Hybrid closed-loop systems for managing blood glucose levels in type 1 diabetes: a systematic review and economic modelling

Health Technol Assess. 2024 Dec;28(80):1-190. doi: 10.3310/JYPL3536.

Abstract

Background: Hybrid closed-loop systems are a new class of technology to manage type 1 diabetes mellitus. The system includes a combination of real-time continuous glucose monitoring from a continuous glucose monitoring device and a control algorithm to direct insulin delivery through an insulin pump. Evidence suggests that such technologies have the potential to improve the lives of people with type 1 diabetes mellitus and their families.

Aim: The aim of this appraisal was to assess the clinical effectiveness and cost-effectiveness of hybrid closed-loop systems for managing glucose in people who have type 1 diabetes mellitus and are having difficulty managing their condition despite prior use of at least one of the following technologies: continuous subcutaneous insulin infusion, real-time continuous glucose monitoring or flash glucose monitoring (intermittently scanned continuous glucose monitoring).

Methods: A systematic review of clinical effectiveness and cost-effectiveness evidence following predefined inclusion criteria informed by the aim of this review. An independent economic assessment using iQVIA CDM to model cost-effectiveness.

Results: The clinical evidence identified 12 randomised controlled trials that compared hybrid closed loop with continuous subcutaneous insulin infusion + continuous glucose monitoring. Hybrid closed-loop arm of randomised controlled trials achieved improvement in glycated haemoglobin per cent [hybrid closed loop decreased glycated haemoglobin per cent by 0.28 (95% confidence interval -0.34 to -0.21), increased per cent of time in range (between 3.9 and 10.0 mmol/l) with a MD of 8.6 (95% confidence interval 7.03 to 10.22), and significantly decreased time in range (per cent above 10.0 mmol/l) with a MD of -7.2 (95% confidence interval -8.89 to -5.51), but did not significantly affect per cent of time below range (< 3.9 mmol/l)]. Comparator arms showed improvements, but these were smaller than in the hybrid closed-loop arm. Outcomes were superior in the hybrid closed-loop arm compared with the comparator arm. The cost-effectiveness search identified six studies that were included in the systematic review. Studies reported subjective cost-effectiveness that was influenced by the willingness-to-pay thresholds. Economic evaluation showed that the published model validation papers suggest that an earlier version of the iQVIA CDM tended to overestimate the incidences of the complications of diabetes, this being particularly important for severe visual loss and end-stage renal disease. Overall survival's medium-term modelling appeared good, but there was uncertainty about its longer-term modelling. Costs provided by the National Health Service Supply Chain suggest that hybrid closed loop is around an annual average of £1500 more expensive than continuous subcutaneous insulin infusion + continuous glucose monitoring, this being a pooled comparator of 90% continuous subcutaneous insulin infusion + intermittently scanned continuous glucose monitoring and 10% continuous subcutaneous insulin infusion + real-time continuous glucose monitoring due to clinical effectiveness estimates not being differentiated by continuous glucose monitoring type. This net cost may increase by around a further £500 for some systems. The Evidence Assessment Group base case applies the estimate of -0.29% glycated haemoglobin for hybrid closed loop relative to continuous subcutaneous insulin infusion + continuous glucose monitoring. There was no direct evidence of an effect on symptomatic or severe hypoglycaemia events, and therefore the Evidence Assessment Group does not include these in its base case. The change in glycated haemoglobin results in a gain in undiscounted life expectancy of 0.458 years and a gain of 0.160 quality-adjusted life-years. Net lifetime treatment costs are £31,185, with reduced complications leading to a net total cost of £28,628. The cost-effectiveness estimate is £179,000 per quality-adjusted life-year.

Conclusions: Randomised controlled trials of hybrid closed-loop interventions in comparison with continuous subcutaneous insulin infusion + continuous glucose monitoring achieved a statistically significant improvement in glycated haemoglobin per cent in time in range between 3.9 and 10 mmol/l, and in hyperglycaemic levels.

Study registration: This study is registered as PROSPERO CRD42021248512.

Funding: This award was funded by the National Institute for Health and Care Research (NIHR) Evidence Synthesis programme (NIHR award ref: NIHR133547) and is published in full in Health Technology Assessment; Vol. 28, No. 80. See the NIHR Funding and Awards website for further award information.

Plain language summary

Type 1 diabetes mellitus is a lifelong condition whereby an individual’s pancreas significantly reduces or stops producing the hormone insulin that manages blood glucose levels. The individual must self-administer insulin and monitor their blood glucose levels. Hybrid closed-loop systems provide a control algorithm that reviews data and the impact of its past actions. Hybrid closed loop can reduce the burden on the patient by taking responsibility for handling the number of data and providing insulin when needed. The aim of this project is to review the clinical and financial benefits of hybrid closed-loop systems for managing glucose in people who have type 1 diabetes mellitus and are having trouble managing their condition. We looked at published studies following precise scientific approaches. We searched several online resources to find these studies. The National Institute for Health and Care Research provided additional studies that had not been published. The studies we found included the following information: people – with type 1 diabetes mellitus (any age group and including pregnant women) technology – people using a hybrid closed-loop system comparison – people using flash or intermittent glucose monitoring + pump therapy results – type 1 diabetes mellitus-related outcomes, such as glucose management, quality of life, heart disease, and complications related to the use of hybrid closed loop. Our online search found 12 randomised controlled trials that compared hybrid closed loop with continuous glucose monitoring + pump therapy. People in the hybrid closed-loop group had better glucose management (their glucose levels dropped by 0.28%). People in the hybrid closed-loop group had better glucose levels in the recommended range (between 3.9 and 10.0 mmol/l). People in the hybrid closed-loop group experienced less hyperglycaemic levels (above 10.0 mmol/l). The financial costs of hybrid closed loop suggest that it is more expensive (£1500) than continuous glucose monitoring + pump therapy. Studies that looked at hybrid closed loop in people with type 1 diabetes mellitus seem to suggest that it is better for diabetes management in terms of glucose levels, better time in range between 3.9 and 10 mmol/l, and less hyperglycaemic levels.

Publication types

  • Systematic Review
  • Review

MeSH terms

  • Algorithms
  • Blood Glucose Self-Monitoring* / economics
  • Blood Glucose* / analysis
  • Cost-Benefit Analysis*
  • Diabetes Mellitus, Type 1* / drug therapy
  • Glycated Hemoglobin / analysis
  • Humans
  • Hypoglycemic Agents / administration & dosage
  • Hypoglycemic Agents / economics
  • Hypoglycemic Agents / therapeutic use
  • Insulin Infusion Systems* / economics
  • Insulin* / administration & dosage
  • Insulin* / economics
  • Models, Economic
  • Quality-Adjusted Life Years
  • Randomized Controlled Trials as Topic

Substances

  • Insulin
  • Blood Glucose
  • Hypoglycemic Agents
  • Glycated Hemoglobin