The Collaborative International Dictionary of English v.0.48:

Diabetic \Di`a*bet"ic\, Diabetical \Di`a*bet"ic*al\, a.
   Pertaining to diabetes; as, diabetic or diabetical treatment.
   --Quian.
   [1913 Webster]

   Diabetic sugar. (Chem.) Same as Dextrose. Diablerie