Peripheral eosinophilia and preserved ratio impaired spirometry (PRISm).

Preserved ratio impaired spirometry (PRISm) may be in the pre-stage of chronic obstructive pulmonary disease. However, little is known about peripheral eosinophils in PRISm. This study ultimately enrolled 7301 community-dwelling participants aged 20-79 years without airflow obstruction. Participants were categorized based on spirometry into two groups: normal spirometry and PRISm. Peripheral eosinophilia is defined by peripheral eosinophil counts ≥300 cells/µL. Multivariable logistic regression model was employed to examine the association between peripheral eosinophil counts and PRISm, as appropriate. