Table 1.
Baseline characteristics.
| Variables | Total n = 197 |
DSI | p-Value | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|
| Low ≦ 6.0 g/day | High ≧ 6.0 g/day | ||||||||||
| ECW/TBW | |||||||||||
| Low ≦ 0.48 n = 62 |
High > 0.48 n = 42 |
Low ≦ 0.48 n = 37 |
High > 0.48 n = 56 |
||||||||
| Age (years) | 70.5 | (12.1) | 73.2 | (13.6) | 72 | (8.6) | 69.8 | (11.5) | 67 | (12.3) | 0.032 b |
| Sex, male (n(%)) | 149 | (75.6) | 43 | (69.4) | 30 | (71.4) | 31 | (83.8) | 45 | (80.4) | 0.30 d |
| Body mass inde (kg/m2) | 24.6 | (4.8) | 22.1 | (3.5) | 26 | (4.7) | 23.7 | (3.3) | 26.9 | (5.4) | <0.001 b |
| Cause of CKD | |||||||||||
| Diabetes mellitus (n(%)) | 62 | (31.5) | 10 | (16.1) | 22 | (52.4) | 8 | (21.6) | 22 | (39.3) | <0.001 d |
| Nephrosclerosis (n(%)) | 55 | (27.9) | 20 | (32.3) | 8 | (19.1) | 12 | (32.4) | 15 | (26.8) | 0.45 d |
| Chronic glomerulonephritis (n(%)) | 24 | (12.2) | 11 | (17.7) | 4 | (9.5) | 4 | (10.8) | 5 | (8.9) | 0.49 d |
| Others (n(%)) | 56 | (28.4) | 21 | (33.9) | 8 | (19.1) | 13 | (35.1) | 14 | (25.0) | 0.28 d |
| Comorbidities | |||||||||||
| Hypertension (n(%)) | 186 | (94.4) | 55 | (88.7) | 39 | (92.9) | 37 | (100) | 55 | (98.2) | 0.005 d |
| Diabetes mellitus (n(%)) | 92 | (46.7) | 18 | (29.0) | 27 | (64.3) | 12 | (32.4) | 35 | (62.5) | <0.001 e |
| Cerebrovascular disease (n(%)) | 65 | (33.0) | 24 | (38.7) | 9 | (21.4) | 16 | (43.2) | 16 | (28.6) | 0.13 e |
| ECW/TBW | 0.48 | (0.04) | 0.45 | (0.03) | 0.5 | (0.03) | 0.46 | (0.02) | 0.5 | (0.02) | <0.001b |
| Laboratory test | |||||||||||
| Hemoglobin (g/dL) | 11.4 | (1.8) | 11.4 | (1.6) | 11.2 | (1.8) | 11.9 | (1.8) | 11.2 | (1.8) | 0.27 b |
| Serum albumin (mg/dL) | 3.9 | (0.5) | 4 | (0.4) | 3.8 | (0.5) | 4 | (0.4) | 3.7 | (0.5) | <0.001 b |
| eGFR (mL/min/1.73m2) | 24.2 | (11.1) | 26 | (10.7) | 23.1 | (10.9) | 24.9 | (11.7) | 22.4 | (11) | 0.29 b |
| 45–59 mL/min/1.73m2 (n(%)) | 8 | (4.1) | 3 | (4.8) | 2 | (4.8) | 1 | (2.7) | 2 | (3.6) | 0.80 d |
| 30–44 mL/min/1.73m2 (n(%)) | 44 | (22.3) | 15 | (4.2) | 9 | (21.4) | 10 | (27.0) | 10 | (17.9) | |
| 15–29 mL/min/1.73m2 (n(%)) | 100 | (50.8) | 35 | (56.5) | 19 | (45.2) | 17 | (46.0) | 29 | (51.8) | |
| <15 mL/min/1.73m2 (n(%)) | 45 | (22.8) | 9 | (14.5) | 12 | (28.6) | 9 | (24.3) | 15 | (26.8) | |
| Urine protein (g/day a) [IQR] | 0.9 | [0.2, 2.2] | 0.5 | [0.1, 1.0] | 0.8 | [0.3, 2.3] | 0.7 | [0.2, 1.8] | 2.2 | [0.9, 4.0] | <0.001 c |
| DSI (g/day a) [IQR] | 5.9 | [4.4, 8.2] | 4.5 | [3.7, 5.4] | 4.2 | [3.2, 5.1] | 7.8 | [6.7, 9.9] | 9.2 | [7.5, 11.2] | <0.001 c |
| Renin-angiotensin inhibitor (n(%)) | 133 | (67.5) | 39 | (62.9) | 31 | (73.8) | 23 | (62.2) | 40 | (71.4) | 0.53 d |
| Diuretics (n(%)) | 62 | (31.5) | 14 | (22.6) | 15 | (35.7) | 5 | (13.5) | 28 | (50.0) | 0.001 e |
| Systolic blood pressure (mmHg) | 133 | (16) | 128 | (16) | 132 | (16) | 132 | (13) | 140 | (17) | <0.001 b |
| Diastolic blood pressure (mmHg) | 74.3 | (8.4) | 72.6 | (8.2) | 72.6 | (8.3) | 76.1 | (7.7) | 76.4 | (8.8) | 0.02 b |
Values are presented as mean (standard deviation) or number (%), unless otherwise specified. a Median (interquartile range); b ANOVA; c Kruskal–Wallis test; d Fisher’s exact test; e chi-square test. IQR: interquartile range; CKD: chronic kidney disease; ECW: extracellular water; TBW: total body water; eGFR: estimated glomerular filtration rate; DSI: daily salt intake; body mass index is calculated as the weight in kilograms divided by the square of the height in meters. eGFR (mL/min/1.73 m2) = 194 × serum creatinine (−1.094) × age (−0.287) × 0.739 (if female). DSI is estimated by measuring 24-h urinary sodium excretion.