Current chronic obstructive pulmonary disease (COPD) management programs and guidelines overdiagnose elderly patients and underdiagnose young ones. An analysis published online July 1 in the BMJ details the problem and calls for the adoption of lower limits of normal (LLN) criteria for airflow obstruction that are specific for different populations.
Martin R. Miller, MD, from the University of Birmingham in the United Kingdom, and Mark L. Levy, MBChB, from the Harrow Clinical Commissioning Group in London, United Kingdom, wrote their article as part of a series in the journal on overdiagnosis.
The Global Initiative for Obstructive Lung Disease (GOLD) strategy documents were introduced in 2001 and were intended to create a new and simple threshold for airway obstruction. A diagnosis of COPD is thus based entirely on an assessment of airway obstruction as measured by the ratio of forced expiratory volume in 1 second (FEV1) divided by the forced vital capacity (FVC).
Although the GOLD guidelines are based on consensus expert opinion, they do not effectively diagnose COPD, Dr Miller and Dr Levy contend. Yet, the GOLD criteria have been adopted by the UK National Institute for Health and Care Excellence and are used extensively throughout the United States, Europe, and Australasia.
GOLD Does Not Work
"The bottom line is that COPD is a heterogeneous disease that is not fully explained by spirometry alone," emphasized Barry J. Make, MD, from National Jewish Health in Denver, Colorado, in an interview with Medscape Medical News. Moreover, COPD’s prevalence and mortality are increasing throughout the world, noted Dr Make, who was not involved in the current analysis.
In their analysis, Dr Miller and Dr Levy propose that the GOLD criteria be refined by the addition of LLN criteria. At a minimum, they suggest, the LLN should be incorporated into future studies of COPD.
The authors explain that when the GOLD definition is applied to England and Wales, 22% of individuals older than 40 years meet the criteria for COPD. In contrast, the LLN criteria would diagnose 13% of individuals older than 40 years as having COPD, suggesting the current system results in a great deal of overdiagnosis.
Harm From Misdiagnosis
They also calculate that as many as 13% of patients diagnosed with COPD under the GOLD criteria may be misdiagnosed (underdiagnosis as well as overdiagnosis). This misdiagnosis could lead to poor outcomes that result from inappropriate treatment. For example, use of the inhaler treatment for COPD increases the risk of the patient developing severe pneumonia, which is an unfortunate outcome for a patient who may not even need the inhaler.
Misdiagnosis may also result in patients missing out on necessary treatment. The authors note that patients who meet only the GOLD criterion for COPD have a higher incidence of heart disease than patients who meet both the GOLD and LLN criteria, suggesting that some patients with heart disease may be misdiagnosed by GOLD as having COPD.
Beyond Spirometry
To confound the issue even further, Dr Make notes that many smokers may perform well on the spirometry test, thereby creating "the myth of the healthy smoker."
He is currently performing what he describes as the "Framingham lung study" to define "what [computed tomography] scans are in people who smoke." The goal of the study is to help physicians move beyond spirometry to better diagnose patients who have symptoms of COPD. This is necessary because COPD is currently underdiagnosed during the early stages of disease, when preventive strategies might be most useful.
The National Institutes of Health has also funded a study to facilitate diagnosis of COPD in smokers and other patients. The goal is to create a five-question questionnaire that is able to diagnose clinically significant COPD.
Until these new guidelines have been created, however, Dr Make called on physicians to "make sure that they incorporate in the test the clinical perspective." He also emphasized that "the face of the diagnosis of COPD will continue to evolve."
Dr Miller has accepted lecture fees from TEVA, Chiesi, GSK, AstraZeneca, Boehringer Ingelheim, and Mundi Pharma for lecturing on the lessons from and his experience as clinical lead for the National Review of Asthma Deaths. Dr Levy has disclosed no relevant financial relationships. Dr Make is on the medical advisory board and/or has received funding for clinical research trials from GSK, Boehringer Ingelheim, Novartis, AstraZeneca, and Spiration.
BMJ. Published online July 1, 2015. Full text
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Cite this: Current Diagnostic Criteria for COPD Inadequate, Experts Say - Medscape - Jul 02, 2015.
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