As I've suggested in other posts, I don't really agree with the whole pre-diabetes thing. It used to be called "borderline diabetes", then they changed the name. Problems I have with it are:
1) People diagnosed like this often think "I'm ok at the moment, just need to be a bit more careful", rather than modifying their diet properly.
2) The levels used to diagnose "pre-diabetes" are well above normal limits, not just a bit. The very most that a true non-diabetic would record as an HbA1c is about 36 according to most medical research, yet we suggest figures in the 40's are merely "pre" diabetic. I think that many people diagnosed as pre-diabetic would fail an oral glucose tolerance test; not necessarily at the +2 hours stage, but under the original rule (when blood was tested every 15 mins during the test) that stated that "any reading above 11.1 at any stage indicated diabetes"
3) Cynically, I believe NICE and the NHS like to have a pre-diabetes classification because it avoids them having to declare the true number of diabetics and ruining their numbers.
To me, pre-diabetes is just diabetes caught early, and more easily managed if approached under the same vigour as any other diabetes.
Don't mean to upset anyone here, but I hate the idea that some (probably not those on here) bury their head in the sand a little.