Impact of choice of inhalers for asthma care on global carbon footprint and societal costs: a long-term economic evaluation

Abstract

Background

While effective asthma control medications reduce the burden of asthma, a significant subgroup of these treatments, namely metered-dose inhalers (MDIs), produce substantial greenhouse gas (GHG) emissions, thus contributing to climate change. This study quantified the global climate impact (i.e. carbon dioxide equivalent [CO₂e] emissions) and costs of long-term status quo asthma inhaler use versus alternative scenarios substituting MDIs with propellant-free dry powder inhalers (DPIs).

Methods

Three scenarios were evaluated across 10-year (2020–2030) and 50-year (2020–2070) time horizons: A (status quo inhaler use), B and C (2% and 5% year-over-year substitution of MDIs with DPIs, respectively). Global inhaler volumes and costs at baseline were sourced from IQVIA, then projected using UN and WHO trends in per capita GDP, urbanization, and asthma population growth. Inhaler spending was assumed to fall by 90% following generic entry in 2030. The carbon footprint per inhaler and health damage factors for disability-adjusted life years (DALYs) were derived from literature. The US government’s central and high-impact estimates for the social cost of carbon (SCC) were used to calculate emissions costs.

Results

Over 50 years, scenario A resulted in 826 million tonnes of CO₂e emissions globally, with an associated SCC between 21% and 65% of the projected global spending on asthma inhalers. In comparison, CO₂e emissions were reduced by 38% and 58% in Scenarios B and C, respectively, and DALYs improved by 33 and 51%. Depending on SCC estimates, Scenarios B and C increased global costs by 7.3% and 16.5%, respectively (central SCC), or decreased costs by 4.2% and 2.6% (high-impact SCC) versus Scenario A. Over 10 years, Scenario A resulted in 97 million tonnes of CO₂e emissions globally, with an associated SCC between 4.4% and 12.2% of projected spending. In comparison, Scenarios B and C were associated with 12% and 24% reductions in CO₂e emissions and improvements in DALYs by 11.5% and 22.7%, respectively.

Conclusions

Global efforts by environmental and health-policy decision-makers to substitute currently available MDIs with DPIs for asthma control would result in substantial reductions in GHG emissions with manageable costs, or potential cost savings, depending on the SCC. Policies that decrease use of MDIs warrant global attention.

Keywords:

• Asthma
• dry powder inhalers
• carbon footprint
• climate change
• social cost of carbon
• economic model

JEL CLASSIFICATION CODES:

• P18
• P1
• P
• O38
• O3
• O
• I18
• I1
• I

Correction Statement

This article has been corrected with minor changes. These changes do not impact the academic content of the article.

Transparency

Declaration of funding

This study was funded by Novartis Pharma AG, whose employees were involved in the study design, writing of the report, and the decision to submit the paper for publication. Novartis Pharma AG had no undue influence over the study results/findings.

Declaration of financial/other relationships

IF, JS, KKS, KN and TS are employees of Analysis Group, Inc. a consultancy that received funding from Novartis Pharma AG to conduct this study. NS was previously an employee of Analysis Group, Inc, which received financial support from Novartis Pharma AG. JM and RI are employees of and own stocks in Novartis Pharma AG. JM received editorial support (preparation, review, and finalization of the manuscript) for this manuscript from Analysis Group; Analysis Group received funding for editorial support from Novartis Pharma AG. All Analysis Group authors (IF, JS, KKS, KN, TS, and NS) provided the editorial support. AC and HK are employees of Novartis Healthcare Private Limited.

A reviewer on this manuscript has disclosed that they have performed consulting, served on advisory boards, or received travel reimbursement from Amphastar, AstraZeneca, Chiesi, Connect Biopharma, GlaxoSmithKline, Mylan, Novartis, Sunovion and Theravance. They have also conducted multicenter clinical research trials for some 40 pharmaceutical companies. The other peer reviewers on this manuscript have no other relevant financial relationships or otherwise to disclose.

Author contributions

All authors contributed to the study design and conception. IF, KKS, KN, and NS conducted the analyses. IF, JS, KKS, KN, NS, and TS drafted the initial manuscript. All authors revised the manuscript. All authors approved the final manuscript as submitted.

Acknowledgements

No assistance in the preparation of this article is to be declared.

Previous presentation

These data were previously presented at the ISPOR EUROPE 2021 Annual Congress.