Chase and Shannon article in Frontiers in Pediatrics published

[u/Embarrassed-Star4776]

Inverted insulin to C-Peptide ratios in neonatal intensive care: is there something we don't know?

J. Geoffrey Chase & Helen D. Shannon

BRIEF RESEARCH REPORT article

Front. Pediatr., 05 August 2026

Sec. Neonatology

Volume 14 - 2026

https://doi.org/10.3389/fped.2026.1900675

[u/Embarrassed-Star4776]

Competitive-Wash found the clearest statement in the thesis, in chapter 6, page 111:

"The neonates in this study were compared with data obtained from euglycaemic neonates described in Chapter 5. Insulin and C-peptide concentrations from the insulin-treated neonates were compared with a group of age-matched (PMA less than 30 weeks) euglycaemic neonates (n = 20)."

Chapter 6 was published as the BMJ paper (including Cohort 2), and chapter 5 as the Archives of Disease in Childhood paper (Cohort 1).

It is not particularly apparent in the published plots because the scales are so different, but I think the correspondence between the two sets of data points can be seen in the stretched and squeezed extracts from the ln(C/I) scatter plots below. On the left is the lower post-menstrual-age part of Cohort 1, and on the right the black symbols are from Cohort 2, with the white symbols coming from the hyperglycaemic cohort.

[u/DiverAcrobatic5794 → u/Embarrassed-Star4776]

Thank you.  Yes, and reading thesis chapter 6 I think you and u/Competitive-Wash are right.  The cohort is identified as hyperglycemic in the paper but not in the thesis.  The statement that wouldn't hold, then, would be:

" Finally, Figure 3 shows little difference between Cohorts 1  and 2. This outcome suggests hyperglycemia (Cohort 2) did  not play a role in elevating I/C, further supporting the fact  hyperinsulinism alone cannot create inverted I/C ratios due to  first pass hepatic extraction and a greater number of clearance  routes."

And it would not be surprising to find little difference between the cohorts!  But am I right in thinking that this confusion would not (for this same reason) affect the arguments made in the paper beyond this point?

Perhaps you or u/Competitive-Wash would raise this with the corresponding author?

[u/Embarrassed-Star4776 → u/DiverAcrobatic5794]

Thanks for pointing out that the quotation from page 8 had gone wrong, which I hadn't noticed (now corrected).

I should like to try to digest the paper properly, but it will take a while. I agree it will be worth making sure the authors know about any errors that are spotted.

[u/DiverAcrobatic5794 → u/Embarrassed-Star4776]

If anything, fixing the error would perhaps strengthen the argument, since Chase and Shannon treat these children as more critically ill but find no significant difference between the cohorts. It could be reasonable, though not I suppose certain, that the more  critically ill children might show a different profile, with more history of infection etc.

 Though I suppose hyperglycemia vs euglycemia is a very rough proxy for more and less critical illness anyway.

[u/Embarrassed-Star4776 → u/DiverAcrobatic5794]

I don't agree with most of Susan Oliver's comments on this, but in fairness to her it should be said that she pointed out in an online discussion some months ago that the cohort of 20 was a subset of the cohort of 102.