Well the guidelines actually tell us all to aim for an A1c of 48 maximum. And I'd say there is no such thing a 'pre diabetes' - you either are diabetic or you ain't. (Much like pregnancy in fact - you either are or you ain't.) However if you are at the end of the scale someone not me chose to call 'pre diabetic' for reasons best known to themselves* - then it should be possible to keep it under control with diet and lifestyle changes. If you need the help of any prescribed anti-diabetic (whatever it is) to control your BG then there is simply no argument, is there?
Once you've got to that stage though it's in your own interest for you to continue with the label 'diabetic', simply because we get extra health checks, eyes, feet, heart, kidneys .... so anything that does go wrong or eg in pregnancy, or anything else that goes wrong that is diabetes related will get detailed attention much sooner than it might if you didn't have the label.
* Perhaps I should comment here that as far as I am concerned there isn't now, never has been and will never be, any 'stigma' attached to anyone of any shape, skin colour or nationality, getting diabetes of any Type. I'd like all the sizeist people in the world to meet all the slim, fit Type 2 diabetics in the world and address their 'You brought it on yourself, you only got it cos you is fat' remarks to them - and see what happens to them next ! LOL