BACKGROUND: The introduction of glucagon-like peptide 1 receptor agonists (GLP-1RAs) has provided new avenues for managing type 2 diabetes (T2D), aiming to achieve optimal glycaemic control while minimising treatment burden. We conducted a multicentre retrospective real-world study to assess the effectiveness of semaglutide once-weekly (OW) in patients previously treated with insulin. METHODS: We included individuals with T2D who were on insulin (basal and/or bolus) and initiated OW semaglutide at 18 specialist care centres. We collected retrospective data on baseline clinical characteristics and updated values of HbA1c and body weight. The primary outcome was the change in HbA1c analysed using the mixed model for repeated measures. Secondary outcomes included the changes in body weight, insulin discontinuation and the change in insulin doses. RESULTS: The study included 674 individuals. At baseline, participants were 61.7 years old, with a mean diabetes duration of 11.5 years and an HbA1c of 8.2%. During a median follow-up of 18 months, OW semaglutide initiation led to a significant reduction in HbA1c (-0.9%) and body weight (-4.3 kg), with 60% of patients achieving HbA1c <
7%. 32.8% of patients discontinued insulin therapy, 72.5% of whom achieved an HbA1c <
7%. Among patients on basal-bolus insulin, 75% completely discontinued bolus, 62% of whom achieved an HbA1c <
7%. Predictors of insulin discontinuation included shorter diabetes duration, lower baseline HbA1c, and lower insulin doses. Among patients who remained on insulin, initiation of OW semaglutide was associated with a decrease in total daily insulin requirement. CONCLUSION: Our study highlights OW semaglutide as a valuable addition to a T2D regimen based on insulin, offering effective glycaemic and weight control with the potential for insulin deintensification or discontinuation.