Currently, patients are diagnosed with COPD following a multifactorial assessment that includes clinical presentation, symptomatology, and risk factors in combination with the gold-standard of spirometry. Hallmark symptoms of COPD include sputum production, cough, and progressive dyspnea. All patients with suspected COPD should undergo spirometry, which is a necessary component for diagnosis. A pertinent and thorough medical history and physical examination are both essential elements for clinical assessment in a patient with suspected COPD. In addition, differential diagnosis should be assessed to ensure that an appropriate diagnosis is made.2
Misdiagnosis and under-diagnosis continues to be a focal problem in the management of COPD.24
While clinicians agree that spirometry is essential for COPD diagnosis, assessments are often omitted in the primary care setting due to various limiting factors.25
Barriers to appropriate spirometry evaluation include lack of time for assessment, lack of available resources, and inadequate training of personnel for accurate measurement. Sufficient training for primary care clinicians26
and enhanced population screening initiatives for high-risk patients24
may increase frequency, accuracy, and confidence in spirometry screening practices.
Despite streamlined, appropriate implementation of spirometry, differential diagnosis in COPD is challenging. In particular, differentiation between asthma and COPD can be difficult for clinicians due to substantial overlap in disease presentation and symptoms. A recent study indicates that a spirometry diagnosis of COPD could be made in approximately 17% of patients previously diagnosed with asthma alone.28
Furthermore, patients with COPD can exhibit some respiratory function reversibility, mimicking patients with an asthma diagnosis. Indeed the possibility of both disorders coexisting is likely more common than expected and can influence management strategies.27
Clinicians should place importance on a thorough medical history and utilize guidance from international guideline resources to ensure proper classification of these patients.2
Due to the aforementioned challenges of diagnosis, various analyses report diagnosis primarily in later stages of the disease. Patients who fall into these later stages of COPD before diagnosis classically exhibit less response to treatment modalities. In addition, while pulmonary function decline is slower in earlier stages of COPD, it becomes more rapid in more advanced disease.30
In short, advances resulting in earlier diagnosis can significantly influence the clinical course of COPD management and the natural history of disease progression.
As well as enhancing the frequency and efficiency of spirometry screening, population screening tools have emerged as options to facilitate earlier diagnosis of COPD. These tools attempt to simplify identification of COPD in the general population by providing a straightforward means for individuals to discuss their respiratory symptoms with a clinician. The self-scored COPD population screener questionnaire (COPD-PS) is one such tool that attempts to encompass a broad group of individuals for screening regardless of smoking history, previous diagnosis, or other clinical information.31
A score from questionnaires such as the COPD-PS is used by clinicians to determine whether or not supplementary assessment of potential COPD diagnosis is necessary. Because the positive predictive value of the COPD-PS is not sufficient for accurate diagnosis alone (approximately 57%), it is important to note that this tool is meant specifically for identification purposes rather than to be used as an exclusive diagnostic test.31
Although further validation and fine tuning of population screening questionnaires such as the COPD-PS are necessary, these tools will likely play a more substantial role in the early identification of COPD in the future.
A key future component of effective COPD disease management includes an appropriate assessment of disease severity through symptom evaluation to guide therapy. Although spirometry is essential for diagnosis, its role seems to be less well defined in regard to ongoing disease state management. While some sources still promote spirometry use in bronchodilator reversibility testing, this test is no longer recommended due to lack of efficacy as a tool to predict treatment response.2
Various assessment tools have been established to better assess COPD disease progress and severity.
The Modified British Medical Research Council (mMRC) questionnaire32
and the COPD Assessment Test (CAT) provide a standardized means of COPD-related health status assessment (). These tools present a format for assessing the impact of COPD on quality of life indicators to help guide clinicians to properly select appropriate, guideline-recommended treatment strategies.2
While the mMRC only evaluates the impact of shortness of breath, the CAT includes assessments of COPD impact on activities of daily living. A recent randomized controlled study indicates that the CAT is a disease-specific instrument that significantly improves the assessment of COPD severity of illness.33
These assessment tests are now recommended as a standard means of assessment during patient follow-up visits2
and are used in combination with spirometry and assessment of exacerbation risk to guide therapy.
Evaluative questions from the COPD Assessment Test (CAT).
Pulmonary imaging has become an area of interest that may play a more significant role in COPD assessment and care in the future. Quantitative pulmonary imaging can provide greater insight into lung structure and function in comparison with spirometry which can only assess disease severity.31
Computed tomography (CT) can provide detailed images of lung structure while magnetic resonance imaging (MRI) can help assess lung function including lung parenchyma function and airway thickening. Significant weaknesses of these imaging studies include the need for both CT and MRI studies for appropriate lung assessment, availability, and cost.34
Although CT is fast and provides high-resolution images, regular CT scans can promote harmful cumulative radiation.35
While these imaging modalities can help clinicians assess patients further, they carry with them both disadvantages and risks while their true role in COPD care remains to be established.
Smoking is the single most influential factor in the natural history of COPD. It must be the first step in modifying the clinical course of COPD and reducing the rate of decline in lung function.36
For this reason, a focus on smoking cessation interventions is likely the principal and most influential factor in COPD management. Although the most important strategy, smoking cessation may prove especially challenging in these patients, and should be approached utilizing both behavioral and pharmacological therapy when appropriate.39
Various first line pharmacotherapy options for tobacco dependence, are available, including varenicline, bupropion SR, and nicotine replacement therapies;2
treatment selection should be patient-specific, focusing on particular patient characteristics, preference, and contraindications.40
A comprehensive and multilevel approach to smoking cessation including both patient counseling and support along with pharmacotherapy is optimal,41
and this approach has been shown to provide the best benefit for long term quit rates.36
Although controversial due to low quality evidence, long-term oxygen therapy has been shown to decrease mortality in patients with severe resting hypoxemia.2
Likewise, it is currently a common non-pharmacologic therapy recommendation in this patient population in the hope of also improving functional performance and health-related quality of life.2
However, the same benefit has not been found in patients with mild to moderate hypoxemia. Despite the need for additional studies to illustrate the benefits of long-term oxygen therapy, ethical constraints of withholding oxygen therapy will likely be a limiting factor in future prospective studies.42
The anti-inflammatory and immunomodulatory effects of macrolide antibiotics as described in the literature,43
along with increased rates of early clinical response with their use, have increased their use in patients with acute infectious COPD exacerbations.44
These desirable effects have led to the investigation of macrolides for a potential role in the prevention of acute COPD exacerbations. Modest improvements in time to acute exacerbations, frequency of exacerbations, quality of life,45
and also number of moderate to severe exacerbations46
have all been reported with the use of macrolide prophylaxis in patients with COPD. As described previously, any reduction in acute exacerbations has the potential to translate into significant economic savings.
However, it is important to note that none of these studies have indicated a mortality benefit, and significant adverse effects and collateral damage from year-long use of macrolide therapy should be seriously considered. Recently, the US Food and Drug Administration issued a Drug Safety Communication on the widespread use of azithromycin, and the risk of potentially fatal heart arrhythmias.47
Ototoxicity and the potential for drug–drug interactions should also be considered with long-term macrolide therapy. Perhaps of even greater concern, the spread of antibiotic resistant isolates poses a threat to both macrolides and various other antimicrobials that exhibit similar mechanisms of action, and are thus affected by similar resistance gene mutations.45
For these reasons, antibiotic prophylaxis is not endorsed by current guidelines.2