The Effect of a Post-Bronchodilator FEV1/FVC < 0.7 on COPD Diagnosis and Treatment: A Regression Discontinuity Design.

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 (FEV1/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 FEV1/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 FEV1/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 FEV1/FVC < 0.7 on COPD diagnosis and treatment. Results: Among 27 817 clinical encounters, involving 18 991 patients, a post-bronchodilator FEV1/FVC < 0.7 was present in 14 876 (53.4%). The presence of a documented post-bronchodilator FEV1/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 FEV1/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 FEV1/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.

Gender Differences in the Diagnosis of Chronic Obstructive Pulmonary Disease after Spirometry.

Background: Women are more likely than men to report delays in the diagnosis of chronic obstructive pulmonary disease (COPD), though the etiology of these delays is unknown. We sought to test whether delays in COPD diagnosis persist after the performance of spirometry. Methods: We used the Optum Labs Data Warehouse to identify patients 18 years of age and older without a prior diagnosis of COPD, with a post-bronchodilator forced expiratory volume in 1 second (FEV1) to forced vital capacity (FVC) ratio of less than 0.7 on spirometry. We used a Cox proportional hazards model to compare the time to diagnosis after spirometry in men and women, adjusting for age, race, ethnicity, tobacco use, and post-bronchodilator FEV1/FVC. Results: The probability of receiving a COPD diagnosis after the performance of spirometry was lower among women than men (adjusted hazard ratio [aHR] 0.66, 95% confidence interval [CI] 0.50 to 0.88). Conclusion: In this retrospective cohort study of patients with spirometric evidence of obstruction, the time to diagnosis of COPD was greater among women than men. While previous vignette-based studies have found that gender differences in the diagnosis of COPD resolve with the performance of spirometry, we found that gender differences persist after spirometry has been performed. Clinicians were less likely to diagnose COPD in women even when spirometry supported this diagnosis.

Analysis of Devices Authorized by the FDA for Clinical Decision Support in Critical Care.

This case series study examines the clinical evidence cited for US Food and Drug Administration­approved clinical decision support devices for use in the critical care setting.

Global, Race-Neutral Reference Equations and Pulmonary Function Test Interpretation.

Importance: Race and ethnicity are routinely used to inform pulmonary function test (PFT) interpretation. However, there is no biological justification for such use, and it may reinforce health disparities. Objective: To compare the PFT interpretations produced with race-neutral and race-specific equations. Design, Setting, and Participants: In this cross-sectional study, race-neutral reference equations recently developed by the Global Lung Function Initiative (GLI) were used to interpret PFTs performed at an academic medical center between January 2010 and December 2020. The interpretations produced with these race-neutral reference equations were compared with those produced using the race and ethnicity-specific reference equations produced by GLI in 2012. The analysis was conducted from April to October 2022. Main Outcomes and Measures: The primary outcomes were differences in the percentage of obstructive, restrictive, mixed, and nonspecific lung function impairments identified using the 2 sets of reference equations. Secondary outcomes were differences in severity of these impairments. Results: PFTs were interpreted from 2722 Black (686 men [25.4%]; mean [SD] age, 51.8 [13.9] years) and 5709 White (2654 men [46.5%]; mean [SD] age, 56.4 [14.3] years) individuals. Among Black individuals, replacing the race-specific reference equations with the race-neutral reference equations was associated with an increase in the prevalence of restriction from 26.8% (95% CI, 25.2%-28.5%) to 37.5% (95% CI, 35.7%-39.3%) and of a nonspecific pattern of impairment from 3.2% (95% CI, 2.5%- 3.8%) to 6.5% (95% CI, 5.6%-7.4%) and no significant change in the prevalence of obstruction (19.9% [95% CI, 18.4%-21.4%] vs 19.5% [95% CI, 18.0%-21.0%]). Among White individuals, replacing the race-specific reference equations with the race-neutral reference equations was associated with a decrease in the prevalence of restriction from 22.6% (95% CI, 21.5%-23.6%) to 18.0% (95% CI, 17.0%-19.0%), a decrease in the prevalence of a nonspecific pattern of impairment from 8.7% (95% CI, 7.9%-9.4%) to 4.0% (95% CI, 3.5%-4.5%), and no significant change in the percentage with obstruction from 23.9% (95% CI, 22.8%-25.1%) to 25.1% (95% CI, 23.9%- 26.2%). The race-neutral reference equations were associated with an increase in severity in 22.8% (95% CI, 21.2%-24.4%) of Black individuals and a decrease in severity in 19.3% (95% CI, 18.2%-20.3%) of White individuals vs the race-specific reference equations. Conclusions and Relevance: In this cross-sectional study, the use of race-neutral reference equations to interpret PFTs resulted in a significant increase in the number of Black individuals with respiratory impairments along with a significant increase in the severity of the identified impairments. More work is needed to quantify the effect these reference equations would have on diagnosis, referral, and treatment patterns.