Interpreting the CGM Data

Quick Update: It’s day #6 in National Blog Post Month and the ninth in my exercise streak. At the pool this afternoon, I did three flip-turns; they weren’t pretty, but I did them.

It’s been a while since I talked about where I am with diabetes. I got the data from the CGM trial a while ago, and I spent some time marking up copies of the graphs that the Medtronic rep gave my endocrinologist. It was difficult to draw definitive conclusions from the data because it was full of variability. Hey, that’s diabetes! Nevertheless, here are some of my observations:

  • There is a rise many days, starting at 2-3 AM.
  • Almost every day has a “V” at 11:00AM – noon, a dip ending sharply at lunch.
  • The CGM readings were very spiky.
  • I see a rise after exercise.
  • I over-treated many times.
  • The CGM didn’t catch many big, rapid dips with rebounds (especially during exercise).
  • The first meal has a larger than normal (?) effect.
  • There’s a post-shower bump.
  • My corrective boluses didn’t really work.
  • Often my pump wizard said not to bolus because of insulin on board (IOB), but I really needed it.

The biggest thing I noticed is that my BG levels never really went into the normal range. They started high, went higher after I ate, and then came down to the low end of high. I had previously worried that I was going to have lows (probably because of my experience with NPH) but those worries were more or less unfounded.

Add to these conclusions one feeling I have that I cannot prove definitively. I suspect that my basal rates were too high, leading to an excess of active insulin that masked problems with bolus ratios and timing.

From these observations, I settled on a few actions:

  1. Don’t be such a ‘fraidy-cat about lows.
  2. Do an overnight basal test.
  3. Give a small bolus before disconnecting for my shower.
  4. Bolus 10-15 minutes before meals.
  5. Ask about IOB and “bolus stacking” (which I did).
  6. Get a prescription for CGM sensors.
  7. Only 4-8g for a defensive treat.
  8. Try to do less defensive treating.
  9. Bolus for everything I eat.

Some of these are easier to do, some harder. The overall realization that my blood glucose stays high and that it doesn’t take long for my BGs to rise after eating were very illuminating. It seems to me that my BG readings have been better since I started making these changes. I know that my fasting readings have been inside the target range more often than not. And exercise has been easier, too. And although I’ve been surprised by my A1c on many occasions, I hope to see some improvement because of these changes.

This entry was posted in Data-betes, Diabetes, Life Lessons, NaBloPoMo, NaBloPoMo 2010. Bookmark the permalink.

One Response to Interpreting the CGM Data

  1. Ah, the dreaded overnight basal testing!

    We made a couple of these changes and saw dramatic results as seen in our most A1c. We began pre-bolusing for at least part of our daughter’s meal (she’s six so what she eats varies widely) and increased basals for a few hours overnight.

    I’m afraid we need to do another round of overnight testing soon.

    We don’t have a CGM, but I have to wonder if the data wouldn’t overwhelm me!

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