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General Information


  • common, preventable, and treatable pulmonary disease generally caused by significant exposure to noxious particles or gases (such as cigarette smoke) and characterized by persistent and progressive respiratory symptoms, airflow limitation due to chronic airway inflammation, and destruction of lung parenchyma1

Also called

  • chronic obstructive pulmonary disease
  • chronic bronchitis
  • emphysema
  • chronic obstructive lung disease
  • COLD


  • terms "emphysema" and "chronic bronchitis" not included in Global Initiative for Chronic Obstructive Lung Disease (GOLD) definition of COPD1
    • chronic bronchitis - cough and excess sputum production for ≥ 3 months per year in each of 2 consecutive years
    • emphysema - pathological term describing destruction of gas exchanging surfaces of lung (alveoli)
  • COPD exacerbation defined as acute worsening of respiratory symptoms, resulting in the need for additional therapy1 (see also Acute exacerbation of COPD)

Severity classification

  • Global Initiative for Chronic Obstructive Lung Disease (GOLD) severity classification of airflow limitation in COPD1
    • diagnosis of COPD applied to patients with airflow limitation, defined as forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) ratio < 0.7
    • based on postbronchodilator FEV1
      Table 1. GOLD Classification for Severity of Airflow Limitation
      Severity FEV1
      GOLD 1 (Mild)≥ 80% predicted
      GOLD 2 (Moderate)50%-79% predicted
      GOLD 3 (Severe)30%-49% predicted
      GOLD 4 (Very severe)< 30% predicted

      Abbreviations: FEV1, forced
                                          expiratory volume in 1 second; GOLD, Global Initiative for
                                          Chronic Obstructive Lung Disease.

  • symptom severity assessments include1
    • modified British Medical Research Council (mMRC) questionnaire evaluates breathlessness based on scale of 0 (breathless with strenuous exercise) to 4 (too breathless to leave the house or breathless when dressing or undressing)
    • COPD Assessment Test (CAT) is an 8-item questionnaire worth 5 points each (overall score range 0-40) that may aid in determining disease-specific, health-related quality of life (see CAT websiteOpenInNew for questionnaire and user guide)
  • GOLD severity assessment based on symptom burden and risk of exacerbation1
    • Group A
      • 0 exacerbations or 1 exacerbation not leading to hospital admission
      • mMRC score 0-1
      • CAT score < 10
    • Group B
      • 0 exacerbations or 1 exacerbation not leading to hospital admission
      • mMRC score ≥ 2
      • CAT score ≥ 10
    • Group C
      • ≥ 2 exacerbations or ≥ 1 exacerbation leading to hospital admission
      • mMRC score 0-1
      • CAT score < 10
    • Group D
      • ≥ 2 exacerbations or ≥ 1 exacerbation leading to hospital admission
      • mMRC score ≥ 2
      • CAT score ≥ 10


General references used

  1. Global Initiative for Chronic Obstructive Lung Disease (GOLD). Global strategy for the diagnosis, management, and prevention of COPD. GOLD 2019OpenInNew
  2. Qaseem A, Wilt TJ, Weinberger SE, et al. Diagnosis and management of stable chronic obstructive pulmonary disease: a clinical practice guideline update from the American College of Physicians, American College of Chest Physicians, American Thoracic Society, and European Respiratory Society. Ann Intern Med. 2011 Aug 2;155(3):179-91OpenInNew, editorial can be found in Ann Intern Med 2011 Aug 2;155(3):IOpenInNew, commentary can be found in Ann Intern Med 2012 Jan 3;156(1 Pt 1):68OpenInNew

