Rotation Prep

Published March 6, 2023

A brief refresher with useful tables, figures, and research summaries

Chronic Obstructive Pulmonary Disease

Chronic obstructive pulmonary disease (COPD) is characterized by persistent expiratory airflow limitation due to destruction of lung parenchyma and decrease in elastic recoil. COPD is associated with chronic airway and parenchymal inflammation, and the resultant airway obstruction leads to air trapping and hyperinflation. The decline in lung function in COPD is generally progressive.

Risk Factors

The most important risk factor for developing COPD is cigarette smoking. An estimated 25% of individuals with a history of cigarette smoking develop COPD. Globally, inhalation of biomass fuel emissions is another important etiologic agent. Other risk factors include occupational dusts, vapors, fumes, and genetic factors.


The principal pathophysiological features of COPD are shown in the following image.

Pathophysiological Features of Airflow Obstruction in Chronic Obstructive Pulmonary Disease

Airflow obstruction in COPD is largely due to emphysema, characterized by disruption of the alveolar walls, along with inflammation of lung tissue, fibrosis, and mucus plugging in the distal airways (Panel A, normal distal airway surrounded by intact alveolar walls; Panel B, abnormal distal airway surrounded by disrupted alveolar walls). Alveolar attachments provide a radial tethering effect that is essential for keeping small airways patent in the normal lung. Airways narrow at smaller lung volumes because of decreased lung elasticity and weaker tethering effects. Consequently, maximal expiratory airflow decreases as the lung empties and ceases at 25 to 35% of total lung capacity. The remaining air is termed the residual volume. In patients with COPD who have emphysema, the disruption of alveolar attachments, coupled with distal airway disease, causes a substantial decrease in maximal expiratory airflow (Panel A, normal flow; Panel B, reduced flow). Residual volume may account for as much as 60 to 70% of predicted total lung capacity. Patients with COPD must breathe at larger lung volumes to optimize expiratory airflow, but this requires greater respiratory work because the lungs and chest wall become stiffer at larger volumes. These effects are accentuated with exercise. A normal respiratory system meets the increased ventilatory demands of exercise by increasing both tidal volume and respiratory rate, with little change in the final end-expiratory lung volume. In patients with COPD, the respiratory rate does increase in response to exercise, but with insufficient expiratory time, breaths become increasingly shallow and end-expiratory lung volume progressively enlarges (Panel A, normal response to exercise; Panel B, response with COPD). This phenomenon is called dynamic hyperinflation and is thought to be an important factor in the reduction of exercise capacity and the development of dyspnea.


(Source: Outpatient Management of Severe COPD. N Engl J Med 2010.)


Although spirometry is needed to make a diagnosis of COPD (see Investigations below), evaluation of symptoms, exacerbation history and risk, and physical examination findings provide important clues.

Presentation: COPD should be considered in anyone with the following symptoms:

  • chronic cough

  • chronic sputum production

  • dyspnea

  • history of risk factors, including exposure to tobacco smoke, occupational dusts, vapors, fumes, and the presence of genetic factors

Patient symptoms can be rated using objective scales such as the following:

Exacerbation history: The 2023 Global Initiative for Chronic Obstructive Lung Disease (GOLD) report replaced the ABCD assessment tool with the ABE Assessment Tool to account for the importance of exacerbations independent of level of symptoms. This new tool classifies patients’ disease severity into three groups (A,B, and E) rather than the previous four groups. Groups A and B remain unchanged, while Group E represents the combination of Groups C and D to highlight the important role of exacerbations.

ABE Assessment Tool


(Reprinted with permission from the 2023 Global Strategy for Diagnosis, Management, and Prevention of COPD. ©2023 Global Initiative for Chronic Obstructive Lung Disease, all rights reserved.)

Prognostic factors: The BODE Index for COPD Survival (Body mass index, airflow Obstruction, Dyspnea, and Exercise) is a simple, multidimensional grading system that incorporates the patient’s body mass index (BMI), degree of airflow obstruction (FEV1), subjective dyspnea symptoms (mMRC Dyspnea Scale), and exercise capacity (6-minute walking distance). The BODE index can be used to predict the risk of death from any cause and from respiratory causes in patients with COPD. The score ranges from 0 to 10; for every 1-point increase in the BODE index, the hazard ratio for all-cause mortality increases by 1.34 and for respiratory-related mortality by 1.62.

Physical exam: A number of physical exam findings can hint at an underlying diagnosis of COPD and vary with the severity of the disease. These findings are a manifestation of airway obstruction, hyperinflation, and chronic hypoxemia. Patients may present with varying degrees of tachypnea, respiratory muscle use, and pursed-lip breathing.

  • Hyperinflation: On examination, patients may appear cachectic from increased respiratory efforts. An increased anteroposterior-to-lateral diameter >0.9 is indicative of hyperinflation (barrel-shaped chest).

  • Wheeze: On auscultation, diminished breath sounds may be heard due to decreased airflow. Auscultated wheeze has a high-positive-likelihood ratio for the diagnosis of COPD.

