Asthma and COPD Overlap: A Distinct Syndrome or Not?

In an interview with Donald P. Tashkin, MD, of the University of California Los Angeles, he offered some insights on his presentation at the 2018 AAAAI Annual Meeting, titled “The Overlap of Asthma and COPD (ACOS) is a Distinct Syndrome that Changes Treatment and Patient Outcomes.”

Q: In a debate-like session, you are speaking about the overlap of asthma and chronic obstructive pulmonary disease (COPD) as a distinct syndrome. Can you discuss your point of view on the topic?

A: Very few things in life are exactly black and precisely white. The asthma/COPD overlap (ACO) does exist, but it is not a distinct syndrome. But, neither is asthma itself or COPD itself a distinct syndrome. Both are heterogeneous and consist of a variety of phenotypes with varying underlying pathophysiologies. And the same is true of ACO. That’s my argument.

How do we know that ACO exists? There’s a wealth of information in the literature indicating that some patients with COPD have an asthma component, and some patients with asthma develop COPD. For example, there was an epidemiologic study that was carried out in Tucson, Arizona, and a randomly sampled population was followed for more than two decades. It turned out that those who had active asthma at the age of 20, which is an age far below that at which COPD emerges, had a greater risk of developing COPD in later life than even those who smoked, which is a major risk factor for COPD.

The problem with ACO is that there’s no consensus on how to define it. Several groups have proposed criteria, and most of what has been proposed includes at least two components: A history of asthma before the age of 40 and a marked response to a bronchodilator.

This topic is important because patients with ACO have worse outcomes, according to the literature. There is agreement in the literature that patients with ACO have worse quality of life, an increased risk of exacerbations, and an increased risk of hospitalization. Therefore, it’s important to identify these individuals to reduce the disease burden.

There is the argument that we don’t know how to treat ACO because no one has studied it in a clinical trial setting, which is true. The reason that it has not been studied with respect to response to different treatment options is there’s no consensus on how to define it. So, most of the studies regarding different interventions in COPD have excluded patients with asthma and vice versa for COPD.

I think we need to agree on a set of criteria for diagnosing ACO and then study a population to determine its natural history, underlying past physiology, and response to treatment.

Q: What are the challenges for physicians treating patients with ACO?

A: The major challenge is identifying ACO. We know that there is frequent misclassification of COPD as asthma, and there may be misclassification of asthma as COPD.

Q: What are the key takeaways of your session?

A: The takeaways are to recognize that ACO does exist, and it is a condition that needs to be identified in patients. If you have a patient over the age of 40 with asthma, just think about the possibility that there could be a COPD component. The same is true in cases with COPD. Most patients with COPD do not required an inhaled corticosteroid, according to the most recent guidelines, but those who have an asthma component—or ACO—need to have these agents included as part of their regimen. For patients who have ACO, treatment ought to incorporate some of the pharmacologic agents that are most appropriate for COPD, in addition to asthma.