CGM use is associated with lower HbA1c in people with T1D. We hypothesize early CGM initiation will improve longer term HbA1c.

Youth with newly diagnosed T1D from July 2018 to May 2019 (pilot cohort, n=65), were offered CGM initiation in the 1st month of T1D diagnosis with 62 initiating CGM. We compared HbA1c outcomes in this pilot cohort with those diagnosed in 2014-2016 (control cohort, n=272) with follow-up duration restricted to 15 months. HbA1c trajectories were visualized using locally estimated scatter plot smoothing (Figure 1) and compared using a generalized mixed effects regression model adjusted for baseline characteristics (HbA1c at onset, age, sex, race and insurance type).

Mean HbA1c at diagnosis was higher in the pilot cohort (12.0% vs. 10.7%). Over the first 15 months of T1D, CGM was initiated in 95% of the pilot cohort (78.5% within 30 days), whereas 56% initiated in the control cohort (1.8% within 30 days). Adjusting for baseline characteristics, mean HbA1c levels were 0.5% lower (95%CI: -1.0, -0.1) in the pilot cohort at 3 months and 1.7% lower (95% CI: -2.6, -0.8) at 6 months compared to the control cohort. Differences beyond 6 months were also in the expected direction and statistically significant at the 0.05 level.

Early initiation of CGM in the new onset period was associated with lower HbA1c compared to historic controls. These data suggest that early CGM initiation should be considered a part of standard new onset T1D care.


P. Prahalad: None. V. Ding: None. A. Addala: None. C. New: None. B.P. Conrad: None. A. Chmielewski: None. E. Geels: None. J. Leverenz: None. A. Martinez-Singh: None. P. Sagan: None. J. Senaldi: None. A. Freeman: None. D. Scheinker: None. K.K. Hood: Research Support; Self; Dexcom, Inc. Speaker’s Bureau; Self; LifeScan, Inc., MedIQ. M. Desai: None. D.M. Maahs: Advisory Panel; Self; Eli Lilly and Company, Insulet Corporation, Medtronic, Novo Nordisk A/S. Consultant; Self; Abbott, Sanofi. Research Support; Self; Bigfoot Biomedical, Dexcom, Inc., Roche Diabetes Care, Tandem Diabetes Care.

Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at