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@Rachox I've had corticosteroid injections. Both times they raised my glucose levels which stayed up higher for several days, but then came back down again to my usual levels. I imagine with a course it would take somewhat longer, but it might be worth doing a forum search as this topic as cropped up on previous occasions.
(I also needed to use corticosteroid eye drops long term and years before I got diabetes, and I did wonder in retrospect whether these together with statins, may have been in part responsible for causing my T2 - but when I checked, those eye drops don't apparently cause a rise in glucose!
)
Robbity