Diagnostic Instability and Reversals of Chronic Obstructive Pulmonary Disease Diagnosis in Individuals with Mild to Moderate Airflow Obstruction.

RATIONALE: Chronic obstructive pulmonary disease (COPD) is a chronic, progressive disease, and reversal of COPD diagnosis is thought to be uncommon. OBJECTIVES: To determine whether a spirometric diagnosis of mild or moderate COPD is subject to variability and potential error. METHODS: We examined two prospective cohort studies that enrolled subjects with mild to moderate post-bronchodilator airflow obstruction. The Lung Health Study (n = 5,861 subjects; study duration, 5 yr) and the Canadian Cohort of Obstructive Lung Disease (CanCOLD) study (n = 1,551 subjects; study duration, 4 yr) were examined to determine frequencies of (1) diagnostic instability, represented by 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, defined as how often an individual's COPD diagnosis at the study outset reversed to normal by the end of the study. MEASUREMENTS AND MAIN RESULTS: Diagnostic instability was common and occurred in 19.5% of the Lung Health Study subjects and 6.4% of the CanCOLD subjects. Diagnostic reversals of COPD from the beginning to the end of the study period occurred in 12.6% and 27.2% of subjects in the Lung Health Study and CanCOLD study, respectively. The risk of diagnostic instability was greatest for subjects whose baseline FEV1/FVC value was closest to the diagnostic threshold, and the risk of diagnostic reversal was greatest for subjects who quit smoking during the study. CONCLUSIONS: A single post-bronchodilator spirometric assessment may not be reliable for diagnosing COPD in patients with mild to moderate airflow obstruction at baseline.

Addressing the misdiagnosis of asthma in adults: where does it go wrong?

INTRODUCTION: Asthma is diagnosed based on patients' respiratory symptoms of wheeze, cough, chest tightness and/or dyspnea together with physiologic evidence of variable and reversible expiratory airflow limitation. A high prevalence of overdiagnosis, underdiagnosis and misdiagnosis of adult asthma has been reported in the literature. Areas covered: Misdiagnosis of asthma in adults can occur in the community due to physicians' failure to confirm airflow limitation using spirometry, the relatively poor sensitivity of spirometry to absolutely rule in asthma, the complexity of multiple asthma phenotypes and endotypes, and the inherent day to day variability of asthma symptoms and airflow limitation. Consequences of asthma misdiagnosis to the patient and to the healthcare system include increased medication costs, increased potential side effects related to unnecessary use of medications and lost opportunities to diagnose the true cause of patients' respiratory symptoms. Expert commentary: Here we provide a review of the problem of misdiagnosis of adult asthma and suggestions for how to decrease the risk of misdiagnosis.