Flash glucose monitoring can increase the time within which the blood glucose level is in the range of 70 to 180 mg/dl compared to blood glucose self-monitoring, and shorten the time with hypoglycemia. This was shown in the LIBERATES study in patients with Type-2 diabetes mellitus after acute coronary syndrome (ACS). The results were presented at the virtual annual meeting of the European Association for the Study of Diabetes in September 2020.
Flash glucose monitoring systems, such as the Freestyle-Libre system continuously measure sugar levels in the tissue, while the fingertip blood glucose self-monitoring system provides only a current sugar level as an isolated snapshot. Continuous measurement makes it easier to understand the effects of food, physical activity, or medication.
For this purpose, a sensor is attached to the back of the upper arm, which continuously measures and stores sugar values in the tissue with a probe of about 5 mm long that is placed under the skin. The sugar values can be read by the sensor using a reader.
The LIBERATES study (Glucose control in patIents with diaBEtes following myocaRdial infArction: The role of a novEl glycaemic monitoring) examined this new method of monitoring glucose levels compared to glucose self-measurement in patients with type-2 diabetes who had suffered a heart attack. This group of patients was selected because their life expectancy is significantly reduced and they have a high risk of recurrence.
141 people were enrolled in the trial within 5 days of having a heart attack. The control group consisted of 72 subjects, which used the usual self-monitoring blood glucose device (SMBG) but also wore a Freestyle-Libre system for research purposes without knowing its values. The intervention group (n = 69) only used the Libre system.
The group with the freestyle Libre system was asked to read the respective sensor at least every 8 hours, otherwise, the data would be overwritten. Over the entire study period of 90 days, the subjects scanned the system values on average six times a day.
The study’s primary endpoint was a time in the range of 70 to 180 mg/dl glucose concentration from day 76 to day 90, based only on the values from the days when at least 80% of the data had been recorded.
The median age of the test subjects was 63 years, 73% were men. This high proportion of men can be explained by the fact that the patients had to have suffered a heart attack when they enrolled in the trial. The BMI was 31 kg/m². On average, the participants had been suffering from diabetes for 13 years.
20% also had neuropathy, 19% retinopathy. Coronary heart disease was present in 27% of cases. 55% were treated with insulin, 45% with sulfonylureas. 86% received further blood sugar-lowering therapies. Antihypertensives were used in 98% of cases, anticoagulants in 99% of cases, and lipid-lowering drugs in 93% of cases, so this was a well-treated group.
The demographic parameters of the two groups were well comparable.
The Bayesian analysis showed that subjects in the intervention group had an additional 17min/24h in the predefined blood glucose range of 70-180 mg/dl (time in range or TIR) compared to the SMBG group. However, this was not statistically significant.
In a frequentist analysis, flash monitoring led to an additional 48min/24h TIR, but this was not statistically significant either.
The duration of hypoglycemia was significantly reduced by 80 minutes between day 76 and 90 when flash glucose measurements were taken, mainly due to less hypoglycemia in patients taking sulfonylureas. The HbA1c value fell by 0.6 percentage points in both groups.
The authors concluded that flash glucose monitoring can successfully contribute to lowering HbA1c levels in type-2 diabetics after myocardial infarction and that it also further reduces the risk of hypoglycemia compared to SMBG.
Ajjan R, Improving glucose control in patients with diabetes following myocardial infarction: The role of a novel glycaemic monitoring strategy. Virtual EASD Annual Meeting 2020 S11