Diagnostic Instability and Reversals of COPD Diagnosis in Subjects with Mild to Moderate Airflow Obstruction.

COPD is a chronic progressive disease and reversal of COPD diagnosis is thought to be uncommon. The objective of this study was to determine whether a spirometric diagnosis of mild or moderate COPD is subject to variability and potential error.

The authors examined two prospective cohort studies that enrolled subjects with mild to moderate post-bronchodilator airflow obstruction. The Lung Health Study (N=5861, study duration =5 years) and the CanCOLD study (N=1551, study duration = 4 years) were examined to determine frequencies of: 1) Diagnostic instability- how often patients initially met criteria for a spirometric diagnosis of COPD but then crossed the diagnostic threshold to normal and then crossed back to COPD over a series of annual visits, or vice-versa; and 2) Diagnostic reversals- how often an individual’s COPD diagnosis at the study outset reversed to normal by the end of the study.

A single post-bronchodilator spirometry assessment may not be reliable to diagnose COPD in patients with mild to moderate airflow obstruction at baseline.