Background: Automated insulin delivery (AID) systems integrate continuous glucose monitoring (CGM) and insulin pumps with algorithms that adjust insulin delivery. While randomized controlled trials (RCTs) demonstrate improvements in glycemic outcomes with AID, large-scale real-world data (RWD) analyses are needed to evaluate performance in routine care. Methods: This retrospective, registry-based cohort study included adults (≥18 years) with type 1 diabetes (T1D) in the Swedish National Diabetes Register (NDR) from 2014 to 2024. Hemoglobin (Hb)A1c values were averaged per person-year and aggregated by clinic. Insulin delivery/glucose monitoring combinations included multiple daily injections (MDIs) with blood glucose meter (MDI-BG), MDI with CGM (MDI-CGM, reference), conventional continuous subcutaneous insulin infusion with blood glucose meter (CSII-BG), CSII with CGM (CSII-CGM), and AID systems (Tandem Control-IQ technology, Medtronic 670G, and Medtronic 780G). Mixed-model regression assessed HbA1c outcomes, with treatment, year, age, diabetes duration, gender, body mass index, physical activity level, smoking habits, and clinic size as fixed effects; with random effects for clinics; and weighting by clinic sample size. Results: After adjusting for the covariates, AID systems were associated with significantly lower HbA1c compared with MDI-CGM: β = −4.0 mmol/mol (95% confidence interval CI −4.3 to −3.7, P < 0.001), with individual system effects, Tandem Control-IQ technology β = −4.8 mmol/mol (95% CI −5.2 to −4.5, P < 0.001), Medtronic 780G β = −3.1 (−3.5 to −2.7, P < 0.001), and Medtronic 670G β = −2.9 (95% CI −3.5 to −2.4, P < 0.001). CSII-CGM also outperformed MDI-CGM: β = −1.7 mmol/mol (95% CI −1.9 to −1.4, P < 0.001). Differences between the Tandem and Medtronic AID systems were significant ( P < 0.001). Conclusions: In a nationwide RWD analysis, AID use was consistently associated with clinically and statistically significant HbA1c reductions in adults with T1D, with the greatest effect for Tandem Control-IQ technology. These findings align with RCTs and international RWD, supporting AID as a preferred technology in routine diabetes care for T1D.
Ståhl et al. (2026) studied this question.