A Mixed‑Methods Assessment of Inhaler Sustainability across the Respiratory Care Pathway

Technical Summary: A Mixed-Methods Assessment of Inhaler Sustainability across the Respiratory Care Pathway

Problem Statement
While inhalers are clinically indispensable for managing asthma and chronic obstructive pulmonary disease (COPD), their lifecycle generates significant environmental impact. Current sustainability efforts have predominantly focused on reducing carbon emissions at the device level, specifically by switching from hydrofluoroalkane (HFA) propellant-based pressurised metered-dose inhalers (pMDIs) to lower-carbon alternatives like dry powder inhalers (DPIs). However, this approach is insufficient because:

1. Lifecycle Complexity: Device substitution does not address material waste, limited circularity in supply chains, or end-of-life disposal challenges.
2. Clinical Constraints: Switching devices is not always clinically appropriate or feasible for all patients.
3. Implementation Gap: There is limited empirical evidence on how sustainability is prioritized alongside clinical safety, usability, and service delivery in routine primary care, where most inhalers are prescribed and managed.
4. Systemic Interdependencies: Behaviors regarding disposal and prescribing are shaped by socio-technical factors (regulation, workflow, infrastructure) rather than individual choice alone.

Methodology
The study employed a convergent mixed-methods design informed by Socio-Technical Systems (STS) theory, conducted in the United Kingdom between August 2024 and January 2025. This theoretical framework treats sustainability as an emergent property of interactions between people, technologies, organizational routines, and regulatory contexts.

• Qualitative Component: Semi-structured interviews were conducted with 29 stakeholders across the inhaler lifecycle, including patients, healthcare professionals (HCPs), policymakers, industry representatives, and sustainability experts. Data were analyzed using reflexive thematic analysis.
• Quantitative Component: Two cross-sectional surveys were administered:
  • Patient Survey (n=65): Focused on inhaler appearance, recognition, and the influence of device color on use.
  • HCP Survey (n=76): Focused on knowledge, attitudes, and behaviors regarding inhaler disposal and recycling.
• Integration: Qualitative and quantitative findings were analyzed separately and then triangulated during the interpretation phase to identify system-level barriers, trade-offs, and leverage points.

Key Results
The findings indicate that inhaler sustainability is a system-level challenge shaped by four interconnected stages of the lifecycle:

1. Upstream Design and Regulation: Sustainability is heavily constrained by regulatory requirements. Changes to materials, propellants, or design features require extensive testing and approval (often 3–7 years), creating a tension between innovation speed and environmental goals. Furthermore, design features like color are critical for patient safety and recognition but are not formally standardized, meaning sustainability-driven design changes could inadvertently compromise usability.
2. Prescribing and System Constraints: Clinical effectiveness, patient capability, and cost remain the primary drivers of prescribing. Sustainability is often secondary due to:
   • Electronic Prescribing Systems: Default lists often prioritize pMDIs over DPIs.
   • Cost Pressures: Lower-carbon options (e.g., certain DPIs) can be more expensive than pMDIs.
   • Workload: Switching devices requires additional time for training and follow-up, which is scarce in routine consultations.
3. Human Factors and Usability: Patients rely heavily on visual cues, particularly color, to identify and differentiate inhalers. Survey data revealed significant heterogeneity in this reliance:
   • 59% of COPD patients reported color affected their use consistency, compared to 29% of asthma patients.
   • Lower-income households (income <£30,000) showed higher reliance on color (56%) compared to higher-income groups (44%).
   • This suggests that sustainability-driven changes to device appearance could create equity risks and increase the risk of medication errors for vulnerable subgroups.
4. End-of-Life Disposal and Recycling: Disposal is the least integrated stage of the care pathway. While 85.5% of HCPs were aware of disposal issues, only 12.5% reported a formal recycling scheme in their setting. Barriers are predominantly structural (lack of infrastructure, funding, and clear ownership) rather than motivational. Patient disinterest was rarely cited as a primary barrier; instead, the lack of clear pathways and incentives prevents implementation.

Key Contributions

• Systemic Perspective: The study moves beyond carbon-footprint modeling to demonstrate that inhaler sustainability is a socio-technical system problem. It highlights that isolated interventions (e.g., promoting DPIs or recycling bins) are unlikely to succeed without addressing interdependencies across design, regulation, prescribing, and waste infrastructure.
• Equity and Usability Evidence: It provides empirical evidence that device color is a critical safety cue, particularly for COPD patients and lower-income groups. This challenges the assumption that sustainability changes can be implemented without considering their impact on patient safety and health equity.
• Implementation Gap Identification: The research identifies a disconnect between awareness and practice in disposal, driven by structural deficits rather than lack of motivation among clinicians or patients.

Significance and Claims
The paper claims that achieving inhaler sustainability requires whole-system action rather than isolated device-level changes. The authors argue that:

• Sustainability outcomes are produced through interactions across the entire respiratory care pathway.
• Interventions must embed environmental considerations into innovation and regulation (upstream) while simultaneously aligning prescribing systems, protecting patient safety/usability, and developing reliable end-of-life infrastructure (downstream).
• Shifting responsibility to patients or frontline clinicians without structural support (e.g., dedicated time, funding, clear pathways) is ineffective.
• Future efforts must balance environmental goals with clinical safety, usability, and equitable access, ensuring that sustainability does not come at the cost of medication adherence or safety.

The study concludes that a lifecycle-oriented approach is necessary to make sustainable inhaler use feasible, emphasizing that "sustainability is rarely prioritised in prescribing, and recycling pathways were poorly embedded in care" without coordinated system-level support.