Al Rizzo, MD: Understanding Asthma-COPD Overlap

The overlap between asthma and chronic obstructive pulmonary disease (COPD) can be identified by the similar exacerbations, the frequent effect on respiratory symptoms, and even therapies.

Yet there’s clear distinctions that separate the 2 respiratory conditions—primarily, the potential for patient outcomes. In a recent interview with MD Magazine®, Al Rizzo, MD, chief medical officer of the American Lung Association, explained what’s currently known in the link and disparities between asthma and COPD.

MD Mag: How do we currently identify disparities between asthma and COPD? How do the conditions’ overlap influence care?

Rizzo: Interesting question. I'll answer the last question first.

There's an entity called asthma-COPD overlap syndrome that right now, the pulmonary community is not sure what exactly that means. So let's take them one at a time. They have a lot of common findings.

Asthma and COPD both involve inflammation in the airway. The inflammation is not quite the same in asthma and COPD. We start with asthma—the inflammation is usually caused by either an allergen that people are exposed to, possibly an irritant that they inhale, or an infection that triggers an immune system change in the airways that causes inflammation.

Not everybody has to be allergic, to have a specific allergy in order to get that inflammation triggered. But once the airway is a little more sensitive, a little more inflamed, it's going to lead to symptoms such as coughing, of wheezing when the proper trigger is exposed. And that can be a mild moderate or severe case.

Individuals with mild asthma may only have a cough when they get around a change in their environment and inhale a trigger. Others, unfortunately, have significant inflammation that narrows the airway—makes it hard to breathe and ends up in a hospital for what they call an exacerbation of the asthma, or an asthma attack.

Those individuals often need ongoing maintenance therapy, which usually includes a drug called an inhaled steroid, because the inflammation that needs to be controlled—along with the combination of bronchodilators, long-acting beta agonist, long-acting muscarinic agents. And also, leukotriene-modifying agents in asthma, more recently, the last several years, have resolved.

We've also seen the development of what's called biologics, because we know the inflammation in the airways for asthmatics can include eosinophilic inflammation as well as allergic inflammation. And the biologics are more designed to nip that immune system early on, before it's allowed to release the chemicals that lead to the inflammatory process in the airways.

Asthma, by itself, tends to be a little more younger age group than COPD. Often, it does have identifying features such as the allergies I mentioned. And most asthmatics can be controlled with the drugs that we have available to us if they adhere to the drugs.

Asthma, unlike COPD patients, can feel very good in between their attacks and often don't feel like they have a chronic illness that needs medication on a daily basis. So, it's constantly a struggle to make patients understand why a controller medication or daily maintenance medication is being given, and how important it is to stick with that. Some individuals stop it during certain seasons, or they don't think they have any triggers, and sometimes they can get away with it.

But unlike that, COPD is a more chronic condition where the symptoms are there pretty much all the time, and can get worse. So if we switch to COPD—the inflammation as I mentioned, there's not always a clear cut, as far as eosinophils or allergic in nature. There's another kind of inflammation that's going on in the airways, attributed to exposures along the way.

I mentioned already, tobacco is one of the main triggers. But other inhaled irritants can cause the same type of inflammation, and there may be genetic reasons why some individuals have a higher risk of COPD. A number of other studies are looking at long-term changes that go on in patients with COPD, so as to potentially identify how we can trigger or intervene at the right time.

COPD patients unfortunately, they tend to be a little older. They also tend to have other comorbidities more commonly. This would include heart disease, diabetes, obesity, just because that age group starts to have the chronic illnesses of aging.

Unfortunately, COPD is in some ways a marker—that individuals who have heart disease and COPD tend to do worse. The inflammation in the COPD may be the same type of inflammation that's going on in the blood vessels that affect the heart. So, we often see individual COPD succumbing to heart disease sooner than they otherwise would.

COPD right now is not curable. It is a disease we can treat with medication to help control symptoms. Individuals sometimes include lung transplantation as a way to control the severe progression, but often COPD patients, because their comorbidities and they often tend to be older, are not necessarily the best candidates for transplantation.