Lancet Publishes Results of Abbott's Flash Glucose Monitoring System

The trial showed use of the flash glucose monitoring system dramatically reduced the number of finger sticks while significantly reducing hypoglycemia, including at night.

The journal Lancet today published results of the IMPACT trial, which found that Abbott’s Freestyle Libre investigative flash glucose monitoring (FGM) system decreased hypoglycemia in patients with type 1 diabetes (T1D) an average of 74 minutes per day, for a 38% reduction compared with a control group. Results were first presented at the 76th Scientific Sessions of the American Diabetes Association (ADA) in New Orleans.

Led by Jan Bolinder, MD, of the Karolinska Institutet, researchers enrolled 328 patients with well-controlled T1D in 23 diabetes centers across Europe. After screening and baseline steps, the patients were divided into intervention and control groups. All had T1D at least 5 years and had been on their insulin regimen at least 3 months. Of note, patients were excluded if they had already used a continuous glucose monitoring device or were considered unaware of when they were experiencing hypoglycemia, a condition that becomes more common as persons with T1D age and progress with the disease—and for which glucose monitoring becomes more critical.

The FGM system differs from CGM technology in several ways; notably, the FGM is factory calibrated, so finger sticks are reduced even more dramatically than with CGM. The sensor is designed to last 14 days. The lack of finger sticks did not reduce the amount of information available to patients; monitoring increased to an average of 15 scans per day.

Other key results for the intervention group include:

  • A 40% reduction in the time spent in hypoglycemia at night, defined as 11 pm to 6 am. Hypoglycemia (defined as 3.9 mmol/L or 70 mg/dL) at night is of greatest concern to those with T1D
  • A 50% reduction in serious hypoglycemia, or <55 mg/dL
  • At 6 months, glycated hemoglobin (A1C) levels were unchanged at 6.7%, but the group was well-controlled at the start of the trial
  • Routine finger sticks were reduced by 91%

Of note, FGM does not make use of the alarms that are well-known to patients who use CGM. In an accompanying editorial, Hood Thabit, MD PhD; Lia Bally, MD; and Roman Hovorka, PhD, wrote, “The device does not provide low or high glucose alarms, but this reduction in functionality has surprisingly little effect on user acceptability.”

Indeed, the quality-of-life aspects of the technology have received good reviews from diabetes advocacy groups, such as diaTribe, which wrote about the results at ADA.

The editorial writers suggest that the exclusion of poorly controlled patients may limit how much the results can be generalized to the T1D population, but they note that adherence was high, which may make FGM a good option in populations for whom alarms and finger sticks would deter to close monitoring of blood glucose levels. Advocates in the T1D community who have opposed moves by payers to steer patients toward a single manufacturers say limiting choices ignores that fact that diabetes is different for every person, and that maintaining choice is critical.

Abbott Diabetes Care funded the study.


1. Bolinder J, Antuna R, Geelhoed-Duijvestijn P, Kroger J, Weitgasser R. Novel glucose-sensing technology and hypoglycaemia in type 1 diabetes: a multicentre, non-masked, randomised controlled trial [published online September 12, 2016]. Lancet. 2016; S0140-6736(16)31535-5.

2. Thabit H, Bally L, Hovorka R. Available at a flash: a new way to check glucose [published online September 12, 2016]. Lancet. S0140-6736(16)31582-3.