A systematic review of glucocorticoid use in type 1 diabetes: Glycaemic effects and clinical management strategies.

Glucocorticoids (GCs) are widely utilised for the treatment of inflammatory and autoimmune conditions but often precipitate significant hyperglycaemia. People with type 1 diabetes (PWT1D) may be particularly affected due to the challenges of adjusting insulin dosing, for which recommendations remain unclear. Our aim is to synthesise the evidence on the glycaemic effects of GCs in PWT1D across various formulations, doses and administration routes, and to outline management strategies. In August 2025, a systematic search of MEDLINE, Embase and CENTRAL was conducted in accordance with Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. Eligible studies included adult PWT1D exposed to GCs and reported glycaemic outcomes and/or management strategies. Twenty-two studies were included, comprising 368 PWT1D. GC exposure was consistently associated with marked hyperglycaemia and increased insulin requirements. Oral and intravenous GC regimens required substantial insulin dose escalation, in many cases up to 70% from baseline. During pregnancy, antenatal corticosteroids were best managed with structured subcutaneous or intravenous insulin protocols. Local injectable GCs caused delayed but prolonged excursions and required careful blood glucose (BG) monitoring. Emerging data suggest that automated-insulin delivery (AID) systems attenuate BG elevation but still require user intervention. Thus, GC therapy in PWT1D destabilises glycaemic management, though impact and timing vary by formulation, dose, administration route, patient-specific factors and clinical context. Proactive, individualised insulin adjustments aligned with GC pharmacokinetics and frequent BG monitoring or continuous glucose monitor use represent the most practical current strategy. Further research is required to develop evidence-based guidelines and to clarify the role of AID.