You're a quick study, Mandy.
A hoped-for Lantus response will see the run of the cat's numbers in each cycle form wide, shallow, 'smile' shaped curves.
Assuming the cat is not yet in well-regulated numbers, the idea then is to use tiny dose adjustments to
g-r-a-d-u-a-l-l-y nudge the 'smile' curve down into better and healthier numbers. This takes a little time, but this is advantageous because:
1. It gives the kitty's body time to relearn how to respond properly to insulin again, and to become accustomed to running in a lower, healthier BG range.
2. Making larger dose adjustments (e.g. 1 unit at a time) increases the probability of jumping over the 'goldilocks' dose that the cat needs. Too high an insulin dose can, counterintuitively, drive numbers higher, since the cat's bodily defences will jump in to drive up - and keep up - BG levels in order to protect the cat from constant threat of hypoglycaemia. This means that BG levels for too much insulin can look very much like those for too little insulin. Instead of gentle smile curves, overdosed cats tend to have high and flat BG numbers, or even 'inverted smile' curves, where numbers mid-cycle run higher than at preshot times. (Occasionally this leads to some cats being prescribed higher and higher doses of insulin with no improvement seen - and greater hypo risk).
3. Gradual adjustments reduce the risk of hypoglycaemic episodes.
I have had a look at Sissy's spreadsheet. Based on the available data, Sissy seems to be having a
beautiful response to her Lantus. With the exception of occasional outliers (which are normal, and to be expected) she is getting lovely gentle smile curves on both AM and PM cycles.
Most cats run lower at night. So does Sissy. Nothing abnormal about AM cycle numbers being higher than PM cycle numbers.
Sissy's morning AMPS values are higher than the PMPS values. This again is very, very common (
dawn phenomenon). Often the AMPS value is the very last value to come down into the normal BG reference range when a cat is going into remission. Also, if a cat runs lower to a safe but 'unfamiliarly low' BG level during the night that can cause a little bit of a bounce which may also feed into the higher AMPS.
As you correctly observe, Sissy has shown she can drop quite a bit in the PM cycle when she is only receiving 1 unit of Lantus on the AM cycle. If she were to receive 2 units on the AM cycle it could potentially push her early PM cycle numbers down further. That, in turn, could perhaps cause a counter-regulatory reaction leading to an even higher spike in the AMPS, or perhaps set off bounces of greater amplitude and duration - which can make regulation trickier.
Another possible consequence of lopsided dosing is that, with a 2-unit dose given in the daytime, the PMPS may become too low to safely allow a dose of insulin to be given at all for the evening cycle. (Note: For cats on doses where the PMPS is regularly too low to permit giving insulin, the usual solution is to reduce the dose for both cycles so that there will be a 'shootable' preshot BG both morning and evening.)
At the moment, Sissy looks like she might be a dream of a cat to regulate using steady, gradual dose adjustments. Cats don't become diabetic overnight. It's not possible to pile drive glucose levels down into better ranges by throwing more insulin at one part of the day. The body's homeostatic and circadian mechanisms don't work that way. It takes time - and a little patience - to get their sugars under good control.
That's just my interpretation of Sissy's available data. Other members may offer a different take.
Mogs
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