Changing pump numbers

My endo and I agree on pump settings on every visit, all is good, and then…things change. I wake up high every morning or battle afternoon lows. I cant run back to the endo constantly. I know people here adjust their own pump settings. What general rules do you follow when doing that?

I inform my my endo what I am doing and listen to him if he suggests I might try something different? You have the disease and everyone’s disease is different in terms of managing diabetes. My advise is read and research, listen and learn from others like this group and safely experiment and do tests on yourself. You’ll come up with ways of managing your diabetes that you never thought possible. Good luck!

@PamS, my one hard and fast rule is never to change more than one thing at a time. Then I let at least 2 or even 3 days go by to see how that works. Very basic.

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CGM is a massive help as you can see your trends on 5 minute intervals.

As far as general rules I follow (not giving you medical advice!):
If BG is trending steadily up or down overnight (say after 2am to minimise the effects of dinner carbs or insulin) then basal rates need to go up or down as well. Doing a formal basal test every now and then helps. Getting the basal right first is essential if you don’t want to be constantly chasing your tail with suspending basal and giving corrections.
AFTER basal is sorted:

If spiking high and staying high after meals, increase the insulin:carb ratio (i.e. make the number of carbs per unit of insulin smaller)

If spiking high and coming back down to target after meals, increase the pre-bolus time, and consider “leading with protein” to slow the carb absorption.

If spiking high and then crashing low after meals, increase the pre-bolus time and reduce the carb ratio (i.e. make the number of carbs per unit of insulin bigger)

If corrections on your pump aren’t bringing you down (or are sending you low) then you insulin sensitivity factor (AKA ISF or correction ratio) is off. To test your ISF, you need to have your basal insulin dialled so that your levels stay dead flat, and perform the test with no recent food or insulin in your system (i.e. 3 hours or more after a meal) and without exercising during the test. Starting from a moderate (and steady) high, take your pump calculated correction, and see how close it drops you to your target. Say you start on 180 and your target is 100, and your correction drops you to 120 (after 3 hours, not instantly!). Your correction dropped you by 60 instead of 80, so you need to decrease your ISF (multiply the ratio by 60/80 = 75%).


I never change my basal by more than 0.2 U per hour and yes only thing at a time. I never change the bolus by 0.1u also one at a time.

Those are great rules to emphasize. We all should and need to know the basics (basal rates, carb ratios, insulin sensitivity, etc.) but after knowing the basics we need to test them on ourselves (a great description of how to test for them) and tweak them so they work for us. So my recommendation is to read, research listen and learn the basics and after you do that test them out and experiment safely on yourself. Others can help but we are the only ones that can find solutions to our problems and diabetes management.

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Like everyone says, one parameter at a time, and go by small increments. Basal changes can really creep up on you. But for me, when I first switched to a pump it really wasn’t working for me at all until I finally broke free and started doing my own adjustments. Got tired of running way too high compared to how I was doing on MDI because waiting for trainers to advise the next change took forever. That was pre-CGM, though. Much easier and safer now.

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My endo’s have never changed any of my pump settings. I programmed the first settings myself and kept mine instead of the doctors recommendations the trainer had with her. Never a word was said to me about it. My next endo tried to change something the first time and I immediately spoke up and said no one’s allowed to change anything on my pump except me, it’s my life. She must have made a note as since then she has never even tried to touch it. Neither has she tried to say anything about changing any settings, she just said she noticed I do since my settings had changed. I do well though so they probably don’t feel compelled to have to.

This disease changes so easily at least for me and some others that changes happen maybe not for months, but maybe next week, I would never want to wait or actually even trust an endo to make my changes for me.

It’s always best to make small changes only every few days, unless you are really dropping and it’s a more critical necessity. But for me it seems critical knowledge to be able to change settings yourself.


I don’t think my doctor would even know what sort of settings to put in my pump, let alone how. She’s an internist, not an Endo, and wouldn’t see me if I wasn’t self-suffient. She’d make me drive the 3 hours to see the one and only Endo on the Western slope of Colorado.

I did see that Endo, twice. She never touched my pump, either. First visit was too get started on a pump, last visit was because she wanted absolutely nothing with the t:slim x2 I picked against her advise. I don’t care if she wrote “non-compliance” in my chart. :slight_smile:

This is way too dynamic of a disease to wait around for months to make important changes.

