Cat not responding to insulin

[Chance11]

Hi everyone! I have an almost 11 yr old cat, Chance. First diagnosed with diabetes 2.5 yrs ago, was on vetsulin (didn't know at the time that's not a good choice), switched to wet food pate diet, and was able to come off the insulin in a few months. Fast forward one year, and diabetes were back, level of 511. Got lantus at this time, but he just isn't responding to it... He's been on it for 6 months now and his numbers just won't go under the 200's. I test at home and do regular curves, went as high as 4u 2x/day, and his numbers would bounce higher on the higher dose. On a lower dose he seemed to tolerate better, we still very rarely had reads in the 100's.
https://docs.google.com/spreadsheets/d/1sEzxhC_yipO008QyN8pWwzYp8-x427lNXbqWS5tCH9I/edit?usp=sharing
Here's his chart.
He is now suffering from neuropathy I got him on xobaline (B12) as of 2 days ago, and am now going to try levemir. Could something else possibly be going on that's keeping him from responding to the lantus? A tumor etc? I hope the levemir helps him more than the lantus. Any advice or tips is greatly appreciated!

 

[majandra]

I'm not one of the resident experts here- so I hope someone else stops by soon.
From what I can see of your spreadsheet, your kitty likes to bounce, and/or gets into the dog's food a little.
His best results seemed to be at 1.25U and 3.25U, but you don't have a lot of mid cycle data to see how low he is going. And very little night cycle data, which is when cats tend to go lower. If he is bouncing, it is also possible that your frequent dose changes lately have destabilized him moreso.
Also, your SS is colour coded to show the high greens as if they are hypo. Are you able to change that?
If you haven't already, I would recommend posting in the Lantus forum for some better advice.

 

[Chris & China (GA)]

I think you should go back to the 3.25U dose and get more testing in....when on the 3.25 before, you have a couple of good nadir numbers, but there's just not enough testing during that time to know for sure what's going on.

Some cats just need more than others. It's possible Chance has a high dose condition like acromegaly or IAA, but we don't suggest testing for those until they're above 6U.