Bronchodilator testing may prevent COPD overdiagnosis
NEW ORLEANS — Use of spirometry with bronchodilator testing can help reduce overdiagnosis of COPD as well as help differentiate COPD from asthma and asthma-COPD overlap syndrome, researchers reported at the CHEST Annual Meeting.
“Despite the Global Initiative for Chronic Obstructive Lung Disease (GOLD) recommendation to use the post-bronchodilator FEV1/FVC ratio for diagnosis, spirometry with bronchodilator testing is not routinely used in clinical practice to diagnose COPD,” Srinadh Annangi, MD, from the University of Kentucky School of Medicine, told Healio Pulmonology.
“In this study, we aimed to determine the role of underutilizing bronchodilator testing in potential COPD overdiagnosis and also looked at its role in identifying COPD patients with possible asthma-COPD overlap syndrome — a phenotype of COPD that warrants different management strategies than those for just COPD.”
Annangi and colleagues evaluated more than 8,000 participants in the National Health and Nutrition Examination (NHANES) survey who were aged at least 40 years and underwent pre-bronchodilator spirometry. Of these participants, 625 met the American Thoracic Society spirometry quality standards and had airway obstruction based on an FEV1/FVC ratio less than 0.7 without bronchodilator testing. However, only 61% had airway obstruction based on a post-bronchodilator FEV1/FVC ratio less than 0.7, suggesting that nearly 40% of patients may have been misdiagnosed with COPD if pre-bronchodilator FEV1/FVC ratio was used.
Also among the 381 participants with a post-bronchodilator FEV1/FVC ratio less than 0.7, 3.1% had a history of asthma and bronchodilator reversibility, 4.2% had a history of asthma and blood eosinophilia, 0.7% had a change in FEV1 of 400 mL or greater and blood eosinophilia. These findings indicate that a diagnosis of asthma-COPD overlap syndrome was more likely than COPD alone, the researchers noted.
The prevalence of possible asthma-COPD overlap syndrome among the participants with COPD was 19% when modified Spanish Society of Pneumology and Thoracic Surgery (SEPAR) criteria were used and 7.9% when modified ATS roundtable criteria were used among these 381 participants. Change in FEV1 with bronchodilator testing was included in the proposed major criteria and minor criteria of these definitions.
“Not performing bronchodilator testing with spirometry and thereby excluding the bronchodilator reversibility criteria from definitions might miss 8.6% of participants with asthma-COPD overlap syndrome with SEPAR definition and 31% with ATS roundtable definition,” Annangi said.
The researchers also found that among 244 cases (39%) with pre-bronchodilator but post-bronchodilator ratio less than 0.7, 24 participants (9.8%) had positive bronchodilator reversibility. Among 24 of these participants with positive bronchodilator reversibility, seven experienced wheezing in the past year, five had family history of asthma, seven had change in FEV1 greater than 400 mL and one participant met all three criteria. Prevalence of possible asthma in these 244 participants was 5%.
These participants would otherwise be diagnosed as having COPD if pre-bronchodilator ratio were used. A number of these participants had never been told they had asthma. “Whether asthma was suspected and ruled out in these participants or was never suspected and evaluated for is beyond the scope of our analysis,” Annangi said.
These findings indicate that bronchodilator testing can help prevent COPD overdiagnosis, and subsequent inappropriate treatment and unnecessary resource utilization, as well as identify patients with asthma-COPD overlap syndrome or patients with a possible asthma diagnosis who may be mislabeled as having COPD, according to Annangi.
“We acknowledge the retrospective nature of this study, but that does not undermine the clinical importance of our study findings,” he told Healio Pulmonology. “Further studies should focus on two things: identifying and overcoming barriers among health care providers that prevent bronchodilator testing and prospectively following patients diagnosed with COPD based on pre-bronchodilator FEV1/FVC ratio for clinical outcomes, including symptom improvement and possible delay in identifying alternate diagnosis attributable to their initial symptoms.” – by Melissa Foster
Annangi S. Asthma: From Blood Biomarkers to Biologics and Disease Burden. Presented at: CHEST Annual Meeting; Oct. 19-23, 2019; New Orleans.
For more information:
Srinadh Annangi, MD, can be reached at email@example.com; Twitter: @asnnsri.
Disclosures: The authors report no relevant financial disclosures.