COPD Diagnosis Guidelines Seen as Fool’s Gold

Current guidelines for chronic obstructive pulmonary disease (COPD) should be modified because they overdiagnose COPD in older men, underdiagnose COPD in younger women, and can miss the possibility of heart disease, according to a recent analysis.

Up to 13% of persons thought to have COPD under the Global Initiative for Obstructive Lung Disease (GOLD) criteria have been found to be misdiagnosed, stated the authors, Martin Miller, Professor of Medicine at the University of Birmingham, UK, and Mark Levy, MBChB, of the Harrow Clinical Commissioning Group in London.

Using internationally agreed standards when assessing patients for COPD improves patient care through more accurate diagnosis and saves money by reducing admissions resulting from misdiagnosis and inappropriate therapy, the authors said.

The prevalence and mortality of COPD are increasing globally, they noted. Smoking accounts for 75% of cases.

A new diagnostic threshold for airflow obstruction (FEV₁/FVC <0.7) was introduced in the GOLD report in 2001. This definition contrasts with internationally agreed criteria that use statistically defined lower limits of normal (LLN) for different populations.

The rationale for the change, the authors stated, was that the “new diagnostic criterion was simple so could be easily implemented in non-specialist settings. Treatment of people identified by GOLD criteria would reduce morbidity and mortality.”

Instead, there has been an increase in disease prevalence with use of the GOLD criteria. “The new definition estimates COPD prevalence at 22% in those aged over 40 years in England and Wales compared with 13% using LLN criteria,” they said.

The GOLD criteria also miss 1 in 8 cases of airflow obstruction identified by the LLN, particularly among younger women.

The criteria have been adopted by the UK National Institute for Health and Care Excellence and are used widely in the United States, Europe, and Australasia.

There also is evidence of misdiagnosis. “Up to 13% of people thought to have COPD on GOLD criteria have been found to be misdiagnosed,” the authors stated.

Misdiagnosis of COPD may lead to poorer outcomes “because of adverse effects of inappropriate medication or incorrect treatment,” they wrote.

The authors also noted that the prevalence of heart disease is higher in patients who meet only the GOLD criterion for COPD than in those who meet both LLN and GOLD criteria. “Cardiovascular mortality is unexpectedly high among mildly breathless patients with GOLD diagnosed COPD,” they stated.

In addition, use of inhaler treatment for COPD increases the likelihood of severe pneumonia. “Patients with misdiagnosed COPD are exposed to these risks for no benefit,” they said.

“We argue that clinicians should use the LLN instead when assessing patients for COPD,” the authors concluded. “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.”

The analysis appeared in the July 1, 2015 British Medical Journal.