Table 1.
Baseline characteristics of all patients, lower tertiles and upper tertile.
| Variables | All patients Mean ± SD | Lower Two Tertiles Mean ± SD | Upper Tertile Mean ± SD | Group Difference Mean (95% CI) | P- value |
|---|---|---|---|---|---|
| Patients [N] | 232 | 154 | 78 | ||
| Number of eligible HD treatments during baseline [per patient] | 26.1 ± 13.3 | 26.1 ± 13.1 | 26.1 ± 13.8 | 0.0 (−3.8 to 3.6) | 0.953a |
| Demographics | |||||
| Age [years] | 62.7 ± 15.7 | 66.0 ± 13.8 | 56.2 ± 17.3 | 9.8 (5.3 to 14.2) | 0.001a |
| Race [% white] | 56.0 | 53.9 | 60.3 | −6.4 | 0.357b |
| Gender [% male] | 48.3 | 48.1 | 48.7 | −0.6 | 0.924b |
| Vintage [years] | 2.9 ± 4.6 | 3.3 ± 5.1 | 2.0 ± 3.6 | 1.3 | 0.0136c |
| BMI [kg/m2] | 28.1 ± 6.9 | 28.6 ± 7.0 | 27.3 ± 6.5 | 1.2 (−0.7 to 3.2) | 0.207a |
| ScvO 2 saturation [%] | |||||
| Mean ScvO2 | 58.7 ± 7.3 | 54.9 ± 5.3 | 66.3 ± 4.2 | −11.4 (−12.6 to −10.1) | n.a. |
| Median ScvO2 | 59.1 ± 7.3 | 55.2 ± 5.3 | 66.6 ± 4.2 | −11.4 (−12.7 to −10.1) | n.a. |
| Minimum ScvO2 | 48.4 ± 9.7 | 44.4 ± 8.9 | 56.3 ± 5.7 | −11.9 (−13.8 to −10.0) | n.a. |
| Maximum ScvO2 | 65.2 ± 6.2 | 62.0 ± 4.6 | 71.5 ± 3.6 | −9.5 (−10.6 to −8.4) | n.a. |
| SD ScvO2 | 3.4 ± 1.1 | 3.6 ± 1.1 | 2.9 ± 0.8 | 0.7 (0.4 to 0.9) | <0.001a |
| Start ScvO2 | 59.1 ± 7.4 | 55.4 ± 5.6 | 66.5 ± 4.4 | −11.1 (−12.4 to −9.8) | n.a. |
| End ScvO2 | 57.3 ± 7.8 | 53.5 ± 6.2 | 64.8 ± 4.8 | −11.3 (−12.7 to −9.8) | n.a. |
| End – Start ScvO2 | −1.8 ± 3.6 | −1.9 ± 3.7 | −1.7 ± 3.5 | −0.2 (−1.2 to 0.8) | 0.62 |
| Comorbidities [%] | |||||
| Diabetes | 59.0 | 60.4 | 56.4 | 4.0 | 0.560b |
| CHF | 22.0 | 21.4 | 23.1 | −1.7 | 0.775b |
| COPD | 10.3 | 11.0 | 9.0 | 2.0 | 0.626b |
| Treatment parameters | |||||
| Pre-dialysis SBP [mmHg] | 146.4 ± 22.0 | 143.7 ± 22.9 | 151.7 ± 19.1 | −8.0 (−14.0 to −2.1) | 0.009a |
| Post-dialysis SBP [mmHg] | 140.3 ± 20.1 | 137.8 ± 20.5 | 145.5 ± 18.2 | −7.6 (−13.0 to −2.2) | 0.006a |
| Peridialytic SBP change [mmHg] | −6.1 ± 11.9 | −6.0 ± 11.7 | −6.4 ± 12.4 | 0.4 (−2.9 to 3.7) | 0.820a |
| IDWG [kg] | 2.0 ± 0.8 | 1.9 ± 0.8 | 2.1 ± 0.8 | −0.12 (−0.3 to 0.1) | 0.249a |
