Table 2.
Univariate and multivariate cox regression analyses with patients divided into two groups by treatment week 12 Hb level
| Variable | Univariate analysis | Step-down procedure | |||||
|---|---|---|---|---|---|---|---|
| Hazard ratio | 95% CI | P value | Hazard ratio | 95% CI | P value | ||
| Week 12 Hb (g/dL) | ≥ 11 | Reference | Reference | ||||
| < 11 | 1.37 | 1.21–1.57 | < 0.0001 | 1.26 | 1.05–1.51 | 0.0103 | |
| eGFR | 5 mL/min/1.73 m2 | 0.57 | 0.54–0.60 | < 0.0001 | 0.59 | 0.55–0.64 | < 0.0001 |
| Systolic blood pressure | 10 mmHg | 1.17 | 1.14–1.21 | < 0.0001 | 1.11 | 1.06–1.15 | < 0.0001 |
| Albumin | 0.5 g/dL | 0.71 | 0.68–0.75 | < 0.0001 | 0.7 | 0.65–0.75 | < 0.0001 |
| Age | 10 years | 0.74 | 0.71–0.77 | < 0.0001 | 0.77 | 0.72–0.83 | < 0.0001 |
| Sex | Male | 1.5 | 1.32–1.70 | < 0.0001 | 1.42 | 1.19–1.69 | < 0.0001 |
| History of smoking | Yes | 1.41 | 1.21–1.64 | < 0.0001 | – | – | – |
| History of ESA therapy | Yes | 1.04 | 0.91–1.19 | 0.5148 | – | – | – |
| Diet therapy | Yes | 1.65 | 1.41–1.93 | < 0.0001 | 1.18 | 0.94–1.48 | 0.1442 |
| Etioligy | |||||||
| Diabetic nephropathy | Yes | 1.6 | 1.41–1.81 | < 0.0001 | 1.25 | 1.00–1.55 | 0.0428 |
| Nephrosclerosis | Yes | 0.6 | 0.52–0.70 | < 0.0001 | – | – | – |
| Chronic glomerulonephritis | Yes | 1.12 | 0.97–1.30 | 0.1162 | – | – | – |
| Heart disease (medical history) | Yes | 0.87 | 0.73–1.05 | 0.1707 | – | – | – |
| Comorbidity | |||||||
| Hypertension | Yes | 1.63 | 1.33–2.00 | < 0.0001 | – | – | – |
| Heart failure | Yes | 0.89 | 0.73–1.08 | 0.2561 | – | – | – |
| Angina pectoris or myocardial infarction | Yes | 0.93 | 0.77–1.13 | 0.4964 | – | – | – |
| Diabetes | Yes | 1.39 | 1.23–1.57 | < 0.0001 | – | – | – |
| Hyperlipidemia | Yes | 1.07 | 0.95–1.21 | 0.2270 | – | – | – |
| Concomitant medication | |||||||
| Iron formulation | Yes | 0.86 | 0.71–1.05 | 0.1484 | 0.77 | 0.60–1.00 | 0.0538 |
| ACEIs or ARBs | Yes | 1.29 | 1.13–1.45 | < 0.0001 | 0.87 | 0.72–1.04 | 0.1344 |
| Calcium channel blocker | Yes | 1.9 | 1.66–2.17 | < 0.0001 | 1.3 | 1.07–1.59 | 0.0069 |
| Diuretic | Yes | 1.24 | 1.10–1.41 | 0.0004 | – | – | – |
| Activated carbon product | Yes | 1.67 | 1.44–1.92 | < 0.0001 | 1.27 | 1.04–1.54 | 0.0156 |
| Active vitamin D3 analog | Yes | 1.28 | 1.05–1.57 | 0.0141 | 1.22 | 0.95–1.58 | 0.1160 |
| Antidiabetic drug | Yes | 1.25 | 1.09–1.42 | 0.0007 | 0.84 | 0.67–1.04 | 0.1216 |
| Hypolipidemic drug | Yes | 1.13 | 0.99–1.28 | 0.0558 | – | – | – |
| Sodium bicarbonate | Yes | 2 | 1.69–2.37 | < 0.0001 | 1.46 | 1.17–1.82 | 0.0007 |
| Treatment Week 12 C.E.R.A. dosage | 25 μg/4 week | 1.08 | 1.05–1.11 | < 0.0001 | 1.06 | 1.02–1.10 | 0.0025 |
Among variables for which < 20% of the data were missing, the above clinically significant risk factors that could conceivably be confounding factors were investigated as covariates. Multivariate Cox regression analysis was performed using a model in which covariates were selected by the step-down procedure (excluding covariates for which P was ≥ 0.2)
CI, confidence interval; Hb, Hemoglobin; eGFR, estimated glomerular filtration rate; ESA, erythropoiesis-stimulating agent; ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker; C.E.R.A., continuous erythropoietin receptor activator