CSAC Special Report

Chronic obstructive pulmonary disease (COPD) produces significant morbidity and mortality in countries around the world. Apart from the costs for direct patient care, COPD imposes a further burden on patients in the form of lost wages and the physical and emotional toll taken by the disease. It usually starts in the fourth decade of life after considerable toxic exposure. COPD is an indolent killer and is underdiagnosed and inadequately treated for a variety of reasons.¹

Toxic and genetic factors combine to produce inflammatory changes in the respiratory tree, which lead to the progressive and not fully reversible airflow limitation of COPD. Clinically, chronic cough, sputum production, and shortness of breath are consistent findings at all stages of COPD. The progression of the disease is related to mucus hypersecretion and ciliary dysfunction, which trigger sputum production. The airflow limitations are caused by airway remodeling. Histologic changes in the alveolar walls result in gas exchange abnormalities. Vascular changes lead to ominous pulmonary hypertension and cor pulmonale.

Several risk factors predict the development of COPD. Exposure to tobacco smoke is implicated in 80% to 90% of affected patients worldwide, and smoking is considered the primary risk factor for COPD.² Small percentages of patients have occupational or environmental exposures to toxic substances and irritants. One percent of patients with COPD have alpha₁-antitrypsin deficiency.

In 1999, the National Heart, Lung, and Blood Institute (NHLBI) and the World Health Organization (WHO) formed a consensus panel made up of experts from around the world and named the Global Initiative for Chronic Obstructive Lung Disease (GOLD). The panel produced a report, updated most recently in September 2005, titled Global Strategy for the Diagnosis, Management, and Prevention of COPD.¹ This guideline emphasizes the need to detect and accurately stage COPD so that appropriate pharmacologic and nonpharmacologic therapies can minimize the impact of exacerbations and reduce hospitalizations. A new report is due out in 2006, but the main practice guideline is expected to remain unchanged.

Diagnosis of COPD

All patients with COPD have a chronic cough, sputum production, and some shortness of breath with exertion. The patient may present with these findings long before disease can be documented by pulmonary function testing, but such tests must be performed. COPD progresses at different rates in different patients. In some the disease advances quickly, while others experience a more indolent course. Toxic exposure drives most pathology in patients with COPD, and elimination of toxic exposure can often slow the progression of the disease.

Staging the disease

COPD is staged based on the results of pulmonary function testing. This testing should be done for all patients with chronic cough, sputum production, and shortness of breath. The forced expiratory volume in 1 second (FEV₁) should be measured against the forced vital capacity (FVC), the volume of air exhaled from the lungs with complete expiration. By definition, obstructive diseases have a greater impact on the volume of air expired than on changes in vital capacity. The clinician can intervene at any stage of COPD, and the choice of medication depends on the stage (see Figure 1).

The primary care provider must have timely access to pulmonary function testing for all symptomatic patients as part of the initial workup for COPD. Testing should include a bronchodilatory challenge. If the results of this challenge indicate that the obstructive disease is completely reversible, a diagnosis of asthma should be favored over one of COPD. If the obstruction is only partially reversible, a diagnosis of COPD should be considered. The degree of reversibility, even if only partial, may indicate a positive prognosis if the patient can reduce risk factors.

Stage 0 Early in COPD, patients have classic signs and symptoms (cough, sputum production, shortness of breath) but normal results on pulmonary function tests. Thus, the absence of measurable airway obstruction is designated stage 0, and the patient is said to be at risk.

Stage I Mild COPD manifests with chronic cough and sputum production. Patients have some shortness of breath but may not be aware that their pulmonary function is measurably decreased. FEV₁/FVC is less than 70% of predicted normal values. FEV₁ may equal or exceed 80% of predicted values.

Stage II Moderate COPD is characterized by chronic cough and sputum production, and shortness of breath may limit exertion. Patients may present with only shortness of breath. The FEV₁/FVC is less than 70% of predicted (as in stage I), but the FEV₁ is at least 50% of predicted.

Stage III Severe COPD involves progressive airway limitation, and clinical signs and symptoms worsen. The FEV₁ falls below 50%—but not below 30%—of predicted. Clinically, the patient has more exacerbations with continuing problems of cough and sputum production. This progression markedly impairs quality of life.

Stage IV In very severe COPD, the FEV₁ is less than 30% of predicted or patients are in a chronic state of respiratory failure even if the FEV₁ is greater than 30% of predicted. Hypercapnia and hypoxia are present, and supplemental oxygen therapy may be required to maintain an O₂ saturation higher than 90%. Severe, recurrent exacerbations markedly affect quality of life and threaten survival.

Management of COPD

Long-term treatment goals are to reduce the number of exacerbations, improve quality of life, reduce signs and symptoms, and prevent hospitalizations. The long-term management of COPD relies on several factors. First, pulmonary function tests must be used to assess and monitor disease progression. Second, patients must be educated to reduce avoidable risk factors. Finally, COPD requires proper therapeutic modalities to blunt the impact of disease progression. Inevitably, acute exacerbations manifest as short-term challenges that have to be controlled. So exacerbations must be managed to return patients to previous functionality.

Assessment and monitoring COPD progresses from cough and sputum production toward airway restriction and then respiratory failure. Other diseases that produce similar signs and symptoms but have infectious causes, such as tuberculosis, must be ruled out before management of COPD can proceed. The stage of COPD can be recognized only when signs and symptoms are linked to COPD and pulmonary function testing is done. Periodically, pulmonary function testing should be repeated to assess disease progression.

