A new study of asthma patients with and without a history of drug misuse found that rates of attendance at an annual asthma review were poor across the whole group. Rates of flu vaccination, which is recommended for people with asthma, were also generally low. However, patients with a history of opioid use disorders (OUD) had worse outcomes from asthma.
The study found that people with a history of OUD were even less likely than others to have attended an annual asthma review. They were also more likely to use the oral steroid prednisolone, which suggests their asthma was less well-controlled and they were more likely to have asthma attacks.
The study demonstrates some of the challenges in asthma management, especially for people with a history of OUD. Current UK guidelines acknowledge the role of substance-use in asthma attacks, but new strategies are needed to help this group engage with treatment.
What’s the issue?
In the UK, approximately 5.4 million people receive asthma treatment. Treatment is a programme of supported self-management that includes attending regular asthma reviews, receiving flu immunisations and taking asthma medications as prescribed. Despite this strategy, the UK has one of the highest rates of death from asthma in Europe.
Substance misuse has been associated with poor asthma outcomes. In 2014, a UK National Review of Asthma Deaths identified substance misuse as a factor in 6% of asthma deaths. Small studies have also suggested that people with OUD and asthma have worse respiratory outcomes, in particular, serious asthma attacks, typically with breathlessness and tight chest. There is emerging evidence that inhalation of opioids may lead to irreversible lung damage.
Existing data on substance misuse in asthma comes from small-scale and case-series data. This large scale study was set up to examine potential explanations for these observations and to provide further evidence.
Using a primary care database of 275,151 asthma patients aged 16 to 65, the researchers identified 458 individuals flagged as having a current or past OUD. Each was matched to three controls without a history of OUD, taking into account age, gender, smoking status and socioeconomic status. The researchers found that, over a 12 month period, those with current or past OUD:
- were less likely to attend an annual asthma review
- were more likely to have received three or more prescriptions for an inhaler containing corticosteroids (inhaled corticosteroids, ICS) as preventer therapy
- were more likely to have been prescribed oral prednisolone, which can be used as a marker for asthma attacks
- were more likely to have been diagnosed with the common long-term lung disease, chronic obstructive pulmonary disorder (COPD), which also describes long term breathing difficulties.
Asthma outcomes were worse among OUD patients, but attendance at annual review and rates of immunisation against flu were poor across the whole study group. Less than a third of all those included attended an asthma review and three-quarters missed out on flu immunisation during the study.
Why is this important?
In the UK, supported self-management is the cornerstone of asthma treatment and has been shown to reduce hospital admission and unscheduled medical appointments. This study raises the challenge of how self-supported care can be provided for people with a history of OUDs.
Other health conditions are often neglected in this group. For example, the dual diagnosis of asthma and COPD is more likely in asthma patients with a history of OUD, and is associated with more deaths from all causes. This research could help draw attention to inequality of treatment for long-term conditions in people with OUDs. However, substance misuse is generally under-recorded in primary care databases, and the researchers urge caution in generalising from these results.
The study found low attendance at asthma reviews and a low level of flu immunisation across the whole study group. This suggests that new strategies might be required not only in those with a history of OUD, but also in the general population of asthma patients.
The next steps will be to understand and overcome barriers to accessing asthma care faced by asthma patients with OUD.
Current UK guidelines acknowledge the role of substance misuse in acute asthma exacerbation. These patients, as well as other marginalised groups, could benefit from strategies to help them engage with treatment. This could include up-skilling healthcare professionals who already see OUD patients for other reasons to support management and routine immunisations. This could be more effective than redirecting asthma patients to primary care. Other strategies could include teleconsultations to provide advice to non-attenders, and to reinforce self-management, including how to recognise deterioration and how to access services.
This study has already had an impact locally. Pharmacies providing collections of opioid substitution therapy now promote flu vaccination alongside medication pick up. This year-on-year campaign, led by the Sheffield City Council Drug and Alcohol Action team, has led to a gradual improvement in vaccination rates.
The researchers are developing interventions to improve the lung health of opioid users. Further research is required to identify reasons for poor asthma care among those from vulnerable and marginalised populations and to better understand how OUD affects long-term respiratory outcomes.
You may be interested to read
The full paper: Oliver P, and others. A primary care database study of asthma among patients with and without opioid use disorders. npj Primary Care Respiratory Medicine 2020; 30:17
A case study describing the consequences of poor asthma control in OUD in one patient: Case study: Asthma exacerbation with heroin use, GP Online. (published: 2017)
A summary of the effects of substance-use on asthma and information on getting help: Recreational drugs and asthma, Asthma UK (last updated: 2019)
Nightingale R, and others. Screening heroin smokers attending community drug clinics for change in lung function: A cohort study. Chest 2019;157:3
This research was funded by the NIHR Collaborations for Leadership in Applied Health Research and Care (CLAHRC) with sponsorship from the Academic Health Science network.