BOOST-II UK trial main results published

Published on Wednesday, 10 February 2016 Post

The long awaited results from the landmark BOOST-II UK trial have been published in the New England Journal of Medicine. The article, entitled "Outcomes of Two Trials of Oxygen-Saturation Targets in Preterm Infants” reports the outcomes at 2 years (after their expected date of delivery) for babies who participated in the BOOST-II UK and the BOOST-II Australia trials. Read the paper.

Summary

On 10th February 2016 the New England Journal of Medicine published an article entitled "Outcomes of Two Trials of Oxygen-Saturation Targets in Preterm Infants”. This article reports the outcomes at 2 years (after their expected date of delivery) for babies who participated in the BOOST-II UK trial and the BOOST-II Australia trial. A summary of the findings has been sent to parents whose babies participated in the UK trial who have previously expressed a wish for us to stay in contact with them and to the local principal investigators in recruiting centres.

Publication in 2013

BOOST-II UK recruited 973 infants born at less than 28 weeks' gestation in the UK and Ireland to a randomised controlled trial comparing the effects of targeting arterial oxygen saturations at levels of 85–89% versus 91–95%. As well as the BOOST-II UK trial there were similar trials in the United States, Australia, New Zealand and Canada looking at the same question and using similar protocols. These five trials were designed to be very similar so that their data could be combined in an individual patient data meta-analysis capable of looking in greater detail at the outcomes obtained with more statistical power. This is called the NeOProM Collaboration.

A report of the outcomes of the infants in the BOOST-II UK trial by the time of their hospital discharge was published in the New England Journal of Medicine in May 2013. This report also included similar information about infants in the BOOST-II trials in Australia and New Zealand. The results showed that infants who were randomised into the group who had oxygen saturation targets of 91–95% had improved chances of survival compared with infants who were randomised into the group who had oxygen saturation targets of 85–89%. In addition, severe retinopathy of prematurity was more common with the higher oxygen saturation targets and severe necrotising enterocolitis was more common with the lower oxygen saturation targets.

Publication in 2016

Our new report now includes information about the primary outcomes of the infants in the BOOST-II UK and the BOOST-II Australia trials at 2 years after their expected date of delivery. This compares mortality and the number of infants with one or more forms of disability. Surviving infants were assessed to see if they had hearing or visual problems, or if they had cerebral palsy or severe cognitive impairment.

This latest joint analysis has evaluated data for a total of 2,108 infants (UK 973, Australia 1,135).

We looked at a composite outcome, which was the number of infants who had either died or who had survived with one or more forms of disability. We also looked at these individual components separately.

We found that there were more infants who had died or developed a disability in the group of infants who were targeted with the lower oxygen saturation target range than there were in the group of infants who were targeted with the higher oxygen saturation range. Looking in more detail, this difference was explained by different numbers of infants in each group who died. The follow-up of the infants who had survived showed that there was no evidence of a difference between the groups in the total number of infants who survived who had any of the forms of disability or in the number of infants with any individual form of disability, including severe visual impairment or blindness.

The BOOST-II studies show that using oxygen saturation targets of 91–95% instead of 85–89% results in greater numbers of infants surviving, without affecting the number of infants with disability, including blindness. No benefit of targeting lower oxygen saturations was identified.

What next?

A meta-analysis of all five studies involved in the NeOProM Collaboration will now take place and more details will be provided when the results are available.

If you want to know more about the BOOST-II UK study, please email address boost@npeu.ox.ac.uk.