Hello and welcome to the forum. I think you should mention your diabetes to the clinic as then may want to test your blood sugar levels before and after the work. From what I've seen in the UK it is that healthcare professionals prefer not to undertake operations on patients when glucose levels are very high or there is a risk of hypoglycemia during a procedure, so i'm sure this clinic will have a protocol for dealing with patients with diabetes so you should ask them. But if yours is well controlled then I would have thought your condition should't be a major issue.
Good luck with this anyway and I hope all goes well