OBJECTIVES:  To conduct an economic analysis to assess the short-term cost-effectiveness of insulin degludec (IDeg) after switching from other basal insulins in type 1 diabetes in a real-life practice setting. METHODS: This was a prospective, single-arm, observational follow-up of 476 consecutive patients at Danderyd Hospital who switched to IDeg from their previous basal insulin. A short-term model was used to predict the cost-effectiveness of annual treatment with IDeg vs. other basal insulins, based on a Swedish setting. The long-term impact of HbAwas modelled previously. RESULTS: Mean (SD) duration of diabetes was 22.5 (14.2) years and duration of follow-up was 21.7 (6.0) weeks. The frequency of hypoglycaemia during the 4 weeks prior to end of follow-up vs. the 4-week period immediately prior to switching decreased by 12% (p=0.0127) for non-severe daytime events and by 53% (p<0.0001) for non-severe nocturnal events. Severe hypoglycaemia was reduced by 62% (p=0.0225) during comparator periods of 4 months immediately prior to switching and prior to the end of follow-up. Mean insulin doses decreased by 13.1% (p<0.001) for basal insulin and 7.5% (p<0.001) for bolus insulin. The model estimated a gain of 0.03 quality-adjusted life years (QALYs) due to fewer non-severe and severe hypoglycaemic events, and savings in health care costs of SEK 802 annually. Including indirect costs savings amounted to SEK 1019. Both from a health care (direct costs) and a societal perspective (direct and indirect costs) the incremental Cost-Effectiveness Ratio (ICER) showed IDeg was dominant compared to other basal insulins (i.e. higher effectiveness at lower cost). IDeg was also dominant for a subgroup of patients with repeated hypoglycaemia/unstable glucose with and without the inclusion of indirect costs. CONCLUSIONS: This short-term CEA suggests that switching to IDeg from other basal insulins is a cost-saving option already from year one, even when excluding the long-term impact of reduction in HbA