Chronic Obstructive Pulmonary Disease (COPD) and Asthma: Differential Diagnosis
Chronic obstructive pulmonary disease (COPD) is a common condition in primary care, rising from the fourth leading cause of death in the United States to the third. Asthma has also risen in the U.S. by more than 15% over the past decade. Both conditions affect the lungs, and often have similar symptoms, such as shortness of breath. Together, these conditions account for 20% of visits to family physicians. Despite their similarities, they require different treatment methods and both are underdiagnosed and undertreated.
- Use tools to effectively diagnose chronic obstructive pulmonary disease (COPD) and asthma and help patients self-manage these chronic illnesses.
- Understand the importance of short- and long-term monitoring, maximizing lung function, and managing exacerbations and airflow limitations.
According to the Centers for Disease Control’s (CDC) National Asthma Control Program, asthma is getting worse. In the last decade, the proportion of people with asthma in the United States grew by nearly 15%. Asthma led to:
- 439,400 hospitalizations (2010)
- 1.8 million emergency department visits (2011)
- 14.2 million physician office visits (2010)1
American Lung Association reports that COPD is the third leading cause of death in America, claiming the lives of 134,676 Americans in 2010.2
Differentiating chronic obstructive pulmonary disease (COPD) from asthma can be complicated, especially in older adults and individuals who smoke. Initial diagnosis of these conditions requires the identification of patients at risk of, or likely to have, chronic airways disease. Physicians must also rule out other potential causes of respiratory symptoms. Asthma-COPD overlap syndrome (ACOS), which shares features with both asthma and COPD, should also be considered. More information from the Global Initiative for Chronic Obstructive Lung Disease’s (GOLD) Asthma, COPD, and Asthma-COPD Overlap Syndrome can be found here(goldcopd.org).
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 in the airways and the lungs to noxious particles or gases.”3. Airflow limitation in COPD may be improved with use of bronchodilators. COPD typically occurs in individuals 40 years of age and older. It is estimated that 12.7 million individuals 18 years of age and older in the United States have been diagnosed with COPD.4 However, approximately 24 million adults in the United States have evidence of impaired lung function, which indicates that COPD may be underdiagnosed.
The prevalence of COPD varies considerably by state, from less than 4% in Washington and Minnesota to greater than 9% in Alabama and Kentucky. The median prevalence in the United States is 5.8%.5 The states with the highest prevalence of COPD—Alabama, Illinois, Kentucky, Oklahoma, Tennessee, and West Virginia—are clustered along the Ohio and lower Mississippi rivers.5
The Global Initiative for Asthma (GINA) defines asthma as “a heterogeneous disease, usually characterized by chronic airway inflammation. It is defined by the history of respiratory symptoms such as wheeze, shortness of breath, chest tightness, and cough that vary over time and in intensity, together with variable expiratory airflow limitation.”6 It is a disease of reversible airways obstruction that has many different phenotypes (i.e., observable characteristics such as clinical presentation and triggers), each which has a different genetic/environmental cause and responds differently to treatment. Unlike COPD, which typically develops later in life, asthma most often begins in childhood. According to the CDC, more than 6 million children and 16.5 million adults in the United States have asthma.7
In 2010, COPD was the primary diagnosis in 10.3 million physician office visits, 1.5 million emergency department (ED) visits, and 699,000 hospital discharges.8 According to the American Lung Association, the United States spent $29.5 billion in direct costs and $20.4 billion in indirect costs for COPD in 2011.2 Much of the direct cost of COPD is for hospitalizations following exacerbations. Direct costs also include home care and home oxygen therapy. Indirect costs include lost workdays and disruption of life. The more severe an individual’s COPD, the higher the associated costs.
