AsthmaREDUCE- CarbonNCT07825441
RandomisED Control Trial to Understand Whether Prescribing Choice for inhalErs is Influenced by Knowledge of the CARBON Footprint (REDUCE Carbon)
A study testing WAN Inhaler Guidelines plus carbon footprint information and WAN Inhaler guidelines only in people with Asthma, run by Portsmouth Hospitals NHS Trust at 1 site in United Kingdom.
Trial summary
Climate change is a huge and present threat, with the devastating effects being increasingly seen in everyday life. The NHS contributes substantially to the UKs carbon footprint with an estimated 23 million tonnes gCO2Eq per year, 3% of which comes from pMDIs. Read more about this study
- Who is it for?
- Ages 18 years and olderHealthy volunteers can take part
- Conditions the study is for
- Asthma
- What is being tested?
- WAN Inhaler Guidelines plus carbon footprint information and WAN Inhaler guidelines only
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 3,782 participants
- Where
- 1 siteUnited Kingdom
- Study dates
- 1 Mar 2022to 28 Aug 2025
- Phase
- Interventional
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- Healthy volunteers accepted
- Adult, Older adult
Who may be able to join
- Aged ≥18 years
- Working as an HCP within the NHS in a primary or secondary care setting
- Able to provide written e-consent
- Able to understand and complete the clinical case scenarios
Who cannot join
- Inability to understand or comply with study procedures and/or inability to give fully informed consent.
Trial locations and contacts
1 site in 1 country.
United Kingdom1 site
Portsmouth Hospitals University NHS Trust, Research Department
Portsmouth, Hampshire, PO63LY
About this study
Climate change is a huge and present threat, with the devastating effects being increasingly seen in everyday life. The NHS contributes substantially to the UKs carbon footprint with an estimated 23 million tonnes gCO2Eq per year, 3% of which comes from pMDIs. There are a number of alternative inhalers, such as DPIs, which do not use propellant and therefore have a significantly lower carbon footprint. There is a call to move towards greener inhalers as part of the NHS long term plan for sustainability, to reduce the carbon footprint and therefore the environmental impact and help protect the health of our patients today and in the future.
When recommending an inhaler, a number of factors are usually considered including the ability of the patient to use the device and its cost. Up until now the environmental impact of each inhaler is not routinely available and therefore is not normally considered in prescription choice. Given the increasing evidence supporting the sizeable impact that pMDIs are having on global warming, there needs to be a shift in practice where the climate impact forms part of the decision-making process.
This study is looking to explore prescribing behaviours surrounding inhaler selection and in particular whether knowledge of the carbon footprint of inhalers has any sway on prescribing preference. By better understanding the decision-making process, this will allow the production of more comprehensive asthma management guidelines and potentially facilitate a drive to greener inhaler prescribing practices.
Read the detailed description
Inhalers are some of the most commonly prescribed medicines in the UK and can be expensive. They form the mainstay of treatment for asthma and COPD. They comprise either a pressurised metred dose inhaler (pMDI) or a dry powder inhaler (DPI). Despite global legislation some years ago that removed chlorofluorocarbons (CFCs) from inhalers (Montreal Protocol) due to their harmful effect on the ozone layer; there remains a large difference in the carbon footprint between pMDIs and DPIs. pMDIs have a higher carbon footprint than DPIs and contribute substantially to global warming. The effects of this are to be seen in everyday life and it is the responsibility of all individuals to 'reduce their carbon footprint'.
The environmental impact of inhaler use also comes from plastic waste from discarded inhalers. Over 50 million inhalers are prescribed in the UK each year1, and most of these will end up in landfill sites where they take centuries to biodegrade. There are an increasing number of schemes to recycle inhalers and local pharmacies will often provide these facilities, but this is not routinely advertised to patients.
Current guidelines recommend that where either a pMDI or DPI will be equally as good for the patient then the environmental impact of the inhaler should be considered. TheNational Institute for Health and Care Excellence (NICE) provides national guidance and advice to improve health and social care. Their guidance includes an algorithm to choose the best inhaler for a patient. Whilst this is helpful on an individual patient basis, there is currently no legislation that mandates the use of DPIs in preference to pMDIs.
The study hypothesises that if Health Care Professionals (HCPs) are provided with the information on the carbon footprint of each inhaler, this may influence the type of inhaler they recommend, i.e., with all things being equal they may show a preference for low carbon DPIs over high carbon pMDIs because of concerns over global warming.
A simple online study has been designed to test whether HCPs, if given information regarding the environmental impact of inhalers, as part of an asthma treatment guideline, are more or less likely to recommend a low carbon inhaler. By better understanding how the inclusion of carbon data influences inhaler prescription choice, we will be able to clarify whether the inclusion of carbon data in asthma treatment guidelines is likely to be beneficial in facilitating a drive to greener inhaler prescribing practices.
- Conditions
- Asthma
- Being tested
- WAN Inhaler Guidelines plus carbon footprint information, WAN Inhaler guidelines only
- Keywords
- Carbon Footprint, Inhalers, Asthma, pMDIs
- Medical subject headings
- Asthma
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
WAN Inhaler Guidelines plus carbon footprint informationOther
Wessex Asthma Network inhaler guidelines plus the carbon footprint infromation for individual inhalers.
