Transitioning from standard insulin pumps to hybrid closed loop (HCL) systems can improve glycemic control in patients with type 1 diabetes, but may also carry a risk of early worsening of diabetic retinopathy. Findings presented at EASD 2025 reveal that this risk is particularly relevant in patients with long-standing diabetes and pre-existing retinal disease.

In this study, 67 adults with type 1 diabetes who upgraded from standard pumps to HCL systems were assessed for retinopathy progression. Patients had a mean diabetes duration of 29.5 years, and 69% had pre-existing diabetic retinopathy. Following HCL initiation, 73% of patients experienced a reduction in glycated haemoglobin, averaging 8 mmol/mol. Over a mean follow-up of 199 days, seven patients exhibited progression of retinopathy, three improved, and 39 remained stable. Notably, 14% of patients with significant HbA1c reduction experienced retinopathy progression, and some required laser treatment. Factors such as age, baseline glycated haemoglobin, or diabetes duration did not predict progression.

These findings underscore the importance of integrating retinal surveillance with HCL initiation, especially in patients with long-standing diabetes or pre-existing retinopathy, to prevent adverse ocular outcomes while optimizing glycaemic control.