Recommendation grading systems used

  • Global Initiative for Chronic Obstructive Lung Disease (GOLD) grades of recommendation
    • Evidence A - based on randomized controlled trials with rich body of high-quality evidence without any significant limitation or bias
    • Evidence B - based on randomized controlled trials with important limitations or limited body of evidence
    • Evidence C - based on nonrandomized trials or observational studies
    • Evidence D - based on panel consensus judgement
    • Reference - GOLD strategy for diagnosis, management, and prevention of COPD (GOLD 2019OpenInNew)
  • European Respiratory Society/American Thoracic Society (ERS/ATS) uses Grades of Recommendation, Assessment, Development, and Evaluation (GRADE)
    • strength of recommendations
      • Strong recommendation - certainty that desirable consequences of intervention outweigh undesirable consequences, or vice versa
      • Conditional recommendation - uncertainty that desirable consequences of intervention outweigh undesirable consequences, or vice versa
    • quality of evidence determination
      • High - randomized controlled trial without methodological limitations; inconsistency in results; indirectness in population, intervention, or outcome; or imprecision in estimates, or observational studies with very large magnitude of effect with RR > 5 or < 0.2 and no threats to validity
      • Moderate - downgraded randomized controlled trials or upgraded observational studies
      • Low - well-done observational studies with control groups
      • Very low - any other evidence (for example, case reports or case series)
  • British Thoracic Society (BTS) grading system for recommendations
    • grades of recommendations
      • Grade A
        • at least 1 meta-analysis, systematic review, or randomized controlled trial (RCT) rated as 1++ and directly applicable to the target population, or
        • body of evidence consisting principally of studies rated as 1+, directly applicable to target population and demonstrating overall consistency of results
      • Grade B
        • body of evidence including studies rated as 2++, directly applicable to target population and demonstrating overall consistency of results, or
        • extrapolated evidence from studies rated as 1++ or 1+
      • Grade C
        • body of evidence including studies rated as 2+, directly applicable to target population and demonstrating overall consistency of results, or
        • extrapolated evidence from studies rated as 2++
      • Grade D
        • evidence level 3 or 4, or
        • extrapolated evidence from studies rated as 2+
      • Good Practice Point - important practical point for which there is no research evidence, nor is there likely to be any research evidence
    • levels of evidence
      • 1++ - high-quality meta-analyses, systematic reviews of RCTs, or RCTs with very low risk of bias
      • 1+ - well-conducted meta-analyses, systematic reviews of RCTs, or RCTs with low risk of bias
      • 1- - meta-analyses, systematic reviews of RCTs, or RCTs with high risk of bias
      • 2++
        • high-quality systematic reviews of case-control or cohort studies
        • high-quality case-control or cohort studies with very low risk of confounding or bias and high probability that relationship is causal
      • 2+ - well-conducted case-control or cohort studies with low risk of confounding or bias and moderate probability that relationship is causal
      • 2- - case-control or cohort studies with high risk of confounding or bias and significant risk that relationship is not causal
      • 3 - nonanalytical studies (for example, case reports, case series)
      • 4 - expert opinion
    • Reference - BTS guideline on pulmonary rehabilitation in adults (23880483Thorax 2013 Sep;68 Suppl 2:ii1OpenInNew), commentary can be found in 24408022Thorax 2014 Apr;69(4):387OpenInNew
  • Public Health Service (PHS) guideline panel Strength of Evidence ratings
    • Strength of Evidence A - multiple well-designed randomized clinical trials, directly relevant to the recommendation, yielded a consistent pattern of findings
    • Strength of Evidence B - some evidence from randomized clinical trials supported the recommendation, but the scientific support was not optimal
    • Strength of Evidence C - reserved for important clinical situations in which Panel achieved consensus on recommendation in the absence of relevant randomized controlled trials
    • Reference - United States Department of Health and Human Services/Public Health Service clinical practice guideline on treating tobacco use and dependence 2008 update (DHHS 2008 May PDFPictureAsPdf)
  • United States Preventive Services Task Force (USPSTF) grades of recommendation (June 2007 to June 2012)
    • Grade A - USPSTF recommends the service with high certainty of substantial net benefit
    • Grade B - USPSTF recommends the service with high certainty of moderate net benefit or moderate certainty of moderate-to-substantial net benefit
    • Grade C - clinicians may provide the service to select patients depending on individual circumstances; however, only small benefit is likely for most individuals without signs or symptoms
    • Grade D - USPSTF recommends against providing the service with moderate-to-high certainty of no net benefit or harms outweighing benefits
    • Grade I - insufficient evidence to assess balance of benefits and harms
    • Reference - USPSTF Grade DefinitionsOpenInNew
  • American College of Physicians (ACP) guideline grading system
    • strength of recommendation
      • Strong - benefits clearly outweigh risks and burden, or risks and burden clearly outweigh benefits
      • Weak - benefits closely balanced with risks and burden or uncertainty in estimates of benefits, risks, and burdens
      • Insufficient - balance of benefits and risks cannot be determined
    • quality of evidence
      • High - randomized trials without important limitations, or overwhelming evidence from observational studies
      • Moderate - randomized trials with important limitations (inconsistent results, methodologic flaws, indirect, or imprecise), or exceptionally strong evidence from observational studies
      • Low - observational studies or case series
      • Insufficient - evidence is conflicting, poor quality, or lacking
    • Reference - ACP methods for development of clinical practice guidelines and guidance statements (20679562Ann Intern Med 2010 Aug 3;153(3):194OpenInNew)
  • American Thoracic Society/European Respiratory Society (ATS/ERS) grading system for recommendations
    • Grade I - randomized controlled trials
    • Grade II-1 - controlled trials without randomization
    • Grade II-2 - cohort or case-control analytic studies
    • Grade II-3 - multiple time series, dramatic uncontrolled experiments
    • Grade III - opinions of respected authorities, descriptive epidemiology
  • Canadian Thoracic Society (CTS) grading system for recommendations
    • strength of recommendations
      • Grade 1 - strong recommendation, with desirable effects clearly outweighing undesirable effects (or vice versa)
      • Grade 2 - weak recommendation, with desirable effects closely balanced with undesirable effects
    • quality of evidence
      • Grade A - well-designed, randomized controlled trials with consistent and directly applicable results
      • Grade B - randomized trials with limitations including inconsistent results or major methodological weaknesses
      • Grade C - observational studies, and from generalization from randomized trials in 1 group of patients to a different group of patients
    • Reference - CTS clinical practice guideline on Alpha-1 antitrypsin deficiency targeted testing and augmentation therapy (cxh79721030pmdc22536580pCan Respir J 2012 Mar-Apr;19(2):109OpenInNewfull-textOpenInNew)
  • Global Initiative for Asthma (GINA) grading system
    • levels of evidence
      • Evidence A - randomized controlled trials (RCTs) and meta-analyses (rich body of data)
      • Evidence B - RCTs and meta-analyses (limited body of data)
      • Evidence C - nonrandomized trials; observational studies
      • Evidence D - consensus judgment of panel
    • Reference - GINA global strategy on asthma management and prevention (GINA 2018OpenInNew)

