Ep 146 – Asthma diagnosis and treatment: what's changed in the 2024 BTS, NICE and SIGN guideline?

In this episode, Dr Hannah Rosa discusses the new asthma guideline from the British Thoracic Society (BTS), NICE and SIGN, which was published in 2024. This guideline, based on the latest research, contains some big changes, which will hopefully help you to improve the lives of your patients living with asthma. In this first part of a two-episode series, topics covered include when to suspect asthma, how to confirm an asthma diagnosis and the pharmacological treatment pathway in people aged 12 and over. The second part of the series, which will be released later in the year, covers pharmacological treatment in children aged 11 and under, monitoring asthma control and self-management.

Key take-home points

• We should suspect asthma if a patient has symptoms such as wheeze, noisy breathing, cough, breathlessness and chest tightness – especially if these symptoms vary during the day or are seasonal. We should also enquire if any triggers make the symptoms worse or if there is a positive family history for asthma or hay fever.
• We should check for a possible occupational component by asking if symptoms are the same, better or worse on days away from work. If occupational asthma is suspected, we should refer to an occupational asthma specialist.
• To diagnose asthma in people aged over 16 with a history suggestive of asthma, step 1 is to measure the blood eosinophil count or the fractional exhaled nitric oxide (FeNO) level. If the eosinophil count is above the laboratory reference or the FeNO level is 50 parts per billion or more, then asthma can be diagnosed. If these tests are both normal, the next step is to measure bronchodilator reversibility with spirometry, or if spirometry is not available or it is delayed, then to ask our patients to measure peak expiratory flow twice a day for 2 weeks.
• To diagnose asthma in children aged 5 to 16 with a history suggesting asthma, step 1 is to measure the FeNO level. If this is normal, step 2 is to measure bronchodilator reversibility with spirometry, or if spirometry is not available or it is delayed, to measure peak expiratory flow variability. The next step, if needed, is either to perform skin prick testing to check for a dust mite allergy, or to measure the total immunoglobulin E level and perform a blood eosinophil count.
• We should refer to a specialist respiratory paediatrician any preschool child who has had: an admission to hospital or two or more admissions to an emergency department with wheeze in a 12-month period.
• The first treatment step for patients aged 12 and over with newly diagnosed asthma is to offer anti-inflammatory reliever (AIR) therapy, or if they are highly symptomatic, or they have had severe exacerbations, to offer a low-dose maintenance and reliever therapy (MART).
• The next step for patients whose asthma is not controlled on low-dose MART is to increase to moderate-dose MART. If asthma still is not controlled using moderate-dose MART then we are advised to then check the FeNO level, if available, and a blood eosinophil count. If either of these are raised, then we should refer the patient to a specialist in asthma care.
• After starting or adjusting any medication for asthma, we should review the response to treatment after 8 to 12 weeks.
• In 2024, the MHRA issued a new safety alert advising us that we should be aware of the risk of neuropsychiatric reactions when prescribing montelukast.

Key references

1. NICE. Asthma: diagnosis, monitoring and chronic asthma management (BTS, NICE, SIGN). 2024. https://www.nice.org.uk/guidance/ng245.
2. Asthma and Lung UK. Objective diagnostic testing for asthma. 2024. https://www.asthmaandlung.org.uk/healthcare-professionals/adult-asthma/diagnosis-testing/objective-testing.
3. Asthma and Lung UK. Peak flow diary. https://shop.asthmaandlung.org.uk/collections/health-advice-resources/products/peak-flow-diary-1.
4. Asthma and Lung UK. Peak flow variability calculator. https://www.asthmaandlung.org.uk/healthcare-professionals/adult-asthma/diagnosis-testing/perf-calc.
5. NICE. Inhaled corticosteroid doses for the BTS, NICE and SIGN asthma guideline. 2024. https://www.nice.org.uk/guidance/ng245/resources/inhaled-corticosteroid-doses-for-the-bts-nice-and-sign-asthma-guideline-pdf-13558148029.
6. Dweik RA, et al. Am J Respir Crit Care Med. An Official ATS Clinical Practice Guideline: Interpretation of Exhaled Nitric Oxide Levels (FeNO) for Clinical Applications. 2011;184(5):602-615. doi.org/10.1164/rccm.9120-11ST.
7. Nayyar M, et al. Thorax. P121 Raised blood eosinophil count as a predictor of severe asthma exacerbation. 2021;76:A154.
8. MHRA. Montelukast: reminder of the risk of neuropsychiatric reactions. 2024. https://www.gov.uk/drug-safety-update/montelukast-reminder-of-the-risk-of-neuropsychiatric-reactions.