Table 5. Factors associated with serum total p-cresol sulfate according to age.
| Variable | Units | Univariate Correlation (correlation coefficient) | p | Multiple regression analysis (standardized coefficients; Beta) | p |
| All patients | |||||
| Age | 1 year | 0.120 | 0.090* | - | - |
| Male vs female | - | 0.126 | 0.075* | - | - |
| diabetes (yes vs no) | - | 0.322 | <0.001*** | 0.342 | <0.001*** |
| CAD (yes vs no) | - | 0.213 | 0.003** | 0.128 | 0.043** |
| PAOD (yes vs no) | - | 0.137 | 0.058* | - | - |
| Stroke (yes vs no) | - | 0.172 | 0.017** | 0.117 | 0.075* |
| BUN | 1 mg/dL | 0.173 | 0.014** | - | - |
| Hemoglobin | 1 g/dL | 0.169 | 0.017** | - | - |
| Total IS | 1 mg/L | 0.292 | <0.001*** | 0.274 | <0.001*** |
| Older patients by Median (Age ≧59 years old) (N = 105) | |||||
| Male vs female | - | 0.141 | 0.157 | - | - |
| diabetes (yes vs no) | - | 0.405 | <0.001*** | 0.399 | <0.001*** |
| CAD (yes vs no) | - | 0.248 | 0.013** | - | - |
| PAOD (yes vs no) | - | 0.060 | 0.553 | - | - |
| Stroke (yes vs no) | - | 0.269 | 0.007*** | 0.190 | 0.034* |
| BUN | 1 mg/dL | 0.180 | 0.070* | - | - |
| Hemoglobin | 1 g/dL | 0.171 | 0.086* | - | - |
| Total IS | 1 mg/L | 0.249 | 0.012** | 0.266 | 0.003*** |
| Younger patients by Median (Age <59 years old) (N = 104) | |||||
| Male vs female | - | 0.116 | 0.253 | - | - |
| diabetes (yes vs no) | - | 0.154 | 0.140 | - | - |
| CAD (yes vs no) | - | 0.099 | 0.346 | - | - |
| PAOD (yes vs no) | - | 0.259 | 0.012** | 0.260 | 0.008*** |
| Stroke (yes vs no) | - | −0.010 | 0.923 | - | - |
| BUN | 1 mg/dL | 0.203 | 0.044** | - | - |
| Hemoglobin | 1 g/dL | 0.147 | 0.147 | - | - |
| Total IS | 1 mg/L | 0.355 | <0.001*** | 0.315 | 0.001*** |
Abbreviations: CAD, coronary artery disease; PAOD, peripheral arterial occlusive disease; BUN, blood urea nitrogen; IS, indoxyl sulfate.
*: p value<0.1.
**: p value<0.05.
***: p value<0.01.