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