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Unsure how to calculate insulin dosage? Results seem random.

  • Thread starter Thread starter Deleted member 99312
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I understand that you should only have to bolus for food and not to try and correct an incorrect basal amount. I am merely doing that as I evidently (usually) require more in the morning than during the rest of the day and evening when my 1:10 ratio works well. A 1:10 ratio sometimes has worked in the morning even. I just looked at some notes from a few months ago and I ate 28g carbs, took just 3u in the morning and only had a small rise from 4.7 to 5.1 by lunch.

I know you don't strictly need to correct a 7.2 by the way, but I would prefer to be closer to 5 by lunchtime and not stay at 7+ for hours on end like that. I don't believe it is good in the long run. Maybe I'm wrong but I've read some doctors saying this and it makes sense to me. Non-diabetics aren't at those levels for prolonged periods and as we're using insulin there is no reason for us to either, as far as I can see.

Anyway after my 10.3 earlier, I took 6u, ate nothing, and just now was down to 6.2. So as we can see, the insulin is working well when it wants to. I expect this will drop to 4.0 or below so I will account for this when I next eat and dose.
 
(Hope it's okay to post another forum's link here)

Was just reading this, there are others who either take extra bolus insulin in the morning and/or use a higher ratio just for breakfast. So it looks like I was on the right lines with my thinking and it wasn't such a crazy idea. Whether it's ideal or the best way is up for debate of course.

https://forum.diabetes.org.uk/boards/threads/dawn-phenomenon.86775/

What seems to be the case is that your basal requirements will go up and down throughout the day, ie. higher overnight and in the morning etc. and no 'one size fits all' amount will or can be perfect, only a pump with custom tuned dosages could achieve perfection.
 
Dave P said:
My numbers are almost always good upon waking, the only time they aren't is if I made a miscalculation the previous evening, but this is rare.
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That is why I suggested Foot On The Floor, not Dawn Phenomenon.
Some livers react before waking (DP) and some react once you start moving (FotF).
 
In Response said:
That is why I suggested Foot On The Floor, not Dawn Phenomenon.
Some livers react before waking (DP) and some react once you start moving (FotF).
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Aha, sorry, I did read your post before but that term didn't register with me. I have learned a new term today.

It sounds like this is basically what I have been doing:

https://tcoyd.org/2020/07/how-to-manage-foot-to-floor-phenomenon/

Maybe I should just carry on doing this then. If a rise after getting up is common, and increased insulin resistance in the morning is not unusual either, then either or more likely perhaps both of those things probably explains everything. As for the inconsistency, I doubt any perfect solution to this exists, at least not with the tools I have, ie. manual testing and injecting. I test regularly throughout the day and evening so any highs or lows do not go unnoticed for long (and I can sense if I am low without testing, most of the time as well).

As for my background retinopathy, I will just have to hope this doesn't get worse, and maybe even clears up if I'm really lucky.
 
Background retinopathy can appear and disappear again on a regular basis. I was diagnosed with type 1 56 years ago and it used to worry me, but no longer does so. I know I'm not the only one on this forum who had had this experience. My latest report from retinal photographs says that last July it had gone again. I would try not to worry about it too much. Stress only causes BS levels to rise. If you are worried, discuss it with your consultant.
 
Thanks, I'm not unduly worried, my heart did sink a bit when I got the letter last week but I already knew it is common and to brace myself to expect it one day, and not panic if it happened. My instinct was to think what have I done wrong and what do I need to change, but it could be that I don't really need to change anything, hopefully.
 

Hi Dave, just to add a new thought in, (picked up on my type 1 course). A few people had similar problems to you in that seemingly no matter what they did, at certain times during the day their levels were stubbornly higher than they wished. The solution surprisingly was to take LESS insulin, not more. They said that what can happen (especially in the early days of honeymooning or when a person is still producing some of their own insulin which is common), is that the insulin is injected, the body panics and thinks it is going too low too rapidly so it produces glucagon sending levels even higher. They said do not add a correction dose when the reading is under 10 as this would be even more likely to happen with some people, unless it remains around 10 for several hours. Maybe worth trying? I do think you would benefit from a libre because you will get data galore.
 
