Chances are if you have addressed it directly with a physician as being a medical problem ,yes it is
If you go to an emergency department with a diaper we don't care and wouldn't realy note it,unless it had something to do with what you were being seen for,or mechanism of injury,its like when we get a trauma patient and we cut of there clothes there isnt anyone in the corner taking notes sliced of USMC sweatshirt ,hanes t shirt ,blue "docker" style cargo pant ( not otherwise specified brand) jackpot! he had a depends diaper on (We saved it put it in a bag to give to his family) no we don't care about what medical problems you have or how you treat them until we have done primary & secondary surveys to find you current problems ,if you are going to be admitted we will ask your medical history ,conditions etc,name of your physicians treating you etc ,if you say you need diapers that will be relayed to the floor nurses ,and obviously if you name a urologist great .
If you don't, diapers aren't a controlled substance or illegal ,many people wear diapers because of transient medical issues without ever consulting anyone .
In any event unless it involves how or why your there it doesn't matter much , some hospitals actually prefer diapered patients , the point of greatest liability a hospital faces is when patients attempt to ambulate to go to the bathroom and fail,so many hospitals love patients wearing diapers ,or if not mentioned when they get you to a room the nurse will ask "would you like attends" around here that is the generic euphemism nurses are trained to use in place of diaper ( they will be fired if they say diaper,many people take offence to the word and have a tantrum about being being a big person....in my opinion if you can't handle the word diaper"yup this one should be wearing because they never matured")