[exDM69]

How do you tell that the glucose reading measured from blood (the old way) is correct? You can't. The new method is not worse than the old in this respect.

And again, you get at least 8 hours of history graphed on the display now. If it doesn't look sensible (w.r.t eating and insulin doses), you need a backup. If the old fashioned blood glucose meter gives a wrong reading, you are much worse off.

Note that the sensors are tested and approved, not the DIY hack the article talks about.

[acqq]

Old way: you repeat the measurement nothing is in your body. and you konw di you feel e.g. hypo. New way: the sensor needle is simply a little off (in stays sticked). You don’t know, the software doesn’t know. The sensor is not magic that works 100% of the time, it ends in a needle sticked in your body, many ways to go wrong, even if it worked a while.

And the danger of “fully automatic” is there.

[exDM69]

Just to clarify, we were only discussing monitoring and sensors in this subthread. Not closed loop pump systems.

A sensor failure in closed loop is dangerous. I do not know how the control software detects and deals with this. I have no experience with them.

[pimeys]

A closed loop uses the oref0 algorithm, which tweaks your basal levels and therefore cannot react to fast peaks or cause a hypo not easily fixed by having two candies (or giving an alarm if you're not awake). What it does is it detects an upward trend for the last X measurements, sets something such as 300% temporary basal rate, detects the trend reaching the peak, sets a 0% basal rate until you hit the predefined target (for me, 5.5 mmol/l during the day and 6.5 mmol/l at night). Here sudden wrong readings will not cause any harm or danger.

The new oref1 algorithm uses a method called super micro boluses, which can detect a sudden peak or unannounced meal, sees the first jump up, gives you a bolus so it borrows from the basals, setting the basals to 0%. The algorithm works really well for things such as eating a pizza, where you get about 50% of the carbs immediately and the rest + a bit more during the next five hours. So you take a bolus for the food, then when the fat hits in the oref1 will give you tiny boluses.

The latter is more sensitive to sensor failures, so it is on only when you told the system you have some carbs in your body, or if you happen to have a Dexcom G5 or G6 sensor with good noise readings, it will be on all the time and the system knows when the reading is faulty.

[acqq]

Which closed-loop system do you use which can provide both boluses and basals? Can you share? Also do you think Dexcom sensors can be always trusted? Searching, I find something like:

https://forum.fudiabetes.org/t/dexcom-out-of-range-calibrati...

[pimeys]

The oref1 smb is in AndroidAPS release candidates and in OpenAPS. You can't trust anything 100% ever, but you start recognizing when they have problems and can cope with the errors.

[acqq]

Thanks. Readers should also note that the main topic is about the closed loop apparent "revolution." In reality it really can be dangerous, exactly because of the explained sensor problems which are real. To clarify to those that don't know:

The sensors are big things with the needle permanently in your body. You don't want three needles permanently to be sure that at least 2 from 3 work. If you have only one, you have a real problem if you trust it blindly.

Yes, it's good that some people try. But there are real risks, due to the current limitations as explained.

[pimeys]

I'd say that I myself making all the judgements caused way more harm to my body than what the computer can do. It is that much better. Before I used to have nights when my sugar was in a dangerous hypo for hours during the night, luckily not causing too much brain damage. Now all of these problems are gone. Almost all of the scary hypos are gone. My A1c came down from 7.5% to 5.5%. I'm 88% of the time in range, 10% above the 8.5 mmol/l and 2% hypos (none of them at night) which I can correct fast due to alarms.

[acqq]

Thanks a lot. My question is: is the techology as reliable that somebody who is without any technical background (e.g a child on vacation without the parents) able to depend on it?

I know that most of the population is actually not technical, and that they can easily understand “correct when high, eat when low” but complex technical reasoning can’t be expected from them. In that context, sensors not functioning as in ideal lab conditions is a big issue.

[pimeys]

Here in Germany we have a group of diabetics helping each other with the system. Most of us are not so technical, for everybody the system has been a massive improvement compared to their own judgement.

As a type1 you must have a lot of knowledge to be able to survive. The software is a tool you must learn how to use, but takes away lots of burden from the decision making.