Table 1.

Baseline characteristics of the study population by quartiles of FGF-23

CharacteristicFGF-23 QuartileP Value
<96.0 RU/ml (n=964)96.0–145.4 RU/ml (n=966)145.5–238.9 RU/ml (n=965)≥239.0 RU/ml (n=965)
Demographics
 Age (yr)56.1±11.258.2±10.958.5±10.857.8±10.9<0.001
 Women347 (36.0)383 (39.7)453 (46.9)544 (56.4)<0.001
 Race/ethnicity<0.001
  Non-Hispanic white450 (46.7)419 (43.4)402 (41.7)344 (35.7)
  Non-Hispanic black399 (41.4)369 (38.2)382 (39.6)450 (46.6)
  Hispanic71 (7.4)136 (14.1)136 (14.1)149 (15.4)
  Other44 (4.6)42 (4.4)45 (4.7)22 (2.3)
 Annual income <$20,000a184 (19.1)268 (27.7)335 (34.7)410 (42.5)<0.001
Medical history
 Hypertension727 (75.4)839 (86.9)867 (89.8)889 (92.1)<0.001
 Diabetes290 (30.1)440 (45.6)549 (56.9)592 (61.4)<0.001
 Prior atherosclerotic CVD198 (20.5)275 (28.5)329 (34.1)377 (39.1)<0.001
  Myocardial infarction or revascularization144 (14.9)209 (21.6)233 (24.2)262 (27.2)<0.001
  Stroke76 (7.9)79 (8.2)116 (12.0)113 (11.7)<0.001
  Peripheral vascular disease32 (3.3)41 (4.2)74 (7.7)110 (11.4)<0.001
 Congestive heart failure33 (3.4)66 (6.8)99 (10.3)175 (18.1)<0.001
Kidney function
 Estimated GFR (ml/min per 1.73 m2)54.5±14.047.2±13.140.3±12.035.2±13.3<0.001
 Urine albumin-to-creatinine ratio (µg/mg)b15 (5, 121)31 (7, 268)104 (15, 716)212 (28, 1311)<0.001
Traditional CVD risk factors
 Current smoking75 (7.8)97 (10.0)132 (13.7)201 (20.8)<0.001
 Body mass index (kg/m2)30.6±6.731.5±7.032.3±7.833.9±9.1<0.001
 Waist circumference (cm)
  Men103.0±14.7106.5±15.3107.6±16.0110.4±17.1<0.001
  Women100.9±17.6103.5±19.1105.2±18.9109.0±20.4<0.001
 Hemoglobin A1c (%)b5.8 (5.5, 6.5)6.1 (5.6, 7.2)6.3 (5.7, 7.6)6.5 (5.8, 7.9)<0.001
 Total cholesterol (mg/dl)184±39182±41185±47184±530.4
 LDL cholesterol (mg/dl)107±33102±33101±36100±38<0.001
 HDL cholesterol (mg/dl)49±1648±1647±1546±15<0.001
 Serum triglycerides (mg/dl)b112 (78, 160)128 (88, 183)131 (94, 194)140 (102, 207)<0.001
Nontraditional risk factors
 Hemoglobin (g/dl)13.5±1.612.8±1.712.4±1.611.8±1.8<0.001
 Serum albumin (mg/dl)4.1±0.44.0±0.43.9±0.53.8±0.5<0.001
 C-reactive protein (mg/L)b1.9 (0.9, 4.6)2.2 (1.0, 5.0)2.6 (1.1, 6.7)4.1 (1.5, 8.6)<0.001
 Serum phosphate (mg/dl)3.4±0.53.6±0.63.8±0.64.1±0.8<0.001
 Serum calcium (mg/dl)9.2±0.49.2±0.59.2±0.59.1±0.6<0.001
 Intact PTH (pg/ml)b40 (29, 59)47 (33, 74)63 (40, 105)83 (47, 139)<0.001
 N-terminal proBNP (pg/ml)b78 (35, 179)116 (54, 281)196 (82, 460)336 (136, 943)<0.001
Echocardiographyc
 Ejection fraction <50%129 (15.5)159 (18.9)185 (23.0)180 (24.2)<0.001
 Left ventricular mass index (g/m2)47±1250±1353±1358±15<0.001
Medication use
 Antiplatelet392 (40.7)446 (46.2)461 (47.8)466 (48.3)0.01
β-Blocker344 (35.7)446 (46.2)512 (53.1)588 (60.9)<0.001
 ACE inhibitor/ARB577 (59.9)689 (71.3)702 (72.8)669 (69.3)<0.001
 Statin431 (44.7)537 (55.6)589 (61.0)565 (58.6)<0.001
 Loop diuretic175 (18.2)303 (31.4)405 (42.0)567 (58.8)<0.001
  • Unless otherwise noted, values are n (%) or means ± SDs. CVD, cardiovascular disease; ACE, angiotensin-converting enzyme; ARB, angiotensin-receptor blocker.

  • a Sixteen percent of participants declined to respond.

  • b Median (interquartile range).

  • c Ejection fraction was available in 3225 participants and left ventricular mass index in 2880 participants.