Carbon emission reduction associated with dapagliflozin compared to standard of care in the UK: translating the DAPA-HF and DELIVER trial findings to an environmental context
Authors: Mc Ewan P , Chen J , Roberts G , Mullin K , Varela Falcon L , Cowie M 
Published: October 2024

Abstract

Background
Healthcare systems account for 4–5% of UK national greenhouse gas emissions with delivery of care a major component.1 Preventing events that use healthcare resources should contribute to a reduction in emissions, in addition to the primary humanitarian aim of improving patient outcomes. The Dapagliflozin And Prevention of Adverse-outcomes in Heart Failure (DAPA-HF) and the Dapagliflozin Evaluation to Improve the Lives of Patient with Preserved Ejection Fraction Heart Failure (DELIVER) trials demonstrated that dapagliflozin reduced the frequency of hospitalizations for heart failure (hHF), urgent heart failure visits (UHFV) and cardiovascular (CV) death for patients with heart failure (HF).2,3

Purpose
The study objective was to translate predicted differences in clinical events associated with dapagliflozin use in HF to a predicted carbon emission reduction from a UK perspective.

Methods
A previously published model4 based on pooled DAPA-HF and DELIVER event rates was used to predict hHF, UHFV and CV deaths in a cohort of 1,000 HF patients over a 3-year time horizon. Composite greenhouse gas (GHG) emissions (as kg CO2 equivalent) were calculated from components sourced from the Sustainable Healthcare Coalition’s Care Pathway Calculator according to assumed clinical pathways and were applied to predicted incidence of hHF, UHFV and CV death events. Average length of stay was sourced from the National Heart Failure Audit.5 CV deaths occurring outside hospital were assumed to incur no additional carbon emission except that associated with cremation. Proportion of funerals by cremation and associated GHG emissions were sourced from literature.6,7 Future emissions were not discounted, representing the NHS’s aim to approach ‘net zero’.

Results
Over a 3-year time horizon, treatment with dapagliflozin was projected to prevent 74 hHF events, 9 UHFV events and 20 CV deaths per 1,000 patients treated versus placebo. Total estimated GHG emissions associated with hHF (233.2 kg CO2e), UHFV (177.4 kg CO2e), and CV death (251.4 kg CO2e) were 85,660 kg CO2e per 1,000 patients treated with dapagliflozin versus 109,618 kg CO2e per 1,000 patients treated with placebo. The projected total reduction associated with dapagliflozin treatment was 23,958 kg CO2e over 3 years, a 22% reduction versus placebo. Per population (~690,000 HF patients), total emissions prevented by dapagliflozin over 3 years were projected to be equivalent to driving 42 million miles in an average gasoline-powered passenger vehicle.

Conclusion
While the main aim of any therapeutic intervention is to save lives and improve patient outcomes, to capture the full spectrum of benefit to stakeholders the environmental consequences of new therapies should be considered in addition to their clinical and economic effects. Our analysis suggests treating patients with dapagliflozin may contribute to reducing the environmental burden of HF in addition to improving patient outcomes.