Comment on Beato-Víbora et al. A Multicenter Prospective Evaluation of the Benefits of Two Advanced Hybrid Closed-Loop Systems in Glucose Control and Patient-Reported Outcomes in a Real-World Setting. Diabetes Care 2024;47:216–224

We have read with great interest in Diabetes Care the results from the recent multicenter real-world prospective study conducted by Beato-Víbora et al. (1), comparing glucose and patient-reported outcomes 3 months after advanced hybrid closed-loop (AHCL) insulin delivery system initiation (either Medtronic SmartGuard 780G and Tandem T-Slim Control-IQ users). The authors concluded, based on continuous glucose monitoring from 150 participants (87% of whom are aged ≥25 years), that the AHCL systems provided significant and similar improvement in glucose control, partly in line with a recent publication from our group (2). Although we thank the authors for acknowledging our study, we believe a few clarifications need to be made regarding our cohort description and study design. First, our cohort consisted of 48 adolescents and 183 adults (contrary to the 75 participants mentioned in the article), with a median (95% CI) observation period of 283 (270.5–296) days. Throughout follow-ups, we found that 780G users had consistently better continuous glucose monitoring outcome improvements, including percent time in range (%TIR) (70–180 mg/dL), than Control-IQ users, while laboratory HbA_1c improvements were similar between the two groups. We attributed these results to differences in algorithms, sensors, and/or amounts of automated insulin boluses between AHCL systems. In addition, we found that %TIR improvements remained lower in younger participants (<18 years old) than adult ones with a similar baseline %TIR. Moreover, no significant difference in %TIR was found at each step of follow-up until 1 year after AHCL initiation in the younger participants between the systems. It is therefore possible that no difference was shown between the two AHCL systems in terms of glucose efficacy in the study of Beato-Víbora et al. because of the relatively small sample size and the absence of subgroup analysis based on age. Further, often overlooked outcomes, such as quality of life, were included in the study by Beato-Víbora et al., which certainly helps measure a broader extent of AHCL therapy’s benefits. However, although both AHCL systems demonstrated improvements in areas such as diabetes distress, quality of sleep, or fear of hypoglycemia, the scores at baseline and at 3 months remain higher than that of the AHCL studies (3), with no explanation from the authors as to why and no comparison with other studies. This observation has also been noted in a work by Lebbar et al. (4) and warrants attention. Strikingly, our findings show a decrease over time in the percentage of participants reaching recommended goals such as HbA_1c <7% or %TIR >70%, with an absolute decrease of 9.1% and 8.4%, respectively, after 1 year of follow-up. This observation certainly raises questions about the decisive role of the human factor and highlights the importance of consistent clinical follow-up to better identify and support at-risk patients.