Early Evidence of Chronic Obstructive Pulmonary Disease Obscured by Race-Specific Prediction Equations

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 s to forced vital capacity ratio (FEV1/FVC) less than 0.7. However the impact of this recommendation on clinical practice is unknown.

OBJECTIVE

To estimate the effect of a documented post-bronchodilator FEV1/FVC < 0.7 on the diagnosis and treatment of COPD.

DESIGN

We used a regression discontinuity design to measure the effect of a post-bronchodilator FEV1/FVC < 0.7 on COPD diagnosis and treatment.

PARTICIPANTS

Patients included in a national electronic health record database who were 18 years of age and older and had a clinical encounter between 2007 and 2022 in which a post-bronchodilator FEV1/FVC value was documented.

MAIN MEASURES

An encounter was associated with a COPD diagnosis if an international classification of disease 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.

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 increased the probability of a COPD diagnosis by 6.0% (95% confidence interval [CI] 1.1-10.9%) 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 < 0.7 had no effect on the probability of COPD treatment (-2.1%, 95% CI -7.2 to 3.0%).

CONCLUSIONS

The presence of a documented post-bronchodilator FEV1/FVC < 0.7 had only a small effect on the diagnosis of COPD and no effect on corresponding treatment decisions.

Examining discordance in spirometry reference equations: A retrospective study

This study aimed to evaluate discordance, binary classification, and model fit between race-predicted and race-neutral spirometry prediction equations. Spirometry data from 9506 patients (18-95 years old) self-identifying as White, Black, or Hispanic were analyzed, focusing on the lower limit of normal (LLN). Best-fit prediction equations were developed from 3771 patients with normal spirometry, using Bayesian Information Criterion (BIC) to compare models with and without race as a covariate. Results showed that including race as a covariate improved model fit, reducing BIC by at least ten units compared to Race-Neutral equations. Discordance between race-specific and race-neutral equations for detecting airway obstruction and restrictive spirometry patterns ranged from 4% to 13%. Using race-neutral equations resulted in false discovery rates (FDR) of 14% for Hispanics and 45% for Blacks and false negative rates (FNR) of 21% for Hispanics and 27% for Blacks in diagnosing airway obstruction. These findings indicate that removing race as a covariate in spirometry equations increases FDR and FNR, leading to higher misclassification rates. The 4%-13% discordance in interpreting airway obstruction and restrictive patterns has significant clinical implications, underscoring the need for careful consideration in developing spirometry reference equations.

Comparison of Race-Neutral versus Race-Specific Spirometry Equations for Evaluation of Child Asthma

Rationale: Race-based estimates of pulmonary function in children could influence the evaluation of asthma in children from racial and ethnic minoritized backgrounds. Objectives: To determine if race-neutral (Global Lung Function Initiative [GLI]-Global) versus race-specific (GLI-Race-Specific) reference equations differentially impact spirometry evaluation of childhood asthma. Methods: The analysis included 8,719 children aged 5 to <12 years from 27 cohorts across the United States grouped by parent-reported race and ethnicity. We analyzed how the equations affected FEV1, FVC, and FEV1/FVC z-scores. We used multivariable logistic models to evaluate associations between z-scores calculated with different equations and asthma diagnosis, emergency department visits, and hospitalization. Measurements and Main Results: For Black children, the GLI-Global versus GLI-Race-Specific equations estimated significantly lower z-scores for FEV1 and FVC but similar values for FEV1/FVC, thus increasing the proportion of children classified with low FEV1 by 14%. Although both equations yielded strong inverse relationships between FEV1 and FEV1/FVC z-scores and asthma outcomes, these relationships varied across racial and ethnic groups (P < 0.05). For any given FEV1 or FEV1/FVC z-score, asthma diagnosis and emergency department visits were higher among Black and Hispanic than among White children (P < 0.05). For FEV1, GLI-Global equations estimated asthma outcomes that were more uniform across racial and ethnic groups. Conclusions: Parent-reported race and ethnicity influenced relationships between lung function and asthma outcomes. Our data show no advantage to race-specific equations for evaluating childhood asthma, and the potential for race-specific equations to obscure lung impairment in disadvantaged children strongly supports using race-neutral equations.

Race-Specific and Race-Neutral Equations for Lung Function and Asthma Diagnosis in Black Children

Importance

Use of the race-neutral Global Lung Initiative (GLI) equation has been shown to generate decreased lung function measures in Black children and adults. The effect on asthma detection and diagnosis in children is unknown.