| IDWG relative to post-dialysis weight [%] | 2.6 ± 0.9 | 2.5 ± 0.9 | 2.8 ± 1.0 | −0.3 (−0.6 to −0.1) | 0.007a |
| UFV [L] | 1.9 ± 0.8 | 1.9 ± 0.79 | 2.0 ± 0.8 | −0.1 (−0.4 to 0.1) | 0.173a |
| Normalized UFV [mL/kg] | 25.3 ± 9.7 | 24 ± 8.9 | 28 ± 10.7 | −4 (−6.6 to −1.4) | 0.003a |
| Post-dialysis weight [kg] | 77.4 ± 20.4 | 79.0 ± 21.4 | 74.3 ± 18.1 | 4.6 (−0.9 to 10.2) | 0.102a |
| Treatment time [minutes] | 219.0 ± 23 | 217.7 ± 23.8 | 221.5 ± 21.1 | −3.7 (−10.1 to 2.5) | 0.235a |
| Equilibrated Kt/V | 1.5 ± 0.3 | 1.5 ± 0.3 | 1.5 ± 0.2 | 0.0 (−0.1 to 0.1) | 0.610a |
| Laboratory parameters | |||||
| Hgb [g/dL] | 10.6 ± 0.9 | 10.6 ± 0.9 | 10.6 ± 0.96 | 0.0 (−0.3 to 0.3) | 0.962a |
| Serum sodium [mmol/L] | 138.6 ± 3.1 | 138.6 ± 3.2 | 138.7 ± 2.8 | −0.1 (−0.9 to 0.7) | 0.782a |
| Serum potassium [mmol/L] | 4.7 ± 0.6 | 4.6 ± 0.6 | 4.7 ± 0.4 | −0.1 (−0.2 to 0.1) | 0.292a |
| Intact PTH [pg/mL] | 518.3 ± 481.1 | 538.3 ± 498.3 | 478.6 ± 445.4 | 59.7 (−72.9 to 192.2) | 0.376a |
| Serum bicarbonate [mmol/L] | 23.4 ± 2.2 | 23.3 ± 2.3 | 23.7 ± 2.2 | −0.4 (−1.0 to 0.2) | 0.165a |
| Leukocytes [1000/µL] | 7.0 ± 2.0 | 7.2 ± 2.1 | 6.6 ± 1.7 | 0.6 (0.1 to 1.1) | 0.019a |
| Platelets [1000/µL] | 212.9 ± 63.9 | 216.9 ± 65.1 | 205.1 ± 61.3 | 11.8 (−6.5 to 30.1) | 0.204a |
| NLR | 4.4 ± 2.6 | 4.6 ± 2.8 | 3.8 ± 2.0 | 0.79 (0.2 to 1.4) | 0.015a |
| Serum albumin [g/dL] | 3.8 ± 0.4 | 3.7 ± 0.4 | 3.8 ± 0.4 | −0.1 (−0.2 to 0.04) | 0.165a |
| Ferritin [ng/mL] | 780.5 ± 510.2 | 798.8 ± 487.9 | 744.7 ± 552.9 | 54.1 (−86.8 to 195.0) | 0.45a |
| Transferrin saturation [%] | 30.7 ± 9.5 | 29.8 ± 8.9 | 32.6 ± 10.5 | −2.8 (−5.4 to −0.2) | 0.036a |
95% CI, 95% confidence interval; SD, standard deviation; ScvO2, central venous oxygen saturation; BMI, body mass index; CHF, congestive heart failure; COPD, chronic obstructive pulmonary disease; SBP, systolic blood pressure; UFV, ultrafiltration volume; IDWG, interdialytic weight gain; Hgb, hemoglobin; PTH, parathyroid hormone; NLR, neutrophil-to-lymphocyte ratio; n.a., not applicable.
a t test.
bChi-square test.
cWilcoxon test.