From the Research
In well-controlled asthma, the target for sputum eosinophils is generally less than 3% of total inflammatory cells, as this threshold represents optimal control of eosinophilic airway inflammation and is associated with better clinical outcomes, as suggested by recent studies on asthma management 1.
Key Considerations
- Regular monitoring of sputum eosinophil counts can help guide treatment decisions, particularly regarding corticosteroid dosing.
- If sputum eosinophils exceed 3%, this may indicate suboptimal control of airway inflammation despite apparent clinical stability, potentially warranting an increase in inhaled corticosteroids (such as fluticasone, budesonide, or beclomethasone) or consideration of add-on therapies like montelukast or biologics (such as mepolizumab or benralizumab) in severe cases.
- The rationale behind targeting sputum eosinophils is that these cells release inflammatory mediators that contribute to airway hyperresponsiveness, mucus hypersecretion, and airway remodeling.
Treatment Implications
- Even in patients who appear clinically well-controlled based on symptoms and lung function, persistent eosinophilic inflammation may lead to future exacerbations and long-term airway damage if left untreated.
- Studies have shown that combination therapy with inhaled corticosteroids and long-acting beta2-agonists can be effective in achieving asthma control, as it treats both components of asthma pathophysiology, namely inflammation and smooth muscle dysfunction of the airways 2, 3.
- Leukotriene receptor antagonists can also be used as add-ons to inhaled corticosteroid therapy in patients whose asthma is not controlled by inhaled corticosteroids alone 4.
Conclusion Not Applicable
Instead, focusing on the key points:
- The most recent and highest quality study 1 supports the target of less than 3% sputum eosinophils for optimal control of eosinophilic airway inflammation.
- Other studies 2, 4, 3, 5 provide additional context on the management of asthma, including the use of combination therapies and the importance of monitoring and adjusting treatment based on patient response.