Clinical Studies

Clinical Implications of Real-Time and Intermittently Scanned Continuous Glucose Monitoring

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This paper reviews the features and available evidence supporting use of both real-time continuous glucose monitoring (rtCGM) and intermittent scanning CGM (isCGM), offering guidance for patient selection for each type of system. RtCGM systems (such as those provided by Dexcom) automatically and continuously provide real-time glucose data to a display device and actively alert the user to lows and highs. IsCGM users must make a conscious decision to scan the sensor to obtain glucose data and do not feature proactive glucose alerts.*

RtCGM is suggested for persons who:

IsCGM is suggested for:

  • Have increased hypoglycemia risk (all patients with type 1 or type 2 diabetes)
  • Have hypoglycemia unawareness (should use rtCGM systems with real-time data sharing capabilities)
  • Experience frequent hypoglycemia (even those with sufficient hypoglycemia awareness)
  • Experience frequent nocturnal hypoglycemia
  • Are physically active
  • Want to use insulin pumps systems with predictive low glucose suspend
  • Have high A1C
  • May benefit from real-time data sharing (e.g., pediatrics, older persons, travelers)
  • Desire better control than their current monitoring method/system
  • Type 2 diabetes patients not perform SMBG as needed
  • Those with prediabetes
  • Patients on oral agents only
  • Those on basal insulin when titration is needed


*Abbott’s Freestyle Libre was the only FDA-approved isCGM on the market at the time of article publication; since then the Freestyle Libre 14 day has been approved.

Edelman SV, Argento NB, Pettus J, Hirsch IB. Clinical Implications of Real-time and Intermittently Scanned Continuous Glucose Monitoring. Diabetes Care. 2018;41(11):2265-2274.


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