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CGM vs Flash Glucose Monitoring — RACP Adult Medicine MCQ

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EasyEndocrinologyCGM vs Flash Glucose MonitoringRACP Adult Medicine

A 30-year-old man with type 1 diabetes is using flash glucose monitoring (FreeStyle Libre). He checks his glucose 8 times daily but still has significant glycaemic variability (TIR 45%, time below range 64 mmol/mol). HbA1c is 66 mmol/mol. He is on MDI (basal-bolus insulin). He has good carbohydrate counting skills. What is the most appropriate step to improve glycaemic control?

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Correct answer: E — Switch to real-time CGM with alerts (e.g., Dexcom G7)

Flash glucose monitoring (FGM — FreeStyle Libre) provides glucose data but does NOT have predictive alerts for impending hypo/hyperglycaemia. Real-time CGM (rtCGM — Dexcom G7, Medtronic Guardian) provides continuous data WITH predictive alerts (high/low glucose alarms) that reduce hypo and improve TIR. GOLD/DIAMOND trials showed rtCGM reduces HbA1c by ~0.4% and hypoglycaemia in T1DM on MDI. The alerts function is the key differentiator. Consider further upgrade to sensor-augmented pump or HCL system.

Reference: ADS – 2024 – CGM; NICE 2024; GOLD/DIAMOND Trials