'Real-world' Benefit Shown for FreeStyle Libre Glucose Monitor

Miriam E Tucker

February 21, 2017

Use of the novel FreeStyle Libre glucose monitoring system (Abbott) leads to improved glycemic control among people with diabetes, new real-world data indicate.

Findings from deidentified data for more than 50,000 FreeStyle Libre users were presented last week at the Advanced Technologies and Treatment for Diabetes (ATTD) 2017 Congress in Paris by Ramzi Ajjan, MD, associate professor of diabetes and endocrinology at the University of Leeds, United Kingdom.

The FreeStyle Libre system consists of a glucose sensor inserted into the back of the upper arm for up to 14 days and a scanner that users wave over the sensor to obtain readings. Like a conventional continuous glucose monitor (CGM), it measures interstitial fluid glucose levels in real time.

However, it offers the advantages of longer sensor wear, no requirement for calibration, and lower cost. On the other hand, it doesn't have an alarm for users for low and high glucose values.

"It's very different from CGMs. It's a completely different kind of device...a revolution in testing," Dr Ajjan told Medscape Medical News.

The FreeStyle Libre system was licensed in Europe in 2014 and is currently available in over 30 countries and being used by more than 250,000 people living with diabetes.

It is under review by the US Food and Drug Administration, which has already approved a blinded professional-use version of the system for healthcare professionals

The More Scans, the Better the Control

The new data comprise over 400 million individual glucose measurements from 50,831 FreeStyle Libre readers — representing the number of individual users who agreed to have their anonymous data uploaded — scanned over a total of 279,446 sensors. No personal information was available about the patients, such as diabetes type or whether they were using insulin pumps or injections, but likely a high proportion had type 1 diabetes, Dr Ajjan noted.

Overall, the patients performed an average of 16.3 scans per day. When divided into 20 equally sized groups by scan rate (2542 in each), HbA 1c dropped from 8% in the group with the lowest scan rate (4.4 times/day) to 6.7% for those with the highest scan rate (48 times/day).

At the same time, as scan rates increased, hypoglycemia rates below 70, 55, and 45 mg/dL dropped by 15%, 40%, and 49% (all P < .001) and time spent with glucose levels above 180 mg/dL decreased from 10.4 to 5.7 hours/day (P < .001), while time in the range of 70 to 180 mg/dL improved from 12.0 to 16.8 hours/day (< .001).

These data mirror those of a previous randomized clinical trial of 328 well-controlled type 1 diabetes patients, published in September 2016 (Lancet 2016;388:2254–2263). Additional positive data in both type 1 and type 2 diabetes patients were presented the same month at the European Association for the Study of Diabetes meeting in Munich.

"There is now substantial evidence from both real-world usage and clinical studies that reaffirms the powerful impact of FreeStyle Libre," said Jared Watkin, senior vice president, Diabetes Care, Abbott, in a company press release.

"FreeStyle Libre is changing how diabetes has been managed for decades, with one simple swipe. Most important, we're doing that by empowering patients with the information that they need to take action themselves, helping people living with diabetes live fuller, healthier lives."

Feedback Has Been "Very, Very Positive"

Dr Ajjan told Medscape Medical News: "From my point of view as a clinician, if we step away from the trials…I was initially skeptical about this, but the feedback I'm getting is very, very positive.

"People like the device, they like the simplicity of the device, the data, and the way the data are produced. People say 'I understand my diabetes better.' This has helped greatly their management," he noted.

Asked to comment, David T Ahn, MD, an endocrinologist and diabetes technology expert at the University of California, Los Angeles, who was not involved in the FreeStyle Libre trials, told Medscape Medical News : "What I found fascinating in the study is that these people are checking their sugars 16 times a day, which is unheard of. That shows that if you remove a barrier to viewing your blood glucose, patients are more than willing to learn more about their diabetes and get a better sense of where things are....They're not lying when they say finger sticking hurts or is inconvenient."

Which Patients Will FreeStyle Libre Benefit Most?

Dr Ajjan sees the FreeStyle Libre as beneficial for any patient who takes multiple daily insulin doses, regardless of type.

"Type 2 patients on multiple daily injections are no different from type 1, in terms of both hypo- and hyperglycemia," he pointed out, adding that the risk of hypoglycemia may be greater among older type 2 diabetes patients in whom it can lead to falls or heart attacks.

For Dr Ahn, the type 2 diabetes population is the likely primary market for the FreeStyle Libre. "For the insulin-requiring type 2 patient, checking their sugar is a real struggle.…I think for type 2s it could be a real hit," he proffered, adding, "I think the real issue will be cost and insurance coverage."

For type 1 patients, however, Dr Ahn sees a more limited role for the FreeStyle Libre.

"The loss of passive alarms is a pretty big trade-off. Detecting hypoglycemia, especially for those with hypoglycemic unawareness, plays a major role in the benefit of CGM for type 1 patients....The fact that the Libre lacks alarms is a significant disadvantage for a lot of type 1s," he observed.

What Will It Cost, and Will It Be Covered?

Cost and reimbursement are likely to play a major role in how widely the FreeStyle Libre is embraced in the United States, at least. At the time of the current study, in 2015, the majority of users were paying out-of-pocket for the system.

In Europe, the annual cost for one reader and 26 sensors (sensors have to be replaced every 2 weeks) is approximately €1600 (about US $1700 and £1370 as of February 16, 2017), according to Abbott spokesperson Vicky Assardo.

That price is significantly less than conventional CGM, but a bit more than blood glucose monitoring, she told Medscape Medical News, noting that "long term, we look at the value that the product will provide to the customer over time — the value that comes from unlimited testing leading to improved glucose levels and therefore the potential for improved diabetes outcomes."

Today, the FreeStyle Libre is either fully or partially reimbursed in more than 12 countries, and Abbott is currently "actively pursuing reimbursement" in the UK's National Health Service (NHS), according to Ms Assardo.

Dr Ajjan said, "Realistically, we have to use it in selected patients initially and then hopefully the price will come down and we can use it in a broader group of patients."

Dr Ajjan received research support and honoraria from Abbott. Ms Assardo is an employee of Abbott. Dr Ahn has no relevant financial relationships.

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Advanced Technologies and Treatment for Diabetes 2017 Congress; February 16, 2017; Paris, France. Presentation OPO1

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