Objective

To compare the use of race-specific vs race-neutral equations on subsequent asthma diagnosis in children.

Design, Setting, and Participants

The Childhood Asthma Management Program (CAMP, 1991-2012), the Cincinnati Childhood Allergy and Air Pollution Study (CCAAPS, 2001-2010), and the Mechanisms of Progression from Atopic Dermatitis to Asthma (MPAACH, 2016-2024) cohorts were included in this cohort study. Children in the CAMP cohort were aged 5 to 12 years with mild to moderate asthma. The CCAAPS and MPAACH cohorts included infants from atopic parents and children aged 0 to 2 years with atopic dermatitis, respectively. Data were analyzed from November 2023 to May 2024.

Exposures

Race-specific vs race-neutral GLI equations to define lung function.

Main Outcomes and Measures

Percent predicted values of forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), asthma or asthma symptoms, and eligibility for reversibility testing were determined.

Results

Among 1533 children, there were 849 CAMP (median [IQR] age, 8.7 [7.1-10.6] years; 138 [16%] Black, 711 [84%] White, and 498 [59%] male participants), 578 CCAAPS (median [IQR] age, 6.9 [6.7-7.0]; 115 [20%] Black, 463 [80%] White, and 315 [55%] male participants) and 106 MPAACH (median [IQR] age, 7.4 [7.1-7.8] years; 62 [58%] Black, 44 [42%] White, and 62 [58%] male participants). The median (IQR) percent predicted FEV1 in Black children decreased by 11.9 percentage points (pp) (10.4-13.1 pp) in CAMP, 13.5% pp (11.8-14.6 pp) in CCAAPS, and 13.2 pp (11.6-14.6 pp) in MPAACH compared with the race-specific equation. The race-specific equation failed to detect reduced percent predicted FEV1 in 12 of 22 Black children in CCAAPS with asthma symptoms (55%) and 5 of 15 Black children in MPAACH with asthma (41%). In CCAAPS, children with less than 90% predicted FEV1 based on race-specific equations were eligible for postreversibility testing to objectively diagnose asthma. When this asthma diagnostic algorithm was applied, 16 of 36 Black children in CCAAPS (44%) and 6 of 16 Black children in MPAACH (38%) who were not eligible for reversibility testing based on the race-specific equation became eligible with a less than 90% predicted FEV1 based on the race-neutral equation.

Conclusions and Relevance

In this cohort study of 1533 children, the use of the race-neutral equation improved the detection of asthma in children. These results support the universal use of the race-neutral equation to improve asthma detection in children and help guide medical practice toward alleviating asthma-related health disparities.

Implications of Global Lung Function Initiative Spirometry Reference Equations in Northeast Asian Patients With COPD

BACKGROUND

Accurate spirometry interpretation is critical in the diagnosis and management of COPD. With increasing efforts for a unified approach by the Global Lung Function Initiative (GLI), this study evaluated the application of race-specific 2012 GLI and race-neutral 2022 GLI reference equations compared with Choi's reference equations, which are derived and widely used in South Korea, for spirometry interpretation in Northeast Asian patients with COPD.

RESEARCH QUESTION

What are the effects of applying race-specific 2012 GLI, race-neutral 2022 GLI, and Choi's reference equations on the diagnosis, severity grade, and clinical outcome associations of COPD?

STUDY DESIGN AND METHODS

Serial spirometry data from the Korea COPD Subgroup Study (KOCOSS) consisting of 3,477 patients were used for reanalysis using 2012 GLI, 2022 GLI, and Choi's reference equations. The COPD diagnosis and severity categorization, associations with disease manifestations and health outcomes, and longitudinal trajectories of lung function were determined.

RESULTS

Although there was strong concordance in COPD diagnosis comparing 2012 GLI, and 2022 GLI reference equations with Choi's reference equations, a notable portion of patients were reclassified to milder disease severity (17.0% and 23.4% for 2012 GLI and 2022 GLI reference equations, respectively). Relationships between FEV1 % predicted values calculated using 2012 GLI, 2022 GLI, and Choi's equations with clinical outcomes including dyspnea severity, exercise capacity, health-related quality of life, and frequency of exacerbations remain consistently significant. Similar annual decline rates of FEV1 and FVC % predicted were observed among the reference equations used, except for slower annual decline rate of FEV1 in Choi's equation compared with 2022 GLI race-neutral equation.

