BackgroundStructured therapeutic education courses transfer clinical knowledge to empower people to self-manage long-term conditions. Type 1 diabetes requires multiple daily decisions about self-management to maintain glycaemic control and avoid complications. Despite national recommendations, attendance at high-quality courses run by the National Health Service (NHS) is poor. We aimed to understand reasons for poor attendance by examining the pathway from commissioner to service-user in an adult population in south London, UK, in the Barriers to Uptake of Diabetes Education study. MethodsThere were three parts to this mixed-methods study using exploratory sequential design with quantitative dominance. Adults with, or providing care for people with, type 1 diabetes, in two London boroughs were included. In part 1, we compared attenders with non-attenders of courses as recorded in an NHS service-use database. In part 2, a survey of adults with type 1 diabetes and semi-structured interviews were done, and a provider survey was conducted. Focus groups were conducted in part 3. Analysis included exploratory regression models, thematic analysis of interviews, and quantisising data using a mixed methods matrix. FindingsIn part 1, 303 (27%) of 1121 adults were attenders. In univariate analysis, non-attendance was significantly associated with social determinants of health. In part 2 (n=496, 33% response rate), there were 233 non-attenders (47%), 59 (31%) of whom had not heard of the course. Univariate analysis corroborated part 1 findings, with significant differences (all p<0·05) in attendance according to employment status, ethnic origin, and other socioeconomic factors. Exploratory regression analysis identified four key variables associated with attendance: a positive health-care professional message (odds ratio for positive vs negative message 2·77, 95% CI 1·54–5·01; p=0·001), female sex (0·56, 0·36–0·86; p=0·009), educational attainment (university vs secondary school attainment 0·49, 0·3–0·81; p=0·005), and glycaemic control (glycated haemoglobin <7·5% vs 7·5–8·9%; 1·83 1·06–3·14; p=0·03). Four typologies were identified according to individuals' coping strategies: go-getters (high educational attainment, high thirst for knowledge, and internal locus of control leading to self-education and perceived low benefit from the course); not yetters (long-standing diagnosis, previous or current judgmental relationships, unable to prioritise attendance); trodden downers (low numeracy, low self-worth, nervousness of taking control); and diabetes downers (denial of diabetes or avoidant behaviour making it difficult to self-manage). These typologies were integrated with the patient survey to quantify barriers. In part 3 (five focus groups) potential solutions were proposed, such as modular or blended learning options and taster sessions for both health-care professionals and patients. InterpretationSocial determinants of health such as educational attainment, employment status, and gender influence attendance at structured education, but health-care professional attitude to courses is key. Identifying and quantifying typologies on the basis of psychological constructs supports recommendations for service redesign—eg, patient champions, motivational interviewing, and clear clinical pathways integrating education courses. The results are generalisable to other long-term conditions, although our study is limited by response bias. FundingNational Institute for Health Research Collaboration for Leadership in Applied Health Research and Care, South London.