Objectives: Traditional economic evaluations for most health technology assessments (HTAs) have previously not included environmental outcomes. With the growing interest in reducing the environmental impact of human activities, the need to consider how to include environmental outcomes into HTAs has increased. We present a simple method of doing so.
Methods: We adapted an existing clinical-economic model to include environmental outcomes (carbon dioxide [CO2] emissions) to predict the consequences of adding insulin to an oral antidiabetic (OAD) regimen for patients with type 2 diabetes mellitus (T2DM) over 30 years, from the United Kingdom payer perspective. Epidemiological, efficacy, healthcare costs, utility, and carbon emissions data were derived from published literature. A scenario analysis was performed to explore the impact of parameter uncertainty.
Results: The addition of insulin to an OAD regimen increases costs by 2,668 British pounds per patient and is associated with 0.36 additional quality-adjusted life-years per patient. The insulin-OAD combination regimen generates more treatment and disease management-related CO2 emissions per patient (1,686 kg) than the OAD-only regimen (310 kg), but generates fewer emissions associated with treating complications (3,019 kg versus 3,337 kg). Overall, adding insulin to OAD therapy generates an extra 1,057 kg of CO2 emissions per patient over 30 years.
Conclusions: The model offers a simple approach for incorporating environmental outcomes into health economic analyses, to support a decision-maker's objective of reducing the environmental impact of health care. Further work is required to improve the accuracy of the approach; in particular, the generation of resource-specific environmental impacts.