WAN Inhaler guidelines onlyOther
current standard Wessex Asthma Network inhaler guidelines with no information regarding the carbon footprint of individual inhalers
| Study group | Role | What they receive |
|---|---|---|
| Control Arm | Other | Participants receive the current standard Wessex Asthma Network inhaler guidelines with no information regarding the carbon footprint of individual inhalers Receives: Other: WAN Inhaler guidelines only |
| Intervention Arm | Other | Participants receive the Wessex Asthma Network inhaler guidelines plus information containing the carbon footprint for individual inhalers. Receives: Other: WAN Inhaler Guidelines plus carbon footprint information |
What is being measured
The primary outcome is the main question the study is designed to answer.
Health Care Practitioner Preference
The number and proportion of HCPs preferring high or low carbon inhalers between carbon-containing and non-carbon-containing groups, for each case separately and across all cases in total.
Measured: At completion of the online questionnaire (approximately 10 minutes)
Secondary outcomes (4)
Rank Order of Preference
The rank order of preference of carbon footprint, patient's ability to use the device, cost of device, dosing schedule and clinical evidence for the device in carbon-containing and non-carbon-containing groups. Sensitivity analyses will assess the influence of HCP role, care setting, prescribing status, HCP experience, respiratory specialist status, age, use of WAN guidelines and case scenario.
Measured: At completion of the online questionnaire (approximately 10 minutes)
Inhaler Recycling Recommendation
The proportion of HCPs that recommend inhaler recycling to their patients.
Measured: At completion of the online questionnaire (approximately 10 minutes)
Inhaler Recycling Facilities
The proportion of HCPs that have inhaler recycling facilities available in their clinical setting.
Measured: At completion of the online questionnaire (approximately 10 minutes)
Use of Wessex Asthma Network Guidelines
The proportion of HCPs that confirm the use of Wessex Asthma Network guidelines in their clinical practice.
Measured: At completion of the online questionnaire (approximately 10 minutes)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted17 Sep 2026
- Study start1 Mar 2022
- Primary completion28 Aug 2025
- Study completion28 Aug 2025
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for AsthmaStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Model description
- Participants are randomised into either: * The Control arm- Participants receive the current standard Wessex Asthma Network inhaler guidelines with no information regarding the carbon footprint of individual inhalers * The Intervention arm- Participants receive the Wessex Asthma Network inhaler guidelines but which will contain the carbon footprint for individual inhalers.
- Masking
- None (open label)
- Enrolment
- 3,782 participants (actual)
Sponsor and investigators
- Lead sponsor
- Portsmouth Hospitals NHS Trust
- Sponsor type
- Other government
- Responsible party
- Sponsor
- Investigators
- Professor Thomas Brown, Principal investigator, Portsmouth Hospitals NHS Trust
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07825441
- Sponsor's protocol ID
- PHU/2020/51
- Other IDs
- 285768, 21/HRA/5134
- Acronym
- REDUCE- Carbon
- Status last verified
- Sep 2026
- First submitted
- 19 Aug 2026
- Last updated
- 17 Sep 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 17 Sep 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- RandomisED Control Trial to Understand Whether Prescribing Choice for inhalErs is Influenced by Knowledge of the CARBON Footprint (REDUCE Carbon)
- ClinicalTrials.gov ID
- NCT07825441
- Acronym / sponsor ID
- REDUCE- Carbon / PHU/2020/51
- Conditions
- Asthma
- Keywords
- Carbon Footprint, Inhalers, Asthma, pMDIs
- Study type
- Interventional
- Recruitment status
- Completed
- Enrolment
- 3,782 participants (actual)
- Lead sponsor
- Portsmouth Hospitals NHS TrustOther government
- Study start
- 1 Mar 2022 (actual)
- Primary completion
- 28 Aug 2025 (actual)
- Study completion
- 28 Aug 2025 (actual)
- First posted
- 17 Sep 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
Climate change is a huge and present threat, with the devastating effects being increasingly seen in everyday life. The NHS contributes substantially to the UKs carbon footprint with an estimated 23 million tonnes gCO2Eq per year, 3% of which comes from pMDIs. There are a number of alternative inhalers, such as DPIs, which do not use propellant and therefore have a significantly lower carbon footprint. There is a call to move towards greener inhalers as part of the NHS long term plan for sustainability, to reduce the carbon footprint and therefore the environmental impact and help protect the health of our patients today and in the future.
When recommending an inhaler, a number of factors are usually considered including the ability of the patient to use the device and its cost. Up until now the environmental impact of each inhaler is not routinely available and therefore is not normally considered in prescription choice. Given the increasing evidence supporting the sizeable impact that pMDIs are having on global warming, there needs to be a shift in practice where the climate impact forms part of the decision-making process.
This study is looking to explore prescribing behaviours surrounding inhaler selection and in particular whether knowledge of the carbon footprint of inhalers has any sway on prescribing preference. By better understanding the decision-making process, this will allow the production of more comprehensive asthma management guidelines and potentially facilitate a drive to greener inhaler prescribing practices.
