PO118 - Effect of Race-Neutral (GLI Global 2022) versus Race-Based (GLI 2012) Spirometry Reference Equations on Pulmonary Function Test Interpretation in Sarcoidosis
Fortune Alabi (United States)1; Lusmelys Guevara (United States)1; Noah Andersen (United States)1; Jica Garces (United States); Kenny Alvarado (United States)1; Mohammad Ahmadzai (United States)1; Reema Ismail (United States)1;
1 - Florida Lung Asthma and Sleep specialists;
Keywords: Sarcoidosis; GLI Global 2022 reference equations; Racial disparities in lung function;
Select the theme: Challenges in Sarcoidosis Diagnosis and Staging
Type: Original Papers
Presentation: Poster Presentation

Introduction: Introduction: The 2022 GLI Global race-neutral reference equations replaced race-specific values for spirometry interpretation. Their effect on pulmonary function test (PFT) classification in sarcoidosis, a disease with disproportionate burden in Black populations is poorly characterized.

Objectives:  To compare race-based (GLI 2012) and race-neutral (GLI Global 2022) PFT pattern classification in sarcoidosis using a single ATS/ERS algorithm, and to evaluate variation by sex and race.

Materials and Methods: Single-center retrospective cohort of 526 sarcoidosis patients. Z-scores and lower limits of normal for FVC, FEV1, and FEV1/FVC were computed from both GLI 2012 (Hispanic and Other mapped to Other/Mixed) and GLI Global 2022. The same ATS/ERS classifier (Stanojevic 2022) was applied to both, yielding patterns of Normal, Obstructive, Restrictive, Nonspecific, or Mixed. Marginal homogeneity was assessed with the Stuart-Maxwell test and per-category change with McNemar.

Results: 483 patients had paired classifications (mean age 62.5±13.6 years; 64% female; 44% White, 26% Hispanic, 24% Black/African American, 7% Other/Unknown). GLI 2022 reclassified 68 patients (14.1%; Stuart-Maxwell χ²=28.3, df=4, p<0.0001). Normal classifications were essentially unchanged (73.9%→75.8%; NS). The dominant shift was a decline in Obstructive (7.5%→2.7%; McNemar p<0.0001), with a smaller increase in Restrictive (11.6%→14.1%; p=0.04). Reclassification was greatest in Black/African American patients (20.2%; p=0.0003), followed by Hispanic (11.1%; p=0.03) and White (10.9%; p=0.04); rates were similar in males (13.3%) and females (14.5%).

Conclusions: Adoption of GLI Global 2022 race-neutral spirometry equations reclassifies approximately one in seven sarcoidosis patients—predominantly by relabeling Obstructive cases as Normal or Restrictive—with the largest effect in Black/African American patients. The overall proportion classified as Normal changes little, but redistribution among the abnormal patterns has implications for severity grading, and treatment eligibility. Whether these reclassifications alter treatment decisions or outcomes was not addressed by the present study and warrants further investigation.