Hacker News Reader

Comment by haldujai | Hacker News Reader

> However, if your brakes (glucagon) can sometimes fail completely, that could cause you to die almost immediately

Failure detection is via alarms to trigger patient action based on the continuous glucose monitor (which has a different set of reliability issues) as well as patient symptoms.

Hypoglycemia becomes symptomatic long before blood sugar is low enough to result in death or serious debilitation and T1D patients know their symptoms well. The risks are not nearly as dramatic as you're suggesting as one isn't/shouldn't be relying on glucagon to prevent severe hypoglycemia, I don't think any system is designed or being conceived to operate in such conditions.

Hypoglycemia isn't really much of a problem anymore with current CGMs and pumps.

View on HN

> Hypoglycemia becomes symptomatic long before blood sugar is low enough to result in death or serious debilitation and T1D patients know their symptoms well.

There is a what seems to be a significant number of people who don't "feel their lows."

> Hypoglycemia isn't really much of a problem anymore with current CGMs and pumps.

Current CGM's can still require hours of "warm up", and many current pumps still must be removed for things like swimming so they don't get penetrated with water.

> There is a what seems to be a significant number of people who don't "feel their lows."

Severe hypoglycemia to the point of what was described (death) is not reported in any of the recent device studies.

Level 2 or moderate hypoglycemia, very different from death, is reported at < 0.5% in recent closed loop system studies.

> Current CGM's can still require hours of "warm up", and many current pumps still must be removed for things like swimming so they don't get penetrated with water.

Current CGMs are water resistant but conveniently one is also not administering insulin while swimming either. The bionic pancreas is also dependent on CGMs and has the same limitations.

I'm really not sure what point you're getting at. Hypoglycemia is not what's being improved upon with current advancements, it's time in target.

OK thanks, I get your points. What I was getting at is a disagreement with "Hypoglycemia isn't really much of a problem anymore with current CGMs and pumps." Because lots of people on current CGMs and pumps still deal with hypoglycemia, despite these pumps and CGMs making the situation so much better than otherwise.

> Severe hypoglycemia to the point of what was described (death) is not reported in any of the recent device studies.

Are there large-scale studies that show this for a dual hormone control algorithm (the context of this thread)?

You seem to be misunderstanding how these devices work.

Bihormonal pumps do not mean continuous infusions of both insulin and glucagon. The pumps pulse insulin when you're high and glucagon when you're low. They're not both administered at the same time or continuously infused in a "balanced state".

The context in this thread:

> However, if your brakes (glucagon) can sometimes fail completely

A bihormonal system would not result in more insulin being administered than an insulin-only system for a given blood sugar, if the glucagon pump fails we would have an insulin-only system where we have plenty of safety data. There is no mechanism by which a bihormonal system has higher risk of hypoglycemia than existing closed loop insulin system.

To clarify, the context of this thread / what I was originally responding to was:

> In this case, you could be more aggressive in either direction of pushing BG, because you have a safety net.

> Hypoglycemia becomes symptomatic long before blood sugar is low enough to result in death or serious debilitation and T1D patients know their symptoms well.

Often times in an acute setting, yes. However patients who have had diabetes (T1 or T2) for a long time often lose a lot of their hypoglycemia sensitivity and symptoms. It's not nearly that simple.

Hypoglycaemia during sleep is the big one. My hypo sensitivity isn't great, but if I'm awake I'll always notice before it gets really dangerous. Sleeping is a different story though. The days when even a slight low would jolt me wide awake in a sweat are gone though, and now I'm much more reliant on sensor alarms to not just sink silently deeper.

Reply on news.ycombinator.com