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Table 1 Baseline clinical characteristics of patients according to quartiles of BUN levels

From: Blood urea nitrogen is independently associated with renal outcomes in Japanese patients with stage 3–5 chronic kidney disease: a prospective observational study

Variables

All patients (n = 459)

BUN

P

Q1 (n = 128)

Q2 (n = 104)

Q3 (n = 114)

Q4 (n = 113)

(8–23 mg/dL)

(24–30 mg/dL)

(31–41 mg/dL)

(42–94 mg/dL)

Age (years), median (IQR)

72.6 (62.2–78.6)

66.6 (55.1–74.0)

73.6 (65.4–79.0)

73.8 (64.2–80.5)

74.9 (65.4–80.8)

< 0.01

Male, n (%)

320 (70)

85 (66)

73 (70)

73 (64)

89 (79)

0.07

Diabetes mellitus, n (%)

203 (44)

44 (34)

57 (55)

50 (44)

52 (46)

0.02

Hypertension, n (%)

427 (93)

107 (84)

99 (95)

112 (98)

109 (96)

< 0.01

Smoking, n (%)

256 (56)

68 (53)

57 (55)

61 (54)

70 (62)

0.49

Dyslipidemia, n (%)

343 (75)

99 (77)

81 (78)

85 (75)

78 (69)

0.41

Use of RAAS inhibitors, n (%)

357 (78)

102 (80)

80 (77)

93 (82)

82 (73)

0.39

Use of AST-120, n (%)

30 (7)

1 (1)

2 (2)

4 (4)

23 (20)

< 0.01

Use of diuretics, n (%)

163 (36)

26 (20)

40 (38)

46 (40)

51 (45)

< 0.01

SBP (mmHg), mean (SD)

137 (18)

134 (18)

134 (17)

137 (18)

137 (17)

0.34

DBP (mmHg), mean (SD)

72 (12)

74 (11)

71 (14)

73 (11)

69 (11)

0.01

BMI (kg/m2), median (IQR)

22.7 (20.9–25.4)

22.7 (20.6–25.5)

24.0 (21.6–26.3)

22.6 (21.0–25.4)

21.8 (19.7–24.5)

< 0.01

CRP (mg/dL), median (IQR)

0.09 (0.05–0.18)

0.08 (0.05–0.14)

0.12 (0.06–0.20)

0.08 (0.05–0.19)

0.08 (0.05–0.20)

0.05

Daily proteinuria (g/day), median (IQR)

1.10 (0.34–2.99)

0.74 (0.20–2.92)

0.93 (0.21–2.49)

1.52 (0.38–3.31)

1.36 (0.67–2.79)

0.01

Hemoglobin (g/dL), median (IQR)

10.4 (9.1–11.9)

12.1 (10.6–13.4)

10.8 (9.9–12.2)

10.1 (8.9–11.2)

9.0 (8.2–10.1)

< 0.01

eGFR (mL/min/1.73m2), median (IQR)

22.6 (14.7–35.0)

40.8 (33.7–50.4)

28.2 (22.5–33.5)

18.3 (14.1–22.2)

13.1 (10.2–15.8)

< 0.01

Serum albumin (g/dL), median (IQR)

3.4 (3.0–3.7)

3.5 (3.1–3.8)

3.5 (3.1–3.8)

3.4 (3.0–3.7)

3.3 (3.0–3.8)

0.22

Serum phosphorus (mg/dL), median (IQR)

3.7 (3.3–4.2)

3.4 (3.2–3.8)

3.5 (3.2–4.0)

3.8 (3.4–4.1)

4.2 (3.9–4.8)

< 0.01

cSosm (mOsm/kg), median (IQR)

297 (293–301)

293 (290–295)

296 (293–299)

298 (295–301)

302 (299–307)

< 0.01

LVEF (%), median (IQR)

68.4 (63.9–73.1)

68.8 (65.5–73.6)

69.3 (64.0–74.6)

67.6 (62.2–72.3)

68.1 (62.8–72.3)

0.09

LAD (mm), median (IQR)

41 (36–45)

39 (34–43)

42 (38–46)

41 (37–44)

41 (36–46)

< 0.01

  1. Values are expressed as means ± SD, number (percent) or median (IQR). BUN blood urea nitrogen, IQR interquartile range, RAAS renin–angiotensin–aldosterone system, SBP systolic blood pressure, DBP diastolic blood pressure, BMI body mass index, CRP C-reactive protein, eGFR estimated glomerular filtration rate, cSosm calculated serum osmolality, LVEF left ventricular ejection fraction, LAD left atrial diameter