Table 1.
Characteristics and methods of studies included in review (by date).
| Study | Study quality* | Infants enrolled | Drop outs | No. of sites | Mean GA (weeks) | Mean birth weight (grams) | Group allocation | Follow-up | |||
|---|---|---|---|---|---|---|---|---|---|---|---|
| n | n (%) | I | C | I | C | I (n) | C (n) | ||||
| IHDP 1990 |
4 | 985 | 72(7.3) | 8 | 33.0 | 33.0 | 1819 | 1781 | 377 | 608 | 18 yrs |
| Kang 1995 |
2 | 327 | 82(25.1) | 3 | 33.1g | 33.1g | 1938g | 1938g | 197 | 130 | 5 m |
| Saylor 1996 |
3 | 68 | 3(4.4) | 1 | 28.9 | 30.3 | 1107 | 1231 | 34f | 31f* | 7 yrs |
| APIP 1998 |
4 | 328 | 42(12.8) | 2 | 31.0 d P 30.0d PA |
31.0d | 1560 P 1331 PA |
1420 | 116 P 106 PA |
106 | 5 yrs |
| Melynk 2001 |
2 | 55 | 13(23.6) | 1 | 31.4 | 31.6 | 1483 | 1731 | 26 | 29 | 6 m |
| Brisch 2003 |
2 | 87 | 11(12.6) | 1 | 27.0 | 27.0 | 919 | 987 | 43 | 44 | 24 m |
| Ohgi 2004 |
3 | 23 | 1(4.2) | 1 | 30.3 | 30.3 | 1273 | 1360 | 12 | 11 | 6 m |
| Gianni 2006 |
2 | 36 | 0(0) | 1 | 28.3 | 27.5 | 892 | 836 | 18 | 18 | 36 m |
| Kaaresen 2006 |
4 | 146 75a |
7(3.2) | 1 | 30.2 | 29.9 | 1402 | 1393 | 72 | 74 75b |
5 yrs |
| Melynk 2006 |
3 | 260 | 13(5.8) | 2 | 31.3 | 31.4 | 1683 | 1627 | 147 | 113 | 2 m |
| Glazebrook 2007b |
3 | 233 | 11(4.7) | 6 | 28.5d | 29.0d | 1121 | 1220 | 112 | 121 | 24 m |
| Koldewijn 2009 |
3 | 176 | 1(0.6) | 7 | 29.6 | 30.0 | 1242 | 1306 | 86 | 90 | 7 yrs |
| Newnham 2009 |
3 | 68 | 5(7.4) | 1 | 31.3 | 33.7 | 1590 | 1619 | 35 | 33 | 24 m |
| Teti 2009 |
3 | 194 | 21(10.8) | 4 | 30.6 | 30.0 | 1455 | 1397 | 99 | 95 | 4 m |
| Milgrom 2010 |
4 | 45 | 0(0) | 1 | 27.5 | 27.7 | 981 | 999 | 22 | 23 | 0 |
| Neu 2010 |
2 | 87 | 8(9.2) | 5 | 33.1 | 33.4e 33.4e |
1990 | 1880 1980 |
31 | 29e 27e* |
4 m |
| Spittle 2010 |
4 | 120 | 3(2.5) | 2 | 27.3 | 27.4 | 1029 | 991 | 61 | 59 | 24 m |
| Ravn 2011 |
4 | 118 | 0(0) | 1 | 33.3 | 33.2 | 1935 | 1919 | 61 | 57 | 12 m |
Note: *Study methodological quality was assessed by Cochrane Collaboration’s Tool [44].
GA = gestational age; I = Intervention group; C = Control or comparison group; m = months; yrs = years
Programs: APIP = Avon Premature Infant Project; IHDP = Infant Health Development Program; P = Portage intervention; PA, = Parent Advisor intervention
a Matched term controls
b Cluster RCT with washout and crossover
c Case matched by developmental risk score, then randomly allocated to groups
d Median
e Holding comparison group; e* Control group
f Early intervention group; f* Late intervention group
g Overall mean for cohort