May I ask a question or two please. You say that before being a type 1 you were type 2...was this a misdiagnosis or were you actually insulin resistant and type 2? How bad is the back ground retinopathy, has it been discussed with your medical professional? It is my believing that it is sustained high BS that will damage the eyes by leaving glucose deposits in the vessels. Going low isn't bad for your eyes the way you are and most of us do, it's having high BS for prolonged time then going low quickly. This makes the vessels have wiggle due to the fluctuating pressure caused by high and low blood pressure. Having an hour or two in the 10's to early teens won't have a pronounced effect on that.
 
To add to this, I was told a sudden change in blood glucose could damage them too. This is why I was told to gradually lower my glucose levels when I was initially diagnosed (DKA and so as you can imagine very high levels for a while pre diagnosis!) They gave me fortnightly targets for lowering blood glucose rather than going straight down.

Sorry to hear things haven't been smooth. If there is still insulin being produced that would explain a lot. It certainly doesn't have to be like this for ever!

A few things I've experienced which might add to the things to discuss with your DSN... I used to be fine on one basal insulin injection a day, but gradually found I needed to split it. I've then found the split ratio has drastically changed. Used to need more over night than in the morning, now I need only 5U in the evening but 15U in the morning. The Libre helped clarify these needs for me. If I change doses I usually tweak by 0.5 units or 1 unit at a time. Having the larger morning dose means I can adjust based on the activity I know I'm doing that day more flexibly without worrying about night hypos.

I also find a huge difference in when I need to prebolus based on the exercise already done that day. So because I'm more sedentary over night I need to prebolus for breakfast earlier than I do for lunch/dinner. But if I have just been at the desk in lockdown then I also need a longer prebolus time for lunch. Of course this doesn't explain 'incorrect' dose just timing of dose.

Not answers, but hopefully helpful things to think about/discuss with your DSN. Good luck, it won't always be this hard to stay stable but we all have more difficult periods.
 
Technician87 said:
May I ask a question or two please. You say that before being a type 1 you were type 2...was this a misdiagnosis or were you actually insulin resistant and type 2?
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I don't understand the question. On initial diagnosis in 2014 I was type 2, at that time I had very high blood sugars to the point my vision was very blurry and it permanently changed my previously perfect eyesight so I now need glasses to read which I never did before. However, no sign of retinopathy at that time or since until this year. I got my blood sugar back into the normal range and controlled it well, with a high fat, low carb diet which worked until 2019 when I found my blood sugars wouldn't go below the low to mid teens for a few weeks, I was then tested and put on insulin and formally classified as type 1. Does that answer your question and what is the point of you asking please?

How bad is the back ground retinopathy, has it been discussed with your medical professional?
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One small bleed in one eye only.

A test on mice showed that prolonged low blood sugar made them go blind. How low and for how long, I don't know. Whether a person can tolerate regularly going into the 3s, and in my case sometimes I have gone as low as the 2s or even I think I've had like 1.7 a few times, for as long as a few hours if I've been in bed and woken up that way, I don't know - do you know? Or are we guessing here. I *hope* that is not causing any problems. I suspect it could be, so is best avoided - as are prolonged highs above 8.

Or are you saying that regularly going low or high (say 2-3 on the low side, and 10-12 on the high side) for a few hours will never result in eye damage? I find that hard to believe. I'd like to believe it, because it would make life a lot easier. I may hope to live another 30-40 years as I am in my late 40s. So I am young enough that it is not good enough for me to just 'slow down' the rate of retinopathy progression, I need to not have any at all if I want to see in future.
 

