Australian Doctor 16th June 2023 16JUNE2023 issue | Page 36

Clinical Focus

16 JUNE 2023 ausdoc . com . au
| THE | RESPIRATORY ISSUE
Therapy Update

Asthma in adults

NEED TO KNOW
Asthma is one of the ‘ big five ’ respiratory diseases , which together cause significant global disease burden . Alongside asthma in this list are COPD , acute respiratory infections , TB and lung cancer .
Respiratory medicine
Dr Sarah Kentwell ( left ) is an advanced trainee in thoracic medicine . Dr Alistair Cook ( centre ) is a respiratory and sleep physician at the Metro North Hospital and Health Service ; department of thoracic medicine , Royal Brisbane and Women ’ s Hospital ; and Thoracic Research Centre at The Prince Charles Hospital , University of Queensland .
Professor Kwun Fong ( right ) is a respiratory and sleep physician at the Metro North Hospital and Health Service ; department of thoracic medicine , Royal Brisbane and Women ’ s Hospital ; and Thoracic Research Centre at The Prince Charles Hospital , University of Queensland .
GPs have a pivotal role to play in the appropriate diagnosis and management of this chronic respiratory condition .
Confirming the diagnosis is critical to avoid unnecessary and excessive use of preventer therapies and to avoid missing other diagnoses .
The main goals of care are to reduce the risk of exacerbations , control dayto-day symptoms , minimise medication side effects and prevent fixed airway remodelling .

ASTHMA is a common chronic respiratory condition that affects more than 250 million individuals worldwide . 1 Despite significant advances in our understanding of this condition over the past 30 years , asthma-related morbidity is common , and preventable hospital admissions and deaths still occur .

Asthma care can be delivered by a wide variety of clinicians — including adult and paediatric respiratory physicians and immunologists , nurses and allied health practitioners — although the primary care practitioner occupies the central and most critical role in diagnosis and management .
The episodic nature of asthma can make the diagnosis challenging , and normal spirometry despite a history of suggestive symptoms is a common conundrum . Appropriate initial options include repeating the test at a later date or performing two weeks of peak-flow readings .
If empiric ICS therapy is justified by significant symptoms , a significant ( greater than 12 % and 200mL ) improvement in cough syndrome , inducible laryngeal obstruction , breathing-pattern disorders , smoking-related COPD , bronchiectasis , heart failure , interstitial lung disease , pulmonary embolism and medication-related cough . 2
In addition to the missed opportunity to manage these conditions in their own right , inappropriately attributing them to asthma will often lead to unnecessary use
Many conditions can coexist with or mimic asthma and give the incorrect impression of severe disease .
ICS are the cornerstone of management and should be incorporated into treatment of asthma of all severities , including reliever-only therapy for mild asthma .
Long-acting bronchodilators are an add-on therapy if control is suboptimal despite moderate-dose ICS .
Symptom control has classically been the main prompt for therapy escalation or de-escalation , although biomarkers , such as blood eosinophils and fractional exhaled nitric oxide , can also aid decision-making .
Diagnosis
Asthma is an inflammatory condition characterised by variable airflow limitation accompanied by typical symptoms of wheeze , breathlessness , cough and chest tightness . 2 These features are often episodic and occur in response to triggers , such as inhaled allergens , viral infections , exercise , and certain medications such as beta blockers and NSAIDs .
The diagnosis requires confirmation of variable airflow obstruction by demonstration of spirometry evidence of bronchodilator reversibility , demonstration of peak flow variability or evidence of bronchial reactivity via provocation testing .
FEV1 after four weeks of ICS treatment can also confirm the diagnosis . 2 If a patient is already established on an ICS , repeat spirometry after cautious withdrawal of preventer therapies should be considered . Bronchial provocation testing represents a definitive test that can also be an effective way to rule out the diagnosis of asthma . 3
The importance of confirming the diagnosis is twofold : to avoid excessive use of preventer therapies and to ensure alternative diagnoses are not being missed .
Many conditions can coexist with or mimic asthma and give the incorrect impression of severe disease . In adults , these may include chronic upper airway
of salbutamol and ICS or oral corticosteroids
, which is not without risks .
Management
Goals
Once a diagnosis of asthma is established , the goals of care are to control symptoms and mitigate the risk of future adverse events , including asthma exacerbations , airway remodelling and medication side effects . 2 Preventing asthma exacerbations is of particular importance as these events can be associated with future exacerbation risk , lung function decline , significant corticosteroid burdens , social and economic disruption and mortality . 4 Specific
Persistent symptoms or exacerbations despite high-dose ICS therapy should prompt referral to specialist care , where advanced pharmacological therapy and multidisciplinary care can be facilitated .
traits that are independent risk factors for asthma exacerbations include insufficient ICS therapy ; high SABA use ( ≥3 200- dose canisters a year ); poor adherence to preventers or incorrect inhaler technique ; smoking , including e-cigarettes ; and comorbidities , such as obesity , chronic rhinosinusitis , gastro-oesophageal reflux , food allergy and mood disorders . 5 , 6 A low FEV1 ( less than 60 % predicted ) is also a risk factor for exacerbations , as is elevation of markers of eosinophilic inflammation , such as blood eosinophils and fractional exhaled nitric oxide ( FeNO ). 2 These risk factors are all potential targets for intervention and should be actively screened for and managed where possible .
General approach As our understanding of asthma evolves , we now appreciate the role of airway inflammation as the primary driver — rather than the mechanical effects of bronchoconstriction . This is reflected in the place of corticosteroids as the cornerstone of asthma management . ICS decrease the risk of asthma exacerbations , improve symptom control and reduce asthma-related death . This therapy is now recommended for all patients with asthma . 7 , 8
Recent society guidelines now discourage the use of SABA therapy alone . Either an ICS – formoterol combination as needed or a regular low-dose ICS plus SABA as needed are the preferred options for mild asthma . 2 This is based on recent evidence demonstrating ICS – formoterol combinations are superior to SABA alone at reducing severe exacerbations . 9
Patients with mild asthma , characterised