Asthma/Obstructive Pulmonary Disease Overlap

Update on Definition, Biomarkers, and Therapeutics

August Generoso; John Oppenheimer

Disclosures

Curr Opin Allergy Clin Immunol. 2020;20(1):43-47. 

In This Article

Therapeutic Approaches

Currently, no firm therapeutic approach exists for ACO. It has been argued that clinicians do not actually have the scientific information necessary to make specific treatment recommendations as studies in clearly defined patient populations of ACO have yet to be performed.[4] With that said, clinical decision making with regard to ACO is simply guided by a clinician's overall impression of whether a patient has more asthma-like or COPD-like disease.[3] Physicians are then left to choose a treatment approach without substantiated evidence of efficacy in this specific group.

Despite the above, there are reasonable default approaches that should be considered. These include smoking cessation and pulmonary rehabilitation when indicated.[3] Moreover, stressing the importance of vaccinations (such as influenza and pneumococcal pneumonia) will be paramount for potential ACO patients given their predisposition to increased morbidity. In addition, as described by Postma et al.[10] the recommended default position in ACO seems to be to start therapy for asthma (usually with an ICS), with step-up therapy often adding a LABA, LAMA, or LABA/LAMA combination possibly earlier in the treatment algorithm than would be considered for asthma. The previously discussed 2016 expert panel proposed that ICS combined with a LABA may be reasonable for ACO patients, especially in those with elevated serum or sputum eosinophils.[7] This recommendation is reinforced by a study by Pascoe et al.[24] who found that the short-term benefits of ICS for COPD patients are greater in those with evidence of a T2 high phenotype (as indicated by elevated blood eosinophil counts ≥2%). Similarly, Siddiqui et al.[25] found that peripheral blood eosinophilia in COPD patients was associated with a favorable response to ICS and LABA therapy. As such, ACO patients could possibly derive similar benefits. Of note, as there is concern for the use of LABAs in patients with asthma, the presence of an asthmatic component warrants concomitant use of ICS.[26] However, this does raise the concern of possible adverse effects of ICS (especially when overused), as ICSs have been associated with an increased risk of pneumonia in patients with COPD.[27]

As for LAMAs, though historically used mostly for COPD, this class of drugs has established a therapeutic role in step-up therapy in asthma. Peters et al.[3] found that the addition of tiotropium to a LABA and ICS combination improved symptoms and lung function in patients with uncontrolled asthma.[28] Moreover, leukotriene modifiers may be of value in those with atopy.

For potential ACO patients, the prudent approach may be to avoid monotherapy with LABA or LAMA alone. ICS should concomitantly be used so that symptoms are not simply masked by the LABA or LAMA, but instead the underlying inflammatory disease is appropriately treated with the ICS. In summary, until formal therapeutic trials are performed, it is reasonable to consider the early addition of a LABA and/or a LAMA to an ICS in ACO, while considering potential adverse effects of each of these agents upon choosing therapy.

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