Switching to Pump - Dose Changes

Hi all

I started on my new Ping on Saturday …yay!!

My question to all you pumpers is: When you made the switch from shots, what were the changes in doses you experienced? I have heard that most people wind up using a lower dose of basal. I’m starting reduced by 20% and may even end up reducing it a tad more. But what about bolus? Do you find that you also reduced your boluses (changed your I:C ratios to cover a bit more carbs with a unit of insulin)?

It’s been many years since I started pumping but if I remember correctly my insulin dose decreased. When I switched from Minimed to Animas I ended up needing to decrease my basal rates by about 10%. My sensitivity had to go up a little bit too (ie less insulin).

It is different than on MDI. For one thing with shots you’re pretty much limited to whole units so you end up rounding up or down a little whereas you don’t on the pump. It will also more precisely calculate your bolus dose. When I was on shots I never carried a calculator with me so I also kept my I:C ratio easy to figure out in my head.

Thanks, Diana. It didn’t dawn on me that the insulin dose changes might be different on different pumps!

If I’m understanding correctly, it does sound like in addition to being able to bolus for fractions of a unit, you decreased your I:C ratios as well? (One unit of insulin covered more carbs )

I ended up cutting back more than 20% also. At the time, I was still getting my thyroid where it needed to be so I am not sure how much was the pump and how much was from my thyroid finally leveling out. I did keep my same bolus amounts but did bump up my sensitivity levels.

I am having a pump issue right now and temporarily doing MDI. I added 20% to my current pump basal and it was not quite enough.

Yes, thyroid definitely plays into it. For me I did it backwards; I had thyroid problems long before diabetes. My levels and replacement dose were stable for quite awhile and then when I got diabetes it flucuated and I had to change doses of Synthroid.

When you say sensitivity levels, Kelly, you mean your correction factor? (How many points one unit of insulin will drop you). But your I:C ratios didn’t change? (Sometimes I find it hard to talk about these things because we use different terms and I get it backwards if I refer to “raising or decreasing” something…lol

Yes, I mean my correction factor and my carb ratios did not change. We better not talk debits & credits! A credit to cash means less cash but a credit to income means more income!

I started out by reducing my basal by about 25% of my Lantus dose and that was pretty close. I don’t recall how much it changed in the first few weeks of tweaking but it wasn’t too far from that. Now, between pump and weight loss, it’s down about 35% from where I was pre-pump.

I always had a lot of trouble with getting a good I:C on MDI. It always seemed that small doses (1-2u) would have a much lower proportional affect as more moderate/large doses (3-5u). I’d say the ratio itself probably didn’t change very much, but if I went back on MDI I’d probably have to add on ~1u for the ‘site-saturation’ effect on lower doses (or whatever the cause is). I guess a better way of saying that is I would have seen minimal effect of 1u on MDI but see a very clear effect with 0.5u or less on the pump. On the other hand, the larger doses are probably in the same ballpark.

Ouch! That is why when I lived in Guatemala when I started on insulin I insisted on speaking English with my doctor. One slight word difference or tense difference and I could be doing the very opposite of what he was saying!

Thanks John. Yes, I will do the fine tuning after a bit more data. But it sounds like I’m right in guessing the basal might need a tad more reduction (I’m at 20% down to start) but not really the I:C ratios. Thanks for the suggestion of looking back and seeing how much correction I am doing. John Walsh mentions that in Pumping as well.

Hopefully your doctor really understood English - one mixed up word and he could have told you the wrong thing!

I know what you mean about the small doses, Tom; one of the many insulin inponderables! I have a 1:18 ratio for dinner and usually eat enough carbs for 2 units which works fine. But when I’ve occasionally had salad or something that was 18 or less and did one unit it ended up not being enough. I can already see how nice it is to have the smaller percentages to play with, especially for dinner. I think pumps are especially good for insulin sensitive people where say 2 units isn’t enough but 3 is too much!