INTERPRETATION

Application of GLI reference equations for spirometry interpretation in Northeast Asian patients with COPD has potential implications on disease severity grade for clinical management and trial participation, and maintains consistent significant relationships with key disease outcomes.

Application of the European Respiratory Society/American Thoracic Society Spirometry Standards and Race-Neutral Equations in the COPDGene Study

Rationale: For spirometry interpretation, the European Respiratory Society (ERS) and American Thoracic Society (ATS) recommend using z-scores, and the ATS has recommended using Global Lung Initiative (GLI) "Global" race-neutral reference equations. However, these recommendations have been variably implemented, and the impact has not been widely assessed in clinical or research settings. Objectives: To evaluate the ERS/ATS classification of airflow obstruction severity. Methods: In COPDGene (Genetic Epidemiology of COPD Study) (N = 10,108), airflow obstruction has been defined by an FEV1/FVC ratio <0.70, with spirometric severity graded from class 1 to class 4 based on race-specific percent predicted (pp) FEV1 cutoff points as recommended by the Global Initiative for Chronic Obstructive Lung Disease (GOLD). We compared the GOLD approach, using National Health and Nutrition Examination Survey III race-specific equations, versus the application of GLI Global equations using the ERS/ATS definition of airflow obstruction as an FEV1/FVC ratio below the lower limit of normal and z-score-based FEV1 cutoff points of -1.645, -2.5, and -4 ("zGLI Global"). We tested the four-tier severity scheme for association with chronic obstructive pulmonary disease outcomes. Measurements and Main Results: The lowest agreement between ERS/ATS with zGLI Global and the GOLD classification was observed in individuals with milder disease (56.9% and 42.5% in GOLD stages 1 and 2, respectively), and race was a major determinant of redistribution. After adjustment for relevant covariates, zGLI Global distinguished all-cause mortality risk between normal spirometry and the first grade of chronic obstructive pulmonary disease (hazard ratio, 1.23; 95% confidence interval, 1.04-1.44; P = 0.014) and showed a linear increase in exacerbation rates with increasing disease severity in comparison with GOLD. Conclusions: The zGLI Global severity classification outperformed the GOLD criteria in the discrimination of survival, exacerbations, and imaging characteristics.

Comparison of race-specific and race-neutral GLI spirometric reference equations with an Indian reference equation

BACKGROUND

Despite the increasing popularity and use of Global Lung Function Initiative (GLI) spirometric reference equations, the appropriateness of the race-specific and race-neutral GLI spirometric reference models among the Indian population has not been systematically investigated.

METHODS

In this cross-sectional analysis, we used spirometric measurements of 1123 healthy Indian adults (≥18 years of age). We computed reference values and z-scores for forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), and FEV1/FVC from race-specific and race-neutral GLI reference equations as well as from a widely used Indian reference equation. We studied heterogeneity between GLI equations and the Indian equations using Bland-Altman analysis, and the differences between the reference and observed values were compared using the Friedman test.

RESULTS

In Bland-Altman analysis, significant heterogeneity in FVC and FEV1 between race-specific and Indian equations was observed (bias: 10.4 % and 14.1 %, respectively), with less bias for FEV1/FVC (3.76 %). The race-neutral equations showed almost similar bias (9.8 %, 13.8 %, and 3.8 % for FVC, FEV1, and FEV1/FVC, respectively). Median differences in race-specific reference values from observed values for FVC and FEV1 were 0.49L and 0.44L, respectively, decreasing slightly with race-neutral equations (0.46L and 0.43L) whereas Indian models showed minimal differences (FVC: 0.10L, FEV1: 0.05L). Z-scores for FVC and FEV1 were significantly different between race-specific and race-neutral GLI equations, and both differed from Indian equations.

CONCLUSION

Both race-specific and race-neutral GLI reference equations are significantly different from the Indian equations, which underscores the importance of determining the suitability of global reference models before being used indiscriminately.

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.

Spirometry Interpretation After Implementation of Race-Neutral Reference Equations in Children

Importance

The implications of adopting race-neutral reference equations on spirometry interpretation in children remain unknown.