I find it hard to agree with these last few statements if I’m honest. Obviously 2-3 on the low side is really dangerous & needs to be treated ASAP, but being above 8? I’ve just had a check up with my DSN after being on my new pump a month. My estimated a1c with carelink is 48.7 & I’m regularly between 7-10mmol throughout the day, when asleep between 5-7mmol. After exercise I will usually be around 12-13mmol for an hour or two. My eyesight is better than it’s ever been, no blurry vision etc. My a1c before pump was 83 & now with results that your saying are bad for your health my a1c is 48.7.

My DSN also said, as long as I’m in range between 3.9-10mmol she is more than happy, I actually got an email saying “wow, 86% in range I wouldn’t recommend any changes’. But without a doubt more than 50% of that time in range will be the higher end of 7-10.
 

I am not saying 8-10 is dangerous today, you could probably be at 8-10 24/7 for years and have no problems I imagine. I wouldn't advise it though. Nor am I saying such levels give blurry vision. I don't know what my levels were when I had blurry vision as I never asked (diabetes was all new to me and I never thought to ask, and they never thought to tell me). I had originally gone to the doctor due to feeling unwell and also urinating loads frequently. I can assume my blood sugars were extremely high, probably 20+ or something. They put me on gliclazide and metformin and my blurred vision went away, except I now can't read anything remotely small without glasses.

If you are happy with your personal situation then that is all that matters, and the same goes for me. In my experience, DSNs can set a low bar which they believe (or at least tell you) is perfectly good, but in reality it may not be. There is a good reason why some diabetes experts recommend the best way to avoid long term complications is to get as close to normal blood sugars as possible. Non-diabetics aren't spending hours each day at 12-13. If you think that will work out well for you then good luck with that, I hope you're right. You cannot draw any conclusions that those numbers are not doing you any harm just because your vision is perfectly good today because the damage causes no symptoms until it's at an advanced stage, hence the diabetic eye screening programme.

Some DSNs are not very knowledgeable about this disease, that is my experience. I had one when I was type 2 who informed me I had 'reversed' my diabetes and she looked at me blankly when I tried to explain to her that the only reason my hba1c was in the normal range was that I was having to half starve myself and eat ultra low carb etc. and that if I had truly 'reversed' it then I'd be able to eat at least somewhat normally. But they seem to be trained not to think, but just to follow a script, so hba1c = good, all is good. It's very stupid. So we have to think for ourselves. Of course I was proven right not too long after because for someone who had allegedly 'reversed' their diabetes, I ended up needing to go on insulin for life.

I even had to fight to be referred to the hospital in 2019 because a stupid GP was angry with me for testing myself when I suspected I had high blood sugar. "You shouldn't test yourself, you don't need to, you're type 2! Your hba1c is normal!" He even told me I didn't have diabetes! This is the standard of healthcare we have to deal with. It's a lottery whether you get someone who knows what they're doing or not.
 
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Hi sorry to be late to the discussion.
I have read this thread several times and don't understand why you changed from 10u to 6u. This seems a big change to me to do in one step. I think I would have tried 9u or 8u. If you make too big a change then this can cause instability. I would advise to try and keep things steady for several days and watch what happens.

Your carb to insulin ration will alter throughout the day. You may need to use different ratios at different times of the day.

BG testing before meals and for T1 four hours later after injection to be back at starting point. Testing 2 hours afterwards is more important for T2 but once the 4 hour test is right the you can adjust the two hour test by varying the time between insulin and eating.

Spikes will show in your HbA1c test and since you say these are ok then your control sounds ok.

With your eye problem a single bleed in one eye is not really a problem provided it is monitored. If it gets worse then a quick bit of laser sorts it these days. I know best not to get it but try not to worry over it. Stress can ruin your glucose control.

Looking around this and other forums people seem controlled by the numbers. Some days the theories don't work and it is all random. Try and control the numbers but don't let them control you.

Save you looking me up been type 1 for 57 years.
 
It's pretty simple to understand the rationale behind me doing it isn't it? It's right there in the opening post.

When I started at 7.2, ate 21g and took 10u, I fell to 3.3.