I think his English was better than my Spanish at that time! And he did keep translation software up on his laptop while we spoke in case he needed a word. But still I always did the old counselor “reflective statement” thing, as in, “So Kelly you seem to be saying that one wrong word and he could have told me to take a lethal dose of meds, is that correct?” LOL. Living in another country is always an adventure. There’s language misunderstandings and then there are cultural ones too. Like everytime I wanted to refil one of the many meds I take, I’d go to the pharmacy and present my prescription list, and they’d always ask, “So you need all of your meds refilled?” I’d say no, just x and y and they’d hand me back the script. I finally understood that they don’t really care if you have a prescription there and just starting writing down the names of the ones I needed filled.

Both basal and bolus doses decreased roughly 20%. Not sure about IC ratio since it fluctuates all over the place.

Ok, I’m confused. Don’t you determine your bolus doses according to your I:C ratio?


My IC ratio fluctuates all over the place, but not drastically. I can’t tell if the pump has resulted in more or less of a ratio because I just leave whetever setting is in my pump as a rough average and hope I don’t have to correct too much either way. I do change them occasionally, but only if they are trending and I’m getting consistent differences in BG readings that can be corrected by changing my IC ratio. So, for example, if I’m missing workouts and I know that I’ll keep missing workouts, i’ll go in and change my IC ratios accordingly.

I did the same thing while on MDI. There doesn’t seem to be much of a difference in my ratios between being on MDI and the pump, honestly.

The difference in bolus amount is probably based on a couple of things, given the fact that i’m using the same IC ratio guestimates:

On MDI, I generally rounded up to the next highest unit, while the pump can just calculate and deliver an exact amount. I’m also having to take less correction boluses on the pump. I’m guessing that’s due to better absorption at the site for the pump. Based upon the boluses I logged on MDI and the bolus amounts dispensed by my pump, I’m looking at about 20% less total amount bolused per day on a pump while using the same given carb ratio guesstimates. It’s not a great amount, the difference between bolusing 9 to 12 units a day on MDI and 7 to 11 units a day on a pump, but it’s a consistent difference.

As for my basal, who knows? I went from using 12 units of lantus a day to between 10 and 11 units of Novalog for my basal needs. Lantus is so screwy, I’m just glad to be off the stuff.

Thanks for explaining. I forgot that I no longer have to round up (and so take a bit more) or chance a bit under and going high. Also the less accurate dosing and then having to correct. With my dinner ratio of 1:18, it was pretty hard to get it right consistently. Even with a rocky first day, and still adjusting to my pump I’m already very happy and glad I made this choice! (Not having to pay for the pump made it even better!)

Each pump handles basal delivery or bolus calcs a little bit differently so things can change even with changing pumps. Animas delivers a basal pulse every 3 minutes whereas Minimed delivered the same basal rate in fewer pulses. Animas also rounds a little bit differently than the Minimed did so I believe I’m getting a smidge more insulin for boluses. I traded in my Minimed to reduce my copay so did not do a head to head comparison so it’s just an overall impression but I believe it’s correct.

I’m not sure if my I:C ratios changed or not. I don’t think they did though. That’s the one thing that tends to vary a bit with me anyway so it’s something I need to adjust or tweak more often anyway as opposed to any other pump setting. Shrug.

In the long run doesn’t really matter. What matters is what works and to be aware that anytime you make a change there will be a period of adjustment. Or at least that’s how I look at it.

Thanks, Diana. Other than my first day when I bent the cannula and wasn’t getting any insulin all day…god knows how I did that…it’s going pretty well so far and my numbers are pretty good! I’m so happy to have my Ping.


No kidding though. It’s only been 4 months on the pump after being on MDI for 25 years, but i’m already, happily, forgetting what it was like to, essentially, be taking pot shots at insulin doses. I pretty much used round numbers for everything. I would have just gone with an IC ratio of 1:15, rounded up on the next insulin dose, then called it a day until I had to correct.

I’m sounding like a broken record, but the absolute biggest difference is being able to get off the long acting insulin and really nail down basal rates. That just opens up a whole world of possibilities when it coems to dialing in everything else.