Abstract / Summary
Overweight and obesity complicate insulin treatment in adults with type 2 diabetes mellitus (T2DM), requiring consideration of glycaemic control, insulin requirements, body weight, and treatment burden. This scoping review mapped insulin treatment modification (ITM) strategies, synthesised their reported outcomes, and identified evidence gaps among insulin-treated adults with T2DM and overweight or obesity. Five electronic databases were searched following Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRISMA-ScR) and updated Joanna Briggs Institute methodological guidance. Thirty-three studies were classified into four ITM domains: add-on therapy to insulin, switching to advanced insulin formulations, simplifying complex insulin regimens with adjunctive therapy, and switching to fixed-ratio combinations. Intensification was generally studied in patients with higher baseline glycated haemoglobin or insulin requirements, whereas simplification was more often evaluated in those receiving complex insulin regimens. Insulin-dominant intensification generally increased total daily insulin dose, while intensification incorporating Glucagon-Like Peptide-1 Receptor Agonists (GLP-1RAs) or Sodium-Glucose Cotransporter-2 Inhibitors (SGLT2i) commonly reduced insulin requirements and body weight. Simplification generally reduced insulin requirements and/or injection burden while maintaining or improving glycaemic control, with weight reduction frequently reported. Direct comparisons and obesity-specific subgroup analyses were limited. Intensification and simplification should therefore be considered complementary rather than opposing approaches, with outcomes influenced by therapeutic components and patient characteristics.