Hello Anna, like you my insulin levels have dropped significantly over the past 2 years. This time two years ago I was on 36 units of Lantus which, thanks to hypos, I slowly had to reduce to 20 units by the time I got my pump a year ago. Since then I've dropped my basal further to 13u, so I'm now on one third of the basal rate I was on two years ago!!! Also my I:C ratio used to be 1:1 across the board. It's now 1u:20g in the morning (sometimes 1:30) and 1:15 at other times. So my insulin needs have changed dramatically but a recent cortisol test showed that my levels were normal. I don't have Addisons.
Like you I have weight loss, fatigue, dizziness on standing up. I also have vomiting.
I've recently been diagnosed with gastroparesis which could explain my hypos but I do cater for slow digestion on the pump by using combo boluses. Also, I often wait until my BG rises after eating before I bolus. These are just techniques I've adopted to protect myself. I'm not saying it's the right way to do things but as you know you have to do anything to stop hypos when you live alone.
However I've also been recently diagnosed with a condition called Pancreatic Exocrine Insufficiency or PEI for short. This is where the pancreas doesn't enough enzymes needed to digest food. Most doctors associate it with heavy drinkers or as a result of pancreatitis or pancreatic surgery or cancer. However none of these factors apply to me.
Last year I did some research because I couldn't understand why I was having so many hypos some weeks then at other times I would have days where my BG would run high. My DSN was very unsupportive. So I went to Dr Google and I came across this article
http://www.thejournalofdiabetesnursing.co.uk/media/content/_master/3857/files/pdf/jdn18-8-320-3.pdf which I can't create a link to.
In short the article suggests that perhaps 50% of Type 1 diabetics may have PEI caused by atrophy of the pancreas which in turn could be caused by lack of insulin production. This can lead to malnutrition, sickness and variable blood sugars as well as unpleasant bowel symptoms which thankfully I don't have!!! The research discussed in the article was based on a very small study but suggests that more research should be done and PEI should be considered in diabetics with symptoms.
PEI can be diagnosed by doing a faecal elastase test so I asked my diabetic consultant to do the test. The results came back confirming that my elastase levels were indeed low and so I've recently started taking pancreatic enzymes. The article says that the diabetics in the study found that the number of hypos they had fell after 16 weeks. I haven't been taking the enzymes for that long so I don't know yet if the enzymes will eliminate or reduce the number of the hypos.
I haven't had a chance yet to discuss the recent diagnosis with my consultant. But I'll be seeing him next week and I'll be interested to hear if he thinks the PEI or gastroparesis (or both) could be the cause of my hypos and vomiting.
Once the usual suspects have been ruled out and there is no obvious reason for hypos/falling insulin needs, there are of course a number of conditions that can be the cause such as Celiacs Disease, Addisons, Gastroparesis and possibly PEI. If there are other possible contenders I would be interested in hearing about them I presume that your diabetic clinic has checked you out for these conditions?