  • Cyanosis: Examination of the hands may reveal cyanosis or nicotine staining.

For more information on the value of the physical exam in the diagnosis of airway obstruction, see this review.


Spirometry: A spirometry measurement of the ratio of postbronchodilator forced expiratory volume in one second [FEV1] to forced vital capacity (FEV1 /FVC) <0.7 is typically consistent with the diagnosis of COPD. GOLD classifies the severity of COPD based on the following spirometric measurements:

Gold Grades and Severity of Airflow Obstruction in COPD


(Reprinted with permission from the 2023 Global Strategy for Diagnosis, Management, and Prevention of COPD. ©2023 Global Initiative for Chronic Obstructive Lung Disease, all rights reserved.)

Initial Treatment

Smoking cessation: A discussion of the importance of smoking cessation is key with COPD patients to reduce the reduced risk of mortality (see Smoking Cessation in the Ambulatory Care rotation guide).

Vaccination: Influenza vaccination reduces serious illness and death in COPD patients. The Centers for Disease Control and Prevention additionally recommends routine vaccination against pneumonia, pertussis, SARS-CoV-2, and herpes zoster.

Bronchodilators: First-line pharmacologic agents for treatment of COPD are inhaled bronchodilators (beta2-agonist or anticholinergics) alone, in combination, or with the addition of inhaled glucocorticoids, depending on the patient’s symptoms. Commonly used maintenance inhalers are categorized into the following four groups:

  • long‐acting beta2‐agonists (LABAs)

  • long‐acting muscarinic antagonists (LAMAs)

  • LABA/inhaled glucocorticoid combinations

  • LABA/LAMA combinations

The LABA/LAMA combination appears to have an advantage over monotherapy or LABA/inhaled glucocorticoid therapy in reducing COPD exacerbations. Additionally, data show a trend that combined therapies (LABA/LAMA and LABA/inhaled glucocorticoid) lead to a greater improvement in symptom and quality-of-life scores than monotherapies. A growing body of evidence suggests that inhaled glucocorticoids are more effective in patients with high blood eosinophil levels than in patients without high levels.

Initial Pharmacologic Management of COPD Patients


Abbreviations: LAMA, long-acting muscarinic antagonists; LABA, long-acting beta2-agonists; ICS, inhaled corticosteroids

(Reprinted with permission from the 2023 Global Strategy for Diagnosis, Management, and Prevention of COPD. ©2023 Global Initiative for Chronic Obstructive Lung Disease, all rights reserved.)

Supplemental oxygen: The use of supplemental oxygen is associated with reduced mortality but is indicated only if partial pressure of oxygen is ≤55 mm Hg or oxygen saturation is ≤88% while respiring ambient air. Patients with COPD and moderate desaturation (resting oxygen saturation of 89% to 93% or moderate exercise-induced desaturation) do not appear to benefit from supplemental oxygen.

Chronic macrolide therapy: In former smokers, chronic macrolide therapy with azithromycin has been shown to prevent COPD exacerbations and improve symptoms. This treatment can be considered in patients with persistent symptoms despite optimal inhaled therapy.

A simplified algorithm for the initial assessment and management of patients with COPD is provided below:

Algorithm for the Evaluation and Treatment of Persons with COPD or at Risk for COPD


(Source: Update on Clinical Aspects of Chronic Obstructive Pulmonary Disease. N Engl J Med 2019.)

COPD Exacerbation

COPD exacerbation is the acute change in baseline dyspnea, cough, and/or sputum beyond day-to-day variation that necessitates a change in therapy. Exacerbations are associated with reduced lung function and quality of life and increased morbidity and mortality. Exacerbations are typically associated with respiratory infections caused by viral and bacterial triggers, as described in the following table:

Microbial Pathogens in COPD


(Source: Infection in the Pathogenesis and Course of Chronic Obstructive Pulmonary Disease. N Engl J Med 2008.)

Treatment of COPD Exacerbations:

  • Glucocorticoids are associated with improved oxygenation and shortened recovery time and hospitalization duration. Treatment duration is usually 5–7 days.

  • Antibiotics are also frequently prescribed for management of COPD exacerbations, especially those associated with increased purulence of sputum. Chronic macrolide therapy is associated with a reduction in COPD exacerbations.

  • Noninvasive mechanical ventilation should be the first mode of ventilation in COPD patients with respiratory failure and no absolute contraindications (e.g., altered mental status or facial trauma that precludes safe wearing of the noninvasive mask).

See the Pocket Guide to COPD Diagnosis, Management and Prevention: 2023 Report, for a summary of the newest guidance on diagnosis and outpatient management of COPD.


Landmark clinical trials and other important studies


Webber EM et al. JAMA 2022.


Lacasse Y et al. N Engl J Med 2020.

This underpowered randomized trial provides no indication that nocturnal oxygen has a positive or negative effect on survival or progression to long-term oxygen therapy in patients with COPD.

