Skip to main content

Table 2 Analysis of survival

From: Population based trends in mortality, morbidity and treatment for very preterm- and very low birth weight infants over 12 years

Year

1996-2008

  

1996

 

2000

 

2004

 

2008

 

Characteristics

No. (%)

p-value 1. - 2.

relative risk

No. (%)

p-value 96 - 00

No. (%)

p-value 00 - 04

No. (%)

p-value 04 - 08

No. (%)

p-value 96 - 08

Overall mortality rate

412 (13.3)

  

95 (13.2)

0.04

122 (15.8)

0.04

98 (13.0)

0.20

97 (11.5)

0.15

Mortality rate by gender

           

   1. females

177 (11.7)

0.55

1

41 (12.0)

0.26

54 (13.8)

0.07

38 (10.5)

0.91

44 (10.7)

0.41

   2. males

235 (14.8)

 

1.13

54 (14.3)

0.06

68 (17.7)

0.22

60 (15.3)

0.09

53 (12.3)

0.24

Mortality rate by mode of delivery1

           

   1. spontaneous

107 (18.9)

0.17

1.65

33 (19.0)

0.70

29 (20.3)

0.54

23 (18.1)

0.95

22 (17.9)

0.75

   2. caesarean section

273 (11.4)

 

1

58 (11.1)

< 0.01

86 (14.5)

0.03

70 (11.5)

0.03

59 (8.8)

0.06

Mortality rate by location of birth

           

   1. inborn2

376 (13.4)

0.89

1.06

81 (13.0)

0.01

112 (16.3)

0.02

92 (12.9)

0.26

91 (11.6)

0.23

   2. outborn

36 (12.7)

 

1

14 (14.3)

0.43

10 (11.4)

0.60

6 (14.0)

0.51

6 (10.9)

0.47

Mortality rate by number of infants

           

   1. singleton

308 (14.4)

0.50

1.31

75 (13.9)

0.17

87 (15.9)

0.30

73 (14.2)

0.60

73 (13.4)

0.75

   2. multiples

104 (11.0)

 

1

20 (11.2)

0.05

35 (15.4)

0.03

25 (10.4)

0.18

24 (8.1)

0.09

Mortality rate by gestational age3

           

   < 26

186 (56.0)

 

6.8a

40 (58.8)

0.26

60 (64.5)

0.05

45 (54.2)

0.15

41 (46.6)

0.02

   26-27

115 (23.1)

 

4.7a

25 (26.0)

0.95

34 (25.8)

0.51

30 (23.3)

0.17

26 (18.4)

0.04

   28-29

52 (7.5)

 

2.0a

14 (8.2)

0.69

13 (7.4)

0.83

12 (7.0)

0.92

13 (7.3)

0.50

   30-31

46 (4.0)

 

1.3a

11 (4.0)

0.78

10 (3.7)

0.68

9 (3.2)

0.77

16 (5.0)

0.32

Characteristics

p0.5 (p0.05-p0.95)

p-value 1. - 2.

mean

p-value 96 - 00

Mean

p-value 00 - 04

mean

p-value 04 - 08

mean

p-value 96 - 08

Birth weight (g)

           

   1. survivors

1225 (630-1840)

< 0.001

1283

0.49

1279

0.94

1264

0.05

1244

0.01

   2. deaths

795 (480-1625)

  

943

0.02

835

0.11

918

0.79

935

0.89

Gestational age (week)

           

   1. survivors

30 0/7 (25 0/7 - 33 5/7)

< 0.001

30 2/7

0.56

30 0/7

0.96

29 6/7

0.02

29 6/7

< 0.01

   2. deaths

26 3/7 (23 6/7 - 31 5/7)

  

27 2/7

0.10

26 5/7

0.90

26 5/7

0.32

27 0/7

0.52

  1. p0.5 = 50th percentile = median, p0.05 = 5th percentile, p0.95 = 95th percentile, 1cephalic forceps and cephalic ventouse deliveries were not listed separately, 2 inborn = born in one oft the nine perinatal centres, 3 children born > 32 completed gestational weeks were not listed separately, a relative to the older age groups