Background: Adults with poorly controlled type 1 diabetes (T1D) who are missing meal boluses are typically excluded from clinical trials of diabetes technologies. We investigated the long-term real-life outcomes of the Tandem Control IQ automated insulin delivery (AID) system in adults with T1D who are missing meal boluses. Methods: In this single-center study with 30 adults with T1D, we evaluated efficacy (A1c and time in target range [TIR]) and safety (time below range [TBR]) in adults with T1D who initiated Tandem Control IQ with minimal or no user-initiated boluses (auto >90%) compared with age, gender, and diabetes duration matched adults with T1D with intermediate (auto 50%-90%) and high bolusing behaviors (auto 10%-49%). Results: Regardless of engagement with Control IQ system, there were significant improvements in A1c and TIR in all three groups over 3, 6, and 12 months. Compared with baseline, there was significant decrease in A1c by 1.6% ± 0.8% and increase in TIR by 19.3% ± 6.4% (P < 0.001 for both) over 12 months of Tandem Control IQ use in auto >90% use group without increasing TBR. Conclusions: Tandem Control IQ is effective in lowering A1c and improving TIR without increasing TBR regardless of users' engagement with the system. Therefore, adults with T1D with high A1c who are mostly missing meal boluses should not be considered as inappropriate candidates for Control IQ AID system.
Keywords: Auto bolus; No bolus; Tandem Control IQ; Type 1 diabetes.