Contributor: Dr. Staci-Marie Norman, PharmD, CDE

This month I want to talk to you about the best thing since sliced bread - continuous blood glucose monitoring! I know you are probably saying “Really? Best thing since sliced bread?” so let me give you the back story for this proclamation.

My father has had type 2 diabetes for about 13 or 14 years. He had been well managed on lifestyle modifications and pioglitazone (an oral diabetes medication). About four years ago, he was diagnosed with an autoimmune lung disease that could only be treated through a lung transplant. On October 12, 2018, my father received a new lung! Believe me, this is a miracle procedure and has improved my father’s quality of life and hopefully, length of life. But there are some downsides. Probably the biggest downside is going from one daily medication to nineteen medications spaced out over four times per day. And because of the potential side effects and drug interactions with the anti-rejection medications, he had to be taken off the pioglitazone and very quickly had to learn about basal and bolus insulin regimens and all of the blood glucose monitoring that comes with intensive insulin dosing. My father has been doing a super job and slowly but surely is getting the hang of all these “new normals”. Being the good CDE daughter, I suggested he try continuous blood glucose monitoring using the FreeStyle Libre. Here is where the proclamation comes from - my father is over the moon happy with not having to prick his finger 4-6 times per day! You saw that coming, right!? But, he also started telling me about how he is able to track where his blood sugar is going and how it reacts to what he eats or the exercise that he has done. He even started telling me about how it is helping him better understand how his mealtime insulin works (he has a set dose plus correction) and why I would get so upset with him when he would take his mealtime insulin and then not eat!! Talk about a change! So, want to learn more about this type of blood glucose monitoring?

There are currently four continuous blood glucose monitors on the market. I’m going to give you a quick overview of each monitor and their similarities and differences.

DexCom: Has two models G5 and G6

• Equipment: Both have a receiver, transmitter, and sensors. The receiver is a one-time investment, the transmitter has to be replaced every three months, and the sensors are what are attached subcutaneously on either the arm or abdomen. The G5 sensor is good for seven days and the G6 sensor for ten days.
• Calibration: The G5 requires two fingersticks per day to calibrate; the G6 requires no fingersticks but has a calibration option to improve accuracy. There is a 2-hour “warm-up” period after placing a new sensor.
• Software: Both have some ability to have information shared to other devices (smartphones) and other people (parents, doctors, etc.) and Tandem x2 insulin pump. Clarity companion app automatically uploads data and generates reports.
• Alerts: Realtime alerts for high, low, rate of change, predictive urgent low. “Always sound” feature will sound alters when a phone is on silent. Alerts can also be customized for different times and days.
• Cost: Both the G5 and G6 have an initial investment of around $500 for the receiver. The annual cost for the transmitters and receivers is approximately $4800 for the G5 and $6000 for the G6. These are cost without insurance coverage.

FreeStyle Libre:

• Equipment: A receiver and 14-day sensors.  The receiver requires up to a 3-hour charge every seven days.
• Calibration: No fingersticks requires and no calibration option. There is a 1-hour “warm-up” period
• Software: Can use either the receiver or a smartphone to see data, with readings updated every 60 seconds and recorded to memory every 15 minutes. The sensor can store data up to 8 hours if not read. The “reader” will accept notes or events that are added by the user. Data can also be shared with others.
• Alerts: No real-time high or low alerts currently.
• Cost: Most inexpensive with one-time sensor cost of approximately $70 and annual sensor cost of approximately $1300 without insurance.

Medtronic Guardian 3:

• Equipment: Your smartphone with the Guardian Connect app, rechargeable transmitter, and seven-day sensors. The transmitter requires 10 to 20 minutes of charge every seven days.
• Calibration: Requires a fingerstick calibration every 12 hours, it will stop generating data if calibration is not done. There is a 2-hour “warm-up” period.
• Software: Uses Guardian Connect app on a smartphone or integrated into the Medtronic Guardian3- 670G pump. There is real-time sharable data through the Guardian Connect app. It will also generate reports through the Sugar IQ companion app.
• Alerts: There are real-time alerts for high, low, rate of change, or predictive low/high excursions. Alerts can be customized for different times and days. Vibration and audio alerts are limited to the phone’s options.
• Cost: Approximate annual cost of the sensors is $3400 before insurance.

Be aware that all of these continuous blood glucose monitors have to use adhesives to keep the sensor and transmitter in place for the 7-14 days. Each has different adhesive overlays, but you may have to experiment with different overlays to get the one that works best for you. Because of the extended time the FreeStyle Libre sensor is in place, the biggest complaint has been the adhesive giving way. One that my dad has tried and liked is the Skin Grip over-patch that he found on Amazon, but there are many out there.

The other warning is that you shouldn’t give up your trusty old blood glucose meter, keep it as a backup because if your blood glucose is changing rapidly (say trending towards hypoglycemia) your fingerstick reading will still be more accurate in that situation.

So, are you ready to try the “best thing since sliced bread?”

Dr. Staci-Marie Norman, PharmD, CDE received her bachelors from Purdue University (’94) and her Doctor of Pharmacy from the University of Oklahoma (’96). In 2000 Dr. Norman added to her credentials by becoming a Certified Diabetes Educator. She is currently the Clinical Coordinator and staff pharmacist for Martin’s Pharmacy. Dr. Norman is a national faculty member for the American Pharmacist Association, teaching certificate programs in both diabetes and cardiovascular disease. She serves on the advisory board that oversees development and revision of these programs. Along with teaching and development responsibilities for APhA, Dr. Norman serves as a peer reviewer for research grants and publication submission. Dr. Norman has also spoken for Abbott, Bayer, Lilly, Mannkind, and Lifescan as a diabetes specialist.