Steroids are well known as a side effect to raise B/G and interfere with Glucose take-up from within the bloodstream. I noticed that you are in the pre-diabetic stage, however if you had been classified as diabetic I would have suggested that you contact your DR and see if he/she would agree to your Steroids being taken on alternative days so that your B/G can get a chance at stabalising itself .whilst taking the steroids.
It might be worth asking even as a pre-diabetic, though your DR might not advise this course of action bearing in mind that in general your B/G control levels would seem to be very good.