How GPs can improve asthma outcomes and protect the environment

Australia’s National Asthma Council (NAC) is urging GPs to consider dry powder inhalers (DPIs) wherever possible, in an effort to improve patient outcomes as well as reduce the reliance on hydrofluorocarbon inhalers filled with ‘potent global warming gases’.
 
To help GPs and patients make the shift, the NAC has released its first information paper on the impact of pressurised metered dose inhalers (pMDIs), which also contains practice points on how to minimise wastage while maintaining good asthma control.
 
NAC Guidelines Committee member Dr Brett Montgomery, who is a Perth-based GP, told newsGP he was shocked when he found out about the climate impact of inhalers and the scale of the problem.
 
In 2022, Dr Montgomery, alongside his colleague John Blakey, wrote in the Australian Journal of General Practice how a simple shift in preferred treatment could significantly change someone’s carbon footprint.
 
‘To provide some perspective, the reduction in carbon footprint achieved by a person switching from regular pMDI use to DPI use [approximately 420 kg CO2e annually] is similar to them switching their petrol car to a hybrid [approximately 500 kg CO2e annually] or becoming vegetarian [approximately 660 kg CO2e annually],’ they wrote.
 
With more than five million prescriptions issued each year, pMDIs are the most common reliever medicine used in Australia, while an extra six million salbutamol pMDIs are estimated to be sold over the counter annually.
 
pMDIs have a much larger impact than other inhalers because they contain hydrofluorocarbon propellants, which are released during use and through leakage after disposal. 
 
Dry powder inhalers and soft mist inhalers have a 100–200-fold lower carbon footprint than pMDIs.
 
Annual Australian greenhouse gas emissions from short-acting beta2-agonists (SABA) inhalers have been estimated to be equivalent to over 350,000 tonnes of carbon dioxide – as polluting as driving a petrol car from Sydney to Perth more than 360,000 times.
 
The switch to DPIs could also result reduced asthma symptoms and greater prevention of severe exacerbations, Dr Montgomery explains.
 
‘We know that a quarter of people with asthma in Australia have both poor asthma control and use little or no inhaled corticosteroids,’ he said.
 
‘Health professionals can help educate patients to understand that while SABAs do give quick relief, they can, if used on their own, leave patients at risk of exacerbations, hospitalisation or worse.
 
‘For many people with asthma who tend only to take their medicines when driven to do so by symptoms, swapping to an anti-inflammatory reliever strategy can be a positive change, and it is usually easy to change to a dry powder inhaler at the same time.’
 
Not only can GPs make a greener choice when commencing people on an inhaler, Dr Montgomery also thinks there needs to be further investigation to ensure the diagnosis is correct.
 
‘There is evidence that overdiagnosis of asthma is common,’ he said.
 
‘Ideally, diagnosis should be confirmed with spirometry or other lung function tests.’
 
An analysis of the carbon footprint of as-needed budesonide-formoterol in mild asthma found that DPIs were associated with 95.8% lower carbon footprint compared with as-needed salbutamol pMDIs.
 
However, there are some patients for whom a pMDI is still the best option.
 
‘Some people are best served by conventional pMDIs, like children – especially under the age of six – or people with significant difficulty inhaling quickly,’ Dr Montgomery said.
 
‘But for a large proportion of adolescents and adults, a dry powder inhaler, or soft mist inhaler, will be appropriate and avoid emitting the propellant gases of metered dose inhalers.
 
‘If a pMDI is genuinely the safest choice for a patient, we should not make people feel guilty about using their inhalers.’
 
What has made things even easier here, Dr Montgomery says, is the 2020 listing of budesonide-formoterol as a single inhaler for use purely as-needed in mild asthma.
 
‘This gives immediate relief [beta-agonist: formoterol] but also the protection of a preventer [inhaled corticosteroid: budesonide] and this is available in a dry-powder inhaler,’ he said.
 
‘For my many patients who struggled to remember their regular preventer, it also tends to give them better asthma control.

‘It’s a win-win.’
 
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