A randomized controlled pilot study of continuous glucose monitoring and flash glucose monitoring in people with Type 1 diabetes and impaired awareness of hypoglycaemia

Abstract

AimHypoglycaemia in Type 1 diabetes is associated with mortality and morbidity, especially where awareness of hypoglycaemia is impaired. Clinical pathways for access to continuous glucose monitoring (CGM) and flash glucose monitoring technologies are unclear. We assessed the impact of CGM and flash glucose monitoring in a high‐risk group of people with Type 1 diabetes.MethodsA randomized, non‐masked parallel group study was undertaken. Adults with Type 1 diabetes using a multiple‐dose insulin‐injection regimen with a Gold score of ≥ 4 or recent severe hypoglycaemia were recruited. Following 2 weeks of blinded CGM, they were randomly assigned to CGM (Dexcom G5) or flash glucose monitoring (Abbott Freestyle Libre) for 8 weeks. The primary outcome was the difference in time spent in hypoglycaemia (below 3.3 mmol/l) from baseline to endpoint with CGM versus flash glucose monitoring.ResultsSome 40 participants were randomized to CGM (n = 20) or flash glucose monitoring (n = 20). The participants (24 men, 16 women) had a median (IQR) age of 49.6 (37.5–63.5) years, duration of diabetes of 30.0 (21.0–36.5) years and HbA1c of 56 (48–63) mmol/mol [7.3 (6.5–7.8)%]. The baseline median percentage time < 3.3 mmol/l was 4.5% in the CGM group and 6.7% in the flash glucose monitoring. At the end‐point the percentage time < 3.3 mmol/l was 2.4%, and 6.8% respectively (median between group difference −4.3%, P = 0.006). Time spent in hypoglycaemia at all thresholds, and hypoglycaemia fear, were different between groups, favouring CGM.Conclusion CGM more effectively reduces time spent in hypoglycaemia in people with Type 1 diabetes and impaired awareness of hypoglycaemia compared with flash glucose monitoring. (Clinical Trial Registry No: NCT03028220)

A Type 1 diabetes technology pathway: consensus statement for the use of technology in Type 1 diabetes

“…These improvements are of a similar magnitude to those seen in studies of CSII alone [34,35]. Notably, in a head-to-head study conducted in people with impaired awareness of hypoglycaemia, CGM with alarms had a greater impact on hypoglycaemia risk than flash GM [37]. Notably, in a head-to-head study conducted in people with impaired awareness of hypoglycaemia, CGM with alarms had a greater impact on hypoglycaemia risk than flash GM [37].…”

Flash forward: a review of flash glucose monitoring

“…2). Users performed an average of 16.3 scans per day [median (interquartile range) 14 (10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20)]. Estimated HbA 1c levels decreased (P<0.001) as the scan rate increased, from 64 mmol/mol (8.0%) to 50 mmol/mol (6.7%) from the lowest (mean 4.4 scans/day) to the highest (mean 48.1 scans/ day) groups, while time below 3.9, 3.0 and 2.5 mmol/l decreased by 15%, 40% and 49%, respectively (all P<0.001).…”

“…In this instance, blood glucose should be relied on. Dexcom G5 real-time CGM is likely to be superior to FreeStyle Libre for reducing hypoglycaemia in those with impaired awareness [12].…”

“…The lack of alarms is a concern for those with impaired awareness of hypoglycaemia who are likely to be dependent on alarms to alert them to impending hypoglycaemia [12].…”

Comparison of continuous and flash glucose monitoring in Type 1 diabetes: methodological inconsistency precludes hypoglycaemia conclusions

“…Recently Diabetic Medicine , Reddy and colleagues published the original article ‘A randomized controlled pilot study of continuous glucose monitoring and flash glucose monitoring in people with Type 1 diabetes and impaired awareness of hypoglycaemia’ . In the randomized, non‐masked parallel group study, 40 adults with Type 1 diabetes using a multiple‐dose insulin‐injection regimen with a Gold score of ≥ 4 or recent severe hypoglycaemia were randomized to either real‐time continuous glucose monitoring (rt‐CGM; Dexcom G5) or flash glucose monitoring (Abbott FreeStyle Libre) for 8 weeks, following 2 weeks of blinded CGM (Dexcom G4 with 505 software).…”