So, here is my 3 cents 
I am not diabetic, nor are any of my children.
One of my children has an amputation due to a congenital condition. That said, amputation is hard. Its hard to go through, and hard to live, especially if one does not have insurance to get a good prosthetic. My child is able to be active and do pretty much anything that a kid can normally do.
What I see here is that between the diabetes and food addictions it can be hard to get weight under control, and it can be very difficult to exercise. Now, couple that with an inability to be mobile because of an amputation. I’m certain that designing sockets for people who are of “large size” (no offense intended to anyone here) can’t be easy. Residual limbs change, and the limb may not be capable of supporting the prosthetic. Also, any damage that exists in the leg needs to be dealt with, such as pressure sores, non-healing scars, etc. And if the limb changes enough then a new socket has to be made. Its not good enough to keep piling on the ply-socks (anything more than 5-7 in my opinion is too much). My child currently uses between 3-5 ply socks, but I’ve heard of people going up to 20-25+. That’s a case when a new socket should be made, but again, money and insurance comes up and if someone can’t afford it they will make due with an ill-fitting leg.
The point is that, yeah, I can see that death rate goes up after amputation. Put people on keto early on so that they can reverse diabetes and other metabolic conditions. Amputations shouldn’t have to happen, but if they do then people should also be put on keto at the same time to better their health.