Chronic obstructive pulmonary disease (COPD) is a general term that describes progressive respiratory diseases including emphysema and chronic bronchitis. COPD is characterized by decreased airflow over time and increased inflammation.
Why Asthma and COPD Are Often Confused
Asthma is largely considered a separate respiratory disease, but is occasionally mistaken for COPD because it has similar symptoms. These include: chronic coughing, wheezing, and shortness of breath.
“Millions of Americans currently have COPD and they don’t know it because they are undiagnosed or are given a diagnosis of asthma or bronchitis,” said Dr. Phillip Factor, Chief of Pulmonary, Critical Care, and Sleep Medicine at Beth Israel Medical Center. “Better appreciation of symptoms—especially in current and past smokers—can lead to COPD patients gaining an earlier entry into the healthcare system and an earlier diagnosis.” Early diagnosis is often critical to preserving lung function in people with COPD.
Still, roughly 40 percent of known COPD sufferers also have asthma, which is considered a risk factor for developing the disease. As you age, the likelihood of this duel-diagnosis increases.
Differentiating Asthma and COPD
Age of the Patient
While airway obstruction is central to both diseases, the time when COPD symptoms first present themselves can help distinguish them from asthma. For instance, people who have asthma are typically diagnosed as children, explained Dr. Neil Schachter, Medical Director of the Respiratory Care Department of Mount Sinai Hospital and Professor of Pulmonary, Critical Care and Sleep Medicine. On the other hand, COPD symptoms usually present only in adults over the age of 40 who are current or former smokers.
“Spirometry is really the easiest way to diagnose COPD,” continued Dr. Schachter. “It remains the cornerstone of making a diagnosis, but physicians have other ways of anticipating COPD, such as with CT scans. Arterial blood gas studies are not done as regularly anymore. There are also instant methods of determining lung function by using a peak flow meter and that test is also available for home use.”
Response to Treatment
Although both COPD and asthma respond well to treatments such as smoking cessation and airway-opening medications like bronchodilators, lung function is only fully reversible in asthma patients. A diagnosis of asthma along with COPD often means a significantly accelerated decline in lung function as the COPD progresses—even in patients with mild forms of the disease.
The triggers that cause exacerbations of COPD and asthma are also different. Asthma is usually acutely worsened by exposure to allergens, cold air, and exercise. COPD exacerbations are largely caused by respiratory tract infections like pneumonia and influenza. COPD can also be made worse from exposure to environmental pollutants.
Despite those differences, COPD and asthma symptoms seem outwardly similar, especially the shortness of breath that characterizes both diseases. As it is for asthma patients, airway hyper-responsiveness (rapid spasms of the bronchioles) is a common feature of COPD, affecting 60 to 80 percent of patients.
Co-morbidities, or diseases and conditions that coexist along with the primary disease (either asthma or COPD) are also frequently similar. They include high blood pressure, impaired mobility, insomnia, sinusitis, migraine, depression, stomach ulcers, and cancer. Typically, more than 20 percent of COPD patients have three or more co-morbid conditions.