When I started the next day at 5.5, ate 21g again, if I fell by the same amount then I could be having a severe hypo. You don't have to be a maths genius to figure it out. You say don't let the numbers control you which doesn't mean anything - of course 'the numbers' control us, it's up to you if you choose to ignore that or not. You are free to do that, I'm not interested in browbeating anyone to do anything they don't want to do.

Spikes will show in your HbA1c test and since you say these are ok then your control sounds ok.
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That doesn't make sense either. Any given hba1c could be as a result of good or bad control, the hba1c number alone doesn't tell you that. Few people in the health service seem to grasp that though.

Looking around this and other forums people seem controlled by the numbers. Some days the theories don't work and it is all random. Try and control the numbers but don't let them control you.

Save you looking me up been type 1 for 57 years.
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I think there is always a danger that some people who have been fortunate end up thinking that their good fortune is directly as a result of stuff they did. Like people who smoke for decades and never get lung cancer, or who drink to excess for decades but never get liver failure (until they do, suddenly).

There are people with excellent control who develop retinopathy which doesn't even respond to laser. Then there are people with mediocre control who never get retinopathy. These are the outliers, and then there are the majority who need to watch what they do and yes, the numbers. We do all need to watch our numbers. At least, I will continue to watch mine.

Now I have figured out the mystery I made this thread to solve, thanks to the poster who taught me about the foot on the floor phenomenon which led me to do more reading about it, I now know better how to manage all this.
 
Further to the debate about what numbers are 'good enough', this is what I go by:

https://www.bloodsugar101.com/diabetic-eye-disease
 
Hi Dave! I could have wrote your message!

background retinopathy I had this and the following year it reversed and clear 4 yrs since So there is hope and background is the mildest form

High sugars/insulin resistance in the morn I am plagued with this. What helps is taking my glucophage before bed works wonders also avoiding eating before bed maybe a very small snack if absolutely necessary.

Unpredictable sugars yes thats me and it is soul destroying and so frustrating Like you I note an error and the following day I change something but it goes totally against me.

You would feel like giving up but when I look at my time in range on the Dexcom its actually not all that bad! I am a perfectionist and can be very hard on myself so I try my best not to let it get to me as I have had and still manage anxiety and i know it is hugely related to managing this horrible disease.

So my advice is dont be too hard on your self protect your mental health. I try to eat plenty of foods packed with antioxidants in particular anything with lutein and zeanthine (pardon my spelling) as these two are very good for the eyes! So what you cant fix I hope the antioxidants step in reducing inflammation and the oxidative stress caused by high blood sugars (google this many diseases and diabetic complications caused by oxidative stress) Plenty of avocados spinach green tea anything colourful! Manage stress get enough sleep enough excercise and enjoy life have fun (hard these days ) not too much alcohol no smoking....all these things will give your body the best chance to survive the ravages of high sugar

And remember many people have lived for many many years without ever getting any or just mild complications. Wishing you all the health in the world!
 
I was only thinking If your ratio was actually 1;2.5 then 8 units balanced the carb and 2 units reduced your BG by 4. The next day taking 6 units that was not enough for the carb so your BG would rise. I have no idea what your ratio is but 1:10 seems very low to me but then everyone is different. 2 units would reduce my BG by about 4.I would really like to be able to change mine by half units!

My target value is 6.5 with a range of 5 to 8. The idea being I am always fit to drive.

As I said doing what for me is a big change would upset my control for days. Unfortunately a change in one day tends to ripple through the system and all sorts of things effect how it all works.. There tend to be background effects some pushing up and some pushing down so they cancel and then suddenly they all go in the same direction. Disaster!

Keeping your BG too low can also have long term problems.

I'm glad to hear you still intend to watch the numbers but the numbers aren't the beginning and end of it. I find some people spend there life trying to get the numbers so close to a level line they forget to live life. Non diabetics have levels that go up to 10 and they don't get diabetic long term effects!

I have long term effects. 4 of them. If I didn't have diabetes three of them would be classed as genetic predisposition. The consultants pick up on diabetes as a reason for your problem. Yes it might make you more likely to get it.

