Recurrent low fasting blood sugar

I’ve been having recurrent low fasting bs (40’s) over the last few weeks and trying to figure out what to do. I’ve been T1D diabetic for 46 years, so I’m very seasoned with my disease and I have been on the 670G and guardian sensor for 1 year (Lantus and Humalog prior to that for several years). I’ve have to shut my automode and sensor off at night due to it waking me up 1-4 times a night. The pump waking me up has been happening pretty much since I’ve been on this pump. Sometimes it would wake me up due to a low or high (which is good), sometimes because my automode would tell me minimal or maximum basal delivery and needs a bs check to continue. Other times it would wake me up to tell me I need to change my infusion or sensor in the next 1-2 days, or it just wants me to check my bs to calibrate. I’m thoroughly frustrated with these frequent waking in the night. I really like the concept of automode but I think Medtronic needs to fix these glitches. I’ve had my guardian transmitter replaced 3 times. I also tried just turning my automode off but I continued to get woken up 1-2 times per night. I also have tried having a late night snack ( half pb sandwich with a glass a milk), but still woke up low. I’ve tried talking to my endo, but she’s pretty useless. She thinks things are fine because my A1C is 6.3 , so I’m stuck trying to figure this out for myself. Has anyone had similar issues and what did you do?

Hi @Elizabeth67 what are you doing at dinner time? How big of a bolus? What kind of carbs,fats,fiber, etc? I go through a thing every couple years where I don’t need insulin for a week or so. Then it goes back to (my) normal. And I know this will come off as incredibly obvious but if you don’t need insulin, don’t take as much, or any, if your bs is good. Also, go by finger stick readings not guardian readings for this kind of troubleshooting. Cheers good luck :four_leaf_clover:

Hi @Elizabeth67
Like you, I am a longtime T1D - 45 years this year. Unfortunately, I don’t know much about the 670G. I was a longtime Medtronic user (20+ years), but made the change to the Tandem tSlimx2 last July, with the DexCom CGM, now the G6. I really wanted to do the Medtronic, but Medicare would not cover their sensors and I had been paying out of pocket for several years. It was a good move for me. I have not made the switch to full auto mode, but use IQ control. I am surprised at how frequently It anticipates a low and therefore suspends insulin delivery for a period of time. So while I can’t address your specific issue, I have some more general comments. 1) Does the pump have a sleep mode? and are you using it? 2) Can you set the night time target to a higher goal? 3) Have you looked closely at your time in range? This might be a better measure of control than relying solely on A1C. My long time endo (whom I loved) retired a bit over a year ago and I started seeing his partner, who is a younger. The first thing he did that was a bit different was to comment that my A1C was too low - it had been in the 5.7-5.9 range for more than a year, and I was thrilled. He felt it was because of frequent hypoglygycemia in the early morning hours. We tweaked my overnight basal rates, and my time in range improved dramatically. My A1C is now in the 6.2-6.7 range and all of us are much happier.
Hope some of this helps.

Have you verified your sensor readings with fingersticks? If your sensors are reasonably accurate and false readings are not causing insulin over-delivery, then the problem is most likely to be nighttime basal rates that are too high. They might have been good in the past, but things change. I have a very happy ex-Medtronic customer for the last two weeks. When you have the option to get a new system, I suggest Tandem X2 with Control IQ.

Hi Joe. Thanks for your advice. I never go by my sensor glucose, always my blood sugar readings. My dinner bs are almost always good but tend to spike a couple hours after dinner, especially when I eat carbs, which I try to limit. I’m not a big carb eater and usually will only eat about 30-40g at dinner and bolus between 3-4 units (sensitivity of 3 hrs). I honestly hate carbs and what it does to my bs readings but know I need them.

I don’t think it has a sleep mode but I may try and set up another basal (a lower one) from 12a-8a

Yes. I never go by my sensor reading and always confirm my lows with an actual finger stick.

Hi Elizabeth @Elizabeth67, first the “good news”. Medtronic appears to have heard your complaint [from many other 670G users] and is/has apparently made fixes in the soon-to-be-released 780G; beta testers have said the 780 is an improvement…

Now the not-so-good. As others here have written or implied, a pump can work only if you, the user, have given it the chance to do its job by giving it parameters that match YOUR CURRENT insulin requirements; that is, accurate basal rates for ALL hours of the day; accurate insulin:carbohydrate ratios; credible insulin-sensitivity factors for time of day; accurate carbohydrate counts for EVERYTHING that goes in through your mouth. Think of how many times your insulin dose has changed over the years compare the timing and amount of insulin you took yesterday with the total amount of insulin you took in one or two injections per day in 1974.