Detailed description
Inhalers are some of the most commonly prescribed medicines in the UK and can be expensive. They form the mainstay of treatment for asthma and COPD. They comprise either a pressurised metred dose inhaler (pMDI) or a dry powder inhaler (DPI). Despite global legislation some years ago that removed chlorofluorocarbons (CFCs) from inhalers (Montreal Protocol) due to their harmful effect on the ozone layer; there remains a large difference in the carbon footprint between pMDIs and DPIs. pMDIs have a higher carbon footprint than DPIs and contribute substantially to global warming. The effects of this are to be seen in everyday life and it is the responsibility of all individuals to 'reduce their carbon footprint'.
The environmental impact of inhaler use also comes from plastic waste from discarded inhalers. Over 50 million inhalers are prescribed in the UK each year1, and most of these will end up in landfill sites where they take centuries to biodegrade. There are an increasing number of schemes to recycle inhalers and local pharmacies will often provide these facilities, but this is not routinely advertised to patients.
Current guidelines recommend that where either a pMDI or DPI will be equally as good for the patient then the environmental impact of the inhaler should be considered. TheNational Institute for Health and Care Excellence (NICE) provides national guidance and advice to improve health and social care. Their guidance includes an algorithm to choose the best inhaler for a patient. Whilst this is helpful on an individual patient basis, there is currently no legislation that mandates the use of DPIs in preference to pMDIs.
The study hypothesises that if Health Care Professionals (HCPs) are provided with the information on the carbon footprint of each inhaler, this may influence the type of inhaler they recommend, i.e., with all things being equal they may show a preference for low carbon DPIs over high carbon pMDIs because of concerns over global warming.
A simple online study has been designed to test whether HCPs, if given information regarding the environmental impact of inhalers, as part of an asthma treatment guideline, are more or less likely to recommend a low carbon inhaler. By better understanding how the inclusion of carbon data influences inhaler prescription choice, we will be able to clarify whether the inclusion of carbon data in asthma treatment guidelines is likely to be beneficial in facilitating a drive to greener inhaler prescribing practices.
Study design
- Primary purpose
- Other
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- None (open label)
- Number of arms
- 2
- Model description
- Participants are randomised into either: * The Control arm- Participants receive the current standard Wessex Asthma Network inhaler guidelines with no information regarding the carbon footprint of individual inhalers * The Intervention arm- Participants receive the Wessex Asthma Network inhaler guidelines but which will contain the carbon footprint for individual inhalers.
| Arm | Type | Receives |
|---|---|---|
| Control Arm | Other | Other: WAN Inhaler guidelines onlyParticipants receive the current standard Wessex Asthma Network inhaler guidelines with no information regarding the carbon footprint of individual inhalers |
| Intervention Arm | Other | Other: WAN Inhaler Guidelines plus carbon footprint informationParticipants receive the Wessex Asthma Network inhaler guidelines plus information containing the carbon footprint for individual inhalers. |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (4 listed)
- Aged ≥18 years
- Working as an HCP within the NHS in a primary or secondary care setting
- Able to provide written e-consent
- Able to understand and complete the clinical case scenarios
Key exclusion criteria (1 listed)
- Inability to understand or comply with study procedures and/or inability to give fully informed consent.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| WAN Inhaler Guidelines plus carbon footprint informationWessex Asthma Network inhaler guidelines plus the carbon footprint infromation for individual inhalers. | Other | Intervention Arm |
| WAN Inhaler guidelines onlycurrent standard Wessex Asthma Network inhaler guidelines with no information regarding the carbon footprint of individual inhalers | Other | Control Arm |
Primary outcome
Health Care Practitioner Preference
Time frame: At completion of the online questionnaire (approximately 10 minutes)
The number and proportion of HCPs preferring high or low carbon inhalers between carbon-containing and non-carbon-containing groups, for each case separately and across all cases in total.
4 secondary outcomes
Rank Order of Preference
Time frame: At completion of the online questionnaire (approximately 10 minutes)
Inhaler Recycling Recommendation
Time frame: At completion of the online questionnaire (approximately 10 minutes)
Inhaler Recycling Facilities
Time frame: At completion of the online questionnaire (approximately 10 minutes)
Use of Wessex Asthma Network Guidelines
Time frame: At completion of the online questionnaire (approximately 10 minutes)
Results and safety
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 17 Sep 2026.
- Related InfoLink provided by the sponsor.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Professor Thomas Brown principal investigator
Portsmouth Hospitals NHS Trust
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing WAN Inhaler Guidelines plus carbon footprint information and WAN Inhaler guidelines only in people with Asthma, run by Portsmouth Hospitals NHS Trust at 1 site in United Kingdom.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 4 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: finished, as of the sponsor's last update on 17 Sep 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United Kingdom. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
The study is completed, but results are not available in the source record. That does not mean the treatment did or did not work.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Health Care Practitioner Preference (time frame: At completion of the online questionnaire (approximately 10 minutes)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 17 Sep 2026.