Objective

To examine how spirometry results and patterns change when transitioning from Global Lung Function Initiative (GLI) race-specific reference equations (GLIR, 2012) to GLI race-neutral reference equations (GLIN, 2023).

Design, Setting, and Participants

Cross-sectional study of spirometry tests conducted in children aged 6 to 21 years between 2012 and 2022 at 2 large academic pediatric institutions in the US. Data were analyzed from September 2023 to March 2024.

Exposures

Data on participant characteristics and raw test measurements were collected. Forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and FEV1/FVC z scores and percent predicted were calculated using both GLIR and GLIN. In addition, test results were categorized into normal, obstructive, suspected restrictive, mixed, suspected dysanapsis, and uncategorized patterns based on z scores calculated using GLIR or GLIN.

Main Outcomes

For each spirometry result, the difference between z scores and percent predicted when transitioning from GLIR to GLIN was calculated. The proportion of tests with a normal pattern and individual spirometry patterns changed by GLI reference equation applied were also examined.

Results

Data from 24 630 children were analyzed (mean [SD] age, 12.1 [3.8] years). There were 3848 Black children (15.6%), 19 503 White children (79.2%), and 1279 children of other races (5.2%). Following implementation of GLIN, FEV1 and FVC z scores decreased in Black children (mean difference, -0.814; 95% CI, -0.823 to -0.806; P < .001; and -0.911; 95% CI, -0.921 to -0.902; P < .001, respectively), while FEV1 and FVC z scores slightly increased (0.073; 95% CI, 0.069 to 0.076; P < .001). Similar changes were found when using percent predicted. In Black children, the number of tests with a normal pattern decreased from 2642 (68.7%) to 2383 (61.9%) (χ21 = 204.81; P < .001), mostly due to tests with a normal pattern transitioning to a suspected restrictive or uncategorized pattern. Opposite, albeit smaller, changes in spirometry results and patterns were seen in White children. In adjusted models, Black children had approximately 3-fold higher odds than White children of changing spirometry pattern following the implementation of GLIN (adjusted odds ratio, 3.15; 95% CI, 2.86 to 3.48; P < .001).

Conclusions

Pronounced differences in spirometry results and patterns were found when switching between GLI reference equations, which markedly differed by race. These findings suggest that the implementation of GLIN is likely to change the treatment of children with chronic lung diseases that are more prevalent in underrepresented minorities, such as asthma.

The prevalence and mortality risks of PRISm and COPD in the United States from NHANES 2007-2012

BACKGROUND

We estimated the prevalence and mortality risks of preserved ratio impaired spirometry (PRISm) and chronic obstructive pulmonary disease (COPD) in the US adult population.

METHODS

We linked three waves of pre-bronchodilator spirometry data from the US National Health and Nutritional Examination Survey (2007-2012) with the National Death Index. The analytic sample included adults ages 20 to 79 without missing data on age, sex, height, BMI, race/ethnicity, and smoking status. We defined COPD (GOLD 1, 2, and 3-4) and PRISm using FEV1/FVC cut points by the Global Initiative for Chronic Obstructive Lung Disease (GOLD). We compared the prevalence of GOLD stages and PRISm by covariates across the three waves. We estimated adjusted all-cause and cause-specific mortality risks by COPD stage and PRISm using all three waves combined.

RESULTS

Prevalence of COPD and PRISm from 2007-2012 ranged from 13.1%-14.3% and 9.6%-10.2%, respectively. We found significant differences in prevalence by sex, age, smoking status, and race/ethnicity. Males had higher rates of COPD regardless of stage, while females had higher rates of PRISm. COPD prevalence increased with age, but not PRISm, which was highest among middle-aged individuals. Compared to current and never smokers, former smokers showed lower rates of PRISm but higher rates of GOLD 1. COPD prevalence was highest among non-Hispanic White individuals, and PRISm was notably higher among non-Hispanic Black individuals (range 31.4%-37.4%). We found associations between PRISm and all-cause mortality (hazard ratio [HR]: 2.3 95% CI: 1.9-2.9) and various cause-specific deaths (HR ranges: 2.0-5.3). We also found associations between GOLD 2 (HR: 2.1, 95% CI: 1.7-2.6) or higher (HR: 4.2, 95% CI: 2.7-6.5) and all-cause mortality. Cause-specific mortality risk varied within COPD stages but typically increased with higher GOLD stage.

