Table 1.

Characteristics of the participants in CKiD by ambulatory BP status

CharacteristicOverall CohortNormotensionaIsolated BP Load ElevationbHypertensionc
N (%)533 (100)213 (40)123 (23)197 (37)
Median age, yr (IQR)13 (9, 16)13 (10, 15)13 (9, 16)12 (9, 16)
Maled326 (61)123 (58)85 (69)118 (60)
Raced
 White366 (69)167 (78)84 (69)115 (58)
 Black76 (14)15 (7)20 (16)41 (21)
 Other91 (17)31 (15)19 (15)41 (21)
Cause of CKD
 Glomerular142 (27)63 (30)30 (24)49 (25)
 Nonglomerular391 (73)150 (70)93 (76)148 (75)
Age- and sex-adjusted BMI z-score (IQR)d0.3 (−0.4, 1.3)0.3 (−0.5, 1.4)0.6 (−0.1, 1.5)0.2 (−0.5, 0.9)
Median eGFR in ml/min per 1.73 m2 by bedside Schwartz (IQR)51 (34, 66)54 (34, 68)51 (39, 64)49 (31, 64)
Hemoglobin, g/dl (IQR)13 (12, 14)13 (12, 14)13 (12, 14)13 (12, 14)
Serum albumin, g/dl (IQR)4.3 (4.1, 4.6)4.4 (4.2, 4.6)4.3 (4.2, 4.6)4.3 (4.1, 4.6)
Left ventricular hypertrophy at baselined62 (12)14 (7)15 (12)33 (17)
Clinic systolic BP indexd,e0.88±0.100.84±0.080.88±0.080.93±0.10
Clinic diastolic BP indexd,e0.82±0.140.77±0.120.80±0.120.89±0.15
Awake systolic BP indexd0.91±0.080.86±0.060.91±0.050.98±0.07
Awake diastolic BP indexd0.88±0.100.81±0.070.88±0.060.96±0.10
Awake systolic BP loadd13 (3, 33)3 (0, 9)14 (3, 26)40 (19, 59)
Awake diastolic BP loadd13 (5, 31)6 (2, 10)16 (7, 27)36 (21, 55)
Asleep systolic BP indexd0.92±0.100.85±0.060.91±0.041.00±0.07
Asleep diastolic BP indexd0.92±0.130.81±0.070.92±0.061.03±0.11
Asleep systolic BP loadd14 (0, 39)0 (0, 6)15 (5, 28)50 (28, 75)
Asleep diastolic BP loadd21 (6, 47)5 (0, 12)28 (19, 36)56 (33, 75)
Antihypertensive medication use362 (68)152 (71)77 (63)133 (68)
Awake systolic BP loadd
 0% to <25%366 (68)213 (100)90 (73)63 (32)
 25% to <50%89 (17)0 (0)33 (27)56 (28)
 50%–100%78 (15)0 (0)0 (0)78 (40)
Asleep systolic BP loadd
 0% to <25%340 (64)213 (100)86 (70)41 (21)
 25% to <50%89 (17)0 (0)35 (28)54 (27)
 50%%–100%104 (19)0 (0)2 (2)102 (52)
Awake diastolic BP loadd
 0% to <25%365 (69)213 (100)86 (70)66 (34)
 25% to <50%102 (19)0 (0)35 (28)67 (34)
 50%–100%66 (12)0 (0)2 (2)64 (32)
Asleep diastolic BP loadd
 0% to <25%284 (54)213 (0)44 (36)27 (14)
 25% to <50%126 (24)0 (0)78 (63)48 (24)
 50%–100%123 (23)0 (0)1 (1)122 (62)
  • Values are means±SD or N (%), unless otherwise specified. IQR, interquartile range; BMI, body mass index.

  • a Normotension was defined as awake and asleep systolic BP and diastolic BP index <1.0 (e.g., mean ambulatory BP <95th percentile for sex and height), as well as awake and asleep systolic BP or diastolic BP load <25%.

  • b Isolated BP load elevation was defined as awake and asleep systolic BP or diastolic BP index <1.0, with awake or asleep systolic BP or diastolic BP load ≥25%.

  • c Hypertension was defined as ambulatory awake or sleep systolic BP or diastolic BP index ≥1.0, regardless of BP load.

  • d Statistically significantly different by BP control category (P<0.05).

  • e Clinic BP readings were indexed to the 95th percentile thresholds for age, sex, and height; an index of 1 would represent a clinic BP that was exactly at the 95th percentile for age, sex, and height derived from the National High BP Education Program Fourth Report as in prior CKiD studies.