New COPD diagnostic schema identifies additional individuals at risk of poor respiratory outcomes

The diagnosis of chronic obstructive pulmonary disease, or COPD, is improved by incorporating CT lung imaging and respiratory symptoms. This fresh, multidimensional approach better identifies patients who are at risk of poor respiratory outcomes, while ruling out those who have airflow obstruction without respiratory symptoms or structural lung disease, Surya Bhatt, M.D., and colleagues report in the Journal of the American Medical Association.

This new COPD diagnostic schema, which includes chest imaging, respiratory symptoms and spirometry, identified additional individuals at risk of poor respiratory outcomes."

Surya Bhatt, M.D., professor, Department of Medicine, University of Alabama at Birmingham Marnix E. Heersink School of Medicine and director, Center for Lung Analytics and Imaging Research

The schema includes airflow obstruction on spirometry as the major criterion and minor criteria based on chest imaging and respiratory symptoms. Imaging includes visual signs of emphysema and airway wall thickening on computed tomography, and symptom-based criteria consider difficulty breathing, reduced quality of life and the presence of chronic bronchitis. Under the new framework, a patient must have airflow obstruction and at least one minor criterion or, in the absence of airflow obstruction or if lung function tests are not available, at least three of five minor criteria.

Bhatt and colleagues found that, among 9,416 participants enrolled in a multicenter cohort, those newly diagnosed with COPD by the schema had greater all-cause and respiratory-specific mortality, more frequent exacerbations, and faster lung function decline compared with people classified as not having COPD based on the new classification. This new diagnostic schema included additional individuals with high respiratory morbidity and excluded some with airflow obstruction who had no symptoms or evidence of structural lung disease.

Before this study, clinicians had increasingly recognized that lung function tests did not capture all aspects of the complex heterogeneous disease COPD, a leading cause of disability and death. Some 392 million people globally, and 16 million in the United States, are estimated to have COPD.

"This new diagnostic schema will likely change the way we diagnose COPD and enable its diagnosis, even in the absence of overt airflow obstruction on spirometry," Bhatt said. "Whether treating individuals newly diagnosed this way will result in improved outcomes remains to be tested, but practitioners have already been using imaging and symptoms to diagnose COPD. This new schema sets some parameters to operationalize this."

In an editorial in JAMA, Francesca Polverino, M.D., Ph.D., called the study a milestone in COPD diagnosis. "COPD classification has remained overly dependent on airflow limitation as the main diagnostic criterion," Polverino wrote. "What truly sets this reclassification apart is its groundbreaking assertion that airflow obstruction is no longer a requirement for a COPD diagnosis."

In the system proposed by Bhatt and colleagues, airflow obstruction remains the major criterion for COPD. "However, what makes this model significantly more inclusive and reflective of clinical COPD diversity are the minor criteria, which are split between imaging and symptom-based factors," said Polverino, a professor at the Baylor College of Medicine, Houston, Texas.

Bhatt is corresponding author of the study, "A new multidimensional diagnostic approach for chronic obstructive pulmonary disease," and Edwin K. Silverman, M.D., Ph.D., Brigham and Women's Hospital, Boston, Massachusetts, and James D. Crapo, M.D., National Jewish Health, Denver, Colorado, are co-senior authors. Other UAB authors include Mark Dransfield and Sandeep Bodduluri, UAB Department of Medicine Division of Pulmonary, Allergy and Critical Care Medicine; and Arie Nakhmani, UAB School of Engineering Department of Electrical and Computer Engineering.

The study includes 52 authors from 24 universities and institutions in the United States and Canada.

At UAB, Bhatt works in the Division of Pulmonary, Allergy and Critical Care Medicine.