Synthesized Recommendation Grading System for DynaMed

  • DynaMed systematically monitors clinical evidence to continuously provide a synthesis of the most valid relevant evidence to support clinical decision-making (see 7-Step Evidence-Based MethodologyOpenInNew).
  • Guideline recommendations summarized in the body of a DynaMed topic are provided with the recommendation grading system used in the original guideline(s), and allow DynaMed users to quickly see where guidelines agree and where guidelines differ from each other and from the current evidence.
  • In DynaMed (DM), we synthesize the current evidence, current guidelines from leading authorities, and clinical expertise to provide recommendations to support clinical decision-making in the Overview & Recommendations section.
  • We use the Grading of Recommendations Assessment, Development and Evaluation (GRADE)OpenInNew to classify synthesized recommendations as Strong or Weak.
    • Strong recommendations are used when, based on the available evidence, clinicians (without conflicts of interest) consistently have a high degree of confidence that the desirable consequences (health benefits, decreased costs and burdens) outweigh the undesirable consequences (harms, costs, burdens).
    • Weak recommendations are used when, based on the available evidence, clinicians believe that desirable and undesirable consequences are finely balanced, or appreciable uncertainty exists about the magnitude of expected consequences (benefits and harms). Weak recommendations are used when clinicians disagree in judgments of relative benefit and harm, or have limited confidence in their judgments. Weak recommendations are also used when the range of patient values and preferences suggests that informed patients are likely to make different choices.
  • DynaMed (DM) synthesized recommendations (in the Overview & Recommendations section) are determined with a systematic methodology:
    • Recommendations are initially drafted by clinical editors (including ≥ 1 with methodological expertise and ≥ 1 with content domain expertise) aware of the best current evidence for benefits and harms, and the recommendations from guidelines.
    • Recommendations are phrased to match the strength of recommendation. Strong recommendations use "should do" phrasing, or phrasing implying an expectation to perform the recommended action for most patients. Weak recommendations use "consider" or "suggested" phrasing.
    • Recommendations are explicitly labeled as Strong recommendations or Weak recommendations when a qualified group has explicitly deliberated on making such a recommendation. Group deliberation may occur during guideline development. When group deliberation occurs through DynaMed-initiated groups:
      • Clinical questions will be formulated using the PICO (Population, Intervention, Comparison, Outcome) framework for all outcomes of interest specific to the recommendation to be developed.
      • Systematic searches will be conducted for any clinical questions where systematic searches were not already completed through DynaMed content development.
      • Evidence will be summarized for recommendation panel review including for each outcome, the relative importance of the outcome, the estimated effects comparing intervention and comparison, the sample size, and the overall quality rating for the body of evidence.
      • Recommendation panel members will be selected to include at least 3 members that together have sufficient clinical expertise for the subject(s) pertinent to the recommendation, methodological expertise for the evidence being considered, and experience with guideline development.
      • All recommendation panel members must disclose any potential conflicts of interest (professional, intellectual, and financial), and will not be included for the specific panel if a significant conflict exists for the recommendation in question.
      • Panel members will make Strong recommendations if and only if there is consistent agreement in a high confidence in the likelihood that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. Panel members will make Weak recommendations if there is limited confidence (or inconsistent assessment or dissenting opinions) that desirable consequences outweigh undesirable consequences across the majority of expected patient values and preferences. No recommendation will be made if there is insufficient confidence to make a recommendation.
      • All steps in this process (including evidence summaries which were shared with the panel, and identification of panel members) will be transparent and accessible in support of the recommendation.
    • Recommendations are verified by ≥ 1 editor with methodological expertise, not involved in recommendation drafting or development, with explicit confirmation that Strong recommendations are adequately supported.
    • Recommendations are published only after consensus is established with agreement in phrasing and strength of recommendation by all editors.
    • If consensus cannot be reached then the recommendation can be published with a notation of "dissenting commentary" and the dissenting commentary is included in the topic details.
    • If recommendations are questioned during peer review or post publication by a qualified individual, or reevaluation is warranted based on new information detected through systematic literature surveillance, the recommendation is subject to additional internal review.