Yes, my words are not consoling. May I suggest, that you cease using “auto mode” for a while as you carefully analyze your insulin needs, and the timing of your insulin? You have some wonderful tools at your fingertips for this: Medtronic CareLink, which I used for years, and and Tidepool, among many others. Begin first with your basal rates; initially create a Pattern that has two-hour intervals and enter current your carb-ratios and basal rates but make your NEW evening rates about 15% less. Run this for a couple of days observe how you feel and what both your BG and BGL [blood glucose as well as interstitial glucose levels] readings show. Keep in mind that interstitial “lags” blood glucose - in both directions.

Also keep in mind that in old-time insulin users like us, I’ve been using insulin since the mid-1950’s, the effectiveness of insulin - even the rapid-acting like Humalog - curve is slightly elongated. Message me, if you wish and I might be able to make suggestions; I am NOT a licensed medical professional.

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Hi Dagmar @dagster1, I like what you wrote. Yes, long-time persons with diabetes are advised to not have HbA1c below 6% for fear of hypoglycemia unawareness, especially during sleep, UNLESS we are using sensors and software, like you are using, that will suspend insulin. A few years ago, I was advised to keep my A1c above 6.2%. Now using Control IQ I’m very comfortable with my 5.8% and a TIR above 90%.

As you know, a “great” A1c doesn’t mean everything unless it also means that we are also avoiding the extreme highs and wows - my A1c was lower when my standard deviation was way high.

If you are thinking of moving to Control IQ, keep in mind that the “sleep mode” includes a 110 mg/dl target and, when necessary, basal rates will automatically increase when the G6 sensor exceeds 120 mg/dl. In “normal mode”, the CIQ target is 120 mg/dl [equivalent to A1c = 120] and will NOT increase basal flow until the G6 reads 160 mg/dl.

@Elizabeth67, thanks for confirming you’re verifying sensor data with fingersticks for lows. The info about spiking after evening meals changes my suggestion a little - it adds in two important variables. The spiking after dinner could mean you need an earlier prebolus. The other issue is that in trying to avoid the spike you are getting too much insulin, either from an incorrect carb ratio or through the automated actions of your insulin pump. I’m not familiar with the 670, but it doesn’t have a good reputation with friends who left it for a Tandem. So my ideas are see if your pump is adding insulin to address the spike, test your nighttime basal rate to see if it’s too high. Now, one more issue… research from the last few years demonstrates that short insulin activity duration times are not good for most people, and lead to insulin stacking in automated insulin delivery systems. That’s why Tandem’s CIQ software has a non-adjustable duration of 5 hours. When your duration is set to an unrealistically short duration time, that tricks the pump software into giving insulin when it’s not needed. If you need more info about that, let me know and I’ll dig up a link to a research paper. Discuss this with your endo, but most automated systems do best with duration set to 5-6 hours.

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Thank you Dennis. I will try it.

Hi Elizabeth. One suggestion for getting along with 670 in auto mode is to options smartguard automode and then shut off the automode bg alert. You’ll sleep better and have a lot less stress…

Hi Dennis, I appreciate all the information. I have an endo appointment coming up in a couple of weeks. I definitely have mixed feelings about Control IQ. I wasn’t able to get the DexCom G6 until February (Medicare time lag), so I feel I’m still on the learning curve of the tSlim/DexCom basal IQ combo. I altered both both my low and high alerts: the low because 80 was too high for my preference, so set at 70. The high is set 160, mostly so I determine whether action is require. The 70 might be a bit lower than desired, but 75 was not an option. I just need to remind myself to respond rapidly more to the low alerts. I am confident that, like so many other things that changed for the better in my life with T1D, Control IQ will be a benefit. Just another learning curve to tackle!

