Guidelines for chronic obstructive lung disease over-diagnose older men and under-diagnose younger women, claim two UK respiratory experts.
They claim that up to 13% of people thought to have COPD under the Global Initiative for Obstructive Lung Disease (GOLD) are actually misdiagnosed because it is too simple and does not account for other factors.
The GOLD guidelines should be modified argue Professor Martin Miller, from the Institute of Occupational and Environmental Medicine at Birmingham University, and Dr Mark Levy, from Harrow Clinical Commissioning Group.
“Patients with misdiagnosed COPD are exposed to these risks for no benefit”
Martin Miller & Mark Levy
In the meantime, they suggest that clinicians should use alternative, internationally agreed standards when assessing patients for COPD, which they say would lead to more accurate diagnosis and reduce admissions resulting from misdiagnosis and inappropriate therapy.
GOLD was published in 2011 and uses a simple diagnostic threshold for airway obstruction of a post-bronchodilator FEV1/FVC of <0.7, but with no account taken of age, sex, or other factors.
It was subsequently adopted by the National Institute for Health and Care Excellence in its 2010 COPD guidance, replacing the previously accepted lower limits of normal (LLN) criteria for FEV1/FVC.
However, the GOLD definition estimates COPD prevalence at 22% in those aged over 40 years in England and Wales, compared with 13% using LLN criteria, argue Professor Miller and Dr Levy.
Research also shows that it misses one in eight cases of airflow obstruction identified by the LLN, particularly among younger women, they added.
Meanwhile, they quoted other studies suggesting that up to 13% of people thought to have COPD on GOLD criteria have been found to be misdiagnosed.
Misdiagnosing patients may lead to poorer outcomes “because of adverse effects of inappropriate medication or incorrect treatment”, they warned.
For example, they suggest that people meeting only the GOLD criteria for COPD have a higher prevalence of heart disease than people who meet both LLN and GOLD criteria.
Furthermore, use of inhaler treatment increases the likelihood of developing severe pneumonia.
“Patients with misdiagnosed COPD are exposed to these risks for no benefit,” they wrote in the British Medical Journal.
They said NICE guidelines and the GOLD strategy documents “should be modified because they over-diagnose COPD in older men while missing the possibility of diagnosing heart disease; they also under-diagnose COPD in young women”.
They argue that clinicians should use the LLN instead when assessing patients for COPD.
They said: “Adoption of this criterion, which is programmed into most spirometry software, will help to improve patient care through more accurate diagnosis of obstructive airflow diseases as well as leading to other investigations for alternative diagnoses when appropriate.
“Clinics focusing on breathless patients should consider including echocardiography and other cardiovascular investigations as well as spirometry to ensure correct diagnosis,” they added.