Renal issues and food

Hi vets, My boy is a 15 year old Pomeranian. He was never officially diagnosed with kidney disease, but when I had his teeth cleaned in January, his levels were slightly elevated when they did pre-anesthetic bloodwork . They had me retest a month later, and although his CRE dropped to nearly normal, his BUN was still elevated (see pic attached). The vet had me switch him from Go! Dog food to Royal Canin Kd diet. He was doing fine before switching but slowly he’s been not wanting any food, not even wet food that I give him. He will eat the wet food for a day (RC or Hills) and then not want it anymore. I have spent over $200 in the past few weeks on food that I end up tossing out and I’m feeling so defeated. His levels didn’t seem bad to me (I am in Canada) and the vet didn’t seem concerned, but now I’m wondering if it progressed further. Funny thing is, he will gobble up his sister’s food (kitten Royal Canin kibble) and any wet food of hers if I’m not careful. He will also scarf down Caesar wet food which I know aren’t great. Loves freeze dried chicken treats too. He goes for walks, drinks fine, and uses the bathroom normally still. I should mention he’s a rescue and only has 3 teeth left as of his last cleaning in January. I know fed is better than nothing but is there any suggestions for foods? He likely won’t do kibble as he has always hated kibble. I’ve given up on KD foods. I currently give him Kidney Support Gold drops which I’ve been doing daily for the past 4 months. Not sure if it’s doing anything but I’ll try anything at this point. Is Caesar’s really awful? The protein on them seem low, but I’m new to this world and I am not sure what other brands of wet food to try that may be a bit healthier. I attached his recent bloodwork from March to show his levels. Thanks in advance.

Hello -There may be another reason for your pom to be off his food - for example, he could be nauseous for an unrelated reason, or it could be a symptom of kidney disease.  Most dogs- even potentially poorly ones - will eat novel food that is more palatable than their normal food, while refusing to touch their normal food, if they feel 'off' for any reason.  There is a discussion to be had with your vet about how best to proceed.  Kidney levels may have been evaluated in conjunction with a water sample or other markers, because the urea and crea levels can go up and down eg with dehydration.  I do not have that information available, so it sounds really important to talk over Caesar's case with his vet.    Please also let them know about the supplements before giving more, because they can make a considerable difference to the quality of a patient's diet.