Uncontrolled diabetes if left untreated can certainly contribute to raised B/P and poor general circulation to the fine veins and capilaiaries as well as to the main arteries, principly due to the raise 'sugar' levels in the bloodstream which will coats all the internal 'pipework' inside the body. If left untreated it can contribute to many of the side effects that we diabetics can suffer from, and for this reason controlling Blood Glucose levels are just as important as controling Blood Pressure.
Generally B/P readings for a diabetic should ideally be close to 120/70 but most Dr's would accept a B/P reading of less then 140/80 in the general population.
Where B/P readings are taken they should be taken in three successive reading at approx. 5 min intervals, with the individual sitting and fully relaxed and not stressed, and from the 3 reading their B/P is the mean average of all 3 readings.
Medications are usually supplied if the B/P is in excess of 140/80 and many medications particularly the 'Statins' do have long term proven health benifits for the diabetic, though I would suspect many on this site will dissagree as they unfortunately also have a few side effects.