DynaMed Editorial Process

Special acknowledgements

  • The American College of Physicians (Marjorie Lazoff, MD, FACP; ACP Deputy Editor, Clinical Decision Resource) provided review in a collaborative effort to ensure DynaMed provides the most valid and clinically relevant information in internal medicine.
The American College of Physicians (Steven Weinberger, MD, FACP, Chief Executive Officer) provided editorial feedback regarding essential clinical content on this topic as part of the ACP-EBSCO Health collaboration on selected internal medicine DMP topics.
  • DynaMed topics are written and edited through the collaborative efforts of the above individuals. Deputy Editors, Section Editors, and Topic Editors are active in clinical or academic medical practice. Recommendations Editors are actively involved in development and/or evaluation of guidelines.
  • Editorial Team role definitions
    Topic Editors define the scope and focus of each topic by formulating a set of clinical questions and suggesting important guidelines, clinical trials, and other data to be addressed within each topic. Topic Editors also serve as consultants for the internal DynaMed Editorial Team during the writing and editing process, and review the final topic drafts prior to publication.
    Section Editors have similar responsibilities to Topic Editors but have a broader role that includes the review of multiple topics, oversight of Topic Editors, and systematic surveillance of the medical literature.
    Recommendations Editors provide explicit review of DynaMed Overview and Recommendations sections to ensure that all recommendations are sound, supported, and evidence-based. This process is described in "Synthesized Recommendation Grading."
    Deputy Editors are employees of DynaMed and oversee DynaMed internal publishing groups. Each is responsible for all content published within that group, including supervising topic development at all stages of the writing and editing process, final review of all topics prior to publication, and direction of an internal team.

How to cite

National Library of Medicine, or "Vancouver style" (International Committee of Medical Journal Editors):

  • DynaMed [Internet]. Ipswich (MA): EBSCO Information Services. 1995 - . Record No. T115557, COPD; [updated 2018 Dec 04, cited place cited date here]. Available from Registration and login required.
  • KeyboardArrowRight

    Overview and Recommendations

    • Background

    • Evaluation

    • Management

  • Related Summaries

  • KeyboardArrowRight

    General Information

    • Description

    • Also called

    • Definitions

    • Severity classification

  • KeyboardArrowRight


    • Who is most affected

    • Incidence/Prevalence

    • Likely risk factors

    • Possible risk factors

    • Factors not associated with increased risk

    • Associated conditions

  • KeyboardArrowRight

    Etiology and Pathogenesis

    • Causes

    • Pathogenesis

  • KeyboardArrowRight

    History and Physical

    • KeyboardArrowRight


      • Chief concern (CC)

      • History of present illness (HPI)

      • Medication history

      • Past medical history (PMH)

      • Family history (FH)

      • Social history (SH)

    • KeyboardArrowRight


      • General physical

      • Skin

      • Chest

      • Lungs

      • Extremities

    • Severity assessment

  • KeyboardArrowRight


    • Making the diagnosis

    • Differential diagnosis

    • Testing overview

    • Blood tests

    • KeyboardArrowRight

      Imaging studies

      • Chest x-ray

      • Computed tomography (CT)

