Use of caffeine in the NICU as a treatment for apnea of prematurity is a topic that has certainly seen it’s fair share of coverage on this blog. Just when you think there is an aspect of treatment with caffeine that hasn’t been covered before, along comes a new paper to change my mind.
The Caffeine for Apnea of Prematurity study or CAP, demonstrated that caffeine given between 3-10 days of age reduced the incidence of BPD in those treated compared to those receiving placebo. As an added benefit, in follow-up studies of these patients there appeared to be a benefit to neurodevelopmental outcomes as well at 18-21 months but this was lost by school age with groups being equivalent. In recent years evidence has mounted that starting caffeine earlier in the time course (<3 days and in many cases in the first hour after birth) has led to less need for intubation and BPD. What has really not been known though is whether the use of caffeine in this way might have any long term benefits aside from these short term outcomes.
Dr. Abhay Lodha from Calgary and a group of researchers led by Prakesh Shah from the Canadian Neonatal Network using our robust Canadian network data have tried to answer this with their paper Early Caffeine Administration and Neurodevelopmental Outcomes in Preterm Infants
The group studied were <29 weeks’ gestation born between April 2009 and September 2011 and admitted to Canadian Neonatal Network centres. As defined in the paper “Neonates who received caffeine were divided into early- (received within 2 days of birth) and late-caffeine (received after 2 days of birth) groups. The primary outcome was significant neurodevelopmental impairment, defined as cerebral palsy, or a Bayley Scales of Infant and Toddler Development, Third Edition composite score of <70 on any component, hearing aid or cochlear implant, or bilateral visual impairment at 18 to 24 months’ corrected age.”
There were 2018 neonates included in the analysis with 1545 in the early group and 563 in the late. It is worth noting that there were 473 infants lost to follow-up meaning that there was about an 80% follow-up rate. Looking at the characteristics of those infants lost to follow-up there were no striking differences that one would expect between them and the group followed.
What did they find?
The odds of BPD (aOR 0.61; 95% CI 0.45–0.81), PDA (aOR 0.46; 95% CI 0.34–0.62), and Severe Neurologic Injury – parenchymal injury or GR III/IV IVH or PVL (aOR 0.66; 95% CI 0.45–0.97) were reduced in the early- caffeine group. The primary outcome was also found to be significantly different as per the table below demonstrating the odds after logistic regression analysis.
So early caffeine seems to be good. Is that all then?
I am very happy to see these results but a few questions remain. Before we get too enthusiastic, I find myself thinking back to the early 2000s after the initial CAP results showed an apparent difference in outcome. The question is whether the reduction in odds seen here for the primary outcome will persist as these children age. Will we see a tendency for the differences to vanish as these children enter school age? I suspect we might but that doesn’t mean all is lost here. What the authors have demonstrated clearly is that early caffeine is not harmful as there is no suggestion of those infants exposed to caffeine so shortly after birth fare worse than those treated later.
Also as the authors state, what isn’t clear is how caffeine works to decrease the risk of developmental impairment. In the discussion they offer some insightful thoughts as to what may be at play and I agree that certainly an anti-inflammatory effect may be responsible for some of the effect. I do wonder though if one could tie the reductions to the lower likelihood of BPD. Development of BPD has been shown many times over to be associated with worse developmental outcomes. Aside from the anti-inflammatory effect mentioned, could the avoidance of early intubation and therefore reduced risk of BPD from positive pressure ventilation be the reason?
In the end if the results persistent into school age, the reason won’t really matter and I hope it does. Will see what happens when we revisit this cohort in a few years but in the meantime I think this paper certainly confirms in my mind the need to give caffeine and make sure it’s provided early!