Table 3.
Univariate and Case-Mix–Adjusted Regression Analysis of Physical Health Composite Score
| Univariate |
Case-Mix–Adjusted |
||||
|---|---|---|---|---|---|
| Variables | No. | Estimate (95% CI) | P | Estimate (95% CI) | P |
| Age (/decade) | 375 | ||||
| ≤50 y | −2.56 (−4.02 to −1.10) | <0.001 | −2.65 (−4.11 to −1.19) | <0.001 | |
| >50 y | 1.59 (0.19 to 2.99) | 0.03 | 1.69 (0.28 to 3.09) | 0.02 | |
| Male | 375 | 1.90 (−0.21 to 4.01) | 0.08 | 2.12 (0.03 to 4.21) | 0.05 |
| Black race | 375 | −0.08 (−2.20 to 2.04) | 0.9 | 0.48 (−1.62 to 2.59) | 0.7 |
| ESRD vintage (/1 y) | 375 | 0.15 (−0.02 to 0.32) | 0.08 | 0.17 (0.001 to 0.34) | 0.05 |
| Primary language not English | 375 | 2.72 (−0.02 to 5.47) | 0.05 | 2.94 (0.09 to 5.80) | 0.04 |
| Education levela | 372 | ||||
| <High school graduate | 1.06 (−1.69 to 3.80) | 0.5 | 0.61 (−2.14 to 3.36) | 0.7 | |
| High school graduate | 0.26 (−2.29 to 2.80) | 0.8 | 0.20 (−2.32 to 2.72) | 0.9 | |
| Does not live with family | 372 | 1.16 (−1.19 to 3.50) | 0.3 | 1.23 (−1.13 to 3.60) | 0.3 |
| Insurance statusb | 372 | ||||
| Employer group health insurance or privately purchased |
0.39 (−2.24 to 3.02) | 0.8 | 0.53 (−2.07 to 3.14) | 0.7 | |
| Government insurance for the poorc | 0.22 (−2.27 to 2.71) | 0.9 | 0.28 (−2.24 to 2.80) | 0.8 | |
| Diabetes | 370 | −4.55 (−6.60 to −2.49) | <0.001 | −4.11 (−6.27 to −1.95) | <0.001 |
| Congestive heart failure | 370 | −3.46 (−6.10 to −0.82) | 0.01 | −3.16 (−5.86 to −0.46) | 0.02 |
| Peripheral arterial disease | 370 | −5.77 (−8.89 to −2.65) | <0.001 | −6.04 (−9.19 to −2.89) | <0.001 |
| Stroke | 370 | −5.17 (−9.20 to −1.14) | 0.01 | −4.48 (−8.51 to −0.44) | 0.03 |
| enPCR (/0.1 g/kg/d) | 371 | 0.36 (−0.01 to 0.74) | 0.06 | 0.48 (0.09 to 0.86) | 0.01 |
| Residual renal clearance (/1 mL/min)d | 372 | ||||
| Randomized patients | 8.74 (0.04 to 5.72) | 0.04 | 8.29 (0.02 to 5.61) | 0.04 | |
| Not randomized patients | 0.05 (−1.80 to 1.79) | 0.8 | 0.06 (−1.80 to 1.81) | 0.8 | |
| Creatinine (/1 mg/dL) | 372 | 0.61 (0.26 to 0.95) | <0.001 | 0.63 (0.24 to 1.01) | 0.002 |
| Phosphate (/1 mg/dL) | 372 | 0.20 (−0.41 to 0.82) | 0.5 | 0.24 (−0.39 to 0.87) | 0.5 |
| Hemoglobin (/1 g/dL) | 346 | 0.71 (−0.13 to 1.55) | 0.1 | 0.63 (−0.19 to 1.46) | 0.1 |
| PTH (/0.1 pg/L) | 364 | 1.85 (−0.44 to 13.4) | 0.2 | 0.26 (0.001 to 0.53) | 0.05 |
| Albumin (/1 g/dL)d | 372 | ||||
| Daily Trial | 0.56 (0.27 to 0.85) | <0.001 | 0.56 (0.27 to 0.85) | <0.001 | |
| Nocturnal Trial | 0.02 (−0.39 to 0.42) | 0.9 | −0.05 (−0.45 to 0.36) | 0.8 | |
| Calcium (/1 mg/dL) | 364 | 0.78 (−0.40 to 1.96) | 0.2 | 1.09 (−0.09 to 2.28) | 0.07 |
| Bicarbonate (/1 mmol/L) | 363 | −0.06 (−0.34 to 0.21) | 0.6 | −0.07 (−0.35 to 0.20) | 0.6 |
| LV mass (/10 g) | 349 | −0.04 (−0.25 to 0.16) | 0.7 | −0.13 (−0.35 to 0.10) | 0.3 |
| BMI (/1 kg/m2) | 353 | −0.13 (−0.27 to 0.01) | 0.07 | −0.10 (−0.24 to 0.04) | 0.2 |
| ICW volume/weight (/1 dL/kg) | 351 | 2.53 (0.87 to 4.20) | 0.003 | 3.53 (0.72 to 6.33) | 0.01 |
| Phase angle (/0.1°) | 351 | 0.07 (−0.01 to 0.14) | 0.07 | 0.05 (−0.03 to 0.13) | 0.2 |
| Randomly assigned | 375 | 4.43 (1.38 to 7.48) | 0.005 | 4.30 (1.29 to 7.31) | 0.005 |
| Nocturnal trial | 375 | −0.89 (−3.26 to 1.47) | 0.5 | −0.90 (−3.26 to 1.46) | 0.5 |
Note: The physical health composite score is a weighted average of scores deriving from 8 scales of self-reported health status: Physical Functioning, Role-Physical, Bodily Pain, General Health, Vitality, Social Functioning, and Role-Emotional, scored 0-100.
Abbreviations: BMI, body mass index; CI, confidence interval; enPCR, equilibrated normalized protein catabolic rate; ESRD, end-stage renal disease; ICW, intracellular water; LV, left ventricular; PTH, parathyroid hormone.
The reference group is individuals with education beyond high school.
The reference group is government insurance not awarded by income level (Medicare plus Canadian Health).
Medicaid and/or other state/county programs.
Variables showed a statistically significant interaction with trial or randomization status.