Table 3. Risk factors associated with anemia in patients with CKD, using multivariate logistic regression.
| Variables | Univariate | Multivariate | ||||||
|---|---|---|---|---|---|---|---|---|
| β | SE | OR | 95% CI of OR | β | SE | OR | 95% CI of OR | |
| Age (/1 yr increase) | 0.030 | 0.004 | 1.03 | 1.02–1.04 | - | - | - | - |
| Female | 0.453 | 0.088 | 1.57 | 1.32–1.87 | - | - | - | - |
| CKD stage (compared to stage 1) | ||||||||
| 2 | 0.524 | 0.247 | 1.69 | 1.04–2.74 | 0.678 | 0.314 | 1.97 | 1.07–3.64 |
| 3a | 1.477 | 0.233 | 4.38 | 2.78–6.91 | 1.452 | 0.309 | 4.27 | 2.33–7.83 |
| 3b | 2.058 | 0.226 | 7.83 | 5.02–12.20 | 1.846 | 0.302 | 6.33 | 3.51–11.40 |
| 4 | 3.510 | 0.233 | 33.50 | 21.20–52.90 | 3.123 | 0.318 | 22.70 | 12.20–42.40 |
| 5 | 5.511 | 0.500 | 247.30 | 92.80–659.00 | 4.575 | 0.675 | 97.00 | 25.80–364.50 |
| Cause of CKD (compared to glomerulonephritis) | ||||||||
| DN | 1.769 | 0.128 | 5.87 | 4.57–7.54 | 1.558 | 0.246 | 4.75 | 2.93–7.69 |
| Hypertensive nephropathy | 0.214 | 0.126 | 1.24 | 0.97–1.59 | - | - | - | - |
| Polycystic kidney disease | −0.354 | 0.140 | 0.70 | 0.53–0.92 | - | - | - | - |
| Others | 0.549 | 0.188 | 1.73 | 1.20–2.50 | 1.062 | 0.305 | 2.89 | 1.59–5.26 |
| Unemployed | 0.765 | 0.088 | 2.15 | 1.81–2.55 | - | - | - | - |
| Marriage (compared to married) | ||||||||
| Unmarried | 0.441 | 0.152 | 1.55 | 1.15–2.09 | - | - | - | - |
| Divorced or widowed | 1.174 | 0.228 | 3.23 | 2.07–5.06 | - | - | - | - |
| Income (compared to high) | ||||||||
| Middle | 0.453 | 0.112 | 1.57 | 1.23–1.96 | - | - | - | - |
| Low | 0.852 | 0.131 | 2.34 | 1.81–3.03 | - | - | - | - |
| Education (compared to graduated college or over) | ||||||||
| Graduated middle or high school | 0.503 | 0.094 | 1.65 | 1.38–1.99 | - | - | - | - |
| Graduated elementary school or none | 1.006 | 0.143 | 2.74 | 2.07–3.62 | - | - | - | - |
| Smoking (compared to never) | ||||||||
| Former | −0.044 | 0.097 | 0.96 | 0.79–1.16 | - | - | - | - |
| Current | −0.602 | 0.128 | 0.55 | 0.43–0.70 | −0.548 | 0.254 | 0.58 | 0.35–0.95 |
| Modified Charlson comorbidity index (compared to ≤ 3) | ||||||||
| 4–5 | 1.214 | 0.103 | 3.37 | 2.75–4.12 | - | - | - | - |
| 6–7 | 1.671 | 0.133 | 5.32 | 4.10–6.90 | - | - | - | - |
| ≥ 8 | 1.889 | 0.291 | 6.61 | 3.74–11.70 | - | - | - | - |
| BMI (compared to 23.0–24.9) | ||||||||
| < 18.5 | 0.608 | 0.291 | 1.84 | 1.04–3.25 | 0.502 | 0.478 | 1.65 | 0.65–4.21 |
| 18.5–22.9 | 0.205 | 0.115 | 1.23 | 0.98–1.54 | 0.433 | 0.187 | 1.54 | 1.07–2.23 |
| 25.0–29.9 | −0.306 | 0.112 | 0.74 | 0.59–0.92 | −0.522 | 0.183 | 0.59 | 0.41–0.85 |
