Severe diabetes

can shorten a life. Even if it is managed as carefully as possible it presents problems every day.
I had a friend in the UK who had such problems. She was a lovely, intelligent person who supported me at a critical point. She ran a complex operation involving students and staff which often put her under a great deal of pressure. Somehow she always managed to retain her sense of humour and laugh at something once the crisis was over. She found solutions to problems when other people were throwing their hands up and saying nothing could be done. We worked in the same place and saw each other almost daily. About once a month she would finish work and come for the evening meal. 
   "H...," I would say, "If we make...."
I know other people rarely invited her out. They thought it was too difficult to provide for her but several of the students saw it differently. We enjoyed her company and her wicked sense of humour.
We kept in touch after I left the UK.  We would each write several times a year. She liked "real letters" so I wrote actual letters. 
It was some years before she admitted that her eyesight was failing.
And yes, it was the diabetes which was causing her eyesight to fail. Although she had been careful, perhaps more careful than most, diabetes was causing a range of serious issues. She just didn't want to talk about it. 
Eventually she admitted that her health was failing but even then she did not tell me just how serious it was. There was just one letter this last year. She had typed it but it was clear that she could not see what she had written because there were errors in it that she would once have corrected. Someone else had addressed the envelope. I suppose I knew then that the situation was deteriorating more than she would admit to me.
But, I sent the usual Christmas card with the annual letter. I prefaced it with a thanks to the person who read it to her. Nobody read it to her. She died a week before I sent the letter and I had a reply from her niece telling me "it was the diabetes" and that she had been in danger of losing both feet.
Diabetes is a complex and serious disease. It isn't simply a matter of taking insulin and eating what you want to eat. It is a daily issue, several times a day. It is constant monitoring. 
H...handled it well but it still caused those major issues. Perhaps it is just as well she did not have to endure further major issues  - but I, and many others, will miss her.