Aims/hypothesis <p>Hybrid closed-loop insulin delivery systems are increasingly regarded as the preferred therapy for type 1 diabetes, although evidence in older adults remains limited. The aim of this randomised study was to evaluate the effectiveness and safety of the MiniMed 780G system in individuals with type 1 diabetes aged ≥65 years, with HbA_1c&lt;86 mmol/mol (10%), who were naive to this technology, with the primary endpoint based on glycaemic management (time in range). Vascular status and other glycaemic metrics were assessed as secondary outcomes.</p> Methods <p>This single-centre, open labelled (outcome assessors were not masked), randomised, controlled, parallel-group trial enrolled 34 participants who were randomly assigned in a 1:1 ratio using a computer-generated randomisation schedule to either advanced hybrid closed-loop (AHCL) therapy or control therapy (multiple daily injections or continuous subcutaneous insulin infusion) and followed for 12 months.</p> Results <p>Twenty-nine participants completed the study. Baseline characteristics, including glycaemic metrics, were comparable across groups (<i>p</i>&gt;0.05). The AHCL group demonstrated a rapid and sustained improvement in glycaemic management, with time in range increasing from 57.4% at baseline to 79.7% at 12 months (<i>p</i>&lt;0.001), accompanied by reductions in hyperglycaemia as reflected by time above range and time above range 2 (nominal <i>p</i>&lt;0.001; <i>p</i>&lt;0.001), and with no increase in hypoglycaemia across time below range and time below range 2 (nominal <i>p</i>=0.463; <i>p</i>=1). Adjusted between-group differences favoured AHCL for time in range (15.7% [95% CI 8.6, 22.6]) and HbA_1c (−5 mmol/mol; [95% CI −9.7, −0.4 mmol/mol] [−0.46%; −0.89%, −0.04%]). No serious adverse events or episodes of diabetic ketoacidosis or severe hypoglycaemia occurred. Post-occlusive reactive hyperaemia showed a shortening of time to maximal flow in the AHCL group, indicating a favourable numerical trend towards improved microvascular function (nominal <i>p</i>&gt;0.05). Retinal vascular status assessed using artificial intelligence remained stable throughout follow-up in both eyes (nominal <i>p</i>=0.710 and <i>p</i>=0.563, respectively).</p> Conclusions/interpretation <p>The MiniMed 780G system appears effective for glycaemic management and safe for use in older adults with long-standing type 1 diabetes and a high burden of comorbidities. A non-statistically significant numerical tendency (<i>p</i>&gt;0.05) in the improvement of vascular function that requires further confirmation was also observed.</p> Trial registration <p>ClinicalTrials.gov NCT06207838</p> Graphical Abstract <p></p>