| > 30.0 | −0.401 | 0.194 | 0.67 | 0.46–0.98 | −0.640 | 0.320 | 0.39 | 0.21–0.73 |
| Pulse pressure (compared to 1st quartile) | ||||||||
| 2nd quartile | −0.028 | 0.126 | 0.97 | 0.76–1.25 | - | - | - | - |
| 3rd quartile | 0.363 | 0.127 | 1.44 | 1.12–1.84 | - | - | - | - |
| 4th quartile | 0.869 | 0.125 | 2.45 | 1.92–3.13 | - | - | - | - |
| WBC count (compared to 1st quartile) | ||||||||
| 2nd quartile | −0.133 | 0.121 | 0.88 | 0.69–1.11 | −0.486 | 0.194 | 0.62 | 0.42–0.90 |
| 3rd quartile | −0.129 | 0.121 | 0.88 | 0.69–1.11 | −0.638 | 0.204 | 0.53 | 0.35–0.79 |
| 4th quartile | −0.273 | 0.122 | 0.76 | 0.60–0.97 | −1.230 | 0.223 | 0.29 | 0.19–0.45 |
| Albumin, g/dL (compared to ≥ 4.0) | ||||||||
| < 4.0 | 1.274 | 0.108 | 3.58 | 2.89–4.42 | 0.64 | 0.204 | 1.89 | 1.27–2.86 |
| CRP, mg/dL (compared to < 0.3) | ||||||||
| 0.3–0.9 | 0.129 | 0.112 | 1.14 | 0.91–1.42 | - | - | - | - |
| 1.0–2.9 | 0.076 | 0.121 | 1.08 | 0.85–1.37 | - | - | - | - |
| ≥ 3.0 | 0.394 | 0.144 | 1.48 | 1.12–1.97 | - | - | - | - |
| TSAT, % (compared to ≥ 20) | ||||||||
| < 20 | 0.933 | 0.129 | 2.54 | 1.98–3.27 | 1.445 | 0.204 | 4.24 | 2.84–6.33 |
| Ferritin, ng/mL (compared to ≥ 100) | ||||||||
| < 100 | −0.070 | 0.087 | 0.93 | 0.79–1.11 | −0.366 | 0.151 | 0.69 | 0.52–0.93 |
| Total cholesterol, mg/dL (compared to < 200) | ||||||||
| 200–239 | −0.299 | 0.113 | 0.74 | 0.59–0.93 | - | - | - | - |
| ≥ 240 | −0.060 | 0.195 | 0.94 | 0.64–1.38 | - | - | - | - |
| Calcium (compared to 4rd quartile) | ||||||||
| 1st quartile | 2.079 | 0.139 | 8.00 | 6.09–10.5 | 1.543 | 0.236 | 4.68 | 2.95–7.43 |
| 2nd quartile | 1.125 | 0.118 | 3.08 | 2.44–3.89 | 1.049 | 0.187 | 2.85 | 1.98–4.12 |
| 3rd quartile | 0.557 | 0.130 | 1.75 | 1.35–2.25 | 0.739 | 0.197 | 2.09 | 1.42–3.08 |
| Phosphorus (compared to 1st quartile) | ||||||||
| 2nd quartile | 0.076 | 0.141 | 1.08 | 0.82–1.42 | - | - | - | - |
| 3rd quartile | 0.535 | 0.117 | 1.71 | 1.36–2.15 | - | - | - | - |
| 4th quartile | 1.916 | 0.139 | 6.79 | 5.17–8.93 | 1.145 | 0.234 | 3.14 | 1.99–4.97 |
| 24-hour urine protein, mg/day (compared to < 300) | ||||||||
| 300–999 | 0.761 | 0.120 | 2.14 | 1.69–2.71 | - | - | - | - |
| 1,000–3,000 | 1.060 | 0.130 | 2.89 | 2.24–3.72 | - | - | - | - |
| > 3,000 | 1.836 | 0.166 | 6.27 | 4.53–8.68 | - | - | - | - |
SE = standard error, OR = odd ratio, CI = confidence interval, CKD = chronic kidney disease, DN = diabetic nephropathy, BMI = body mass index, WBC = white blood cell, CRP = C-reactive protein, TSAT = transferrin saturation.