medwireNews: People with type 1 diabetes and poor glycemic control benefit from use of intermittently scanned continuous glucose monitoring (isCGM) versus self-monitored blood glucose (SMBG), report the Flash UK investigators.
During the 24-week trial, average glycated hemoglobin (HbA1c) levels fell from 71.6 to 62.8 mmol/mol (8.7 to 7.9%) in people randomly assigned to use isCGM (ie, flash glucose monitoring) and from 69.9 to 67.7 mmol/mol (8.5 to 8.3%) in those using SMBG, giving a significant 5.35 mmol/mol difference favoring isCGM.
Besides focusing on people with initially poor glucose control, Flash UK is the first randomized trial of the FreeStyle Libre 2 device. This still requires the user to scan it to obtain glucose readings, but it now communicates automatically with the app to the extent required to trigger an alarm if glucose levels stray outside of the target glucose range. The trial funding came from Diabetes UK, rather than from Abbott.
The investigators presented the findings this week at the 2022 Diabetes UK Professional Conference. Introducing the session, Emma Wilmot (University Hospitals of Derby and Burton NHS Foundation Trust) explained that Flash UK was designed to address concerns from the UK’s National Institute for Health and Care Excellence (NICE) that the efficacy of isCGM has to date been demonstrated only in people who already had relatively well-controlled blood glucose.
Flash UK therefore included only people with HbA1c levels of 7.5% (58.5 mmol/mol) to 11% (97.0 mmol/mol). Indeed, a quarter of the 156 trial participants had levels of 9% or higher (≥75.0 mmol/mol).
During the panel discussion, co-investigator Lalantha Leelarathna (Manchester Diabetes Centre, UK) noted that the team excluded people with HbA1c higher than 11% because of the high likelihood that such people “have other factors that are contributing to high A1c that are maybe not amenable to flash intervention.”
He added that further increasing the entry HbA1c range would increase the standard deviation and therefore require more participants to achieve the same statistical power.
The team also excluded people with complete loss of hypoglycemia awareness or multiple recent episodes of severe hypoglycemia, as these people may benefit more from real-time CGM. The included participants were an average age of 43.5 years, 55.8% were men, almost all (97.4%) were White, and 28.2% were using an insulin pump. None were current users of glucose-sensing technologies.
A total of 72 and 69 people in the isCGM and SMBG groups, respectively, were included in primary analysis, of whom 36.1% versus 21.7% achieved HbA1c of 7.5% or below by week 24, which was again a significant difference favoring flash glucose monitoring. Also, significantly more people using isCGM than SMBG achieved HbA1c reductions of at least 0.5% or 1.0%, and some of these differences were seen from week 12.
Blinded CGM data at baseline and from weeks 22 to 24 revealed that people in the isCGM group were spending around 2 hours/day more within the blood glucose range of 3.9–10.0 mmol/L (70–180 mg/dL). This improvement came via reductions in time spent in both hyperglycemia and hypoglycemia.
The researchers also reported that people assigned to flash monitoring had increased treatment satisfaction with no change in diabetes distress. The intervention comfortably met the NICE threshold for cost-effectiveness.
Rounding up the trial’s findings and implications, Leelarathna concluded: “Based on this study, as well as previously published data, we call for universal funding of flash glucose monitoring in all adults with type 1 diabetes.”
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