Table 1.
Baseline characteristics of study participants by tertile of serum sodium level
| Variable | Tertile 1 (≤138 mmol/L) (n = 1,777) | Tertile 2 (139–140 mmol/L) (n = 2,927) | Tertile 3 (≥141 mmol/L) (n = 4,109) | P value |
|---|---|---|---|---|
| Age, years | 68 ± 9 | 67 ± 10 | 68 ± 9 | <0.0001 |
| Sex, n (%) male | 1208 (68) | 1968 (67) | 2527 (62) | <0.0001 |
| Race, n (%) white | 1131 (64) | 1686 (58) | 2231 (54) | <0.0001 |
| Study randomization group, n (%) intensive treatment group | 887 (50) | 1460 (50) | 2072 (50) | 0.88 |
| Prevalent CVD, n (%) | 346 (20) | 559 (19) | 886 (22) | 0.025 |
| Prevalent heart failure, n (%) | 55 (3) | 87 (3) | 176 (4) | 0.006 |
| Prevalent CKD, n (%) | 468 (26) | 814 (28) | 1249 (30) | 0.003 |
| Smoking status, n (%) | 0.003 | |||
| Never smoked | 722 (41) | 1294 (44) | 1855 (45) | |
| Former smoker | 776 (44) | 1238 (42) | 1744 (42) | |
| Current smoker | 279 (16) | 395 (14) | 510 (12) | |
| MAP, mm Hg | 98 ± 11 | 99 ± 11 | 99 ± 12 | 0.0025 |
| Heart rate, bpm | 69 ± 13 | 68 ± 12 | 68 ± 12 | 0.0002 |
| Body mass index, kg/m2 | 29.2 ± 5.7 | 30.3 ± 5.9 | 29.9 ± 5.7 | <0.0001 |
| eGFR, ml/minute/1.73 m2 | 73.7 ± 21.8 | 72.5 ± 20.7 | 70.2 ± 20.1 | <0.0001 |
| Urinary albumin to creatinine ratio | 9.9 (5.8, 24.3) | 9.0 (5.4, 19.3) | 9.8 (5.7, 22.6) | 0.058 |
| Antihypertensive agents, no./patient, n (%) | 0.005 | |||
| 0 | 139 (8) | 290 (10) | 376 (9) | |
| 1 | 529 (30) | 928 (32) | 1317 (32) | |
| 2 | 656 (37) | 993 (34) | 1362 (33) | |
| 3 | 357 (20) | 595 (20) | 816 (20) | |
| 4 | 96 (5) | 121 (4) | 238 (6) | |
| Diuretic use, n (%) | 938 (53) | 1361 (47) | 1835 (45) | <0.0001 |
| Serum sodium, mmol/L | 137 ± 2 | 140 ± 1 | 142 ± 1 | <0.0001 |
| Pulse pressure, mm Hg | 61 ± 15 | 60 ± 14 | 63 ± 15 | <0.0001 |
Data are mean ± SD, median (interquartile range), or n (%).Comparisons across tertiles were made using a Chi-square test for categorical data and analysis of variance for continuous variables. Abbreviations: CKD, chronic kidney disease; CVD, cardiovascular disease; eGFR, estimated glomerular filtration rate (Modification of Diet in Renal Disease equation); MAP, mean arterial pressure.