If it only takes a month or less of poor control to get DKA then having had the condition 57 years if I only have 1 bad day a year then that's nearly 2 months of bad control. No wonder I have long term problems.

You imply that I am fortunate and it has nothing to do with my control. You may be right in which case why did I bother> If it was only a matter of luck. In which case why are you worried about your numbers it won't make any difference as you were unlucky. For the first 30 years of me being diabetic there were no BG monitors so numbers didn't exist. Makes it more difficult to control. I don't consider I'm lucky to get it in the first place.

You think you have a solution to your problem so good luck with that
 
Morning all, I don’t post often but wanted to say how interesting this thread is, and how much I have learnt, my reading have been erratic to be polite recently, and I read several comments which have given me information and also made me realise I am not alone. Thank you everyone who has contributed to this discussion, much appreciated.
 
stillgoingstrong said:
I would really like to be able to change mine by half units!
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Hi - just in case you're not aware, there are pens which do half units. Which you need will depend on your insulin, so for example I use NovoNordisk insulin and have the Novopen Echo.
 
Another long term (50 years) T1 here who's had on again off again background retinopathy for decades. First 15 years pre glucometer (and abysmal control in my teens). In my late twenties I was told that I'd need laser treatment by 40 but I'm still laser free at 59. (Have I been lucky?, probably/possibly yes, but I think those folk who start to get early complications after reasonable control are unlucky, outliers in the other direction). But ophthalmologists are very very used to treating diabetics now and blindness is a pretty rare end result - the eye tests are there just because they've learnt how to treat the eyes. Remember there are folk out there who maintain hba1cs above 10 for years - these are the ones who are risking serious diabetic complications.

My ratios certainly vary throughout the day, and I've got some insulin resistance. If I can get through the night OK (no hypos, no hypers) on my basal amount I'm happy, I know I need more insulin when I wake even though I just have coffee with a bit of milk for breakfast. It's easy enough to sneak a bit of extra insulin if my basal is lacking at points during the day. And exercise makes a massive difference to my insulin resistance, if I exercise just after taking bolus I know it will act more fiercely.

@Dave P would probably benefit from a cgm, if he's in the UK and testing 8 times a day or more he'd probably qualify for a free one. Also, have you considered moving to a pump? That would allow you to change basal rates during the day and allow for easier fine tuning.... (Though I suspect with an hba1c of 5.9 the clinicians will be reluctant to change anything, that 5.9 puts you firmly in the highest percentile of well controlled T1s). But one note of caution about frequent hypos for long term T1s. They can result in loss or reduction in hypo awareness, which is really bad news (and the reason why some clinicians get upset if they think your hba1c is "too low").

You were probably never T2, but always a misdiagnosed T1/LADA (late onset T1). Because insulin production goes down gradually for late onset T1s they very frequently get an initial T2 diagnosis, and reducing carbs keeps their levels normal because their reduced insulin production can cope with a lower carb load. Eventually their insulin production goes too low and they suddenly get rediagnosed as T1, which in fact they were all along.

And as far as reverse engineering those calculations go, you need to factor in two ratios
1) carb ratio (can vary by time of day and activity level)
2) correction ratio (which you haven't mentioned) .

Dave P said:
Yesterday morning 7.2, ate 21g, 10u, at noon 3.3. Drop of 3.9.

This morning 5.5, ate 21g, 6u, at noon 8.9. Rise of 3.4.
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final bg = initial bg - (insulin left over after amount needed for food)/correction ratio

Insulin difference between two days is 4 units, level difference is 7.3, which suggests you have a correction ratio of roughly 1 unit of insulin to 2mmol/L at that time of day (4:7.3). 9 units would probably have been enough yesterday, 8 units today. That does seem like a lot of insulin for just 21g but I suspect that that is the dawn phenomena for you. (Of course, I'm assuming that the DP is not affected by starting blood sugar and that your carb to insulin ratio is the same both days, which are not necessarily true. And there is the other factor that you may or may not be randomly producing your own insulin.)
 
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