Frequency of Flash Glucose Monitoring Scans and Hemoglobin A1c in Real Life

Introduction: In patients with type 1 diabetes mellitus (T1D) the relationship between low number of self-monitoring of blood glucose (SMBG) measurements and elevated hemoglobin A1c (HbA1c) levels has been reported. However, the optimal frequency of SMBG has not been defined. Flash glucose monitoring (FGM) is an emerging technology allowing patient with diabetes to measure interstitial glucose concentrations in a non-invasive manner, with patients obtaining more measurements than with SMBG.

Materials and Methods: We collected data from 103 adult T1D patients using FGM technology in real life for at least 28 days. We recorded patients demographics, diabetes duration, type of treatment (CSII or MDI) and we downloaded FGM data to the Abbott Freestyle Libre software, which provides the number of daily FGM scans and estimates of HbA1c based on continuous glucose profile readings. The correlation between median FGM scan frequency over 28 days and the estimated HbA1c was analyzed using Spearman rho. We also computed HbA1c median levels for quintiles of scan frequency and compared them using Kruskal-Wallis test.

Results: A significant correlation was found between median scan Spearman rho was -0.48 (p<0.0001). Moreover, median HbA1c level decreased significantly from the first (3-5) to the third (10-14) quintile of daily scan frequency [from 69 mmol/mol (IQR 62 to 78) to 54 mmol/mol (49 to 50), p#x003C0.0001] and remained unchanged thereafter, i.e., from the third to the fifth (24-50) quintile daily scan frequency [from 54 mmol/mol (49 to 50) to 53 mmol/mol (45 to 56), p=0.7638].

Conclusions: In T1D patients we confirmed that frequent measurements of interstitial glucose benefits glucose control in real life conditions.The maximum benefit in term of HbA1c decrease is obtained between 10 to 14 scans daily, a number of glucose measurements that would unlikely be sustainable with SMBG.