Table 1.
Baseline characteristics according to tertiles of urinary sodium concentration.
| All (n = 1,439) |
Tertiles of urinary sodium concentration | P value | |||
|---|---|---|---|---|---|
| Low | Intermediate | High | |||
| <69 mmol/L (n = 479) |
69–103 mmol/L (n = 481) |
>103 mmol/L (n = 479) |
|||
| Clinical variables | |||||
| Age (year) | 65.3 ± 10.7 | 66.1 ± 10.6 | 65.6 ± 10.5 | 64.0 ± 10.8 | 0.008 |
| Male, n (%) | 835 (58%) | 252 (53%) | 282 (59%) | 301 (63%) | 0.006 |
| Body mass index (kg/m2) | 31.2 ± 6.3 | 31.2 ± 6.4 | 30.7 ± 6.0 | 31.9 ± 6.3 | 0.02 |
| Active smoking, n (%) | 152 (11%) | 48 (10%) | 48 (10%) | 56 (12%) | 0.66 |
| Diabetes duration (years) | 14.5 ± 10.0 | 15.9 ± 10.1 | 15.1 ± 10.4 | 12.5 ± 9.3 | <0.001 |
| HbA1c (%) | 7.8 ± 1.6 | 7.7 ± 1.7 | 7.8 ± 1.7 | 7.7 ± 1.5 | 0.47 |
| History of cardiovascular disease, n (%) | 276 (19%) | 113 (24%) | 87 (18%) | 76 (16%) | 0.005 |
| Systolic blood pressure (mmHg) | 132 ± 18 | 131 ± 18 | 134 ± 18 | 133 ± 16 | 0.03 |
| Diastolic blood pressure (mmHg) | 72 ± 11 | 71 ± 11 | 73 ± 10 | 73 ± 12 | 0.002 |
| Medications use | |||||
| Any Diabetes therapy, n (%) | 1,378 (96%) | 462 (97%) | 457 (95%) | 459 (96%) | 0.62 |
| Oral antidiabetic agent, n (%) | 910 (63%) | 279 (58%) | 294 (61%) | 337 (71%) | <0.001 |
| Insulin, n (%) | 864 (60%) | 322 (67%) | 292 (61%) | 250 (52%) | <0.001 |
| Any antihypertensive therapy, n (%) | 1189 (83%) | 426 (89%) | 394 (82%) | 369 (77%) | <0.001 |
| Diuretics, n (%) | 655 (46%) | 268 (57%) | 210 (44%) | 177 (37%) | <0.001 |
| RAAS blockers, n (%) | 900 (63%) | 316 (66%) | 301 (63%) | 283 (60%) | 0.05 |
| Beta blockers, n (%) | 483 (34%) | 185 (39%) | 163 (34%) | 135 (28%) | 0.002 |
| Calcium channel blockers, n (%) | 448 (31%) | 162 (34%) | 146 (31%) | 140 (29%) | 0.23 |
| Renal parameters | |||||
| eGFR (ml·min−1 per 1.73 m−2) | 73 ± 25 | 65 ± 27 | 73 ± 24 | 81 ± 19 | <0.001 |
| uACR (mg/g) | 3.0 (12.9) | 4.1 (18.2) | 3.5 (15.1) | 2.4 (7.6) | <0.001 |
| Diabetic nephropathy (normo-/micro-/macroalbuminuric): n (%) | 528 (43%)/421 (34%)/293 (24%) | 163 (40%)/119 (29%)/127 (31%) | 173 (41%)/149 (35%)/100 (24%) | 192 (47%)/153 (37%)/66 (16%) | <0.001 |
| UNa (mmol/L) | 89 ± 41 | 45 ± 15 | 85 ± 10 | 135 ± 26 | <0.001 |
| UK (mmol/L) | 52 ± 25 | 47 ± 26 | 51 ± 24 | 59 ± 24 | <0.001 |
| U : Pcreat | 91 (89) | 70 (85) | 82 (78) | 114 (84) | <0.001 |
| Estimated 24 h Na excretion (g/day) | 4.6 ± 1.8 | 3.5 ± 1.4 | 4.9 ± 1.5 | 5.5 ± 1.7 | |
| NT-proBNP (pg/mL) | 113 (270) | 155 (530) | 113 (241) | 83 (147) | |
| Copeptin (pmol/L) | 6.7 (8.0) | 6.7 (10.7) | 6.2 (7.2) | 7.3 (6.7) | 0.07 |
| Presence of glycosuria: n (%) | 494 (34%) | 143 (30%) | 170 (35%) | 181 (38%) | 0.03 |
Quantitative variables are described by mean ± SD or median (IQR).
History of cardiovascular disease = history of stroke or myocardial infarction; RAAS blockers = angiotensin receptor blockers and/or ACE inhibitors. eGFR, CKD EPI equation; uACR, urinary albumin/creatinine ratio; UNa, urinary sodium concentration; UK, urinary potassium concentration; U : Pcreat, urinary to plasma creatinine concentration ratio; NT-proBNP, N-terminal pro-brain natriuretic peptide.