Real-world implications of hybrid close loop (hcl) insulin delivery system

Clinical trial data demonstrates improved glycemic control with hybrid close loop (HCL) insulin delivery systems, yet limited real-world data exists. Data from the inaugural cohort of patients initiating a HCL system (Medtronic MiniMed™670G, Medtronic Canada, Brampton, ON) at a university medical center was used to examine real-world utilization and glycemic control following a standardized implementation process.

Mean self-monitored blood glucose (SMBG) per day increased from 5.15 baseline to 6.49 at 6 to 12 weeks ( P <.05) with 3.26 sensor calibrations per day. Time-in-auto-mode was 79.3% at 2 weeks and 72.3% at final follow-up, with 82% of patients spending >50% of time in auto-mode. There were 8.2 auto-mode exits over the final 14-day download. Time-in-target was 67.3% in manual-mode, 73.4% at 2 weeks ( P = .09), and 71.7% by 6 to 12 weeks ( P = .06). Hemoglobin A1c (HbA1c) decreased by 0.51% ( P = .02), while total daily dose and % basal did not change. Patients with HbA1c <7.0% (53 mmol/mol) at baseline spent more time-in-target than those with HbA1c ≥7.0% (53 mmol/mol; 78.0% versus 67.5%) despite spending less time-in-auto-mode (66.5% versus 74.8%).


Thanks for the post, Khurt. My results are, thus far, pretty similar, except I am using Omnipod pump. My 2 week results were about 10% more in range than this particular study average. I have only been using it 2 weeks. You probably know that there will be an observational study released eventually with 1,000 participants. They are collecting data now.

I found another study.

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I like the part you put in bold: “Patients with HbA1c <7.0% at baseline spent more time-in-target than those with HbA1c ≥7.0% despite spending less time-in-auto-mode (66.5% versus 74.8%).”

My relation to that:

I’ve had my new endo for a year now.

About 9 months in we got to talking about closed loop systems. She knows me at least a little by now. She told me I would almost certainly not be satisfied with any closed loop system and I would take it out of auto all the time and be doing manual tweaks all the time.

And she’s almost certainly right.

According to my Medtronic 670G, my 14 day averages were:

Time in automode - 95%
Time in target range - 74%
BG average - 151 mg/dl

How do u feel about your stats, Don?

Better than in the past, but trying to improve going forward. However, I now have my own record of how I am achieving my goals which I can review on a daily basis.

Good. Glad to hear it. You really need to drop those numbers some more. Keep up the good work!

Your endo us prescient. I also did the same once I have the 607g for a few months.

For me it is:
Time in Automode: 93%
Time in Target Range: 64%
Average BG: 156 mg/dL