Background: The impact of timing of CGM initiation in pump naïve pediatric patients on CGM adherence and hemoglobin A1C remains unclear.

Methods: A 5-site RCT of pump naïve subjects (aged 5-18 years) with type 1 diabetes (T1D) > 1 year was conducted to compare simultaneous pump and CGM (“SIM” group) vs. standard pump therapy with CGM initiation delayed for 6 months (“DEL” group). A step-wise approach to CGM settings was used. Primary outcome was CGM adherence (hours per 28 days (MiniMed™ Veo™ system and CareLink Professional use)) assessed over six months after CGM initiation. The main secondary outcome, A1Cs, was measured centrally at baseline and every 6 months. Linear mixed-models and ordinary least squares models were fitted to further estimate the effect of intervention, and covariates of baseline age, T1D duration, and A1C, as well as gender and clinical site.

Results: We randomized 144 of 152 (95%) eligible subjects into the SIM or DEL intervention. Five (3 SIM, 2 DEL) withdrew before visit 1 and 1 (DEL) a week after pump start, with 70 SIM, 68 DEL eligible for analysis. Baseline mean age was 11.5±3.3(SD) years, T1D duration 3.4±3.1 years, and A1C 7.9±0.9% (range 5.5-11.2%). During the 6th month, median CGM adherence was 485.6 hours (95% CI: 229.5, 585.7) in SIM vs. 408.2 (95% CI: 134.9, 572.8) in DEL, with this difference in adherence translating into an additional 2.8 hours of CGM per day. Median 6-month A1C was 7.9 [IQR: 7.5, 8.4] for SIM vs. 7.8 [IQR: 7.4, 8.4] for DEL. Fitted models suggest those randomized to SIM had better CGM adherence (main effect = 74.4 [95% CI: 26.8, 121.9], p=0.002), with higher adherence among females (p=0.03). Overall, there was no difference in A1C 6 months after CGM initiation (-0.20 [95% CI: -0.45, 0.06], p=0.13).

Conclusion: CGM adherence was higher when initiated at the same time as pump therapy however there was no significant effect on A1C. More research is required to understand why CGM did not have an effect on A1C and examine how CGM may affect other measures of glycemic control.


M.L. Lawson: None. J. Courtney: None. B.J. Bradley: None. K. McAssey: None. C. Clarson: None. S.E. Kirsch: None. J. Curtis: None. F.H. Mahmud: None. C. Richardson: Advisory Panel; Self; Dexcom, Inc.. T. Cooper: None. K. Tang: None.

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