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Yes Dagmar, you and I [and many more here like us] have had many learning curves - right from the first week of diagnosis when we learned how to sterilization a syringe, how to hold and fill a syringe, and finally how to stick that needle into our bodies. And somehow we conquered those and many more obstacles.
Im sure you will have the Basal IQmastered very soon and use that experience to see if you want to take on Control IQ. Keep in mind, at this point once you upgrade your pump to the CIQ algorithm, you can not return to BIQ - although CIQ can be toggled off and the pump worked totally on manual mode. I used my t-Slim on “manual mode” for a year before I got the G6 and began BIQ which I used for only a month before changing to CIQ.
The only thing that “bothers” me about CIQ is that it is so “hands-off” needing only me to enter carbohydrates eaten. In the past when I awakened and had to get up during the night, I would do a finger-stick, and later would always look at my Dexcom reader to see my glucose level; these days, I don’t even bother looking at my pump knowing that my glucose is steady between 85 and 115 mg/dl.

I have had T1D for 35 years, and finally decided to try pumping last year. I have had the 670g for almost 1 year, and actually had to get a new one in Dec because the 1st one cracked, which basically started me all over with the pump ‘learning’ me. I have issues with the basal driving me down too much - often hours after my last meal. I also was going through periods of it waking me 3-4x/night and was about to give up. One of the adjustments I made was my target range. It was set for 100-110. I moved it to 115-125. My endo wasn’t super happy, but I don’t want this thing driving me down, and overshooting, until I’m low. This has helped quite a bit. I have also used the temp target setting for overnight - that tells the pump to keep you closer to 150. It’s intended for exercise, but I have found it useful for keeping the automode from working so hard.
There are definitely pros and cons to this system. Overall, it has been good. Like anything for managing diabetes, there are problems, and they are frustrating.
As for turning the alarms off - I tried that for a while - because it was so annoying and wanted some sleep! But - it allowed me to sleep through a low, in the 40’s, for a few hours…which scared me. I wouldn’t recommend shutting those off. But - making adjustments to where automode is shooting for has been helpful.
Good luck!!

Use the “Audio Option” screen to help quiet the device while sleeping—once in the screen, click down to “All Sensor Alerts”, then down to Begin. From there, be sure to continue on the next screen (it will pop up) & click Save. This will help to SHUT the machine up, although it will still alert if you go too low or too high :woozy_face:

Thank you Karen. I will try that tonight.

Thx deidre for your reply. I’ve tried shutting off the alarms, but to no avail. It still would wake me up when it maxed out or minimal delivery or when it wanted to remind me to change my infusion line soon ( 2 days too soon).

Elizabeth, can you change your base rate for night, to deliver less insulin in the early AM? I have run into this problem recently also. Decided that when I am supposed to be asleep, my brain isn’t and since the brain only uses sugar as it’s fuel, I seem to burn a lot of sugar at night if I am doing too much thinking you might want to eat something before bed. When I go to bed I try not to worry and I know especially now that is a difficult thing to do, your options are Lower your insulin at night, try to control your thoughts, eat before bed I am serious about the brain fuel, had a serious skin problem at one time and the Doc told me that I was blocking the healing my body was trying to do by thinking too much when I was supposed to be sleeping, learned how to meditate. worked quite well. Type 1 for 66 years. Hope this helps. Bye Jan PS> Try to keep my BS above 140 at night .

I’ve been using the 670G for one year and I really appreciate the control it gives me.

The 670G has one basal rate which was determined by you and your endocrinologist. It sounds like you are are waking up with a dangerous BG. This needs immediate attention by your health care provider.

There are only three things you can control with the 670G. 1. Insulin sensitivity 2. Carb ratio and 3. Basal rate. Unlike other pumps, the single basal rate of the 670G in combination with micro boluses from auto mode theoretically keep your BG in check.

It sounds like one of these three things need to be altered. I would suggest contacting your health care provider for guidance. They may recommend going back to manual mode for a short time to capture a week of data to guide these decisions. If you are turning off auto mode selectively, you are not using your pump to its full advantage.

If you are getting unwanted or unnecessary alerts, check your pump and turn off alerts that apply. The maximum and minimum delivery alerts are important. You need to analyze them to determine why you are getting them. You may have Just under or over bolused.

Wearing a pump is hard. It’s frustrating and it does not always go smoothly. However, it is also really wonderful when it works properly. The 670G is a huge improvement over the previous model and the new one will be even better.

If your endocrinologist is not responsive, seek a new one. You are the consumer.