I think you should talk to people normally, but I'm also inclined to be careful about assuming any kind of endearments at all are patronising.
I work with children a lot, and I don't believe in patronising them either, and yet endearments can be fine and even appropriate sometimes.
There can also be significant cultural and regional differences to how people speak. Changes in address due to age can be meant as respectful rather than patronising.
Sometimes objections to endearments can be more about class snobbishness than anything, too, or meant to elevate the person over the carer - you see this less with doctors and more with nurses of in-home care workers.
Some people, under stress or receiving intimate care, much prefer a carer be more formal, because it makes them feel less violated. Othr people really prefer the opposite, because that makes them feel more comfortable. Some people in care situations are starved for affection, including verbal affection, and want that. Some feel people are not listening to them and want some visible signs of respect.
There isn't really one answer, IMO. I generally think it is best in these situations to be sensitive to the person being cared for, but also to just be yourself. If you are from a region where everyone uses endearments, I don't think it's necessary to change that all the time just because, though you also have to try and be situation appropriate.
The other side of that is patients need to try and realise that their carers also come from a lot of different backgrounds and have their own personalities.