Thanks for the reply. My vet had consulted with an internist - that seems to be where the idea of kidney diet food came from. My dog's creatinine level is the only thing that is elevated in her blood. Her BUN level is in the middle of the normal range. Her vet did say that she's pretty sure the elevated creatinine level has to be from the Truvia since she had normal creatinine levels when she did blood work right before spaying. The 2.1 has been consistent for over a year. The internist also suggested a urinalysis - which showed struvite crystals but no white or red blood cells. So now she's on antibiotics for 2 weeks.
I'm not convinced that I want to feed her the K/D diet because when I look at the ingredients in it, I see a lot of things I don't like feeding her - like lots of corn. She's an Australian cattle dog mix, and I have read that they shouldn't eat too much corn. (I don't know if that's true or not; but a lot of ACD people swear it is.) Also, the kidney diet dog food seem to be very low in protein - and Julep is a very active dog. I'm not sure she'll get what she needs nutritionally if she has to eat a diet with lower nutritional value. As it is, she has acted like she was hungry ever since she started eating senior food instead of regular food.
I want to do what's right for her. But I'm not convinced that she's going to get worse. Part of me feels that while her kidneys were damaged by the sweetener, whatever damage was done is done, and she's now stable. Do you have any advice? Would it be worth going to see another vet for a second opinion? (I've been going to our current vet for almost 20 years.)