 (1.7)

    

 Current smoker

392

 

203 (12.0)

160 (12.0)

29 (13.7)

<0.001

 Ex-smoker

811

 

368 (21.8)

372 (28.0)

71 (33.5)

 

 Never smoker

2026

 

1117 (66.2)

797 (60.0)

112 (52.8)

 

BMI (mean, SD)

2637

649 (19.8)

24.8 (5.1)

24.3 (5.1)

24.1 (5.0)

0.051

Diabetes

2332

 

1113 (64.5)

1067 (78.5)

162 (74.3)

<0.001

Hypertension

3225

 

1676 (98.1)

1336 (98.3)

213 (97.7)

0.94

Ischemic Heart Disease

1632

2 (0.1)

705 (41.3)

787 (57.9)

140 (64.5)

<0.001

Cerebrovascular disease

830

 

367 (21.5)

391 (28.8)

72 (33.0)

<0.001

Peripheral vascular disease

552

2 (0.1)

214 (12.5)

275 (20.2)

63 (29.2)

<0.001

Malignancy

257

6 (0.2)

136 (8.0)

100 (7.4)

21 (9.7)

0.85

Hepatitis B Ag

 

142 (4.3)

    

 Negative

3032

 

1599 (96.2)

1240 (96.5)

193 (98.5)

0.17

 Positive

112

 

64 (3.8)

45 (3.5)

3 (1.5)

 

Anti-Hepatitis C

 

160 (4.9)

    

 Negative

3092

 

1641 (99.0)

1260 (98.8)

191 (98.5)

0.41

 Positive

34

 

16 (1.0)

15 (1.2)

3 (1.5)

 

1st dialysis modality

      

 Hemodialysis

3047

 

1651 (96.6)

1220 (89.8)

176 (80.7)

<0.001

 Peritoneal Dialysis

239

 

58 (3.4)

139 (10.2)

42 (19.3)

 

Serum Albumin (g/L, mean, SD)

2698

588 (17.9)

32.3 (6.5)

31.8 (6.2)

31.3 (6.3)

0.034

Last Hb level (g/dl, mean, SD)

2720

566 (17.2)

10.3 (1.7)

10.5 (1.6)

10.7 (1.6)

0.002

TSAT (%, median, IQR)

2531

755 (23.0)

26.0 (19.0–36.0)

25.0 (18.0–35.0)

26.0 (17.0–37.8)

0.34

Serum Ferritin (ng/ml, median, IQR)

2504

782 (23.8)

327.0 (165.0–574.0)

331.0 (176.0–588.0)

401.0 (178.5–769.0)

0.014

Serum Phosphate (mmol/L, median, IQR)

2704

582 (17.7)

1.6 (1.3–2.0)

1.4 (1.2–1.8)

1.3 (1.0–1.6)

<0.001

Serum iPTH (pmol/L, median, IQR)

2453

833 (25.3)

24.3 (11.6–40.7)

19.8 (9.8–32.7)

14.4 (8.3–26.3)

<0.001

Serum calcium (mmol/L, median, IQR)

2004

1282 (39.0)

2.2 (2.0–2.3)

2.2 (2.0–2.3)

2.2 (2.0–2.3)

0.99

  1. eGFR estimated glomerular filtration rate, Hb Haemoglobin, TSAT Transferrin Saturation, iPTH intact Parathyroid Hormone
  2. aLate start, eGFR < 5 ml/min/1.73 m2; Intermediate start, eGFR 5–10 ml/min/1.73 m2; Early start, eGFR ≥ 10 ml/min/1.73 m2.
  3. Ç‚Continuous variables, 1-way ANOVA or Kruskal-Wallis as appropriate; categorical variables, chi-square test