Aims and objectivesTo assess the prevalence of lipohypertrophy, and to compare differences in external, personal and regimen factors in adults with type 1 diabetes and different degrees of lipohypertrophy. BackgroundSuboptimal insulin injection behaviour is associated with lipohypertrophy, which may affect insulin absorption and lead to blood glucose fluctuations. Few, if any studies have investigated how external, personal and regimen factors differ in people with type 1 diabetes and different degrees of lipohypertrophy. DesignA cross-sectional study including adults with type 1 diabetes at a diabetes outpatient clinic in a Norwegian university hospital. MethodsParticipants (n=215) were included consecutively at scheduled appointments. Sociodemographic, diabetes and insulin treatment data, and self-report questionnaires concerning patient activation (Patient Activation Measure), depression (Patient Health Questionnaire-2), diabetes distress (Diabetes Distress Scale), type D personality (14-item Type D scale), treatment satisfaction (Insulin Treatment Satisfaction Questionnaire) and motivation (Treatment Self-Regulation Questionnaire), were collected. Lipohypertrophic injection sites were identified by palpation by diabetes specialist nurses. ResultsLipohypertrophy was present in 53% and was more frequent in insulin pen users (63%) compared to insulin pump users (34%). Participants with two or more lipohypertrophic areas had higher depression scores, lower treatment satisfaction with glycaemic control, higher bolus doses and reported suboptimal injection behaviour compared to those with no lipohypertrophic areas. There were no differences in patient activation, diabetes distress, type D personality or motivation between the groups. Discussion and conclusionCompared to pump treatment, pen treatment requires greater awareness of injection technique. Symptoms of depression and lower treatment satisfaction might affect diabetes self-management and glycaemic control, but the association with lipohypertrophy needs further exploration. Relevance to clinical practiceLipohypertrophy is more frequent in insulin pen users compared to pump users. Nurses should focus on injection technique education, and should also consider screening for depressive symptoms and treatment satisfaction as these factors could be associated with development of lipohypertrophy.