Dr. Martin Miller from the University of Birmingham and Dr. Mark Levy from the Harrow Clinical Commissioning Group in the United Kingdom recently highlighted the risk for misdiagnosing chronic obstructive pulmonary disease (COPD). The study was recently published in the journal The BMJ and is entitled “Chronic obstructive pulmonary disease: missed diagnosis versus misdiagnosis.”
COPD is one of the most common lung diseases and a major cause of morbidity and mortality worldwide, being the third leading cause of disease-related death in the United States. It is a progressive disease in which individuals develop serious problems in breathing with airways obstruction, shortness of breath (dyspnea), cough and acute exacerbations. Estimates show that 210 million people suffer from COPD worldwide, including almost 27 million individuals in the United States. Smoking is considered to be the leading cause of COPD.
The prevalence and mortality of COPD is increasing worldwide. In the United Kingdom in particular, it has been reported that COPD might be severely underdiagnosed, especially among individuals with early disease stages who could benefit from preventive care. In this study, the team reports that the current diagnostic criteria can in fact also lead to a COPD over-diagnosis in certain groups.
COPD diagnosis in patients with cough or sputum production and dyspnea requires a confirmatory spirometric evidence of airflow limitation that is not fully reversible. This measure is established by the ratio of forced expiratory volume in 1 second (FEV1) divided by the forced vital capacity (FVC) of the patient. Internationally agreed standards have been established to define the lower limits of normal FEV1/FVC for different populations. Such criteria take into consideration the patient’s sex, age, height and ethnicity.
In 2001, the Global Initiative for Obstructive Lung Disease (GOLD) defined airways obstruction as a FEV1/FVC value of <0.7, without accounting sex, age, or other parameters. The idea was that this new simple criterion would be easily implemented in non-specialist settings, allowing a greater detection of the disorder and a reduction of the morbidity and mortality associated to it. This definition was adopted by the UK National Institute for Health and Care Excellence (NICE), being also widely used in the United States, Europe and Australasia.
In 2010, GOLD was asked by more than 150 international experts and 12 international organizations to modify the definition of airflow obstruction from a fixed ratio to the internationally accepted lower limit of normal FEV1/FVC.
According to the authors, the current COPD guidelines over-diagnose COPD in older man while they under-diagnose COPD in young woman. In fact, the team estimated that up to 13% of the individuals diagnosed with COPD under the GOLD criteria are actually misdiagnosed. Misdiagnosis can have severe consequences for the patients “because of adverse effects of inappropriate medication or incorrect treatment,” explained the authors according to a news release. For instance, the unnecessary use of inhaler treatment for COPD is known to increase the risk of developing severe pneumonia.
The team emphasizes that the NICE guidelines and the GOLD criteria should be modified, and that clinicians should adopt the internationally agreed standards of lower limits of normal FEV1/FVC when assessing COPD patients. This will ultimately allow a more accurate diagnosis, leading to an improvement in patient care and less costs in hospital re-admissions and inappropriate therapies. The team also advises editors of respiratory journals and their reviewers to “increasingly challenge authors to examine the effect of different methods of diagnosis on their results.”