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Benefits of CGM’s for Type 1 Patients

Real-time monitoring produces significant long-term improvement in HbA1c.

New research presented at EASD shows that use of real-time continuous glucose monitoring (CGM) produces significant long-term improvement in HbA1c among adult patients with type 1 diabetes, regardless of whether they use insulin pumps or multiple daily insulin injections (MDI), new research shows.

Two-year data from the Comparison of Different Treatment Modalities for Type 1 Diabetes Including Sensor-Augmented Insulin Regimens (COMISAIR) study were presented September 11, 2017  at EASD.

They compared changes in HbA1c among 65 patients using one of four treatment regimens: insulin pumps with or without real-time CGM (n = 15 and 20, respectively) and MDI with or without real-time CGM (12 and 18, respectively), with all patients using self-blood glucose (fingerstick) monitoring.

At two years, use of CGM, with or without the pump and with MDI, provided “significant, comparable, and stable improvement of HbA1c, according to researchers. In fact, the combination of CGM and MDI was actually more effective than insulin-pump therapy alone in reducing HbA1c.

What was really important in this study was that this 2-year data is the longest ever for a trial of real-time CGM. And it’s not so important how insulin is injected, said researchers. What’s more important is how patients monitor their glucose.

The second year of data further supported the CGM The 1-year COMISAIR data were published in September 2016 (Diabetes Technol Ther. 2016;18:532-538). At the study start, all patients received a 4-day training program similar to the UK’s Dose Adjustment for Normal Eating (DAFNE), in which they received instructions in timing and dosing of preprandial insulin, prevention of hypoglycemia, carbohydrate counting, and bolus calculations. Patients could then choose the treatment group they preferred.

Of the 65 enrolled, 60 completed 2 years of the study, with all of the patients using CGM using it more than 70% of the time. At 2 years, HbA1c levels in the no-CGM groups had not changed significantly, from 8.4% to 8.0% for the pump group (P = .07) and 8.3% to 8.1% in the injection group (NS).

However, both real-time CGM groups experienced significant HbA1c reductions, from 8.2% to 7.1% in the pump/CGM group and 8.5% to 7.2% in the MDI/CGM group (both P < .001).

More than half (54%) of the two CGM groups achieved an HbA1c below 7% at 2 years, compared with 13% of the no-CGM groups. At the same time, the proportion of time spent in hypoglycemia was reduced from 8% to 6% (P < .01) in the two CGM groups, with no significant difference between them.

There were no episodes of severe hypoglycemia with real-time CGM, vs two in each of the no-CGM groups. However, there was one episode of ketoacidosis in the pump/CGM group. Glycemic variability was also significantly reduced in the two CGM groups (P < .05), with no difference between them.

Dr. Jan Šoupal offered some practical suggestions for success in using real-time CGM with MDI: Patients should be willing to take more bolus doses to correct high blood glucose levels, use short-acting insulin for boluses — including pens that can deliver half units for lean patients — and consider different types of basal insulins from those the patient may already be using.

In addition, for those with pumps or MDI, he advised that careful attention be given to the appropriate CGM settings for high- and low-glucose alarms and target ranges in order to avoid “alarm burnout.” This can be tricky, he noted, since alarm settings that are “too benevolent” can impair glycemic control, but so can excessive alarms.

“We should not forget there is an important psychological aspect.…In clinical practice, if the patient has not improved HbA1c in 3 or 6 months from real-time CGM initiation, this is one of the first things I check,” he said.

Overall, he said, the choice of treatment — pump vs MDI, real-time CGM or just fingerstick monitoring — must be based on individual characteristics, including physical-activity level, hypoglycemia awareness, and personal preference about wearing devices.

“There is a huge variety of patients with type 1 diabetes.…Individualization is crucial.”

Practice Pearls:

  • Real-time continuous glucose monitoring (CGM) produces significant long-term improvement in HbA1c among adult patients with type 1 diabetes.
  • Both real-time CGM groups experienced significant HbA1c reductions, from 8.2% to 7.1% in the pump/CGM group and 8.5% to 7.2% in the MDI/CGM group
  • Diabetes 101 Pump vs MDI, real-time CGM or just finger-stick monitoring — must be based on individual characteristics

References:

Sept 11, 2017 EASD

Šoupal J. CGM combined with either MDI or CSII is superior to standalone MDI or CSII in T1D: 2 years of follow-up in the COMISAIR study [Dexcom-sponsored industry symposium]. European Association for the Study of Diabetes 2017 Annual Meeting. September 11, 2017. Lisbon, Portugal.