Blood eosinophil count and fractional exhaled nitric oxide showed only slight agreement (κ = 0.13, p = 0.20 for BEC ≥300 cells/μL), indicating they reflect distinct inflammatory pathways.
Cohort (n=315)
Blood eosinophil count and fractional exhaled nitric oxide show only slight agreement in a lung cancer screening cohort, suggesting they are complementary but distinct TH2 inflammatory biomarkers.
Effect estimate: κ = 0.13
Absolute Event Rate: 31% vs 18%
p-value: p=0.20
Abstract Rationale Blood eosinophil count (BEC) and fractional exhaled nitric oxide (FeNO) are noninvasive markers of type 2 inflammation (TH2) in COPD, but their relationship and relevance in screening populations remain unclear. This study evaluated the concordance between BEC and FeNO, their association with smoking status, and their distribution across GOLD stages among individuals undergoing lung cancer screening at the Temple Healthy Chest initiative (THCI). Methods In this prospective cohort study, 315 participants underwent lung cancer screening (LCS) in the THCI. EMR data, pre-bronchodilator spirometry, and CT imaging (AVIEW COPD, Coreline) were collected. Blood eosinophil count (BEC) and fractional exhaled nitric oxide (FeNO) were measured. BEC and FeNO levels were compared across all participants and by smoking status using symmetric measures, and their associations with GOLD stage were analyzed using the Kruskal-Wallis test. Results Prospective data were obtained from 315 participants. Among those with ≥300 eosinophils (n = 54) versus 300 (n = 261), FeNO ≥20 ppb was observed in 31% and 18% of participants, respectively, showing slight agreement (κ = 0.13, p = 0.20). Using an eosinophil cutoff of ≥ 150, FeNO ≥20 ppb occurred in 26% versus 15%, with slight agreement (κ = 0.11, p = 0.02). When stratified by smoking status, no significant agreement was found between FeNO ≥20 ppb and eosinophilia among current smokers (≥300 cells/μL: κ = 0.08, p = 0.28; ≥150 cells/μL: κ = 0.07, p = 0.19). Among non-smokers, slight agreement was observed (≥300 cells/μL: κ = 0.20, p = 0.02; ≥150 cells/μL: κ = 0.19, p = 0.02). FeNO and eosinophil levels did not differ significantly across GOLD stages (FeNO: H (3, N = 120) =7.43, p = 0.06); eosinophils: H(3, N = 120) =1.11, p = 0.76). Conclusion BEC and FeNO showed only slight agreement, consistent with how they reflect distinct but interrelated inflammatory pathways. This relationship was more evident in non-smokers and absent in current smokers. Neither marker varied significantly by GOLD stage. These findings suggest BEC and FeNO as complementary, but distinct TH2 inflammatory biomarkers in COPD phenotyping. This abstract is funded by: AztraZeneca and Temple Lung Center
Illipparambil et al. (Fri,) conducted a cohort in COPD / Lung cancer screening (n=315). Blood eosinophil count (BEC) and fractional exhaled nitric oxide (FeNO) was evaluated on Concordance between BEC and FeNO (FeNO ≥20 ppb in BEC ≥300 vs <300 cells/μL) (κ = 0.13, p=0.20). Blood eosinophil count and fractional exhaled nitric oxide showed only slight agreement (κ = 0.13, p = 0.20 for BEC ≥300 cells/μL), indicating they reflect distinct inflammatory pathways.