How to determine insulin sensitivity factor

[littlevoice359]

I have been looking at bolus insulin calculation.

One of the parameters in the formula is Insulin Sensitivity Factor.



Is there any scientific method for determining what this number is and/or how it varies throughout an average day?

 

[helli]

My "scientific" approach was
- make sure my basal is correct. There is no point building on dodgy foundations.
- when my BG was stable and higher than I would like (for me this is about 8mmol/l), I was not exercising eating and had no IOB, I took half a unit of insulin and saw how far my BG fell over the next 2 hours.
- double this and it was my ISF

Although it may change at different times of the day, I keep it the same as it is pretty small so the variation is even smaller.

 

[littlevoice359]

My "scientific" approach was
- make sure my basal is correct. There is no point building on dodgy foundations.
- when my BG was stable and higher than I would like (for me this is about 8mmol/l), I was not exercising eating and had no IOB, I took half a unit of insulin and saw how far my BG fell over the next 2 hours.
- double this and it was my ISF

Although it may change at different times of the day, I keep it the same as it is pretty small so the variation is even smaller.

Cheers. Makes perfect sense.

 

[Inka]

Yes, there’s a formula @littlevoice359 but it’s an estimate so use your knowledge and experience to adjust if needed:

1)Work out your TDD (total daily dose of insulin), ie basal plus bolus over 24hrs
2) Divide 100 by your TDD to get your insulin sensitivity factor - ie how much 1 unit of insulin drops you.

 

[Proud to be erratic]

I also used @helli's approach; trial and learning. My ratio is, coincidentally, 1:2. From 2 successive Consults in c.2023, I was encouraged to soften that ratio and after each Consult I took note, tried for several days and confirmed to myself that 1:2 was still needed. Since then my ratio is accepted.

 

[Eternal422]

Yes, there’s a formula @littlevoice359 but it’s an estimate so use your knowledge and experience to adjust if needed:

1)Work out your TDD (total daily dose of insulin), ie basal plus bolus over 24hrs
2) Divide 100 by your TDD to get your insulin sensitivity factor - ie how much 1 unit of insulin drops you.

I’ve used this formula too and for me it is roughly correct. Mine works out at 1:1.8, I.e. 1U drops me by about 1.8 mmol/L, although there are times in the day when it is much closer to 1:1, which is when hypos occur as I’ve been too aggressive with the bolus!