Endocrine Abstracts

Background: Type 1 Diabetes Mellitus (T1DM) is associated with significantly increased morbidity/mortality due to chronic hyperglycaemia complications and hypoglycaemic events. T1DM affects many paediatric patients (Prevalence 229.3/100,000, incidence 31.1/100,000 in ages 0-15years, peak incidence 10-14). T1DM also places a burden on parents/families, (30% reduce work hours, 11% leave employment, and 64% report disrupted sleep). Long term outcomes depend on glycaemic control and monitoring. Finger prick testing (FPT) is gold standard, but technological advances have allowed a shift in monitoring toward continuous glucose monitoring devices (CGM). Patients using CGM achieve lower HbA1c, reducing eventual complications of chronic hyperglycaemia. Device accuracy is therefore vital to successful T1DM management.

Methods: Bedford Paediatric Diabetes clinic undertook a study recording paediatric T1DM patient/carers’ impressions of their CGM device through a questionnaire assessing device accuracy compared to FPT and identifying barriers to CGM use (MCQ/free text questions).

Results: Of 98 survey respondents, 49% reported ≥1mmol discrepancy between CGM and FPT when device reported normal capillary blood glucose (CBG) (4-10mmol/L). This discrepancy was higher when the CGM reading was outside of this range (hypo/hyperglycaemic) with 65.9% patients reporting ≥1mmol discrepancy (statistically significant P=0.05), and 71% of these patients reporting ≥1.5mmol (P=0.01) discrepancy. Within normal CBG, 62% of Libre 2 users reported ≥1mmol discrepancy vs 42% of Dexcom users. This discrepancy increased when CGM reported CBG<4/>10mmol/L, with 73% of Libre 2 users reporting ≥1mmol discrepancy vs 48% of Dexcom users and 64% of Libre 2 users reporting >1.5mmol discrepancy vs 24% of Dexcom users. Differences in device accuracy were statistically significant in all comparisons (P=0.01). Patient reported barriers to CGM use were: device accuracy (22.4%), skin reactions (20%) and appearance/body image concerns (17%).

Conclusion: CGM is less accurate than gold standard (FPT), with the discrepancy being worse at extremes of CBG. There is notable differences in accuracy between Dexcom and Libre, with Dexcom clearly perceived as more accurate. This study highlights patient perspectives of efficacy of CGM. Further studies are needed to assess quantitative impact on diabetes burden to ensure NHS recommendations for devices maximally improve diabetic control and quality of life.