I had borderline high c-peptide 1.9 ml (lab norm: 0.7-1.9).i stopped taking carbohydrates and in 2 months result was 1.06.problem or risk of diabetes?

Other risk factors: Per your medicine list, you take dexamethasone. Steroids can impact your blood glucose levels, increasing your risk of diabetes. I think the change in your diet was a good thing, and seeing the commensurate decrease in your C-peptide level is promising. If you stay on a lower carb diet, your risk of diabetes will remain low.