There are a couple of reasons it would be good to know what is causing the resistance. First has to do with dosing. If antibodies are in the picture from IAA, then you need to be a little bit more aggressive going up the dosing scale and more cautious when kitty earns reductions. The antibodies can grab and release insulin at what seems like random and inopportune times. It's a pain, but the antibodies are supposed to be self limiting over time.
If it's acromegaly you are dealing with, whether by itself or in combo with IAA, you have to be aware of other conditions caused by the excess growth hormone. To name a few, first there can be thickening of the soft tissues in the throat. That can cause noisy breathing but more importantly, should be taken into consideration if kitty ever has to go under anesthesia. A smaller intubation tube may be needed. Another consideration is organ growth that can occur. Neko has some growth of the liver (not a big deal) but also the heart. The acromegaly was probably also partly responsible for her kidney damage and thickening of her bowels. The heart growth can be the most worrying of them all. It's call HCM or hypertrophic cardiomyopathy. Neko had a slightly enlarged heart for 3.5 years, before it became worth, but I think the SRT helped slow it down. HCM can be the cause of strokes. It's often called the silent killer as there are usually no obvious warning signs. But there are medications that can help if you know about the condition. Side note, I lost another cat to a HCM related stroke 2 days before his scheduled echocardiogram because we suspected HCM.
There may be a heart murmur - but that's non uncommon in older cats. If I know someone has an acrocat and I see any signs that might be heart related, I strongly encourage they talk to the doctor to get the heart checked. Neko had an echocardiogram when she first started her heart murmor.
And one last example of why it's good to know if you have an acrocat - from personal experience. Neko had a sore on her lower gum - it looked like possibly gum disease or an infected tooth. Her vet was already to yank it out. I decided to go to the dental vet instead, because they would do extra monitoring on her heart. Dental vet knew about acromegaly and after X-ray figured out the sore was because there was some soft tissue growth on her lower gum, causing her canine tooth to rub against it. Instead of an extraction, he filed down the upper tooth so it no longer rubbed. I could go on, Neko had arthritis (bony growth) and we had to start buprenorphine regularly for that. Knowledge of acromegaly and what could happen means you know what to look for and can ask those with experience what is needed to help. Chances are your vet has very little experience with how to treat the possible conditions that can happen with acromegaly.
There is a third condition, Cushings, that can cause higher doses too, but it is less common than acromegaly and you'll usually see some skin issues or thinning fur to go with it. There are some treatments for Cusshings, and if a kitty has it, you have to be very careful about handling the skin.