In 2010, more than 70,000 women and approximately 64,000 men died of COPD.9 For more than a decade, more women than men have died of COPD.8 According to the CDC, the rate of mortality due to COPD declined for men in the United States between 1999 (57.0 per 100,000) and 2010 (47.6 per 100,000), but there was no significant change in the mortality rate for women (35.3 per 100,000 in 1999 and 36.4 per 100,000 in 2010).10
In 2010, asthma was the primary diagnosis in 14.2 million physician office visits and there were 1.8 million ED visits for asthma in 2011.1 Nearly 1 in 5 children who had asthma went to an emergency department for care in 2009.11 According to one study, asthma costs the United States $56 billion each year.12 In 2009, the average yearly cost of care for a child who had asthma was $1,039.11 In addition to direct medical costs, indirect costs of asthma include missed school and work days. For example, in 2008, children missed 10.5 million days of school and adults missed 14.2 million days of work due to asthma.11 It is estimated that approximately nine people in the United States die from asthma each day and more women than men die from asthma.11
Individuals aged 65 to 74 years are more likely to report COPD.5 Low economic status is a risk factor for the disease, as those individuals with an annual household income of less than $25,000 were more likely than any other income group to have visited a hospital or emergency department for COPD.5 This risk may be related to disproportionately high cigarette usage, indoor and outdoor pollutants, crowding, poor nutrition, or infections. The states with the highest COPD prevalence are clustered along the Ohio and lower Mississippi Rivers.5
Women are more likely to have asthma than men, yet boys are more likely to have asthma than girls.11 Adults ages 18 to 24 are more likely to have asthma than older adults.11 Many patients outgrow their asthma.
Asthma prevalence and outcomes reveal significant disparities. Physicians are an important part of effective asthma management, but patients in some minority groups may not see a physician regularly as part of their asthma care. According to the National Institutes of Health (NIH), asthma is more common and more severe among women; children; low-income, inner-city residents;13 and African-American and Puerto Rican communities.13 In general, these populations experience above-average rates of ED visits, hospitalizations, and mortality.13 These rates are higher than differences in asthma prevalence would suggest. Social, economic, and cultural factors—ranging from lack of access to quality health care to differences in health beliefs between patients and their physicians—contribute to a greater burden of asthma on some patients.13 In addition, gaps in the implementation of clinical practice guidelines for asthma contribute to the ongoing problem of asthma-related health disparities among at-risk groups.13
The CDC reports the following statistics:
- Multi-race and African-American adults are more likely to have asthma than white adults.
- African-American children are two times more likely to have asthma than white children.
- More than one in four African-American adults and one in five Hispanic adults cannot afford their asthma medications.
- More than one in four African-American adults and nearly one in seven Hispanic adults cannot afford routine physician visits.
- African-American adults are hospitalized for asthma more often than white adults.
- African-American and Hispanic children visit emergency departments for asthma care more often than white children.
- African-Americans are two to three times more likely to die from asthma than any other racial or ethnic group.
- High school graduates and adults with incomes greater than $75,000 are less likely to have asthma.11
These disparities in asthma care and burden suggest that culturally competent clinical and educational approaches are needed. The Guidelines for the Diagnosis and Management of Asthma14 provides guidelines that emphasize the importance of asthma control and introduces approaches for monitoring asthma in high-risk groups and other patients with asthma. The six key messages are:
- Assess asthma severity at the initial visit to determine initial treatment
- Use written asthma action plans to guide patient self-management
- Use inhaled corticosteroids to control asthma
- Assess and monitor asthma control and adjust treatment if needed
- Schedule follow-up visits at periodic intervals
- Control environmental exposures that worsen the patient’s asthma15
The following diagnostic methods and tools to screen for COPD and asthma were compiled from the NIH’s Guidelines for the Diagnosis and Management of Asthma,14 the Global Initiative for Chronic Obstructive Lung Disease (GOLD),3 and the Global Initiative for Asthma (GINA).6
- Presence and degree of inflammation (irritation from smoking is the primary cause of COPD)
- Presence and degree of airflow limitation, including bronchoconstriction, edema, and mucus
- Presence and degree of airways remodeling3
- Medical History
- Recurrent cough, wheezing, sputum production, dyspnea, or repeated acute lower respiratory tract infections
- Symptoms are variable to intermittent in asthma
- Symptoms are chronic and usually progressive in COPD
- Previous treatment for or diagnosis of asthma or COPD
- Exposure to environmental pollutants3
- Recurrent cough, wheezing, sputum production, dyspnea, or repeated acute lower respiratory tract infections
- Physical Exam (often normal)
- Prolonged expiratory phase
- Use of accessory respiratory muscles14
- Spirometry is recommended in all symptomatic patients to make the diagnosis and assess severity.
