The life expectancy of your dog after diabetes diagnosis depends on their age, health, their response to the treatment plan, and your willingness to carry it out thoroughly. Once they are diagnosed, treatment needs to begin immediately, as well as adjustments to diet, exercise etc. Diabetic dogs receiving treatment do not have a significantly shorter lifespan than non-diabetic dogs of the same age and gender. Of course, you need to make some of the concessions to the disease and adjust your dog’s lifestyle accordingly.