Reconsidering Race and Ethnicity for Predicting Normal Lung Function in Spirometry

Abstract

This review describes the impact of race-neutral spirometry reference equations on predicting normal lung function. The European Respiratory Society/American Thoracic Society 2022 interpretation guidance suggests further research on the relationship between pulmonary function results and clinical outcomes to aid interpretation decisions rather than relying solely on the 5^th and 95^th percentiles as statistical end points. Recent research compared how race-specific and race-neutral spirometry reference equations affected clinical outcomes (6-min walk test, abnormal computed tomography, hospitalizations, and clinic visits), symptoms (St George's Respiratory Questionnaire, COPD Assessment Test, dyspnea, and wheezing), and mortality. Race-neutral reference equations were equivalent or better at predicting clinical outcomes from FEV₁ and FVC in most studies. Initial studies showed that switching from race-specific to race-neutral reference equations increased the number of Black persons with potential restrictive lung disorders and decreased the frequency of abnormal test results in Whites and Northeast and Southeast Asians. Similar results were seen in the pediatric population. The severity of lung disease also changed, but primarily in those persons with spirometry values near the lower limit of normal. Changes in ventilatory impairment and severity impact downstream consequences such as eligibility for medical procedures, clinical trials, and employment, as well as financial consequences such as insurance premiums and disability payments. Further research is needed to evaluate the impact of using race-neutral equations in non-Black and non-White populations. Moving forward, clinicians need to understand how race-neutral spirometry equations affect test results and provide meaningful explanations to patients. Equally important, clinicians need to monitor emerging literature, advocate for evidence-based changes, and modify clinical practices as appropriate.