Severe and difficult to treat asthma
INTRODUCTION
In the UK, 5.4 million people are receiving treatment for asthma, of whom over a million people under 16 years old (8.68% of the population).1 Of these, 4% of adults and 3% of children are classified as having severe asthma.1
Despite evidence-based guidelines, asthma-related illness and deaths remain high. Poor asthma control significantly affects quality of life and leads to unscheduled healthcare use and hospital admissions. Around1,400 asthma-related deaths occur each year,2 most of which are considered avoidable or preventable with good asthma care.3
Learning objectives
On completion of this resource, you should have a clearer understanding of:
- The need to assess control in patients with asthma
- Addressing uncontrolled asthma
- The difference between difficult-to-treat and severe asthma
- When to refer for specialist advice
- Eligibility criteria for biologic therapy
This module is offered at an advanced level. Read the accompanying article and answer the five assessment questions, then download the certificate of completion. You should record the time spent on this activity for your CPD portfolio.
Contents
Identifying uncontrolled asthma
Poor asthma control is strongly associated with increased rates of exacerbations, hospitalisations, absenteeism from work or school, impaired lung function, and reduction in quality of life (QoL).
Symptoms associated with poor asthma control include:
- Daytime symptoms more than twice a week
- Any night waking due to asthma
- Use of SABA reliever more than twice a week
- Any activity limitation due to asthma
Using a validated tool such as the Asthma Control Test4 at every review is recommended to identify poor symptom control.
It is important to consider future risk of exacerbations, which can result in permanent airway remodelling and fixed airflow obstruction, and the risk of side effects and comorbidities associated with medication. Frequent courses of oral corticosteroids (OCS), (two or more a year), and short acting bronchodilators (12 or more a year) put patients at greater risk of dying from an asthma attack,5 and patients who require more than three short-acting bronchodilators a year are at greater risk of an asthma exacerbation.6Patients who require frequent courses of OCS are at risk of developing one or more significant comorbidities, including diabetes, osteoporosis and pneumonia.7
Addressing uncontrolled asthma
There are many reasons for potential poor asthma control which should be considered when assessing patients: suboptimal inhaler technique and poor adherence to prescribed medication are common, with up to 80% of patients having poor technique8and 75% reported to have poor adherence.9 Poor adherence with ICS contributes to poor symptom control, resulting in overuse of SABA.
The BTS/ NICE/ SIGN10 and GINA5 guidelines recommend the use of maintenance and reliever therapy (MART) and Anti-inflammatory Reliever (AIR), to ensure that patients are receiving adequate ICS coverage while providing effective symptom relief.
Consider, and where possible reduce, exposure to environmental factors including exposure to allergens and irritants, animals, damp, and mould in the home and workplace. Environmental exposures also include inhaled substances including tobacco smoke, vapes, illicit drugs and passive smoking.
Multimorbidity is common in asthma, is associated with worse quality of life, increased healthcare use and risk of adverse events, and complications from treatment e.g. osteoporosis, cardiovascular and metabolic disease, and should be actively treated.
Difficult-to-treat or severe asthma?
A small proportion of peoplewill have persistent symptoms which are refractory to conventional treatment of inhaled corticosteroids (ICS) and long-acting beta 2 agonist (LABA). This can result significant symptom burden affecting their quality of life and are at greater risk of exacerbations, complications of chronic airway inflammation and potential side effects of OCS. Such patients may have may have difficult-to-treat asthma or severe asthma.
‘Difficult-to-treat’ asthma can be defined as the presence of persisting symptoms, despite medium to high ICS, with second controlled usually a LABA, or maintenance OCS. ‘Difficult-to-treat’ asthma may be due to several reasons including:
- Incorrect diagnosis
- Poor adherence with treatment
- Undiagnosed comorbidities
- Comorbidities which compound the severity of symptoms
These factors make asthma more difficult to manage, and should be addressed when patients present with uncontrolled asthma.
A diagnosis of ‘severe asthma’ is reserved for people with uncontrolled asthma despite good adherence with both optimised high dose ICS and LABA treatment and management of contributory factors, or worsening symptoms when high dose treatment is reduced. It is estimated that 17% of the population with asthma may have difficult to treat asthma, and 3.7% may have severe asthma.5
When to refer for specialist advice and assessment
Use the HASTE11 tool to assist in identifying patients who would benefit from review by the severe asthma services (Table 1).
TABLE 1. HASTE11 TOOL TO IDENTIFY PATIENTS WHO WOULD BENEFIT FROM SPECIALIST ASSESSMENT | ||
H | High intensity treatment | Is the patient the optimised and on high end of treatment? |
A | Adherence | Is the patient taking the correct dose and frequency of prescribed medication |
S | OCS | Has the patient required 2 or more courses of OCS or been admitted to hospital due to asthma in the previous 12 months? |
T | Inhaler Technique | Is the patient’s inhaler technique correct? |
E | Excluded/identified comorbidities | Have conditions that mimic or exacerbate asthma been identified? |
If you answer yes to these questions, make ‘HASTE’ and refer | ||
Biologic therapies
Severe Asthma Services (SAS) provide specialist assessment and treatment, including access to monoclonal biologics and specialist interventions for comorbidities, for people with difficult to treat asthma and severe asthma.
