Primary prevention

Long term reduction of exacerbation risk should be a priority of asthma management in order to decrease risks to the patient and need for oral corticosteroids (which have important short term and cumulative long term adverse effects).[1]​ Even patients with few or no asthma symptoms (or asthma labeled as ‘mild’) can have severe or fatal exacerbations, which may occur with unpredictable triggers (e.g., viral infection, allergen exposure, pollution, stress).[1]​ Asthma exacerbations are best prevented by long-term treatment with inhaled corticosteroids (ICS) and add-on medical therapy in conjunction with treatment of modifiable risk factors such as avoidance of known asthma triggers (e.g., allergens and cigarette smoking) and treatment of comorbidities such as obesity and anxiety.[1][29][39]​ Add-on medical therapy (most commonly with a long-acting bronchodilator) not only improves asthma control but has been shown to reduce asthma exacerbations.[40]

ICS substantially reduce the risk of exacerbations and are an effective preventer drug.[1][13]​ The Global Initiative for Asthma (GINA) recommends starting ICS-containing medication in all patients at diagnosis, or as soon as possible after, and advises that the importance of ICS-adherence should be emphasised to all patients.[1]​ GINA does not recommend short-acting beta-2 agonist-only treatment for asthma, due to the increased risk of severe exacerbations and mortality with this approach.[1]​ The 2019 British Thoracic Society guideline recommends that ICS should be considered for patients who have had an asthma attack in the last two years, are using inhaled beta-2 agonists ≥3 times a week, are symptomatic ≥3 times a week, or are waking one night a week.[13]​ See  Asthma in adults.

For adults who have persistent asthma, but who have suboptimal control of their asthma despite daily use of ICS with a long-acting bronchodilator, the addition of a leukotriene receptor antagonist can be considered.[13] ​Leukotriene receptor antagonists can help to reduce moderate and severe asthma exacerbations and improve lung function and asthma control compared with the same dose of ICS alone. However, current evidence does not support leukotriene receptor antagonists as an ICS-sparing agent.[39]​ Note that there is the potential risk for neuropsychiatric adverse events (e.g., nightmares, mood and behaviour problems, suicidal ideation) with montelukast use: benefits and risks should be carefully considered with the patient before use, and the patient should be closely monitored for these adverse effects during treatment.[1]

To minimise exacerbation risk, all patients should have regular review by a healthcare professional and be educated in asthma self-management, including self-monitoring of symptoms and/or lung function and use of a written asthma action plan: together, these measures dramatically reduce morbidity, including significant reductions in asthma-related hospitalisations and accident and emergency department or unscheduled clinic visits.[1]​ The use of a written, personalised asthma action plan should be strongly encouraged to support self-management and increase its effectiveness.[1][41] Asthma and Lung UK: adult asthma action plan Opens in new window​​​ The asthma action plan helps patients to recognise when their asthma is deteriorating and how to respond appropriately: for example, increasing usual reliever and preventer (controller) treatment, starting a short course of oral corticosteroids, and determining when to seek medical help.[1]

International guidelines also recommend treating modifiable risk factors and comorbidities (e.g. smoking, obesity, anxiety) and giving advice about non-pharmacological therapies and strategies when appropriate (e.g., smoking cessation programmes, physical activity, weight loss, avoidance of triggers).[1] Weight reduction may improve asthma outcomes in obese patients.[42]​ Patients with suspected occupational asthma should be referred for expert advice promptly.[1][13]​ GINA recommends that patients with one or more risk factors for exacerbations should have more frequent review than patients at low risk.[1]​​

Further, international guidelines recommend checking inhaler technique and adherence frequently (e.g., at every visit).[1]​ Following training, inhaler technique worsens over time (with issues often recurring within 4 to 6 weeks of initial training), therefore regular review and correction of technique is important.[1]​ Patients should be involved when choosing inhalers: using an inhaler that the patient prefers and can use correctly promotes adherence and reduces exacerbation risk.[1] In addition to basing the choice on evidence of effectiveness, potential barriers to correct use (e.g., arthritis, cognitive impairment) and adherence (e.g., cost, complicated regimen) should be considered.[1]​ A 2022 Cochrane review reported that a range of digital interventions may lead to better adherence (particularly in those with poor adherence) and reduced exacerbations (based on low-certainty evidence).[1]​ Examples of interventions that appear to be effective are electronic monitoring of inhaler use, electronic inhaler reminders and text messages.[1]

Several cross-sectional studies have shown low serum levels of vitamin D to be linked to impaired lung function, higher exacerbation frequency, and reduced corticosteroid response.[1][43]​ In adults with vitamin D deficiency and asthma, vitamin D supplementation may reduce the rate of asthma exacerbations requiring treatment with systemic corticosteroids.[1] More good-quality evidence is required before definitive clinical recommendations can be made regarding supplementation with vitamin D.[1][44][45]

Adults with asthma are at high risk of developing complications after contracting the influenza virus, yet most adults with asthma do not receive an annual influenza vaccination. Only one third of all adults with asthma and one fifth of adults with asthma younger than 50 years receive the influenza vaccine annually, according to one analysis.[46] One systematic review reported no significant safety concerns or increased risk of asthma-related outcomes (including exacerbations or hospitalisations) after live attenuated influenza vaccination in adults younger than 50 years with mild to moderate asthma.[1]​ Annual vaccination against seasonal influenza and H1N1 is advisable for all people with asthma. GINA advises that people with asthma should also be encouraged to follow their local immunisation schedule for pneumococcal, respiratory syncytial virus, pertussis and COVID-19 vaccinations.[1]

Secondary prevention

Patients who continue to experience asthma exacerbations despite treatment may need to have their treatment stepped up. Before this happens, clinicians need to check patients' adherence to treatment and inhaler technique, review any persistent allergen/irritant exposure, modifiable risk factors and comorbidities that may contribute to symptoms/exacerbations, and confirm that symptoms are due to asthma.[1][13]​​ After a treatment step-up, the patient’s response should be monitored.[1][13]​ The Global Initiative for Asthma (GINA) recommends that patients who are still having frequent exacerbations (e.g., greater than 1 to 2 yearly, repeated accident and emergency department visits) despite good adherence to appropriately stepped up treatment should be referred for expert advice, and that referral should also be considered (alongside alternative treatments) if there is no response to step-up after 2 to 3 months.[1]​ For more details on the chronic management of asthma in adults, see  Asthma in adults.

Applying educational interventions in the emergency department may reduce subsequent asthma admissions to hospital.[76] In addition, educational interventions in the emergency department that target either patients or primary care providers may improve follow-up visits with primary care providers after asthma exacerbations.[75]

A simple, history-based prediction model, combined with spirometry results, may help to identify patients at risk of severe asthma exacerbations. The additional value of fractional exhaled nitric oxide (FeNO) is modest. The model needs to be studied in clinical practice to assess its utility.[77]

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