Table 1 Patient characteristics, levels of biomarkers, and respiratory morbidity.

From: Respiratory morbidity in preterm infants predicted by natriuretic peptide (MR-proANP) and endothelin-1 (CT-proET-1)

  All (n = 229) No BPD/death (n = 203) BPD/death (n = 26) p valuea
Gestational age (weeks)
 Median 29.57 29.86 25.50 <0.001
 [IQR] [27.00, 30.71] [27.79, 31.00] [24.43, 26.29]  
 Range 23.71–31.85 23.71–31.85 23.71–30.14  
Birth weight (g)
 Median 1150 g 1200 g 650 g <0.001
 [IQR] [840, 1410] [910, 1450] [540, 778]  
 Range 370–2440 g 400–2440 g 370–1490 g  
Ethnicity, n (%)
 White 220 (96.1) 197 (97.0) 23 (88.5) 0.002
 Hispanic 4 (1.7) 4 (2.0) 0 (0.0)  
 Black 5 (2.2) 2 (1.0) 3 (11.5)  
Blood sampling (day of life)
 Median 7 7 7 0.02
 [IQR] [7, 7] [7, 7] [7, 8]  
Type or respiratory supportb, n (%)
 Mechanical ventilation 23 (10.0) 12 (5.9) 11 (42.3) <0.001
 CPAP 104 (45.4) 92 (45.3) 12 (46.2)  
 None 101 (44.1) 99 (48.8) 2 (7.7)  
FiO2b
Median 0.21 0.21 0.25 <0.001
[IQR] [0.21, 0.21] [0.21, 0.21] [0.22, 0.30]  
SGA, n (%) 23 (10.0) 15 (7.4) 8 (30.8) 0.001
Male, n (%) 119 (52.0) 108 (53.2) 11 (42.3) 0.402
Any antenatal steroids, n (%) 178 (77.8) 159 (78.3) 19 (73.1) 0.685
Chorioamnionitis, n (%) 51 (22.3) 43 (21.2) 8 (30.8) 0.392
Preeclampsia, n (%) 33 (14.4) 28 (13.8) 5 (19.2) 0.457
Any surfactant, n (%) 123 (53.7) 101 (49.8) 23 (84.6) 0.002
Sepsis, n (%) 42 (18.3) 27 (13.3) 15 (57.7) <0.001
PDA day 7, n (%) 50 (21.8) 37 (18.2) 13 (50.0) 0.001
IVH, n (%) 26 (11.4) 23 (11.3) 3 (11.5) 1.000
Death, n (%) 3 (1.3) 0 (0.0) 3 (11.5) <0.001
MR-proANP (pmol/L)
Median 341.50 308.35 623.50 <0.001
[IQR] [218.50, 588.82] [216.72, 538.10] [458.50, 881.38]  
CT-proET-1 (pmol/L)
Median 202.80 198.30 255.40 0.015
[IQR] [159.25, 301.30] [154.70, 297.95] [202.60, 311.15]  
O2 supplementation (h)
Median 72.0 43.0 2103.9 <0.001
[IQR] [2.5, 726.0] [0.75, 338.9] [1536.4, 2556.0]  
Mechanical ventilation (h)
Median 6.0 1.0 412.4 <0.001
[IQR] [0.0, 47.3] [0.0, 22.0] [111.4, 769.9]  
CPAP (h)
Median 414.3 164.5 938.5 <0.001
[IQR] [51.0, 740.0] [50.0, 601.0] [696.5, 1337.5]  
High flow nasal cannula (h)
Median 160.3 0.0 166.3 <0.001
[IQR] [0.0, 236.5] [0.0, 177.0] [0.0, 424.5]  
Total respiratory support (h)
Median 547.5 341.0 1959.0 <0.001
[IQR] [71.0, 1089.0] [60.5, 941.9] [969.8, 2466.8]  
  1. Chorioamnionitis: clinical or histological signs of infection, PDA: classified by the cardiologist as hemodynamically relevant, total respiratory support: combined duration of mechanical ventilation, non-invasive ventilation, CPAP, and high flow nasal cannula.
  2. BPD bronchopulmonary dysplasia, IQR interquartile range, SGA small for gestational age (birth weight <10th percentile), PDA patent ductus arteriosus, IVH intraventricular hemorrhage (>grade II), MV mechanical ventilation.
  3. ap Values refer to comparisons of patients “No BPD/death” and “BPD/death.”
  4. bOn the day of blood sampling.