Education Helping patients to understand COPD, how it progresses, and how they can help to slow progression is an important part of management. Patients should avoid risk factors. With the exception of genetic factors, the vast majority of risk factors can be modified, no matter what the stage of disease. Obviously, smoking should always be discouraged.³ Other exposures should be analyzed and minimized as well.

Drugs and vaccines The treatment of COPD proceeds in a stepwise fashion, depending on the stage of the disease. Most efforts are aimed at decreasing symptoms and avoiding some complications. However, most medications will not alter the long decline that characteristically occurs in patients with COPD.

Pharmacologic treatments are prescribed to reduce symptoms and prevent exacerbations. Medicines can increase exercise tolerance and improve perceived quality of life, but they have little impact on disease progression. As COPD advances, medication use must be increased to control symptoms. Figure 1 presents medications in the order in which they are added to the treatment regimen.

Bronchodilators help patients empty their lungs and reduce symptoms of breathlessness. They fall into three categories: beta-adrenergic agonists, anticholinergics, and nonselective phosphodiesterase inhibitors.

—Beta-agonists stimulate receptors that relax bronchial smooth muscle. Short-acting (4-6 hours) and long-acting (more than 12 hours) beta-agonists are used alone or in combination. These medications are highly effective and well tolerated. Medications delivered by metered-dose inhaler or particulate inhaler are superior to nebulized forms. All are better than oral preparations, which have systemic effects. Longer-acting agents are more convenient, produce better compliance, and are well tolerated, but they are more costly. Bronchodilators should be used for symptomatic relief of measurable airway obstruction (stage II-IV COPD).

—Anticholinergics block parasympathetic receptors to produce bronchodilation. They are considered safe with few systemic side effects. Short-acting or long-acting preparations are used as monotherapy or combined with beta-agonists (stage II-IV COPD).

—Methylxanthines (such as theophylline) have a narrow therapeutic range where side effects occur at concentrations near or at the therapeutic dose. Toxicities manifest as cardiac arrhythmias, seizures, headaches, insomnia, nausea, and heartburn and may occur in the therapeutic range. Drug interactions are complicated through cytochrome P-450 metabolism. Methylxanthines have a limited role in moderately to severely ill patients. The long-acting agents are better tolerated.

Pulmonary rehabilitation There are three components to pulmonary rehabilitation: education, nutritional counseling, and exercise training. Education helps patients understand the disease and adhere to treatment regimens. Nutritional counseling helps them manage their weight (up or down) to keep optimal body mass. Finally, adhering to a regular exercise routine can improve patients’ quality of life.

Oxygen therapy Chronic hypoxia is significant in patients with stage IV COPD. Any patient with chronic respiratory failure should receive at least 15 hours of daily oxygen therapy to help keep O₂ saturation above 90%. This treatment reduces mortality rates in such patients.

Managing COPD exacerbations

Patients with any increases in shortness of breath, cough, or sputum production should be evaluated. The severity of signs and symptoms determines the aggressiveness of the workup. The major reasons for hospital evaluation include lack of response to early intervention, development of edema or cyanosis, significant or severe underlying COPD, intense presenting symptoms, and advanced age or lack of sufficient home support.

Patients who can maintain oxygenation above 90% may be released to go home. Early follow-up should be considered to ensure therapeutic response. Arterial blood gas analysis is helpful in evaluating a patient with advanced COPD who may require hospital admission. A CBC may not be helpful. Pulmonary function testing may not provide useful data in an exacerbation. However, measurement of peak flow provides comparisons and tracking in a given patient.

Exacerbations with acute increases in sputum production and cough may respond to empiric antibiotic treatment. This treatment is effective for roughly 80% to 90% of patients. Antibiotics are not recommended in the management of stable COPD.

Conclusion

COPD is characterized by airflow limitation that is not fully reversible, is usually progressive, and is associated with an abnormal inflammatory response to noxious particles or gases. Cigarette smoke is the biggest risk factor in patients with COPD, and smoking cessation is critical. Once the diagnosis of COPD has been established, the stage should be determined to guide therapy. Beta-agonists plus oral and inhaled corticosteroids can be used in acute exacerbations to ameliorate cough and shortness of breath. The roles of antitussive agents, mucolytics, and chronic antibiotics are controversial.

1. Global Initiative for Chronic Obstructive Lung Disease. Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease. Updated 2005. Available at: http://www.goldcopd.com/. Accessed July 21, 2006.

2. Global Initiative for Chronic Obstructive Lung Disease. Global Strategy for the Diagnosis, Management, and Prevention of Chronic Obstructive Pulmonary Disease. Updated 2005. Executive Summary. Available at: http://www.goldcopd.com/. Accessed July 21, 2006.

3. Fiore MC, Bailey WC, Cohen SJ, et al. Treating Tobacco Use and Dependence. Clinical Practice Guidelines. Rockville, Md: US Dept of Health and Human Services, Public Health Service; June 2000.

Clinical practice guidelines for managing COPD in a primary care setting

Daniel L. O’Donoghue, PhD, PA-C; Deborah A. Gerbert, PA-C; Lawrence M. Herman, MPA, PA-C; Lyle W. Larson, PhD, PA-C; Marie-Michèle Léger, MPH, PA-C; Robert McNellis, MPH, PA-C; Cynthia Ulshafer, PA-C; Eileen M. Van Dyke, MPS, PA-C

The authors are members and staff of the Clinical and Scientific Affairs Council (CSAC) of the AAPA. This article was written by Daniel L. O’Donoghue, PhD, PA-C, and edited by Sarah Zarbock, PA-C.

Diagnosis of COPD

Staging the disease

Management of COPD

Managing COPD exacerbations

Conclusion