Key components of early intervention programs for preterm infants and their parents: a systematic review and meta-analysis

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	33.1^g	33.1^g	1938^g	1938^g	197	130	5 m
Saylor 1996	3	68	3(4.4)	1	28.9	30.3	1107	1231	34^f	31^f*	7 yrs
APIP 1998	4	328	42(12.8)	2	31.0 ^d P 30.0^d PA	31.0^d	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 75^a	7(3.2)	1	30.2	29.9	1402	1393	72	74 75^b	5 yrs
Melynk 2006	3	260	13(5.8)	2	31.3	31.4	1683	1627	147	113	2 m
Glazebrook 2007^b	3	233	11(4.7)	6	28.5^d	29.0^d	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	33.4^e 33.4^e	1990	1880 1980	31	29^e 27^e*	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

ISSN: 1471-2393