Background: Faster-acting insulin aspart (FiAsp) may improve responsiveness of closed-loop (CL) systems and provide better postprandial glucose (PPG) management due to its more rapid onset and offset compared to insulin aspart (Asp). The Medtronic Advanced Hybrid Closed Loop (AHCL) System features auto-basal and auto-bolus functions.

Aim: To compare PPG control using FiAsp vs. Asp delivered using AHCL.

Methods: Twelve adults with T1D (median HbA1c 7.1% [IQR 6.8, 7.2]; 54mmol/mol [51, 55]) were assigned to FiAsp or Asp (unblinded) in random-order over two-stages (6-weeks duration each) using AHCL. Postprandial periods were defined using set time-blocks for breakfast (06:00-10:00); lunch (11:00-15:00); and dinner (17:00-21:00), based on conventional meal-times and meal distribution. CGM data was analyzed using signed-rank test.

Results: With all postprandial time-block data aggregated, FiAsp demonstrated greater overall time-in-range (TIR) (70-180mg/dL) (p=0.028) and less hyperglycaemia (p=0.041) compared with Asp (Table). TIR was greater during lunch (p=0.034) for FiAsp vs. Asp, with no difference during breakfast or dinner. Over the 6-week duration, FiAsp use trended towards greater TIR vs. Asp (82.7% vs. 80.4%, p=0.07).

Conclusions: FiAsp appears to confer an advantage compared with Asp for PPG control whilst using AHCL even in subjects with high overall TIR.


M.H. Lee: Research Support; Self; Medtronic. Speaker’s Bureau; Self; AstraZeneca, Medtronic. S. Vogrin: None. B. Paldus: Research Support; Self; JDRF. Speaker’s Bureau; Self; Australian Diabetes Society, Medtronic. D. Morrison: None. D. Zaharieva: Speaker’s Bureau; Self; Ascensia Diabetes Care, Insulet Corporation, Medtronic. J. Lu: None. H. Jones: None. S.A. Wyatt: Other Relationship; Self; Medtronic, Ypsomed AG. E. Netzer: None. C.M. Sims: Stock/Shareholder; Self; Medtronic. R. MacIsaac: None. B. Grosman: Employee; Self; Medtronic. A. Roy: Employee; Self; Medtronic. N. Kurtz: Employee; Self; Medtronic. A. Jenkins: Advisory Panel; Self; Abbott, Medtronic. Research Support; Self; Abbott, GlySens Incorporated, Medtronic, Sanofi-Aventis. D.N. ONeal: None.

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