Table 2.
Comparison of patients according to plasma FGF23 levels. Information on the total cohort and stratification by baseline plasma intact FGF23 levels are presented. Data are expressed as number (N) and percentage (%) for categorical variables and as mean ± standard deviation or median [p25–p75] for continuous variables. p-values of low FGF23 vs. high FGF23 are detailed.
| Characteristics | Total Cohort | Patients with Low FGF23 Levels (<p50) | Patients with High FGF23 Levels (≥p50) | p-Value | ||||
|---|---|---|---|---|---|---|---|---|
| N | % | N | % | N | % | |||
| Total | 243 | 100% | 121 | 49.79% | 122 | 50.21% | - | |
| Sex | Female (%) | 120 | 49.38% | 57 | 47.11% | 63 | 51.64% | 0.480 |
| Male (%) | 123 | 50.62% | 64 | 52.89% | 59 | 48.36% | ||
| Age group | 18–39 years (%) | 8 | 3.29% | 6 | 4.96% | 2 | 1.64% | 0.236 |
| 40–49 years (%) | 37 | 15.23% | 22 | 18.18% | 15 | 12.30% | ||
| 50–59 years (%) | 66 | 27.16% | 29 | 23.97% | 37 | 30.33% | ||
| 60–69 years (%) | 95 | 39.09% | 50 | 41.32% | 45 | 36.89% | ||
| 70–79 years (%) | 31 | 12.76% | 12 | 9.92% | 19 | 15.57% | ||
| ≥80 years (%) | 6 | 2.47% | 2 | 1.65% | 4 | 3.28% | ||
| Comorbidities | Diabetes (%) | 110 | 45.27% | 49 | 40.50% | 61 | 50.00% | 0.137 |
| Hypertension (%) | 218 | 89.71% | 109 | 90.08% | 109 | 89.34% | 0.850 | |
| Heart failure (%) | 40 | 16.46% | 19 | 15.70% | 21 | 17.21% | 0.751 | |
| Vascular access | Arteriovenous fistula (%) | 140 | 57.61% | 74 | 61.16% | 66 | 54.10% | 0.266 |
| Hemodialysis catheter (%) | 103 | 42.39% | 47 | 38.84% | 56 | 45.90% | ||
| Hemodialysis parameters | Residual diuresis (%) | 80 | 32.92% | 42 | 34.71% | 38 | 31.15% | 0.555 |
| Hemodialysis vintage (months) | 25 [15–40] | 27 [16–42] | 23 [14–39] | 0.128 | ||||
| Dry weight (kg) | 70.20 ± 7.66 | 70.47 ± 7.74 | 69.92 ± 7.60 | 0.574 | ||||
| Single pool Kt/V (spKt/V) | 1.31 ± 0.20 | 1.35 ± 0.21 | 1.27 ± 0.20 | 0.003 | ||||
| Medications | Angiotensin receptor blockers (%) | 175 | 72.02% | 92 | 76.03% | 83 | 68.03% | 0.165 |
| Calcium channel blockers (%) | 178 | 73.25% | 91 | 75.21% | 87 | 71.31% | 0.493 | |
| Loop diuretics (%) | 46 | 18.93% | 23 | 19.01% | 23 | 18.85% | 0.975 | |
| Vitamin D analogs (%) | 56 | 23.05% | 29 | 23.97% | 27 | 22.13% | 0.734 | |
| Phosphate binders (%) | 209 | 86.01% | 107 | 88.43% | 102 | 83.61% | 0.279 | |
| Calcimimetics (%) | 48 | 19.75% | 23 | 19.01% | 25 | 20.49% | 0.771 | |
| Erythropoietic stimulating agents (%) | 203 | 83.54% | 95 | 78.51% | 108 | 88.52% | 0.035 | |
| Laboratory parameters | Blood ureic nitrogen (mg/dL) | 64.06 ± 12.70 | 62.86 ± 13.56 | 65.24 ± 11.73 | 0.145 | |||
| Intact parathormone (pg/mL) | 565 [284–884] | 379 [233–710] | 697 [479–918] | 0.001 | ||||
| 25-OH vitamin D (ng/mL) | 19.05 ± 8.53 | 19.14 ± 8.12 | 18.96 ± 8.96 | 0.868 | ||||
| Serum phosphate (mg/dL) | 5.15 ± 1.08 | 5.17 ± 1.13 | 5.12 ± 1.03 | 0.725 | ||||
| Total serum calcium (mg/dL) | 8.22 ± 0.98 | 8.24 ± 1.05 | 8.19 ± 0.92 | 0.668 | ||||
| Ferritin (ng/mL) | 467.72 ± 168.45 | 472.89 ± 167.94 | 462.60 ± 169.49 | 0.635 | ||||
| Hemoglobin (g/dL) | 9.45 ± 1.33 | 9.36 ± 1.35 | 9.55 ± 1.31 | 0.263 | ||||
| Intact fibroblast growth factor 23 (pg/mL) | 319 [204–600] | 204 [160–267] | 598 [465–703] | <0.001 | ||||
| Clinical outcomes | SARS-CoV-2 infection (%) | 45 | 18.52% | 16 | 13.22% | 29 | 23.77% | 0.034 |
| COVID-19-related hospitalization (%) | 35 | 14.40% | 12 | 9.92% | 23 | 18.85% | 0.047 | |
| COVID-19-related death (%) | 12 | 4.94% | 4 | 3.31% | 8 | 6.56% | 0.242 | |
| COVID-19-non-related death (%) | 20 | 8.23% | 8 | 6.61% | 12 | 9.84% | 0.360 | |
| COVID-19-related hospitalization or death (%) | 36 | 14.81% | 12 | 9.92% | 24 | 19.67% | 0.032 | |