The Impact of Changing Race-Specific Equations for Lung Function Tests among Veterans with COPD.

The American Thoracic Society recommended a single reference equation for spirometry but the impact to patients is not known. To estimate the effect of changing to a single reference equation among Veterans with chronic obstructive pulmonary disease (COPD). Cross-sectional study including Veterans aged ≥40 to ≤89 years with COPD and spirometry results from 21 facilities between 2010 - 2019. We collected race/ethnicity data from the electronic health record. We estimated the percentage change in the number of Veterans with lung function meeting clinical thresholds used to determine eligibility for lung resection for cancer, lung volume reduction surgery (LVRS), and lung transplant referral. We estimated the change for each level of VA service connection and financial impact. We identified 44,892 Veterans; Asian (0.5%), Black (11.8%), White (80.8%), and Hispanic (1.8%). When changing to a single reference equation, Asian and Black Veterans had reduced predicted lung function that could result in less surgical lung resection (4.4% and 11.1% respectively), while increasing LVRS (1.7% and 3.8%), and lung transplant evaluation for Black Veterans (1.2%). White Veterans had increased predicted lung function and could experience increased lung resection (8.1%), with less LVRS (3.3%), and lung transplant evaluation (0.9%). Some Asian and Black Veterans could experience an increase in monthly disability payments (+$540.38 and $398.38), while Hispanic White and White Veterans could see a decrease (-$588.79). When aggregated, Hispanic Veterans experienced changes attributable to their racial identity, and because this sample was predominantly Hispanic White, had similar results to White Veterans. Changing the reference equation could affect access to treatment and disability benefits, depending on race. If adopted, the use of discrete clinical thresholds needs to be reassessed, considering patient-centered outcomes.