The Effect of a Post-Bronchodilator FEV 1 /FVC < 0.7 on COPD Diagnosis and Treatment: A Regression Discontinuity Design
Listed in
This article is not in any list yet, why not save it to one of your lists.Abstract
Background
Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines recommend the diagnosis of chronic obstructive pulmonary disease (COPD) only in patients with a post-bronchodilator forced expiratory volume in 1 second to forced vital capacity ratio (FEV 1 /FVC) less than 0.7. However the impact of this recommendation on clinical practice is unknown.
Research Question
What is the effect of a documented post-bronchodilator FEV 1 /FVC < 0.7 on the diagnosis and treatment of COPD?
Study Design and Methods
We used a national electronic health record database to identify clinical encounters between 2007 to 2022 with patients 18 years of age and older in which a post-bronchodilator FEV 1 /FVC value was documented. An encounter was associated with a COPD diagnosis if a diagnostic code for COPD was assigned, and was associated with COPD treatment if a prescription for a medication commonly used to treat COPD was filled within 90 days. We used a regression discontinuity design to measure the effect of a post-bronchodilator FEV 1 /FVC < 0.7 on COPD diagnosis and treatment.
Results
Among 27 817 clinical encounters, involving 18 991 patients, a post-bronchodilator FEV 1 /FVC < 0.7 was present in 14 876 (53.4%). The presence of a documented post-bronchodilator FEV 1 /FVC < 0.7 had a small effect on the probability of a COPD diagnosis, increasing by 6.0% (95% confidence interval [CI] 1.1% to 10.9%) from 38.0% just above the 0.7 cutoff to 44.0% just below this cutoff. The presence of a documented post-bronchodilator FEV 1 /FVC had no effect on the probability of COPD treatment ( − 2.1%, 95% CI − 7.2% to 3.0%).
Interpretation
The presence of a documented post-bronchodilator FEV 1 /FVC < 0.7 has only a small effect on the probability that a clinician will make a guideline-concordant diagnosis of COPD and has no effect on corresponding treatment decisions.
