Background and Aims: Initiation of continuous subcutaneous insulin therapy (CSII) in people with type 1 diabetes (T1D) requires conversion of a basal insulin dose to a continuous infusion regimen. There are limited data to guide the optimal insulin profile to rapidly achieve target glucose and minimize healthcare professional input. The aim of this study was to compare circadian and flat insulin infusion rates in CSII naïve adults with T1D.

Materials and Methods: Adults with T1D who met the NICE criteria for CSII were recruited. Participants were randomized to either a circadian profile or a flat basal rate, each calculated from the total daily dose. Basal rate testing was undertaken on days 7, 14 and 28 of CSII and basal rates were adjusted according to protocol. The primary outcome was the between group difference in absolute change in insulin basal rate over 24 hours following 3 rounds of basal testing. Secondary outcomes included the number of basal rate changes and the time blocks. Data from blinded continuous glucose monitoring were also collected.

Results: Seventeen participants (mean age 33.3 (SD 8.6)) were recruited. There was no significant difference in absolute change in insulin basal rates between the two groups (p=0.85) from baseline to the end of the study. In the circadian basal group, there was significant variation in the number of changes made across the 24 one-hour blocks with the most changes early in the morning (p=0.005). In the flat basal group, there were no significant variation in the number of changes made across the time points (p=0.09).

Conclusion: Commencing CSII with a flat or circadian profile does not impact on the magnitude of basal rate insulin changes during optimization in the first 28 days. The circadian profile requires changes at specific time points, while the flat basal rate requires even optimization throughout the 24-hour period. Further development of the circadian profile early in the morning may address this.


S.K. Rilstone: None. M. Reddy: None. N. Oliver: Advisory Panel; Self; Roche Diabetes Care. Research Support; Self; Dexcom, Inc., Roche Diabetes Care. Speaker's Bureau; Self; Dexcom, Inc., Sanofi.



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