Dia-IonX would be helpful for your cat, and would not aggravate any of the other health issues. The organic formula helps to stimulate healing without burdening the body with excessive material that cannot be readily used. It also can be used with any other prescription medications without interference. Many pets have responded favorably to Dia-IonX.
Diabetes must be addressed because it can lead to other diseases such as kidney disease and contribute to more inflammation in the body. When it comes to diabetes, diet is very important. It can be challenging to find the right diet when there is both diabetes which should require a low carbohydrate diet and kidney disease which requires a lower protein diet. Be sure to discuss diet with your veterinarian because many cats show improvement with dietary management. If the diabetes is well regulated you may find there are less inflammatory symptoms such as pain and stiffness. However, if these symptoms persist you could also use Arthro-IonX.
I hope these suggestions give you some encouragement. Please let us know how you do. We would like to keep your cat happy and comfortable.