Correlations between demographic data, selected laboratory measurements, and clinical findings and kynurenic acid (KYNA) content in synovial fluid or serum of patients with rheumatoid arthritis (RA) according to a univariate model of linear regression analysis.
| Variable | KYNA in Synovial Fluid, R2/p | KYNA in Serum, R2/p |
|---|---|---|
| Sex | 0.007/0.364 | 0.008/0.329 |
| Age | 0.017/0.165 | 0.003/0.577 |
| Disease duration | 0.007/0.364 | 0.017/0.158 |
| Weight | 0.017/0.167 | 0.001/0.742 |
| Body mass index | 0.011/0.278 | 0.000/0.989 |
| ESR | 0.005/0.451 | 0.003/0.573 |
| C-reactive protein | 0.035/0.076 | 0.000/0.869 |
| Hemoglobin level | 0.003/0.552 | 0.008/0.336 |
| Hematocrit | 0.003/0.576 | 0.002/0.647 |
| Red blood cell count | 0.013/0.221 | 0.033/0.047* |
| White blood cell count | 0.021/0.117 | 0.000/0.874 |
| Platelet count | 0.000/0.918 | 0.011/0.256 |
| Total serum protein | 0.003/0.545 | 0.017/0.161 |
| Serum albumin | 0.007/0.422 | 0.017/0.196 |
| Fibrinogen | 0.049/0.044* | 0.000/0.973 |
| Morning stiffness | 0.003/0.549 | 0.041/0.037* |
| Pain score | 0.000/0.947 | 0.042/0.031* |
| Tender joint count | 0.020/0.137 | 0.001/0.698 |
| Swollen joint count | 0.005/0.465 | 0.014/0.203 |
| Disease Activity Score 28-ESR | 0.002/0.607 | 0.009/0.324 |
↵* p < 0.05. ESR: erythrocyte sedimentation rate.