I think its likely that massage therapy for the preterm infant has some benefits, unfortunately much of the research is under-powered, badly designed, inappropriately analyzed and overinterpreted.

A case in point is a new study in Early Human Development, which is rapidly becoming the neonatology journal with the worst editorial standards. After previously publishing an article where infants were enrolled and received their intervention before they could be eligible (see below), and more recently publishing extensive corrections that should have been picked up before publication, they now have an article that doesn’t understand the difference between calorie intake and calorie consumption, that has no proper control group, and that shows no understanding regarding normal growth curves in preterm infants. It even manages to present the correlation coefficient between percentage daily weight gain, and actual daily weight gain (surprisingly it was 0.99!! Which was significant!! More than one exclamation mark usually means I am being sarcastic.)

In this study 30 babies were randomized to either get massage therapy or ‘exercise’ that is passive flexion and extension of the limbs. After a 2 day baseline observation period the infants had 5 days of the assigned therapy. Subjects were 28 to 32 weeks, more than 15 days old, were medically stable and were all getting infant formula. As you can see at baseline the infants were not getting enough calories (only about 110 kcal/kg/day on average) and were as a consequence growing poorly (about 11 g/kg/day). The babies actually enrolled were on average 29 weeks at birth and about 30 days old. So according to Fenton’s revised charts they should have been gaining about 37 g a day, or round about 20 g/kg/d, and the actual weight gain at that postnatal age should be slightly increasing every day, so a study without controls would be expected to show an increase in weight gain over a few days.

This study showed that both groups increased their weight gain from before the intervention to the followup, and there was no difference between the groups. So in other words, there is no evidence of any effect of either intervention. Only if there had been a 3rd group, with no extra intervention and only if the nutritional intake was regulated by the study, could you say if there was an effect of one intervention or the other on weight gain. You must also not confuse calorie intake with calorie consumption. The investigators calculated calorie intake, but did nothing to measure consumption (bomb calorimetry on the stools, oxygen consumption, stable isotope techniques etc) which doesn’t stop them making dumb comments about how massage might affect calorie consumption. Of course babies like the ones they studied don’t even regulate their own calorie intake, the medical and nursing staff decide how much milk they will get, and therefore their calorie intake.

Their title ‘Preterm infant weight gain is increased by massage therapy and exercise via different underlying mechanisms’ shows how badly they have misinterpreted their results, and how poor a job the referees have done on this article. The title could have been ‘no evidence of effect of either massage therapy or exercise on weight gain’. The ‘mechanism’ that they refer to is derived from an analysis of the ECG which the authors state showed evidence of an increase in vagal activity.

Now it is possible that massage therapy does indeed have some benefits, but studies like this one give us no evidence of that.

Any attentive readers may remember the study that I mention at the beginning of this post which I wrote about in a post nearly a year ago, that article was so badly written, and poorly refereed that it made absolutely no sense. Infants were randomized at 34.5 weeks, but were only eligible if they were off oxygen by 36 weeks and discharged before 42 weeks, BPD was used as an outcome measure, but was also an exclusion criterion, and so on. I wrote to the editor of my concerns, and received an email back, not from the editor but from the publishers who asked me to submit a letter on their website. I did so, and the letter is, at last check, still with the editors. No response, of any kind, from the editor or from the authors. I presume this means that someone is too embarrassed to reply, but I think the readers of that journal deserve a response.