A project of the European Union Aviation Safety Agency (EASA) aims to provide data to enable more people with diabetes who use insulin to work as commercial pilots and air traffic controllers and to confirm the overall safety of diabetes technology during air travel.

The primary concern about allowing people who use insulin to perform ”safety critical” jobs has been the risk for hypoglycemia, which can lead to impaired judgement or even incapacitation.

High blood glucose can also impair reaction time. However, ”[w]ith advances in insulin therapy and blood glucose monitoring, these stereotypical attitudes can be challenged,” project technical lead David Russell-Jones, MD, professor of diabetes and endocrinology at the University of Surrey, Surrey, the United Kingdom, said during a symposium here at the European Association for the Study of Diabetes (EASD).

Several countries, including Australia, Canada, the United Kingdom, and the United States, allow people with diabetes who use insulin to fly privately for leisure.
– But, in addition to Canada, currently only three countries in Europe — the United Kingdom, Ireland, and Austria — allow them to obtain a license that enables them to fly commercially, under a strict protocol that was first launched by the UK Civil Aviation Authority in 2012. The Irish Aviation Authority joined in 2015, and Austro Control followed in 2016.

Now in its 2nd year, the EASA project focuses mainly on pilots and air traffic controllers, but the data being collected will apply to cabin crew and passengers with diabetes as well, said project manager Julia Mader, MD, associate professor of medicine at the division of endocrinology and diabetology at the Medical University of Graz, Graz, Austria.

– ”The hope that we have with our clinical trial program that is currently ongoing is we will find a more modern approach on how we can handle diabetes while flying, how we can have more countries joining the initiative, and also keeping flying safe for people who have diabetes technology,” she said in her presentation during the EASD symposium.

Fighting Prejudice With Data

The UK protocol requires pilots who use insulin to conduct frequent blood glucose monitoring during flight, specifies thresholds of low and high blood glucose levels for which action must be taken, and requires rigorous documentation and verification.

In 2014, two commentaries on the topic were published in The Lancet Diabetes & Endocrinology. One from Dutch aviation medicine specialists expressed support for pilots who use insulin to fly commercially.
– The other, from French counterparts, decried the practice as ”not medically justified, not ethically and practically admissible, and could jeopardize flight safety.” Among other concerns, they suggested that pilots might deliberately run their glucose levels higher than recommended in order to avoid hypoglycemia, resulting in worsened overall glycemic control.

”What this brought home to me was that there was a lot of opinion but very little evidence, and the only way to fight prejudice is to provide good objective evidence,” Russell-Jones said.

The first preliminary data on the UK protocol were presented at the EASD meeting in 2016 and subsequently published in The Lancet Diabetes & Endocrinology.
– It suggested that glycemic control did not worsen for pilots who followed the protocol and that, over an average follow-up of nearly 2 years, > 95% of glucose readings were in the designated ”safe” range of 5-15 mmol/L (90-270 mg/dL). No episodes of pilot medical incapacitation due to low or high blood sugar were reported.

A subsequent larger study in the United Kingdom, presented at EASD in 2020 and simultaneously published in Diabetes Care, confirmed those findings. Those data showed that ”there has been a steady decline in the number of out-of-range values, probably due to the introduction of continuous glucose monitoring,” Russell-Jones said.

That study also found that there were no problems with implementing the protocol in the cockpit and that it was accepted by fellow pilots, he noted.

One of the first EASA project studies used a hypobaric chamber simulation of atmospheric changes during air travel to confirm a previously described phenomenon: Insulin pumps consistently overdeliver a little more than half a unit on takeoff and underdeliver a bit less on landing. This is due to air bubble formation and reabsorption caused by ambient cabin pressure changes and was consistent across insulin pump brands.

But another EASA-supported study of 49 pilots — seven on insulin pumps and 42 on multiple daily injections — showed that the total number of in-range glucose values was higher among the pump users — 99.3% vs 97.5% — with 0% vs 0.04% of values, respectively, below 4 mmol/L (72 mg/dL).

”There were no differences in median glucose ranges, suggesting that the small insulin delivery with pumps didn’t affect the adult pilots,” Russell-Jones said, noting that those data will be published soon.

Other EASA program studies in various stages of data collection include comparisons of continuous glucose monitors CGM with fingerstick monitoring in people who consume meals while in flight, and analyses of the performance of currently available automated insulin-delivery systems during flight.

Mader said she hopes the project will ultimately bring uniformity to the rules around flying while on insulin throughout Europe. ”The project was actually a call from EASA, so they were opening up. I think the big hindrance will still be the individual national regulations.
– We really should try to see that Europe at least aligns their regulations across the countries. It doesn’t make sense for each tiny country like mine to have a different regulation. We want to try to onboard big countries like Germany, France, Spain, and Italy.”

Russell-Jones said, ”By providing objective evidence, no one can argue. I think we have made inroads. The Americans joined us with their own protocol which is very similar to ours as of 2021 and that’s another big step forward. So, we are making progress, and I’m confident that we’ll get there in the end.”

From www.medscape.com
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