Table 2.
Cox proportional hazards models for the rate of all-cause and cause specific mortality
| Serum sodium category | Unadjusted |
Adjusted |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Model 1 |
Model 2 |
Model 3 |
||||||||||
| HR | 95% Cl | P | HR | 95% Cl | P | HR | 95% Cl | P | HR | 95% Cl | P | |
| All-cause | ||||||||||||
| 1 | 2.04 | 1.95–2.13 | <.0001 | 1.90 | 1.82–1.99 | <.0001 | 1.71 | 1.61–1.82 | <.0001 | 1.44 | 1.34–1.56 | <.0001 |
| 2 | 1.26 | 1.20–1.32 | <.0001 | 1.26 | 1.20–1.32 | <.0001 | 1.20 | 1.13–1.27 | <.0001 | 1.14 | 1.06–1.22 | 0.0004 |
| 3 | 1.07 | 1.02–1.12 | 0.0064 | 1.08 | 1.03–1.13 | 0.002 | 1.06 | 1.00–1.12 | 0.03 | 1.05 | 0.98–1.12 | 0.21 |
| 4 | Ref. | - | - | Ref. | - | Ref. | - | - | Ref. | - | - | |
| 5 | 0.98 | 0.93–1.03 | 0.45 | 0.98 | 0.93–1.03 | 0.34 | 1.00 | 0.94–1.06 | 0.96 | 1.00 | 0.93–1.08 | 0.99 |
| CVD | ||||||||||||
| 1 | 1.07 | 1.05–1.09 | <.0001 | 1.91 | 1.78–2.05 | <.0001 | 1.61 | 1.47–1.76 | <.0001 | 1.42 | 1.27–1.59 | <.0001 |
| 2 | 1.02 | 1.00–1.04 | 0.048 | 1.25 | 1.17–1.35 | <.0001 | 1.12 | 1.03–1.22 | 0.01 | 1.09 | 0.98–1.21 | 0.12 |
| 3 | 1.00 | 0.99–1.02 | 0.60 | 1.08 | 1.01–1.16 | 0.03 | 1.03 | 0.95–1.12 | 0.41 | 1.03 | 0.93–1.15 | 0.53 |
| 4 | Ref. | - | - | Ref. | - | Ref. | - | - | Ref. | - | - | |
| 5 | 1.00 | 0.98–1.02 | 0.92 | 0.94 | 0.87–1.02 | 0.15 | 0.96 | 0.88–1.05 | 0.40 | 1.00 | 0.89–1,12 | 0.99 |
| Infection | ||||||||||||
| 1 | 2.45 | 2.19–2.73 | <.0001 | 2.25 | 2.02–2.51 | <.0001 | 2.29 | 1.98–2.64 | <.0001 | 1.90 | 1.58–2.28 | <.0001 |
| 2 | 1.40 | 1.25–1.57 | <.0001 | 1.39 | 1.24–1.55 | <.0001 | 1.41 | 1.23–1.62 | <.0001 | 1.38 | 1.16–1.64 | 0.002 |
| 3 | 1.08 | 0.96–1.21 | 0.18 | 1.09 | 0.97–1.22 | 0.13 | 1.11 | 0.97–1.27 | 0.11 | 1.14 | 0.96–1.35 | 0.12 |
| 4 | Ref. | - | - | Ref. | - | Ref. | - | - | Ref. | - | - | |
| 5 | 1.06 | 0.93–1.19 | 0.38 | 1.04 | 0.92–1.18 | 0.48 | 1.07 | 0.93–1.24 | 0.33 | 1.05 | 0.87–1.26 | 0.63 |
| Others | ||||||||||||
| 1 | 1.87 | 1.74–2.02 | <.0001 | 1.75 | 1.62–1.88 | <.0001 | 1.07 | 1.05–1.10 | <.0001 | 1.27 | 1.12–1.44 | 0.0001 |
| 2 | 1.22 | 1.13–1.31 | <.0001 | 1.21 | 1.12–1.31 | <.0001 | 1.02 | 1.00–1.04 | 0.13 | 1.09 | 0.97–1.22 | 0.14 |
| 3 | 1.06 | 0.98–1.14 | 0.13 | 1.07 | 0.99–1.15 | 0.08 | 0.66 | 0.99–1.02 | 0.66 | 1.01 | 0.91–1.13 | 0.82 |
| 4 | Ref. | - | - | Ref. | - | Ref. | - | - | Ref. | - | - | |
| 5 | 0.99 | 0.91–1.07 | 0.77 | 0.98 | 0.90–1.06 | 0.65 | 1.00 | 0.98–1.02 | 0.90 | 0.98 | 0.87–1.11 | 0.80 |
CI, confidence interval; CVD, cardiovascular disease; HR, hazard ratio.
Model 1was adjusted for age, sex, duration of hemodialysis, and the length of a dialysis session.
Model 2 was adjusted for Model 1 variables + (hemoglobin, calcium, phosphate, ΔBW% ([pre-HD body weight − post-HD body weight] / pre-HD body weight × 100), change in sodium during dialysis, dialysate sodium concentration, and Kt/V).
Model 3 was adjusted for Model 2 variables + (total cholesterol, albumin, C-reactive protein, and normal protein catabolic rate) + (past history of myocardial infarction, brain infarction, brain hemorrhage, amputation of an extremity, and hip fracture).
Values are presented as means ± SDs.
Serum sodium categories: 1, SNa ≤136 mEq/l; 2, 136< SNa ≤138 mEq/l; 3, 138< SNa ≤140 mEq/l; 4, 140< SNa ≤ 141 mEq/l; 5, 141 mEq/l < SNa.