Those with moderate to severe asthma, especially those who were diagnosed as children, may have an increased risk of developing chronic obstructive pulmonary disease (COPD). According to a 2015 study in the Journal of Thoracic Disease, 16% of people with asthma will develop “insufficient airway reversibility after 21-33 years” living with the disease.  This is because, if uncontrolled with medications, the inner walls of the airways can undergo “remodeling” over time, causing the airways to be irreversibly narrowed—this is where COPD comes in: when the narrowing of airways is no longer reversible. 
Having asthma and smoking also increases the risk of developing COPD. Somewhere between 10 and 20% of smokers, in general, develop COPD —given the already increased risk of developing COPD if you have asthma, not smoking can dramatically reduce your risk of developing COPD. As well, because COPD must be diagnosed with breathing tests (spirometry), if COPD is misdiagnosed as asthma, inadequate or incorrect treatment can allow COPD to continue progressing—oxygen saturation or arterial blood gas tests should be done as well, to confirm the body’s ability to acquire adequate oxygen, which is impaired in COPD but rarely if ever affected in asthma.
While it is not well established what can be done to prevent the development of ACOS, there are a few “golden rules” that can help preserve your lung health. Avoiding COPD risk factors, such as air pollution, smoking, and second-hand smoke, working with chemicals, dust, and fumes , can help prevent COPD and mitigate the risk of asthma developing into COPD. According to the Centers for Disease Control, it is estimated around 21% of people with asthma smoke cigarettes, despite knowing smoking is bad for their asthma.  Avoiding smoking and smoke exposure is extremely important if you have asthma.
Other ways to reduce the risk of COPD include maintaining good health, including exercising regularly and eating well. Exercise can improve the efficiency of the lungs, and reduce symptoms, even if it cannot improve lost lung function —in addition, losing weight can improve symptoms of lung diseases like COPD and asthma.  Your diet can also play an important role. Maintaining a well-balanced diet can help with symptoms of both asthma and COPD, though no specific diet is known to prevent COPD. You will find that some foods may worsen symptoms, like those that cause bloating, but this can vary from person to person and based on disease severity. If you need help figuring out which foods are best, speak with your doctor or ask to be referred to a dietician.
Understanding the overlap of asthma and COPD, as well as how asthma, COPD and ACOS are treated, can help ensure patients are equipped to manage their disease.
Information on this page is for reference and educational purposes only. For more information about COPD, talk to your doctor or primary care provider.
Page last updated: October 29, 2018
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