I will say, though, it’s a little more scary without CGM. You may think you test a lot, but you really can’t appreciate how often and quickly your sugar can change without it. I doubt you could keep it up for long, but I would make a point to set some crazy testing days aside, and test like every 15 minutes for 4 hours after every meal and/or bolus. Data is a powerful tool, no matter how you get it, and can help you make informed, smarter choices…


Excellent advice.
My daughter had an endo that didn’t believe in basal testing. Thought he could dial in pump settings without basal tests. I wouldn’t let him change her pump settings - we make changes ourselves. We locked horns a lot. We don’t go there anyore :laughing:

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Diabetes is dynamic, not static. While good settings can sometimes last for weeks at a time, you can’t depend on them remaining stable. Managing pump settings without a CGM is difficult to do well. Even with 10-15 finger sticks each day, you often have to guess about the glucose values between pricking your finger.

The best situation is for the person wearing the pump to observe the data and make the adjustments. That’s not always feasible and that’s when the doctor can step in to fill in the gap. This often motivates the patient to start doing their own adjustments.

In order to make pump setting changes successfully, it helps to do some reading of books that cover how insulin works and how to experiment to arrive at settings that will work for you. It’s important to realize that these settings may be good for the time being, but they will almost certainly change. To expect anything else will disappoint you.

I see diabetes a do-it-yourself disease. Doctors can help but the treatment breakthroughs often only come when the patient is in the driver’s seat.


Everyone here has given great advice! We are such a knowledgeable bunch aren’t we?!!
I will agree that you always focus on one thing not everything. Overnight is always the easiest to dial in since you don’t eat or exercise. So if that basal is good than break up the day into the parts you have the most trouble with. Sometimes when you key in on one part and correct it, the others come in line. My biggest frustration with basal testing is you need to do it at least three different times to see a pattern. And of course I would go 2 days with the same pattern and than the next time, a completely different pattern. So sometimes it takes a while.
And if you are comfortable with your doctor making changes, cool. It is whatever works for you. I currently talk it through with my endo, talking about patterns I see and we decide together what to do. He doesn’t make changes to my pump, I do but I have allowed doctors to make the changes. Whatever works for you!
Knowledge is power! The more you know and understand how insulin and pumps work, the easier your day to day life can be.

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This is terrific information and thank you to everyone who chimed in. I use the Freestyle Libre, not really a CGM, but it is showing me trends and patterns and it is so easy I test much more often. I HAVE NEVER done basal testing. That seems to me to be step one her (plus reading).
One more question, is there a generally accepted basal/bolus ratio? Like total daily basal is usually x% of total daily boluses?

Great advice from everyone! The only thing I’ll add is that I often tweak basal rates based on infusion site quality. Probably more important to someone like me who has been pumping for many years and may have a bit of scaring at some sites. Just another variable to throw into an already complex mix.

As far as endos adjusting basal rates, I’m happy to hear their recommendations. Maybe I’ll learn something I didn’t know. But I’ll do what I feel is best. I won’t have a doctor micro managing things!

The CDE I’ve been seeing for over 30 years said she just can’t understand endos that dictate pump settings for all the same reasons we’re discussing here.

I’m sure there’s a range that the ratio typically falls into, and such a ratio is often used as a starting point in the absence of other information. But when you can get almost real-time data on your actual requirements, you’re much better off using the numbers from your own testing.
My son is still in and out of honeymoon so his requirements are probably more variable than yours, and the “standard ratios” less likely to be valid, but they still tried to use them for his pump start. The settings they gave us were based on on a 50:50 basal to bolus split, which we already knew from his Dexcom data under MDI was absolute rubbish, as he was having multiple hypos every night even on 0.5 units of Lantus but was having about 4 units of bolus insulin. We took their suggested values, said “thanks for your input, we’ll use our own unless you can explain why we should ignore 2 months worth of CGM reports saying otherwise”. 10 months later and his daily basal is up to about 3.6 units, and insulin:carb ratio has doubled, but he’s still having 3 times more bolus than basal (and that’s with a relatively low carb diet). Changes in bolus and basal insulin requirements haven’t gone in lock step, sometimes we have needed to increase (or decrease) carb ratios by up to 50% while leaving basal the same, other times we have had to increase basal by 25% with no change to carb ratios.