What are the Similarities and Differences COPD and Asthma?

After a recent study, researchers have found that asthma and COPD aren't so different and that they have many things in common. While they are still two separate diseases that should be treated differently, looking at them with a common denominator gives us insight on the best treatments.

One of the primary difference between the two is their triggers. Asthma reactions are triggered by cold air, exercise, and exposure allergens. Alternatively, COPD flare-ups are often caused by different respiratory tract infections.

The CHAIN study, recently published in "Chest", found that 15% of the patients diagnosed with COPD also had features commonly found in patients who have asthma. The researchers diagnosed these patients as having “ACOS” or asthma-COPD overlap (ACO).

Patients labeled as having ACO had a previous diagnosis of asthma or a robust bronchodilator response (BDR), defined as >400 cc and 15%. They also met ACO criteria if they had two of the following: blood eosinophils >5%, immunoglobulin E >100 IU/mL, or two separate bronchodilator tests with a positive BDR (>200 cc and 12%).
Asthma overlapping with COPD isn't a new concept. The line between COPD and Asthma has always been a little blurry to medical researchers.

The National Asthma Education and Prevention Program Expert Panel Report identifies asthma as "a complex disorder characterized by variable and recurring symptoms, airflow obstruction, bronchial hyper-responsiveness, and underlying inflammation."

The executive summary of the Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease (GOLD) defines COPD as "a common preventable and treatable disease, characterized by persistent airflow limitation that is usually progressive and associated with an enhanced chronic inflammatory response."
Both Asthma and COPD have one thing in common – they are considered inflammatory diseases characterized by airflow obstruction.

The main separating factors are demographics, clinical history, and spirometry results. People can develop asthma usually as children or young adults. COPD usually develops after 40, with a history of smoking or exposure to air pollutants.

However, people over the age of 40 can still develop asthma and asthmatics who don't adequately treat their asthma and experience flare-ups can see a steady decline in their lung function. A genetic study concluded that there is little to no common genetic predisposition to COPD and asthma, or if there is, it is being obscured by environmental factors.

Since the treatments for COPD and Asthma are so similar, does it matter how patients labeled with airway diseases receive treatment? The answer is yes. Inhaled corticosteroids (ICSs) are are often used to treat asthma. Some studies have shown that COPD patients with ACO exhibit improvements using inhaled corticosteroids and fewer exacerbations, yet others studies show that corticosteroids used with patients diagnosed with COPD alone may worsen their condition.

In closing, it is always best to consult your doctor or pulmonologist on how to manage and tell the difference between asthma and COPD. With so many treatment options available it is always wise to regularly consult with a physician to ensure proper treatment.

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