- Bronchodilator reversibility of FEV1 greater than 12% and 200 mL6
- Bronchodilator reversibility of FEV1/FVC less than 0.7
- Class 1: FEV1 greater than or equal to 80% (Mild)
- Class 2: FEV1 greater than 80% (Moderate)
- Class 3: FEV1 less than 50% (Severe)
- Class 4: FEV1 less than 30% (Very Severe)3
- A chest X-ray is not needed to make a diagnosis, but is often obtained to exclude other diagnoses (e.g., tuberculosis and bronchiectasis).6
- Screening Questionnaires
- Sleep/Work/Play Asthma Control Questionnaire (available at http://aafa.org/pdfs/SWP%20final%20questionnaire.pdf(aafa.org))
- COPD Assessment Test (CAT) (available at http://www.catestonline.org/images/pdfs/CATest.pdf(www.catestonline.org))
- Medical Research Council (MRC) Dyspnea Index (the MRC breathlessness scale)
Before age 20
After age 40
Lung function that may be normal between symptoms
Abnormal lung function between symptoms
Persistence of symptoms despite treatment
Immediate response to bronchiodilator treatment or to inhaled corticosteroids (ICS) over a period of weeks
Limited relief from rapid-acting bronchodilator treatment
Severe hyperinflation or other changes
Pulmonary symptoms are the hallmark of COPD. However, hypoxia often creates systemic symptoms. Patients who have COPD most commonly present with persistent and progressive dyspnea, chronic cough, and/or sputum production.3 Although COPD cannot be diagnosed on the basis of any of these symptoms alone, COPD should be considered as a possible diagnosis in any patient who presents with one or more of them. This consideration could lead to diagnosis at an earlier stage in the disease at which interventions are more likely to help.3
Though the most common diagnostic dilemma is differentiating COPD from asthma, many other illnesses share symptoms and/or physical findings with COPD. Most can be excluded without an extensive evaluation. Some may require the judicious use of select tests. Differential diagnosis of COPD must take into consideration the symptom complex obtained from the patient’s history and physical examination findings. Spirometry should be performed to make the diagnosis of COPD.3
As noted previously, asthma is the most common alternative diagnosis to COPD, and its symptoms (e.g., shortness of breath, chronic cough, etc.) can mimic COPD. Take into account clinical characteristics and epidemiological factors to narrow down the diagnosis. Smoking incidence and childhood exposure to secondhand smoke are important risk factors for COPD that are more likely to be present in individuals of lower socioeconomic status. However, given the higher incidence of asthma in certain populations, the risks of COPD and asthma may overlap.3
In light of the common features of asthma and COPD, an approach that focuses on the features that are most helpful in distinguishing asthma from COPD is recommended. The diagnostic profile of asthma or COPD can be assembled from a careful history that considers age; symptoms (in particular, onset and progression, variability, seasonality or periodicity, and persistence); history; social and occupational risk factors (including smoking history, previous diagnoses, and treatment); and response to treatment.3
The primary features of asthma include the following:
- Onset before age 20 years
- Symptoms that vary over time, often limiting activity
- A record (e.g., spirometry, peak expiratory flow [PEF]) of variable airflow limitation
- Family history of asthma or other allergic condition
- Lung function that may be normal between symptoms
- Symptoms that vary either seasonally or from year to year
- Symptoms that improve spontaneously or have an immediate response to bronchodilator treatment or to inhaled corticosteroids (ICS) over a period of weeks
- Normal chest X-ray3
The primary features of COPD include the following:
- Onset after age 40 years
- Persistence of symptoms despite treatment
- Abnormal lung function between symptoms
- Heavy exposure to risk factors, such as tobacco smoke or biomass fuels
- Symptoms that worsen slowly over time (i.e., progressive course over years)
- Limited relief from rapid-acting bronchodilator treatment
- Severe hyperinflation or other changes on chest X-ray3
Keep in mind that individuals who have COPD often do not know they have it, do not know when it developed, or are unaware of the severity of their condition. They develop exercise intolerance because of air trapping and exertional dyspnea-related chest expansion.3 Consequently, they minimize their exercise and attribute deconditioning to normal aging. Therefore, they do not experience dyspnea and may respond to open-ended questions by saying that they are “breathing fine.” If these patients do not have exacerbations, their COPD may not interfere with their lives. However, some individuals who have COPD have significant interference with function or frequent exacerbations, and these patients have progressive decline in lung function.3
