Effects from Using a Race-Neutral Prediction Equation for Interpreting Spirometry in an Active-Duty Military Population.

Introduction: The purpose of our analysis was to study the clinical and occupational consequences from switching to a "race-neutral" spirometry reference equation for active-duty service members (ADSMs).

Methods: We hypothesized that switching to a "race-neutral" equation would affect eligibility for deployment and improve clinical accuracy. We tested this hypothesis using data from a prospective cohort study (STAMPEDE II) of ADSMs screened using spirometry pre-deployment. Prevalence of abnormality and z-scores were compared using the "race-neutral" GLI-Global (GLI-G) versus the original GLI 2012 (GLI-R) equations. The relationship between spirometry and deployment respiratory symptoms was modeled using ordinal logistic regression.

Results: Among the 1,632 subjects enrolled in STAMPEDE II, moving to GLI-G decreased z-scores and increased the prevalence of abnormality for Black ADSMs. For White and Hispanic ADSMs, z-scores increased and resulting abnormalities decreased. Among those referred for pre-deployment spirometry per current military protocols (n=155), using GLI-G increased abnormal spirometry from 9.8% to 11.6% (p<0.01), with a significant increase (5 (16.7%) to 14 (46.7%); p=0.01) and decrease (6 (6.5%) to 3 (3.2%); p=0.01) in abnormal spirometry in Black and White subjects, respectively. After adjustment for other factors, the presence of abnormal spirometry, whether defined by GLI-G or GLI-R, did not increase the odds for an increase in respiratory symptoms during or after deployment.

Discussion: Among Black ADSMs, GLI-G decreases z-scores and results in an increase in abnormalities that will affect eligibility for deployment. Moving to a "race-neutral" equation did not improve clinical accuracy for predicting respiratory symptoms during or after deployment.