CONCLUSIONS

The prevalence of COPD and PRISm remained stable from 2007-2012. Greater attention should be paid to the potential impacts of PRISm due to its higher prevalence in minority groups and its associations with mortality across various causes including cancer.

Race Adjustment of Pulmonary Function Tests in the Diagnosis and Management of COPD: A Scoping Review

Aim

Increasing evidence suggests that the inclusion of self-identified race in clinical decision algorithms may perpetuate longstanding inequities. Until recently, most pulmonary function tests utilized separate reference equations that are race/ethnicity based.

Purpose

We assess the magnitude and scope of the available literature on the negative impact of race-based pulmonary function prediction equations on relevant outcomes in African Americans with COPD.

Methods

We performed a scoping review utilizing an English language search on PubMed/Medline, Embase, Scopus, and Web of Science in September 2022 and updated it in December 2023. We searched for publications regarding the effect of race-specific vs race-neutral, race-free, or race-reversed lung function testing algorithms on the diagnosis of COPD and COPD-related physiologic and functional measures. Joanna Briggs Institute (JBI) guidelines were utilized for this scoping review. Eligibility criteria: The search was restricted to adults with COPD. We excluded publications on other lung disorders, non-English language publications, or studies that did not include African Americans. The search identified publications. Ultimately, six peer-reviewed publications and four conference abstracts were selected for this review.

Results

Removal of race from lung function prediction equations often had opposite effects in African Americans and Whites, specifically regarding the severity of lung function impairment. Symptoms and objective findings were better aligned when race-specific reference values were not used. Race-neutral prediction algorithms uniformly resulted in reclassifying severity in the African Americans studied.

Conclusion

The limited literature does not support the use of race-based lung function prediction equations. However, this assertion does not provide guidance for every specific clinical situation. For African Americans with COPD, the use of race-based prediction equations appears to fall short in enhancing diagnostic accuracy, classifying severity of impairment, or predicting subsequent clinical events. We do not have information comparing race-neutral vs race-based algorithms on prediction of progression of COPD. We conclude that the elimination of race-based reference values potentially reduces underestimation of disease severity in African Americans with COPD.

The Impact of Health Care Algorithms on Racial and Ethnic Disparities : A Systematic Review

BACKGROUND

There is increasing concern for the potential impact of health care algorithms on racial and ethnic disparities.

PURPOSE

To examine the evidence on how health care algorithms and associated mitigation strategies affect racial and ethnic disparities.

DATA SOURCES

Several databases were searched for relevant studies published from 1 January 2011 to 30 September 2023.

STUDY SELECTION

Using predefined criteria and dual review, studies were screened and selected to determine: 1) the effect of algorithms on racial and ethnic disparities in health and health care outcomes and 2) the effect of strategies or approaches to mitigate racial and ethnic bias in the development, validation, dissemination, and implementation of algorithms.

DATA EXTRACTION

Outcomes of interest (that is, access to health care, quality of care, and health outcomes) were extracted with risk-of-bias assessment using the ROBINS-I (Risk Of Bias In Non-randomised Studies - of Interventions) tool and adapted CARE-CPM (Critical Appraisal for Racial and Ethnic Equity in Clinical Prediction Models) equity extension.

DATA SYNTHESIS

Sixty-three studies (51 modeling, 4 retrospective, 2 prospective, 5 prepost studies, and 1 randomized controlled trial) were included. Heterogenous evidence on algorithms was found to: a) reduce disparities (for example, the revised kidney allocation system), b) perpetuate or exacerbate disparities (for example, severity-of-illness scores applied to critical care resource allocation), and/or c) have no statistically significant effect on select outcomes (for example, the HEART Pathway [history, electrocardiogram, age, risk factors, and troponin]). To mitigate disparities, 7 strategies were identified: removing an input variable, replacing a variable, adding race, adding a non-race-based variable, changing the racial and ethnic composition of the population used in model development, creating separate thresholds for subpopulations, and modifying algorithmic analytic techniques.

LIMITATION

Results are mostly based on modeling studies and may be highly context-specific.

CONCLUSION

Algorithms can mitigate, perpetuate, and exacerbate racial and ethnic disparities, regardless of the explicit use of race and ethnicity, but evidence is heterogeneous. Intentionality and implementation of the algorithm can impact the effect on disparities, and there may be tradeoffs in outcomes.

PRIMARY FUNDING SOURCE

Agency for Healthcare Quality and Research.