Distinguishing between COPD and asthma can have important implications in terms of management and life expectancy. The clinical examination may suggest asthma or COPD, but no set of clinical findings is diagnostic.3,16 In addition, home lung function tests are not an established way to diagnose COPD, although they are useful for monitoring.3,16
There is a strong likelihood of correct diagnosis if a patient presents with three or more of the features listed above for either asthma or COPD in the absence of features of the alternative diagnosis. However, the absence of any of these features has less predictive value and does not rule out the diagnosis of either disease.3 In the absence of pathognomonic features, a diagnosis is made on the weight of evidence, provided there are no features that clearly make the diagnosis unlikely. Physicians must determine their level of certainty and factor it into their decision to treat.3
Spirometry should be obtained to diagnose airflow obstruction in patients who have respiratory symptoms, particularly dyspnea.17 Without obtaining spirometry, it is difficult to distinguish older adults who have asthma from those who have COPD. Spirometry is the gold standard for diagnosis of both asthma and COPD.3 The Global Initiative for Chronic Obstructive Lung Disease (GOLD), the Global Strategy for Asthma Management and Prevention, and the Global Initiative for Asthma (GINA) 2014 note this test in the diagnostic criteria for both asthma and COPD. It establishes severity/stage based on FEV1 and FEV1/FVC. When diagnosing asthma, the key element is reversibility, so spirometry should be performed both pre- and post-bronchodilator use. Reversibility is defined as increase in FEV1 of 12% or greater from baseline.3 Airflow limitation that is not fully reversible is a hallmark of COPD.
When a patient has a similar number of features of both asthma and COPD, the diagnosis of asthma-COPD overlap syndrome (ACOS) should be considered. According to a clinical description from the Global Initiative for Chronic Obstructive Lung Disease (GOLD) and the Global Initiative for Asthma (GINA), ACOS “is characterized by persistent airflow limitation with several features usually associated with asthma and several features usually associated with COPD. ACOS is therefore identified by the features that it shares with both asthma and COPD.”3,6
Short- and Long-term Monitoring
COPD worsens over time, so routine follow-up and monitoring is essential. Perform spirometry yearly to identify patients who are experiencing a rapid decline.14 Ask specific questions about the patient’s well-being (e.g., by using a questionnaire such as the COPD Assessment Test) every three months.3 Assess symptoms (e.g., cough, sputum production, dyspnea, limitations of activity, sleep disturbances) and smoking status at every visit. In addition, monitor exacerbations and comorbidities, such as heart disease and diabetes. The classification of severity of airflow in COPD is based on post-bronchodilator FEV1.3
The frequent admission of asthma patients to the hospital is used as a measure of inadequate primary care. Therefore, it is vital to concentrate efforts on evaluating a patient’s asthma stage and using stepped therapy and self-management that includes an asthma action plan. Instruct patients who have asthma to monitor their symptoms, possibly with peak expiratory flow (PEF) meter recordings. Be sure their action plan describes what steps to take when their symptoms change. Usually the level of severity of asthma—mild, moderate, or moderate to severe—is based on the level of treatment.6
Exacerbation Management and Lung Function
Smoking cessation is key for all patients who smoke and have COPD. Medications are used to reduce symptoms, reduce the frequency and severity of exacerbations, and improve exercise tolerance. Long-acting formulations are preferred. Current medications for COPD have not been shown to lessen the long-term decline in lung function.3
The most common cause of COPD exacerbations is viral or bacterial infection.18 The medication classes most commonly used to manage exacerbations are bronchodilators, steroids, and antibiotics. Short-acting β2-agonists are preferred in the acute setting.3 Systemic steroids may shorten recovery time, improve FEV1, and improve hypoxemia, but long-term management of COPD with oral steroid medicines is not recommended due to steroid myopathy.19 A five-day course of prednisone (40 mg per day) is recommended.3 Evidence related to the use of inhaled corticosteroids to manage COPD is controversial. Antibiotics should only be prescribed for people with clinical signs of bacterial infection, such as an increase in purulence of sputum.3 The usual empirical choices are amoxicillin with or without clavulanic acid, a macrolide, or tetracycline. The recommended duration of antibiotic therapy is 5 to 10 days.
