This study aimed to evaluate the impact of advanced hybrid closed loop (AHCL) on glycemic control throughout the menstrual cycle (MC) in women with type 1 diabetes. We included 39 pairs of spontaneous MCs from 13 participants, before and after switching from sensor-augmented pump to AHCL. Baseline time below range <70 mg/dL (TBR <70) was significantly higher during the midfollicular phase than during late luteal phase (5.7% ± 5.0% vs. 4.1% ± 3.0%), but similar time in range 70–180 mg/dL (TIR) was observed throughout the MC. After switching to AHCL, a reduction in TBR <70 and an increase in TIR were observed in all phases. Phase-dependent changes in insulin infusion were detected and pre-existing differences in TBR <70 were eradicated (3.5% ± 3.2% vs. 3.0% ± 3.0%). However, TIR became significantly higher during the early follicular phase than during the late luteal phase (79.1% ± 9.3% vs. 74.5% ± 10.0%). In conclusion, AHCL improved glycemic control throughout the MC, but performance differed according to phase.

Background/objectives: Individuals with type 1 diabetes (T1DM) face an elevated risk of cardiovascular disease (CVD), yet the factors driving atherosclerosis remain unclear. This study aimed to assess factors associated with preclinical atherosclerosis development or progression in T1DM. Methods: We conducted a prospective study in T1DM individuals without established CVD, aged ≥40 years, with diabetic kidney disease and/or ≥10 years of T1DM plus another cardiovascular risk factor (CVRF). Baseline evaluation followed a standardized CV risk assessment protocol, including carotid ultrasound and cardiovascular risk estimation using the Steno Type 1 Risk Engine (ST1RE). Ultrasound was repeated after 3–5 years; progression was defined as an increase in plaque number. CVRF control was considered optimal when LDL-cholesterol was within target based on atherosclerotic burden, blood pressure <130/80 mmHg, HbA1c <7%, and non-smoking status. Logistic regression models identified predictors of progression. Results: We included 151 participants (55.6% women; mean age 49.8 ± 8.9 years; T1DM duration 27.3 ± 9.1 years); 42.4% had plaques at baseline. Over a follow-up of 5.22 ± 1.29 years, despite improved CVRF control (p < 0.05), 40.4% experienced progression. Older age (OR 1.38 [1.1–1.8]) and active smoking (OR 3.29 [1.4–7.5]) were significant predictors of progression. Baseline cardiovascular risk measured by the ST1RE independently predicted progression (OR 1.09 [1.03–1.15]) after adjusting for other CVRFs. Persistent smoking (OR 2.52 [1.06–5.99]) and baseline ST1RE (OR 1.06 [1.02–1.11]) remained significant after accounting for baseline and follow-up CVRFs. Conclusions: Despite improved CVRF control, atherosclerosis progression is common in T1D. ST1RE may help identify individuals at highest risk for targeted preventive strategies.