Hybrid closed loop systems for managing blood glucose levels in type 1 diabetes

Hybrid closed loop (HCL) systems use a mathematical algorithm to deliver insulin automatically in response to continuously monitored interstitial fluid glucose levels:

• use a combination of real-time glucose monitoring from a continuous glucose monitor (CGM) device and a control algorithm to direct insulin delivery through continuous subcutaneous insulin infusion (CSII)

NICE guidance states (1):

• Hybrid closed loop (HCL) systems are recommended as an option for managing blood glucose levels in type 1 diabetes for adults who have an HbA1c of 58 mmol/mol (7.5%) or more, or have disabling hypoglycaemia, despite best possible management with at least 1 of the following:
  • continuous subcutaneous insulin infusion (CSII)
  • real-time continuous glucose monitoring
  • intermittently scanned continuous glucose monitoring
• HCL systems are recommended as an option for managing blood glucose levels in type 1 diabetes for children and young people
• HCL systems are recommended as an option for managing blood glucose levels in type 1 diabetes for women, trans men and non-binary people who are pregnant or planning to become pregnant
• Only use HCL systems with the support of a trained multidisciplinary team experienced in CSII and continuous glucose monitoring in type 1 diabetes
• Only use HCL systems if the person or their carer:
  • is able to use them, and
  • is offered approved face-to-face or digital structured education programmes, or
  • is competent in insulin dosing and adjustments

Notes:

• the NICE committee noted "... that the clinical-effectiveness evidence showed that HCL systems are likely to improve blood glucose control in type 1 diabetes. This effect appears to be greater for people with higher baseline HbA1c levels, although the extent of the true effect is uncertain. The committee noted that HCL systems are also effective for people with lower baseline HbA1c levels of around 58 mmol/mol (7.5%)..."

Reference:

• NICE (December 2023). Hybrid closed loop systems for managing blood glucose levels in type 1 diabetes