An as-needed short acting β2-agonist (SABA) alone is considered the first step in treatment for asthma.14 Regular daily low-dose ICS treatment, plus an as-needed SABA, is highly effective to reduce asthma-related exacerbations, symptoms, hospitalizations, and mortality. For patients whose symptoms and/or exacerbations persist in spite of management with low-dose ICS plus an as-needed SABA, a step up in treatment should be considered. However, patients should first be asked about treatment adherence, inhaler techniques, comorbidities, and level of exposure to allergens.14 For adults and adolescents, a combination of low-dose ICS with a long-acting β2-agonist (LABA), plus an as-needed SABA, is the preferred step-up treatment. Another option for adults and adolescents to reduce the risk of exacerbations is a combination of low-dose ICS with formoterol.14 For children ages 5 to 11 years, increasing the ICS dose is preferred to an ICS/LABA combination.14
Long-term ICS therapy is recommended for patients who have asthma and are at high risk of exacerbations.14 The flu vaccine reduces the risk of death and hospitalizations for anyone six months and older with asthma.20
For COPD, initial treatment should provide appropriate management of symptoms with bronchodilators or combination therapy, but not with ICS alone. Asthma should be managed with suitable controller therapy, including ICS, but not with long-acting bronchodilators alone.6
Bronchodilators increase FEV1 by alternating smooth muscle tone.3 The two classes of bronchodilators are β2-agonists and anticholinergics. More recently, a combination of the long-acting anticholinergic umeclidinium and the long-acting β2-agonist vilanterol became available in a once-daily inhaled preparation. Additionally, there are combinations of a long-acting bronchodilator and anticholinergic as well as long-acting anti-muscarinic agents (LAMAs) on the market and in development.
When grading a patient’s condition, inquire in detail about the specifics of his or her exercise capacity, dyspnea, cough, sputum production, and exacerbation frequency. Many asymptomatic patients who have COPD will never require oxygen therapy or experience more severe symptoms. However, early identification of COPD offers patients the opportunity to increase physical activity, improve quality of life, and stop smoking. Patients with more rapid decline in lung function require evaluation for oxygen therapy, right heart failure, and end-of-life decision making.21
The most effective treatment for COPD or asthma is a partnership between the patient and his or her physician. Support patient self-management of COPD or asthma by encouraging smoking cessation, providing routine monitoring, promoting medication regimen adherence, and encouraging physical fitness. Patients should be trained to use inhaler devices properly in order to manage their condition effectively. A printable handout can be found at http://familydoctor.org/familydoctor/en/diseases-conditions/asthma/treatment/how-to-use-a-metered-dose-inhaler.html(familydoctor.org).
Patient resources on COPD treatment, starting with “stop smoking” can be found at http://familydoctor.org/familydoctor/en/diseases-conditions/chronic-obstructive-pulmonary-disease/treatment.html(familydoctor.org).
A written asthma action plan can help patients recognize and appropriately address worsening symptoms. For more information on asthma action plans, including a downloadable plan, please go to http://familydoctor.org/familydoctor/en/diseases-conditions/asthma/treatment/asthma-action-plan.html(familydoctor.org).
AAFP’s tobacco cessation program, "Ask and Act," encourages family physicians to ASK their patients about tobacco use, then ACT to help them quit. This resource can be found at http://www.aafp.org/about/initiatives/ask-act.html.
