Background and aims: this post hoc analysis of the DUAL V study investigated the safety and efficacy of initiating the fixed-ratio combination insulin degludec/liraglutide (IDegLira) once daily at 16 dose steps/units (U) (16 U IDeg; 0.58 mg liraglutide) in adults with type 2 diabetes (T2D) uncontrolled on 20–50 U of insulin glargine U100 (IGlar U100), versus continued IGlar U100 up-titration, across pre-trial daily insulin dose groups (20–<30; ≥30–<40; ≥40–≤50 U). This analysis aimed to confirm that there is no loss of glycaemic control when switching to 16 U IDegLira from a higher pre-trial basal insulin dose. Materials and methods: DUAL V was a 26 week open-label, treat-to-target trial that randomised patients (n=557) with T2D uncontrolled (HbA1c 7–10%) on IGlar U100 (20 50 U) plus metformin to either IDegLira or continued IGlar U100 titration. Results: HbA1c reductions from baseline to end of trial (EOT) were significantly greater with IDegLira versus IGlar U100 for all dose groups. For all dose groups, compared with IGlar U100, IDegLira was insulin sparing, resulted in body weight loss versus body weight gain, and was associated with lower rates of hypoglycaemia (p<0.05, all treatment contrasts). There were no clinically relevant increases in self-measured plasma glucose levels when converting from any dose group to 16 U IDegLira, and no withdrawals due to hyperglycaemia with IDegLira in first 8 weeks. Fasting plasma glucose reductions were similar between treatment arms for all dose groups. For all endpoints except EOT insulin dose, treatment effect was consistent across dose groups. Conclusion: in conclusion, regardless of pre-trial insulin dose group, IDegLira resulted in significantly greater HbA1c and body weight reductions and lower hypoglycaemia rates versus IGlar U100 at a lower EOT insulin dose. Importantly, there was no loss of glycaemic control when converting from any dose between 20–50 U of IGlar U100 to the starting dose of 16 U IDegLira. This maintenance of glycaemic control at a lower insulin dose is likely attributable to the liraglutide component.