I know it is deadly dangerous and would put lots of stress on the person. Type 1 diabetes requires treatment with insulin. Is it also physically painful? Let's assume there are also no any other medical treatments.
To explain why such a question has been asked, it is related to the case of Paul Urey, a volunteer British aid worker who has been captured by Russian forces in Ukraine and made some strange sounding declarations afterwards. He later died "from stress" as they now explain.