Table 3. Immunoreactivity quantification and gene expression study stratified by tertiles of soluble iFGF23 (pg/mL) and cFGF23 (RU/mL) levels.
| Variable | Tertile 1 (<15 pg/mL / <24 RU/mL) | Tertile 2 (15-25 pg/mL / 24-46 RU/mL) | Tertile 3 (>25 pg/mL / >46 RU/mL) | P value for trend |
| N (%) | 22 (34.4) / 21 (32.8) | 21 (32.8) / 22 (34.4) | 21 (32.8) / 22 (34.4) | |
| Log Immunoreactivity levels (μm2) | ||||
| FGF23 | 3.5±0.3 / 3.8±0.3 | 4.1±0.3 / 4.5±0.3 | 4.8±0.3 / 4.9±0.3 | <0.05 / <0.05 |
| FGFR1 | 4.5±0.5 / 4.6±0.3 | 4.4±.3 / 4.6±0.3 | 4.2± 0.4 / 4.5±0.3 | NS / NS |
| FGFR3 | 3.5±0.4 / 3.4±0.7 | 3.5±0.4 / 3.4±0.9 | 3.6±0.3 / 3.5±0.8 | NS / NS |
| Klotho | 4.6±0.5 / 4.7±0.2 | 4.1±0.4 / 4.3±0.4 | 3.6±0.4 / 3.8±0.4 | <0.05 / <0.05 |
| Log mRNA vascular levels (a.u.) | ||||
| FGF23 | 5.1±2.1 / 4.8±3.3 | 6.1±2.3 / 6.5 ±0.3 | 7.2±3.6 / 4.9±0.3 | <0.05 / <0.05 |
| Klotho | 4.3±0.5 / 4.5±0.3 | 4.1±.3 / 4.2±0.3 | 4± 1.4 / 3.9±0.3 | NS / NS |
| Kidney function stage | ||||
| eGFR (mL/ min/1.73 m2) | 85.3±31.6 / 84±24.1 | 74.5±26.2 / 77.7±26.5 | 68.3±15.6 / 70.7±25.6 | <0.05 / <0.05 |
FGF23, fibroblast growth factor 23; FGFR, fibroblast growth factor receptor; a.u., arbitrary units; eGFR, estimated glomerular filtration rate; NS, not significant.