Is the Consensual Threshold for Defining High Glucose Variability Implementable in Clinical Practice?

Diabetes Care. 2021 Jul;44(7):1722-1725. doi: 10.2337/dc20-1847. Epub 2021 Jun 7.


Objective: Estimating glycemic variability (GV) through within-day coefficient of variation (%CVw) is recommended for patients with type 1 Diabetes (T1D). High GV (hGV) is defined as %CVw > 36%. However, continuous glucose monitoring (CGM) devices provide exclusively total CV (%CVT). We aimed to assess consequences of this disparity.

Research design and methods: We retrospectively calculated both %CVT and %CVw of consecutive T1D patients from their CGM raw data during 14 days. Patients with hGV with %CVT >36% and %CVw ≤36% were called the "inconsistent GV group".

Results: A total of 104 patients were included. Mean ± SD %CVT and %CVw were 42.4 ± 8% and 37.0 ± 7.4% respectively (P < 0.0001). Using %CVT, 81 patients (73.6%) were classified as having hGV, whereas 59 (53.6%) using %CVw (P < 0.0001) corresponding to 22 patients (21%) in the inconsistent GV population.

Conclusions: Evaluation of GV through %CV in patients with T1D is highly dependent on the calculation method and then must be standardized.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Blood Glucose
  • Blood Glucose Self-Monitoring*
  • Diabetes Mellitus, Type 1*
  • Glycated Hemoglobin / analysis
  • Humans
  • Retrospective Studies


  • Blood Glucose
  • Glycated Hemoglobin A

Associated data

  • figshare/10.2337/figshare.14461800