IS IT ASTHMA? COPD? OR BOTH? How to Navigate the Sometimes Muddy Waters of Asthma vs. COPD E-bulletin No. 4: July 10, 2007 Eugene R. Bleecker, MD Thomas H. Davis Professor of Pulmonary Medicine and Public Health Sciences Section Head, Pulmonary, Critical Care, Allergy and Immunologic Diseases Co-director, Center for Human Genomics Wake Forest University School of Medicine Winston-Salem, NC

New CME-certified Monograph Available Today! ASTHMA: DISEASE CHARACTERIZATION By Eugene R. Bleecker, MD To view this monograph and other CME-certified activities on related topics in asthma control, please visit www.rethinkasthma.com

On the surface, asthma and chronic obstructive pulmonary disease (COPD) can look alike and represent a spectrum of obstructive airways disease. Both are chronic lung diseases characterized by airflow obstruction and symptoms of wheezing, coughing, and shortness of breath. However, a closer look reveals differences that are important to recognize because a specific diagnosis may affect treatment decisions. The table below summarizes the key characteristics, symptom patterns, and management strategies that differentiate asthma and COPD.

Briefly, asthma is associated with intermittent airflow obstruction that may be fixed in some patients, while COPD is characterized by progressive airflow limitation and a gradual and irreversible loss of lung function. Inflammation underlies both conditions, although its characteristics differ. While asthma is associated with an eosinophilic inflammatory response (although other cell types can be found including neutrophils in more severe asthma), COPD is characterized mainly by increased neutrophil and macrophage response.¹ Airway hyperresponsiveness and responses to bronchodilators and corticosteroids tend to be greater in asthma and less in COPD.

Overlapping patterns. The similarities and differences between asthma and COPD are actually quite complex. Patterns can overlap and differentiation may challenge investigators as well as clinicians. Thus, a number of patients may have elements of both COPD and asthma. In fact, there are populations of severe asthmatics with neutrophil-predominant disease.² And, certainly, most COPD patients have bronchodilator responses and airway hyperresponsiveness.

Disease management. Pharmacologic and nonpharmacologic strategies can control bronchoconstriction and airway inflammation. In general, the goal in asthma is to reduce bronchial inflammation, with inhaled corticosteroids (ICS) serving as the cornerstone of therapy. In COPD, the goal is to manage symptoms and preserve lung function, with long-acting bronchodilators (beta agonists [LABA] and anticholinergics [LAMA]) playing a more prominent role. Recent studies have shown that combined ICS/LABA therapy reduces exacerbations and improves quality of life.³ For patients with both asthma and COPD, optimal therapy remains unclear, but the goal should be an improvement in lung function.

New guidelines. Recently updated guidelines for treating both conditions are available from the Global Initiative for Asthma (GINA; revised November 2006) and the Global Initiative for Chronic Obstructive Lung Disease (GOLD; revised December 2006)^4,5. For help in differentiating COPD symptoms from asthma symptoms, several questionnaires are now available.^6,7

Looking ahead. A number of combination therapies under investigation for both COPD and asthma employ short- and long-acting beta-agonists, anticholinergics, and/or inhaled corticosteroids.^3,8,9 A recent randomized, placebo-controlled study by Calverley et al. found a trend toward reduction of all-cause mortality and significant improvement in the number of exacerbations and lung function in patients with COPD treated with the combination of fluticasone and salmeterol compared to placebo.³ In a study published in April 2007, addition of fluticasone–salmeterol to tiotropium therapy improved lung function, quality of life, and hospitalization rates in patients with moderate-to-severe COPD but did not significantly affect rates of COPD exacerbation.⁹

Technologies such as computed tomography (CT) scans may soon provide valuable diagnostic tools in addition to measures of forced expiratory volume in one second (FEV1).¹⁰ Genetics research may yield tests to help determine a patient's unique risk profile for COPD or asthma, identify patients who are more likely to have severe disease and rapid progression, predict a patient's response to a given therapy, and pave the way for individualized therapy.¹¹

References

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