I really think that the kidney diet is causing the higher numbers. We've had quite a few people come to the boards who couldn't regulate their cats on the prescription kidney diet, and once the diet was changed to a food that was good for both kidney disease and diabetes, there were huge improvements. One cat even went into remission right away. Unless you're in a very late stage of CKD, the low protein diet is going to cause more problems than it helps (e.g. muscle wasting), and the diabetes is the more threatening condition.
Here's a great site that explains the different stages of CKD (the newer term for CRF):
http://www.felinecrf.org/how_bad_is_it.htm Most cats have some loss of kidney function as they age--the good news is that the progression of kidney disease can be stalled with the right diet. My Gabby was diagnosed with borderline stage1/stage 2 kidney disease, and in the 2 1/2 years I had left with her her kidney values did not change at ALL with the kidney-friendly diet I had her on. She passed away from cancer, completely unrelated to the kidney disease. If it weren't for the cancer, I would have had more years left with her.
You simply need a low carb, low
phosphorus canned food, preferably without byproducts (higher quality protein sources are easier on the kidneys). Keeping your cat as hydrated as possible is key to managing the disease, along with low phosphorus foods. Mixing water in with the canned food is one good way to help with hydration.
Here's an updated food list with the values for several premium foods:
https://docs.google.com/leaf?id=0B8...MzhkYTkxOGM4NThk&sort=name&layout=list&num=50. You're looking for something with less than 10% carbs and less than 250 mg/kcal of phosphorus. The foods I would suggest are Merrick's Before Grain Turkey, Wellness Turkey, EVO 95% Chicken & Turkey, and Blue Wilderness Duck. If cost is a problem, EVO and Wellness both sell their foods in large cans, which makes the price comparable to grocery store brands of food. Because higher quality protein means less protein metabolism residue, you really want to try for the human-grade meat if you can.
If those are out of your price range, the next best thing to feed are the low carb Friskie's Special Diet flavors. These are Turkey & Giblets and Salmon Dinner--make sure they are the ones that say "special diet" on the can, though. PetSmart carries them, and some grocery stores. Here is an updated list of just the phosphorus values for many commercial foods. They can be cross referenced with Binky's chart for carb values if there's something on there that you want to feed. On this chart, you're looking for something that is less than 1% phosphorus (these values are on a dry matter basis, not mg/kcal):
http://www.felinecrf.org/canned_food_usa.htm
Changing the diet does require that Skipper no longer has access to dry food. Here are some great tips for cats that are resisting the transition:
http://catinfo.org/#Transitioning_Dry_Food_Addicts_to_Canned_Food_. Don't give up! It can take some time and many different foods and tricks in order to finally get him on a canned diet. If you do end up getting a food with chicken in it, you may just have to feed the cats in separate rooms, or pull up Skippers food as soon as he's done eating. I had one cat with kidney disease, and another that was diabetic, and they ate different foods. Gabby was a light eater and Bandit a gobbler, so I just stayed in the kitchen until she was done eating, and then I picked up the rest of her food and gave it to her in another hr or so. If you feed small portions, usually they finish all in one setting.
As always, remember that
if you are changing the diet BG could lower drastically and if you're not testing frequently and lowering the dose you could have a dangerous hypoglycemic incident on your hands. 5.5u is a very high dose of insulin, and once the carbs are removed Skipper will most likely not need that much insulin.
My concern with the last update is beginning on 3 units of Lantus...to me, that is too high of a starting dose. Lantus works differently so starting with that high of a dose would definitely NOT be my preference. The max I would start is 2 units and even that may cause you to bypass his 'real' dose. When Lantus is injected, it immediately sort of hardens under the skin then precipitates into the bloodstream as the body's ph changes. It will take a few days for it to begin working on those high numbers (5-7 days) so you won't be seeing immediate results BUT when it does start, I would hate for it to be too much already.