Table 4.

Comparisons across CKD stages

CharacteristicCKD StageP Value across Stages
1 (n=370)2 (n=87)3 (n=37)4–5 (n=10)
Baseline data
 Maternal age (yr)31.3±5.533.8±4.533.5±4.132.3±5.2<0.001
 Parity (% nulliparous)54.657.564.970.00.50
 Referral week15.0 (4–39)11.0 (4–38)8.0 (5–33)8.0 (4–28)<0.001
 Systemic disease (%)11.6 (43/370)35.6 (31/87)43.2 (16/37)40.0 (4/10)<0.001
 Hypertension (%)21.6 (80/370)41.4 (36/87)54.1 (20/37)20.0% (2/10)<0.001
 Proteinuria (g/d)
  Baseline0.12 (0–14.6)0.15 (0–6.8)0.50 (0–2.8)0.63 (0.10–3.44)<0.001
  <0.378.4 (286/370)65.1 (56/86)33.3 (12/36)22.2 (2/9)
  ≥0.3 to <0.57.9 (29/370)5.8 (5/86)11.1 (4/36)11.1 (1/9)
  ≥0.5 to <1.05.2 (19/370)8.1 (7/86)33.3 (12/36)33.3 (3/9)
  ≥1.0 to <3.06.0 (22/370)14.0 (12/86)22.2 (8/36)22.2 (2/9)
  ≥3.02.5 (9/370)7.0 (6/86)11.1 (1/9)
Maternal-fetal outcomes
 Cesarean sections48.470.178.470.0<0.001
 Gestational week37.6±2.635.7±3.234.4±2.432.6±4.2<0.001
 Preterm delivery (<37 wk)23.550.678.488.9<0.001
 Early preterm (<34 wk)7.320.737.844.4<0.001
 Birth weight (g)2966.5±6592484±7072226.3±5821639±870<0.001
 SGA score (Parazzini)
  <10%13.317.918.950.00.02
  <5%5.16.05.425.00.12
 Need for NICU10.327.644.470.0<0.001
 General combined outcome34.163.283.890.0<0.001
 Severe combined outcome21.444.859.580.0<0.001
 New-onset hypertension (%)7.9 (23/290)17.6 (9/51)47.1 (8/17)50.0 (4/8)<0.001
 New-onset or doubling of proteinuria20.5 (76/370)37.9 (33/87)86.5 (32/37)70.0 (7/10)<0.001
 CKD stage shift or RRT start7.6 (28/370)12.6 (1/87)16.2 (6/37)20.0 (2/10)0.12
  • Data are presented as the mean±SD, percentage (proportion), or median (range), unless otherwise indicated. CKD stage shift indicates an increase of at least 1 CKD stage. New-onset proteinuria is defined as proteinuria increasing from a baseline level <0.3 to ≥0.3 g/d (calculated in patients with proteinuria <0.3 g/d). P values through CKD stages (P1, stage 1 versus stage 2; P2, stage 2 versus stage 3; P3, stage 3 versus stages 4–5) are illustrated: Maternal age: P1<0.001; P2=1.0; P3=1.0. Parity: P1=0.71; P2=0.57; P3=1.0. Week of referral: P1<0.001; P2=0.17; P3=0.72. Systemic disease: P1<0.001; P2=0.55; P3=1.0. Hypertension: P1<0.001; P2=0.27; P3=0.07. Baseline proteinuria: P1=0.01; P2<0.001; P3=0.36. Cesarean section: P1<0.001; P2=0.46; P3=0.67. Gestational age: P1<0.001; P2=0.08; P3=0.40. Preterm delivery (<37 weeks): P1<0.001; P2=0.007; P3=0.66. Early preterm (<34 weeks): P1<0.001; P2=0.007; P3=0.72. Weight at birth: P1<0.001; P2=0.29; P3=0.08. SGA 10% (Parazzini): P1=0.36; P2=1.0; P3=0.08. SGA 5% (Parazzini): P1=0.99; P2=1.0; P3=0.05. Need for NICU: P1<0.001; P2=0.05; P3=0.30. New-onset hypertension: P1=0.03; P2=0.02; P3=1.0. New-onset or doubling of proteinuria: P1<0.001; P2<0.001; P3=0.34.

  • P values stage 1 versus controls are illustrated: Maternal age: P<0.001. Parity: P=0.28. Cesarean sections, gestational age, preterm delivery (<37 weeks), early preterm delivery (<34 weeks), birth weight, and need for NICU: P<0.001; SGA 10% (Parazzini): 0.16; SGA 5% (Parazzini): 0.70; new-onset hypertension P=0.19.

  • P values for combined outcomes through stages are illustrated: General combined outcome: P1<0.001; P2=0.039; P3=1.0. Severe combined outcome: P1<0.001; P2=0.195; P3=0.289.