    • Biopsy and pathology

    • Pulmonary function tests

    • Other diagnostic testing

  • KeyboardArrowRight


    • Management overview

    • KeyboardArrowRight

      Smoking cessation

      • Overview of smoking cessation

      • Effects of smoking cessation in COPD

      • Achieving smoking cessation (COPD-specific evidence)

      • Smoking cessation topics

    • Diet

    • KeyboardArrowRight


      • Pulmonary rehabilitation

    • Counseling

    • KeyboardArrowRight


      • KeyboardArrowRight

        Recommendations from professional organizations

        • GOLD recommendations

        • ACP/ACCP/ATS/ERS joint recommendations

        • Choosing Wisely

      • Bronchodilator therapy

      • KeyboardArrowRight


        • Inhaled corticosteroids

        • Oral corticosteroids

      • Delivery of aerosol medications

      • Phosphodiesterase 4 inhibitors

      • Oxygen therapy

      • Helium-oxygen mixture

      • Oral mucolytics

      • Prophylactic antibiotics

      • KeyboardArrowRight


        • Influenza vaccination

        • Pneumococcal vaccination

        • Haemophilus influenzae vaccination

      • Statins

      • Central nervous system suppressants to relieve dyspnea

      • Medications for alpha-1 antitrypsin (AAT) deficiency

      • Acetazolamide

      • Other medications

    • KeyboardArrowRight

      Surgery and procedures

      • Lung volume reduction surgery (LVRS)

      • Bronchoscopic lung volume reduction procedures

      • Lung transplant

      • Targeted lung denervation

    • KeyboardArrowRight

      Other management

      • KeyboardArrowRight

        Education and self-management

        • General information

        • Overall efficacy

        • Specific self-management programs

      • Noninvasive ventilation

      • Airway clearance techniques

      • Neuromuscular electrical stimulation of lower limbs

      • Driving

      • Air travel

      • Palliative care

      • Other interventions

    • KeyboardArrowRight


      • Monitoring response to therapy

      • Disease management programs

      • Telehealthcare

      • Outreach healthcare worker programs

      • Interventions to improve adherence

  • KeyboardArrowRight

    Complications and Prognosis

    • Complications

    • KeyboardArrowRight


      • General prognosis

      • Mortality risk factors

      • Prognostic indices

      • Other prognostic factors

  • KeyboardArrowRight

    Prevention and Screening

    • Prevention

    • Screening

  • KeyboardArrowRight

    Quality Improvement

    • Physician Quality Reporting System Quality Measures

    • Quality and Outcomes Framework Indicators

    • Quality indicators

    • Choosing Wisely

    • Choosing Wisely Canada

  • KeyboardArrowRight

    Guidelines and Resources

    • KeyboardArrowRight


      • International guidelines

      • United States guidelines

      • United Kingdom guidelines

      • Canadian guidelines

      • European guidelines

      • Asian guidelines

      • Mexican guidelines

      • Central and South American guidelines

      • Australian and New Zealand guidelines

      • African guidelines

    • Review articles

    • MEDLINE search

  • Patient Information

  • KeyboardArrowRight

    ICD Codes

    • ICD-10 codes

  • KeyboardArrowRight


    • General references used

    • Recommendation grading systems used

    • Synthesized Recommendation Grading System for DynaMed

    • DynaMed Editorial Process

    • Special acknowledgements

    • How to cite

Topic Editor
Linda Nici MD

Site Director, Pulmonary and Critical Care Fellowship Program, and Clinical Professor of Medicine, Brown University Alpert Medical School; Rhode Island, United States

Conflicts of Interest

Dr. Nici declares no relevant financial conflicts of interest.

Recommendations Editor
Allen Shaughnessy PharmD, M Med Ed, FCCP

Professor of Family Medicine and Director of Master Teacher Fellowship, Tufts University; Massachusetts, United States

Conflicts of Interest

Dr. Shaughnessy declares no relevant financial conflicts of interest.

Deputy Editor
Terence K. Trow MD, FACP, FCCP

Deputy Editor of Pulmonary, Critical Care, and Sleep Medicine; Connecticut, United States; Ex-Director of the Yale Pulmonary Vascular Disease Program, Associate Clinical Professor of Medicine, Yale University School of Medicine; Connecticut, United States

Conflicts of Interest

Dr. Trow declares no relevant financial conflicts of interest.

Produced in collaboration with American College of Physicians

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