Endocrine Abstracts

Background: For children with congenital hyperinsulinism (HI), detection and avoidance of hypoglycaemia is the cornerstone of clinical management and poses significant demands on families. Standard of care remains intermittent fingerprick monitoring but the lack of predictive information has resulted in continuous glucose monitoring (CGM) increasing in popularity. Accuracy is suboptimal in this group and family feedback identifies various barriers to use. We aimed to undertake the first evaluation of accuracy and patient experience in the recently released Dexcom G7.

Methods: Ten patients using the Dexcom G6 for the previous two months were switched to the Dexcom G7 for a further two months. Using a ContourNextOne glucometer, patients performed at least four fingerprick checks per day and when CGM reported hypoglycaemia <3.5 mmol/L. Families completed a questionnaire regarding the G6 and G7 devices.

Results: Clinical accuracy of the G7 device was better than the G6, with more of the 2036 paired values in Zone A (no risk) on the Hypoglycaemia Error Grid (93% vs 86%, P<0.001 on chi square) and a higher mean hypoglycaemia detection rate (63% vs 37%, P=0.02 on paired t-test). When asked which was more accurate, 62.5% reported the G7 and 25% the G6. The G7 trended towards a lower mean absolute relative difference but was non-significant (21% vs 26%, P=0.2 on paired t-test). Families reported the G7 receiver was an improvement over the G6 with better battery life and smaller size. G7 sensor insertion was reported as less painful than that of the G6 but not as simple to perform. Almost all families (75%) reported that the G7 sensors were more likely to fail and not last the full 10 days.

Conclusion: In our initial evaluation study of the new generation Dexcom G7 CGM device, we identified an improvement in clinical accuracy measures although no difference in point accuracy. Families reported satisfaction with the G7 receiver and reported less pain on sensor changes. However, device utility was significantly restricted by high sensor failure rate requiring more changes and higher costs.