Table 7. Factors associated with serum total indoxyl sulfate according to age.
| Variable | Units | Univariate Correlation (correlation coefficient) | p | Multiple regression analysis (standardized coefficients; Beta) | p |
| All patients | |||||
| Age | 1 year | 0.001 | 0.988 | - | - |
| Male vs female | - | 0.153 | 0.029** | - | - |
| CAD (yes vs no) | - | 0.132 | 0.067* | - | - |
| PAOD (yes vs no) | - | −0.005 | 0.944 | - | - |
| Stroke (yes vs no) | - | −0.080 | 0.264 | - | - |
| BUN | 1 mg/dL | 0.143 | 0.041** | - | - |
| Creatinine | 1 mg/dL | 0.311 | <0.001*** | 0.285 | <0.001*** |
| Hemoglobin | 1 g/dL | 0.127 | 0.070* | - | - |
| Albumin | 1 g/dL | 0.119 | 0.091* | - | - |
| hs-CRP | 1 mg/L | −0.139 | 0.050* | - | - |
| Total PCS | 1 mg/L | 0.292 | <0.001 *** | 0.239 | 0.001*** |
| Synthetic membrane use (yes vs no) | - | 0.195 | <0.001*** | 0.139 | 0.046* |
| High Flux dialysis (yes vs no) | - | 0.159 | <0.001*** | - | - |
| Older patients by Median (Age ≧59 years old) (N = 105) | |||||
| Male vs female | - | 0.001 | 0.995 | - | - |
| CAD (yes vs no) | - | 0.093 | 0.356 | - | - |
| PAOD (yes vs no) | - | −0.002 | 0.987 | - | - |
| Stroke (yes vs no) | - | −0.058 | 0.563 | - | - |
| BUN | 1 mg/dL | 0.096 | 0.336 | - | - |
| Creatinine | 1 mg/dL | 0.258 | 0.009*** | - | - |
| Hemoglobin | 1 g/dL | 0.064 | 0.520 | - | - |
| Albumin | 1 g/dL | 0.126 | 0.204 | - | - |
| hs-CRP | 1 mg/L | 0.010 | 0.920 | - | - |
| Total PCS | 1 mg/L | 0.249 | 0.012** | 0.224 | 0.021** |
| Synthetic membrane use (yes vs no) | - | 0.106 | 0.286 | - | - |
| Younger patients by Median (Age <59 years old) (N = 104) | |||||
| Male vs female | - | 0.300 | 0.002*** | - | - |
| CAD (yes vs no) | - | 0.180 | 0.082* | - | - |
| PAOD (yes vs no) | - | −0.010 | 0.926 | - | - |
| Stroke (yes vs no) | - | −0.110 | 0.290 | - | - |
| BUN | 1 mg/dL | 0.186 | 0.063* | - | - |
| Creatinine | 1 mg/dL | 0.381 | <0.001*** | - | - |
| Hemoglobin | 1 g/dL | 0.172 | 0.088* | - | - |
| Albumin | 1 g/dL | 0.119 | 0.239 | - | - |
| hs-CRP | 1 mg/L | −0.072 | 0.486 | - | - |
| Total PCS | 1 mg/L | 0.355 | <0.001 *** | 0.274 | 0.004*** |
| Synthetic membrane use (yes vs no) | - | 0.309 | 0.002 *** | 0.241 | 0.012** |
Abbreviations: CAD, coronary artery disease; PAOD, peripheral arterial occlusive disease; BUN, blood urea nitrogen; hs-CRP, high sensitive C- reactive protein; PCS, p-cresol sulfate.
*: p value<0.1.
**: p value<0.05.
***: p value<0.01.