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Table 2 Maternal, pregnancy and perinatal characteristics associated with loss to follow-up and the presence or absence of neurodevelopmental impairment at 2 years of corrected age (N = 1737)

From: Strategies for assessing the impact of loss to follow-up on estimates of neurodevelopmental impairment in a very preterm cohort at 2 years of age

 

Responded to follow-up questionnaire

Presence of moderate to severe neurodevelopmental impairment

Yes (n = 941, 54.2%)

No (n = 796, 45.8%)

p-value

No (n = 683, 81.6%)

Yes (n = 154, 18.4%)

p-value

n (%)

n (%)

n (%)

n (%)

Maternal characteristics

 Maternal age

  ≤ 24y

138 (14.8%)

256 (32.2%)

< 0.001

93 (13.7%)

28 (18.3%)

0.35

  25y-34y

545 (58.3%)

397 (49.9%)

 

399 (58.7%)

85 (55.6%)

 

  ≥ 35y

252 (27.0%)

142 (17.9%)

 

188 (27.6%)

40 (26.1%)

 

  Missing

6 (0.6%)

1 (0.1%)

 

3 (0.4%)

1 (0.6%)

 

 Foreign born/Ethnicity

121 (13.0%)

183 (23.2%)

< 0.001

76 (11.2%)

20 (13.2%)

0.54

  Missing

8 (0.9%)

8 (1.0%)

 

6 (0.9%)

2 (1.3%)

 

 Multiple pregnancy

285 (30.3%)

185 (23.3%)

< 0.001

215 (31.5%)

37 (24.0%)

0.09

 Parity

  First child

580 (61.8%)

367 (46.2%)

< 0.001

442 (64.8%)

86 (55.8%)

0.03

  Second child

225 (24.0%)

211 (26.6%)

 

159 (23.3%)

37 (24.0%)

 

  Third or more

134 (14.3%)

216 (27.2%)

 

81 (11.9%)

31 (20.1%)

 

  Missing

2 (0.2%)

2 (0.3%)

 

1 (0.1%)

0 (0.0%)

 

 Previous cesarean section

90 (9.8%)

99 (13.1%)

0.03

63 (9.4%)

12 (8.1%)

0.62

  Missing

22 (2.3%)

40 (5.0%)

 

16 (2.3%)

5 (3.2%)

 

 PPROM

203 (22.1%)

206 (27.2%)

0.01

145 (21.8%)

37 (24.3%)

0.60

  Missing

22 (2.3%)

40 (5.0%)

 

17 (2.5%)

2 (1.3%)

 

 Antepartum hemorrhage after ≥20 weeks GA

205 (22.2%)

205 (27.0%)

0.31

139 (20.8%)

39 (25.7%)

0.19

  Missing

19 (2.0%)

36 (4.5%)

 

15 (2.2%)

2 (1.3%)

 

 Delivery in level III

657 (70.0%)

530 (66.7%)

0.11

480 (70.5%)

110 (71.4%)

0.45

  Missing

2 (0.2%)

1 (0.1%)

 

2 (0.3%)

0 (0.0%)

 

 Breastfeeding at discharge

649 (69.2%)

427 (53.8%)

< 0.001

486 (71.5%)

97 (63.0%)

0.04

  Missing

3 (0.3%)

3 (0.4%)

 

3 (0.4%)

0 (0.0%)

 

Neonatal characteristics

 Male

529 (56.2%)

426 (53.6%)

0.34

370 (54.2%)

108 (70.1%)

< 0.001

  Missing

0 (0.0%)

1 (0.1%)

 

 

 Gestational age at birth

  23wk-25wk

70 (7.4%)

64 (8.0%)

0.49

36 (5.3%)

24 (15.6%)

< 0.001

  26wk-27wk

166 (17.6%)

109 (13.7%)

 

119 (17.4%)

27 (17.5%)

 

  28wk-29wk

249 (26.5%)

228 (28.6%)

 

174 (25.5%)

50 (32.5%)

 

  30wk-31wk

456 (48.5%)

395 (49.6%)

 

354 (51.8%)

53 (34.4%)

 

 Small for gestational agea

  < 3th percentile

198 (21.0%)

153 (19.2%)

0.80

138 (20.2%)

42 (27.3%)

0.12

  3-10th percentile

111 (11.8%)

97 (12.2%)

 

85 (12.4%)

18 (11.7%)

 

   > 10th percentile

632 (67.2%)

545 (68.6%)

 

460 (67.3%)

94 (61.0%)

 

 Apgar score < 7 (5 min)

109 (11.8%)

117 (15.0%)

0.18

67 (10.0%)

30 (19.7%)

< 0.001

  Missing

21 (2.2%)

17 (2.1%)

 

16 (2.3%)

2 (1.3%)

 

 Surfactant

570 (60.6%)

458 (57.5%)

0.02

393 (57.5%)

111 (72.1%)

< 0.001

 Any CPAPb

810 (86.1%)

649 (81.5%)

0.13

586 (85.8%)

136 (88.3%)

0.35

 Mechanical ventilation

551 (58.6%)

456 (57.3%)

0.07

372 (54.5%)

115 (74.7%)

< 0.001

 Bronchopulmonary dysplasiac

175 (18.8%)

156 (20.0%)

0.59

111 (16.4%)

45 (29.2%)

< 0.001

  Missing

9 (1.0%)

15 (1.9%)

 

7 (1.0%)

0 (0.0%)

 

 Any severe morbidity

111 (11.8%)

90 (11.4%)

0.70

61 (8.9%)

38 (24.7%)

< 0.001

  Missing

2 (0.2%)

9 (1.1%)

 

0 (0.0%)

0 (0.0%)

 

 Any congenital anomalyd

46 (4.9%)

40 (5.0%)

0.75

29 (4.2%)

12 (7.8%)

0.06

 Any Surgery

75 (8.0%)

69 (8.7%)

0.83

39 (5.7%)

27 (17.5%)

< 0.001

 Socioeconomic status

  1 (least deprivated)

236 (25.1%)

107 (13.4%)

< 0.001

182 (26.7%)

36 (23.4%)

0.54

  2

193 (20.5%)

115 (14.5%)

 

146 (21.4%)

27 (17.5%)

 

  3

194 (20.6%)

144 (18.1%)

 

142 (20.8%)

31 (20.1%)

 

  4

149 (15.8%)

173 (21.7%)

 

102 (14.9%)

28 (18.2%)

 

  5 (most deprivated)

140 (14.9)

213 (26.8%)

 

95 (13.9%)

26 (16.9%)

 

  Missing

29 (3.1)

44 (5.5%)

 

16 (2.3%)

6 (3.9%)

 
  1. P-value was adjusted on region of birth and doesn’t include missing category; aUsing intrauterine curves; bContinuous positive airway pressure; cOxygen dependency or assisted ventilation at 36 weeks post menstrual age; dCongenital anomalies reported to Eurocat