Table 4.
Association of baseline fibroblast growth factor 23 concentrations with incident anemia
| Events, Total n | Per 1 SD ln FGF23 | FGF23 Quartiles, RU/ml | P Value for Trend | |||
|---|---|---|---|---|---|---|
| Quartile 1: ≤82.6 | Quartile 2: 82.7–116.2 | Quartile 3: 116.3–182.1 | Quartile 4: ≥182.2 | |||
| Incidence rate, events per 1000 person-yr follow-up (95% CI) | ||||||
| 654 | 114.3 (105.7 to 123.4) | 60.0 (48.6 to 73.2) | 89.4 (74.9 to 105.9) | 136.5 (117.7 to 157.5) | 191.2 (167.5 to 217.3) | <0.001 |
| 1834 | ||||||
| Unadjusted hazard ratio | ||||||
| 654 | 1.51 (1.41 to 1.61) | Reference | 1.52 (1.17 to 1.97) | 2.35 (1.84 to 3.00) | 3.38 (2.67 to 4.28) | <0.001 |
| 1834 | ||||||
| Plus demographic factorsa | ||||||
| 654 | 1.43 (1.32 to 1.53) | Reference | 1.45 (1.11 to 1.88) | 2.18 (1.70 to 2.80) | 2.94 (2.30 to 3.77) | <0.001 |
| 1834 | ||||||
| Plus cardiovascular risk factorsb | ||||||
| 654 | 1.37 (1.26 to 1.48) | Reference | 1.45 (1.11 to 1.88) | 2.06 (1.60 to 2.65) | 2.67 (2.07 to 3.44) | <0.001 |
| 1833 | ||||||
| Plus CKD-specific factorsc | ||||||
| 654 | 1.20 (1.10 to 1.31) | Reference | 1.28 (0.98 to 1.67) | 1.64 (1.27 to 2.12) | 1.80 (1.37 to 2.37) | <0.001 |
| 1833 | ||||||
| Plus markers of mineral metabolismd | ||||||
| 626 | 1.13 (1.04 to 1.24) | Reference | 1.23 (0.94 to 1.62) | 1.54 (1.18 to 2.01) | 1.59 (1.19 to 2.11) | <0.001 |
| 1774 | ||||||
| Sensitivity analyses | ||||||
| Final model plus MCV | ||||||
| 626 | 1.13 (1.04 to 1.24) | Reference | 1.23 (0.94 to 1.62) | 1.54 (1.18 to 2.01) | 1.59 (1.19 to 2.11) | <0.001 |
| 1774 | ||||||
| Final modele | ||||||
| 495 | 1.20 (1.08 to 1.34) | Reference | 1.17 (0.88 to 1.57) | 1.40 (1.04 to 1.87) | 1.59 (1.17 to 2.18) | 0.002 |
| 1448 | ||||||
| Final model plus iron supplementation | ||||||
| 495 | 1.20 (1.08 to 1.34) | Reference | 1.17 (0.87 to 1.56) | 1.40 (1.05 to 1.88) | 1.59 (1.16 to 2.17) | 0.002 |
| 1448 | ||||||
| Final modelf | ||||||
| 621 | 1.13 (1.03 to 1.23) | Reference | 1.24 (0.95 to 1.63) | 1.52 (1.16 to 1.98) | 1.57 (1.18 to 2.09) | 0.001 |
| 1761 | ||||||
| Final model plus ACE/ARB use | ||||||
| 621 | 1.13 (1.03 to 1.23) | Reference | 1.24 (0.95 to 1.63) | 1.50 (1.15 to 1.96) | 1.56 (1.18 to 2.08) | 0.001 |
| 1761 | ||||||
Continuous results are reported as hazard ratios per 1-SD increase in plasma ln-transformed FGF23. n, number; ln, natural log; FGF23, fibroblast growth factor 23; 95% CI, 95% confidence interval; MCV, mean corpuscular volume; ACE/ARB, angiotensin-converting enzyme/angiotensin receptor blocker.
Adjusts for age, sex, race, and ethnicity.
Adjusts for factors in model 1 as well as cardiovascular disease, systolic BP, diabetes, smoking, and C-reactive protein.
Adjusts for factors in model 2 as well as eGFR and urinary albumin-to-creatinine ratio.
Full multivariable model adjusts for factors in model 3 as well as calcium, phosphate, and parathyroid hormone.
Full multivariable model but includes only those individuals with iron supplementation data available.
Full multivariable model but includes only those individuals with ACE/ARB use data available.