- A Stepwise Approach to the Interpretation of Pulmonary Function Tests
- Acute Asthma and Other Recurrent Wheezing Disorders in Children [Clinical Evidence Handbook]
- Pocket Guide for Asthma Management and Prevention(ginasthma.org)
- METRIC Asthma Module
- Indacaterol (Arcapta) for COPD [STEPS]
- The COPD Comprehensive has information on the Diagnostic Criteria for Asthma and the Clinical Features in Differentiating COPD from Asthma (slides 22-29).
1. Centers for Disease Control and Prevention (CDC). Most recent asthma data(www.cdc.gov). Accessed September 6, 2015.
2. American Lung Association. Chronic obstructive pulmonary disease (COPD) fact sheet(www.lung.org). Accessed March 20, 2015
3. Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global strategy for the diagnosis, management, and prevention of chronic obstructive pulmonary disease(goldcopd.org). Accessed March 18, 2015
4. American Lung Association. Trends in COPD (chronic bronchitis and emphysema): morbidity and mortality(www.lung.org). Accessed March 20, 2015.
5. Centers for Disease Control and Prevention. Chronic obstructive pulmonary disease among adults—United States, 2011(www.cdc.gov). MMWR Morb Mortal Wkly Rep. 2012;61:938-943. Accessed March 20, 2015.
6. Global Initiative for Asthma (GINA). Diagnosis of diseases of chronic airflow limitation: asthma, COPD and asthma-COPD overlap syndrome (ACOS)(ginasthma.org). Accessed September 6, 2015.
7. Centers for Disease Control and Prevention. National Health Interview Survey(www.cdc.gov). National Center for Health Statistics. . Accessed September 8, 2015.
8. Ford, IS, Croft JB, Mannino DM, et al. COPD Surveillance – United States, 1999-2011. Chest. 2013;144(1):284-305.
9. Centers for Disease Control and Prevention. National Center for Health Statistics. National Vital Statistics Report(www.cdc.gov). Deaths: Final Data for 2010. Accessed September 8, 2015.
10. Centers for Disease Control and Prevention. Chronic obstructive pulmonary disease (COPD)(www.cdc.gov). Data and Statistics. Accessed September 8, 2015.
11. Centers for Disease Control and Prevention. National Asthma Control Program. Asthma’s impact on the nation(www.cdc.gov). Accessed September 8, 2015.
12. Barnett SB, Nurmagambetov TA. Costs of asthma in the United States: 2002-2007. J Allergy Clin Immunol. 2011;127(1):145-52.
13. National Heart, Lung, and Blood Institute. Reducing asthma disparities(www.nhlbi.nih.gov). Accessed March 20, 2015.
14. National Institutes of Health. Guidelines for the diagnosis and management of Asthma (EPR-3) July 2007(www.nhlbi.nih.gov). Accessed March 20, 2015.
15. National Heart, Lung, and Blood Institute. Asthma care quick reference(www.nhlbi.nih.gov). Diagnosing and managing asthma. Guidelines from the National Asthma Education and Prevention Program. Expert panel report 3. Accessed October 28, 2015.
16. Jones PW, Harding G, Berry P, et al. Development and first validation of the COPD Assessment Test. Eur Respir J. 2009;34:648-654.
17. Armstrong, C. ACP updates guideline on diagnosis and management of stable COPD. Am Fam Physician. 2012;85:204-205.
18. Wedzicha JA, Donaldson GC. Exacerbations of chronic obstructive pulmonary disease. Respir Care. 2003 Dec;48(12):1204-13.
19. Leuppi JD, Schuetz F, Bingisser R, et al. Short-term vs conventional glucocorticoid therapy in acute exacerbations of chronic obstructive pulmonary disease: the REDUCE randomized clinical trial. JAMA. 2013;309:2223-2231.
20. Centers for Disease Control and Prevention. Flu and people with asthma(www.cdc.gov). Accessed September 10, 2015.
21. National Heart, Lung, and Blood Institute. What are the signs and symptoms of COPD?(www.nhlbi.nih.gov) Accessed March 20, 2015.
This content has been supported by Boehringer Ingelheim Pharmaceuticals.