Incorporating Environmental Sustainability Into Health Technology Assessments: Two Adapted Cost-Utility Analyses (CUA) of Insulin Icodec Versus Degludec for Type 2 Diabetes (T2D) Management in England

OBJECTIVES: The growing interest from Health Technology Assessment bodies in including environmental sustainability into health economic (HE) modelling is evident, yet lack of methodological framework is impeding progress. Icodec, the first once-weekly basal insulin reducing number of injections from seven to one per week, offers an opportunity for assessing environmental impact (EI) in HE modelling. This study proposes two methods for evaluating this EI.

METHODS: The long-term EI of icodec compared to degludec (a once-daily basal insulin using a similar pen-injector) was assessed using two adapted CUAs through the PRIME T2D model, accounting for carbon dioxide equivalent emissions (CO2e). Moreover, the study focused on two T2D populations, insulin-naïve and insulin-switches respectively, derived from clinical trials, analyzed over 60 years from an NHS perspective. The first method showcased the environmental benefits of icodec through an integrated CUA compared to a traditional CUA, where CO2e were monetized and included alongside traditional cost parameters. This adaptation resulted in a modified measure, termed green Incremental Cost-Effectiveness Ratio (gICER) in £/QALY gained. The second method involved a parallel approach focusing on EI, resulting in two new metrics derived from literature, the Incremental Carbon Footprint Effectiveness Ratio (ICFER) in kgCO2e/QALY gained and Incremental Carbon Footprint Cost Ratio (ICFCR) in kgCO2e/£ spent.

RESULTS: Both initiating and switching to an icodec regimen was associated with increased environmental benefits compared to a degludec regimen. The integrated analysis improved cost-effectiveness by reducing the gICER by -4.1% for insulin-naïve population and -7.8% for insulin switch population compared to the traditional CUA. Furthermore, the parallel approach demonstrated that initiating an icodec regimen resulted in an ICFER of -533.48 kgCO2e/QALY and ICFCR of 0.4 kgCO2e/£ compared to a degludec regimen.

CONCLUSIONS: This study proposed and demonstrated the concrete impact of incorporating environmental sustainability within HE modelling, enabling a comprehensive framework for future new innovations.