Read the NEJM Journal Watch Summary


Rabe KF et al. N Engl J Med 2020.

Triple therapy with twice-daily budesonide (at either the 160-μg or 320-μg dose), glycopyrrolate, and formoterol resulted in a lower rate of moderate or severe COPD exacerbations than glycopyrrolate–formoterol or budesonide–formoterol.

Read the NEJM Journal Watch Summary


Butler CC et al. N Engl J Med 2019.

In this randomized, controlled trial, the use of point-of-care CRP testing led to decreased prescription of antibiotics with no evidence of harm.


Criner GJ et al. for the GALATHEA and TERRANOVA Study Investigators. N Engl J Med 2019.

In two randomized, controlled trials, targeting the interleukin-5 receptor with the monoclonal antibody benralizumab did not affect the rate of COPD exacerbations.


Dransfield MT et al. for the BLOCK COPD Trial Group. N Engl J Med 2019.

In this study of patients with COPD at risk for exacerbation, treatment with metoprolol did not affect time to first exacerbation, and the trial was stopped early due to futility and a worrisome severe-exacerbation safety signal.


Walters JAE et al. Cochrane Database Syst Rev 2018.

This analysis suggests that the likelihood is low that shorter courses (about 5 days) of systemic glucocorticoids lead to worse outcomes than longer courses (10 to 14 days).


Oba Y et al. Cochrane Database Syst Rev 2018.

This Cochrane Review evaluated current COPD combination and monotherapy inhalers and effect of frequency of COPD exacerbation and quality-of-life scores.


Suissa S et al. Lancet Respir Med 2018.

Initial COPD treatment with LABA/inhaled glucocorticoid inhalers was only more effective than treatment with LAMAs in patients with high blood eosinophil concentrations.


Pavord ID et al. N Engl J Med 2017.

In two phase 3, randomized, controlled trials, targeting the interleukin-5 pathway with monoclonal antibodies reduced COPD exacerbations in patients with an eosinophilic phenotype.


Lange P et al. N Engl J Med 2015.

Most people with COPD were thought to have normal lung function in mid-adult life and then lose it rapidly. In this study, many people with COPD already had low lung function in mid-adult life, before COPD developed.


Magnussen H et al. for the WISDOM Investigators. N Engl J Med 2014.

In this study, patients with severe COPD receiving inhaled glucocorticoids and two classes of long-acting bronchodilators, glucocorticoid withdrawal was noninferior to continuation with respect to exacerbations but was associated with a slight worsening in lung function and symptoms.


Albert RK et al. for the COPD Clinical Research Network. N Engl J Med 2011.

In this randomized, controlled trial in patients with moderately severe COPD, daily treatment with azithromycin for one year was associated with fewer exacerbations.


Vestbo J et al. for the ECLIPSE Investigators. N Engl J Med 2011.

In this study, the rate of change in FEV1 among patients with COPD was highly variable, with increased rates of decline among current smokers, patients with bronchodilator reversibility, and patients with emphysema.


The best overviews of the literature on this topic


Boucher RC. N Engl J Med 2019.

This review article covers the spectrum of muco-obstructive lung diseases including COPD, cystic fibrosis, primary ciliary dyskinesia, and bronchiectasis.


Agustí A and Hogg JC. N Engl J Med 2019.

An updated review of COPD pathogenesis


Celli BR and Wedzicha JA. N Engl J Med 2019.

A comprehensive review of clinical aspects of COPD including diagnosis, management, and follow-up


Postma DS and Rabe KF. N Engl J Med 2015.

Classically, asthma and COPD are viewed as distinct disorders. This article reviews the asthma–COPD overlap syndrome whereby patients have features of both diseases.


Wenzel RP et al. N Engl J Med 2012.

This case vignette explores whether the daily use of macrolides reduces COPD exacerbations.


Niewoehner DE. N Engl J Med 2010.

This case vignette reviews the outpatient management of severe COPD.


Silverman EK and Sandhaus RA. N Engl J Med 2009.

This article provides a review on alpha1-antitrypsin deficiency, which can lead to symptoms of obstructive lung disease.


Cosio MG et al. N Engl J Med 2009.

This article reviews how pulmonary damage caused by cigarette smoke and other environmental toxins can incite inflammatory and immunologic reactions that culminate in COPD. The authors present evidence that autoimmunity has a role in the development of COPD.


Casaburi R and ZuWallack R. N Engl J Med 2009.

This article reviews the indications and evidence for pulmonary rehabilitation in patients with COPD. Patients with unstable angina or recent myocardial infarction may not be good candidates for pulmonary rehabilitation.


Sethi S and Murphy TF. N Engl J Med 2008.

This review examines the role of infections as triggers for COPD exacerbations.


The current guidelines from the major specialty associations in the field


Global Initiative for Chronic Obstructive Lung Disease 2023.


Mangione CM et al. JAMA 2022.


Nici L et al. Am J Respir Crit Care Med 2020.


Qaseem A et al. Ann Intern Med 2011.

NEJM Knowledge+