Improving outcomes of Preterm Infants, early post-discharge intervention programs

The history of early intervention programs is rather mixed. Do they actually help to improve outcomes? The most recent cochrane review was published in 2007 by the amazingly productive Lex Doyle and his colleagues, and was followed by an updated review by the same authors in 2009 (Orton J, Spittle A, Doyle LEX, Anderson P, Boyd R: Do early intervention programmes improve cognitive and motor outcomes for preterm infants after discharge? A systematic review. Developmental Medicine & Child Neurology 2009, 51(11):851-859). There are quite a few studies, 18 in all, but several were quasi-randomised, and the quality of several was low. Many were very small studies, but there was one study with nearly 1,000 babies, and another with just over 300, these were both high quality studies with follow up to school age. The largest study, the US Infant Health and Development Program (IHDP), has reported outcomes to 18 years of age, that study included infants less than 2.5 kg and less than 37 weeks; they randomized them 2:1 to get control more frequently than the intervention, I am not sure why. About half of the babies were less than 2 kg. Overall from the meta-analyses it seems that early cognitive scores are improved by around 0.5 of a standard deviation, up to pre-school testing. Scores at school age are not improved. There was some benefit in the larger babies at 18 years in the IHDP study, but not in the smaller ones. One of the higher quality studies in the systematic review was by Karen Koldewijn and her colleagues. In 2009 they had only published the 6 month outcomes, but they have very recently added preschool results. (Verkerk G, Jeukens-Visser M, Houtzager B, Koldewijn K, van Wassenaer A, Nollet F, Kok J: The infant behavioral assessment and intervention program in very low birth weight infants; outcome on executive functioning, behaviour and cognition at preschool age. Early Human Development 2012, 88(8):699-705.) For this publication there was an extensive analysis of the infants, including tests of executive functioning, behavior, visual motor integration and cognition. There were 151 infants of the originally randomized 176 who were examined (2 had died). They also had a number of term controls, about 40. The overall analysis showed no effect of the intervention program at this age. They did perform subgroup analyses which suggested some benefit in more high risk infants (with BPD or less than 28 weeks, or when the mother was of a low SES), but as always you have to take such analyses with a pinch of salt. Why would this be? An effect on cognitive development that does not generally seem to translate into longer term cognitive outcomes? I think that we are seeing is that there is an overall improvement in cognitive scores as these children age, particularly before they start school, as we showed in the CAP 5 year follow up. Some of that is because of the use of different tests. In the CAP 5 year follow up we examined some variables that were associated with improving cognitive scores and the social and educational background of the parents was important. So it seems that having an enriched environment at home after discharge is very important, but when the home environment is already good, then adding an early intervention program doesn’t have much long term effect. For those children with a more limited home environment these types of programs may have a benefit. Such programs are fairly expensive, but I think the data are positive enough that infants from families of lower socioeconomic status do benefit from early intervention and should be targeted. Who will pay is a question for the health care system where you are.

About Keith Barrington

I am a neonatologist and clinical researcher at Sainte Justine University Health Center in Montréal
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