The SAS act as ‘gate keepers’ to monoclonal biologic drugs, ensuring that only patients meeting NICE eligibility criteria receive them. Criteria include:
- Severe uncontrolled asthma despite taking high-dose ICS
- History of 3 or more severe asthma exacerbations per year, OR
- Regular treatment with oral corticosteroids
- Specific biomarkers such as high eosinophils
NICE11 has approved several monoclonal biologic drugs, which work by blocking the inflammatory pathways in asthma. Careful consideration of the asthma phenotype and associated comorbidities is essential when selecting the most appropriate biologic to achieve optimal clinical outcomes.
Frequency of dosing varies from 2 weekly to 8 weekly, so patient preference should also be considered. In most cases, biologics are self-administrated at home with support from the severe asthma team.
The continual process of assessment, adjustment of treatment and reviewing symptoms to achieve asthma control continues in managing severe asthma, with patients being reviewed and assessed by the SAS, to ensure that those commenced on monoclonal biologics are achieving the clinical outcomes stipulated by NICE, which include:
- Reduction in exacerbations
- Reduction in the requirement for OCS
- Improvement in quality of life.
If response has been suboptimal, the SAS will consider whether to switch to a different biologic or to discontinue biologics altogether. Patients who do not met the NICE criteria for biologics will usually continue to be reviewed and supported by the SAS.
Conclusion
Asthma management requires a continual process of assessment, adjustment and review to achieve the best possible outcomes for patients. This enables poor symptom control to be identified and explored. In many cases, this can be addressed by good asthma care delivered by nurses.
However, a relatively small number proportion of patients will have uncontrolled symptoms, despite inhaled ICS and LABA and are at risk of exacerbations and developing significant comorbidities and complications.
These patients need to be identified and referred to the SAS for assessment for advanced treatments and special interventions. Using a personalised approach in the diagnosis and management of severe asthma, improvement in asthma control and reducing the future risk of complications is achievable, as monoclonal biologics are transforming the lives of people living with severe asthma.
References
- Cumella A, and Renwick L. Living in Limbo: the scale of unmet need in difficult and severe asthma. Asthma UK; 2019. https://www.asthmaandlung.org.uk/sites/default/files/2023-03/living-in-limbo---the-scale-of-unmet-need-in-difficult-and-severe-asthma.pdf
- Office of National Statistics.Deaths from asthma, respiratory disease, chronic obstructive pulmonary disease and flu, England and Wales, 2001-2018 occurrences; 2020. https://www.ons.gov.uk/peoplepopulationandcommunity/birthsdeathsandmarriages/deaths/adhocs/11241deathsfromasthmarespiratorydiseasechronicobstructivepulmonarydiseaseandfluenglandandwales20012018occurrences
- Royal College of Physicians (RCP). Why asthma still kills: National Review of Asthma Deaths;2014. https://www.rcp.ac.uk/media/i2jjkbmc/why-asthma-still-kills-full-report.pdf
- Nathan RA, Sorkness CA, Kosinski M, et al. Development of the asthma control test: a survey for assessing asthma control. J Allergy Clin Immunol. 2004 Jan;113(1):59-65.
- Global Initiative for Asthma (GINA). Global strategy for asthma management and prevention; 2026. https://ginasthma.org/2026-gina-strategy-report/
- Bloom CI, Cabrera C, Arnotorp S, et al. Asthma-Related Health Outcomes Associated with Short-Acting β2-Agonist Inhaler Use: An Observational UK Study as Part of the SABINA Global Program. Adv Ther. 2020;37(10):4190-4208.
- Price D, Trudo F, Voorham J, et al (2018. Adverse outcomes from initiation of systemic corticosteroids for asthma: long-term observational study. J Asthma Allergy 2018;11:193-204.
- Melani AS, Bonavia M, Cilenti V, et al. Inhaler mishandling remains common in real life and is associate with reduced disease control. Respir Med 2011;105:930-938
- Ernst P, Spitzer WO, Suissa S, et al. Risk of fatal and near fatal asthma in relation to inhaled corticosteroid use. JAMA 1992;268:3462-3464
- NICE NG245. Asthma: diagnosis, monitoring and chronic asthma management (BTS, NICE, SIGN); last updated October 2024 https://www.nice.org.uk/guidance/NG245
- AHSN Health Innovation Oxford. Transferring asthma care through improved access to diagnostics and innovative treatments; 2023. https://www.healthinnovationoxford.org/clinical-priorites/respiratory/asthma-biologics-toolkit/asthma-biologics-overview/
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