Table 3. Baseline Characteristics of Individuals at Risk for Development of Atrial Fibrillation According to Fibroblast Growth Factor 23 (FGF23) Quartiles.
| Variable | FGF23 Quartile, RU/mL | P Value | |||
|---|---|---|---|---|---|
| Quartile 1 (≤93.9) (n = 804) | Quartile 2 (94.0-138.6) (n = 805) | Quartile 3 (138.7-227.4) (n = 803) | Quartile 4 (>227.4) (n = 804) | ||
| Age, mean (SD), y | 55.7 (11.2) | 57.7 (11.0) | 57.7 (11.1) | 56.8 (11.4) | <.001 |
| Female sex, No. (%) | 283 (35.2) | 321 (39.9) | 364 (45.3) | 462 (57.5) | <.001 |
| Black, No. (%) | 325 (40.4) | 311 (38.6) | 304 (37.9) | 362 (45.0) | .02 |
| Hispanic, No. (%) | 65 (8.1) | 113 (14.0) | 133 (16.6) | 132 (16.4) | <.001 |
| Current smoking, No. (%) | 65 (8.1) | 81 (10.1) | 106 (13.2) | 170 (21.1) | <.001 |
| BMI, mean (SD)a | 30.3 (6.5) | 31.3 (7.0) | 32.3 (7.8) | 33.8 (9.0) | <.001 |
| Hypertension, No. (%) | 600 (74.6) | 689 (85.6) | 721 (89.8) | 747 (92.9) | <.001 |
| Systolic BP, mean (SD), mm Hg | 123.6 (19.8) | 127.0 (21.5) | 131.2 (23.0) | 132.7 (23.1) | <.001 |
| Diastolic BP, mean (SD), mm Hg | 73.0 (12.3) | 72.4 (12.3) | 72.1 (13.5) | 71.1 (13.0) | .03 |
| ACEI or ARB use, No./total No. (%) | 484/797 (60.7) | 561/797 (70.4) | 574/798 (71.9) | 558/801 (69.7) | <.001 |
| Diuretic use, No./total No. (%) | 323/797 (40.5) | 411/797 (51.6) | 486/798 (60.9) | 598/801 (74.7) | <.001 |
| Total No. of BP medications, mean (SD) | 2.0 (1.5) | 2.4 (1.4) | 2.7 (1.5) | 3.0 (1.4) | <.001 |
| Diabetes, No. (%) | 242 (30.1) | 356 (44.2) | 455 (56.7) | 485 (60.3) | <.001 |
| Heart failure, No. (%) | 23 (2.9) | 28 (3.5) | 51 (6.4) | 92 (11.4) | <.001 |
| Stroke, No. (%) | 59 (7.3) | 59 (7.3) | 72 (9.0) | 97 (12.1) | .002 |
| Cardiovascular disease, No. (%) | 154 (19.2) | 211 (26.2) | 239 (29.8) | 305 (37.9) | <.001 |
| Ratio (IQR) of urinary albumin to creatinine, mg/g | 14.5 (5.0-125.6) | 32.2 (6.4-278.3) | 106.9 (15.0-753.4) | 247.9 (30.2-1443.6) | <.001 |
| Estimated glomerular filtration rate, mean (SD), mL/min/1.73 m2 | 54.9 (13.8) | 47.8 (13.4) | 40.9 (12.1) | 35.3 (13.3) | <.001 |
| CRP level, median (IQR), mg/L | 1.8 (0.9-4.6) | 2.1 (0.9-4.8) | 2.5 (1.0- 6.0) | 4.0 (1.5-8.6) | <.001 |
| Serum calcium level, mean (SD), mg/dL | 9.2 (0.4) | 9.2 (0.5) | 9.2 (0.5) | 9.1 (0.6) | <.001 |
| Serum phosphate level, mean (SD), mg/dL | 3.4 (0.5) | 3.6 (0.6) | 3.8 (0.6) | 4.1 (0.8) | <.001 |
| Intact parathyroid hormone level, median (IQR), pg/mL | 39.0 (28.7-56.0) | 47.0 (32.0-73.8) | 60.6 (38.7-101.0) | 82.5 (46.1-137.1) | <.001 |
| LVMI, mean (SD), g/m2.7b | 46.6 (12.1) | 49.0 (12.2) | 51.9 (13.5) | 56.5 (15.4) | <.001 |
| Left atrial area, mean (SD), cm2 | 22.0 (5.0) | 22.4 (4.9) | 23.2 (5.7) | 24.1 (5.7) | <.001 |
| Ejection fraction, mean (SD), % | 55.5 (7.1) | 54.7 (7.6) | 54.5 (7.8) | 54.3 (8.3) | .02 |
Abbreviations: ACEI, angiotensin-converting enzyme inhibitor; ARB, angiotensin receptor blocker; BMI, body mass index; BP, blood pressure; CRP, C-reactive protein; IQR, interquartile range; LVMI, left ventricular mass index; RU, reference units.
SI conversion factors: To convert calcium level to millimoles per liter, multiply by 0.25; CRP level to nanomoles per liter, multiply by 9.624; parathyroid hormone level to nanograms per liter, multiply by 1.0.
a
Calculated as weight in kilograms divided by height in meters squared.
b
Superscript 2.7 is used to index LV mass to height.