1851-P: Improvements in Time in Range and Time in Tight Range over Four Years Follow-Up Time Using Two Different Advanced Hybrid Closed-Loop Systems

Introduction and Objective: Advanced hybrid closed loop systems (AHCL) demonstrated significant improvement in time in range (TIR) and time in tight range (TiTR) over a mean 1-year follow-up time. Few data are available about longer follow-up periods, according to age and development of microvascular complications (DMCs). Methods: We investigated the change in TIR and TiTR in adults with T1DM over a 4-year follow-up period. We included subjects using MiniMed 780G (MMT780G) and Tandem Control IQ (TCIQ). We evaluated the percentage of participants who developed DMCs over time to assess the possible association between continuous glucose monitoring (CGM) metrics and DMCs' onset. Results: We included 166 subjects, 87 females (52%), mean age 46.2 (SD 15.2) years at baseline, median duration of diabetes 22 [IQR 9-29] years. 92 (55%) used MMT780G and 74 (45%) used TCIQ. There were no differences in age, duration of disease among MMT780G and TCIQ users (p>0.10). AHCL determined a significant and consistent increase in TIR, with mean increase of 9.56% (95% CI 6.62; 12.47%) after 4 years. There was no difference in the improvement of TIR among MMT780G and TCIQ users (p=0.18). TiTR increased consistently over time with a mean increase compared to baseline of 7.64 (95% CI 4.39; 9.89) after 4 years. MMT780G was associated with higher increase of TiTR compared to TCIQ (p<0.01). 24 (14%) of the subjects were ≥65 years old: they achieved better TiTR results compared to youngers over time (β 13.99% [95% CI 6.69; 21.30]). 8 (5%) subjects developed new DMCs while 19(11%) presented a worsening of pre-existing DMCs. There were no differences in TIR and TiTR between those who developed DMCs compared to those who did not (p=0.31). Conclusion: AHCL systems achieved and maintained TIR above the recommended targets over long follow-up period. MM780G reached higher TiTR compared to TCIQ. Older people reached better metrics compared to younger subjects. There were no differences in CGM metrics among those developing or not DMCs. Disclosure L. Lucaccini Paoli: None. A. Rizzi: None. L. Tartaglione: None. L. Vinti: None. F. Napoli: None. E. Grannonio: None. D. Pitocco: None.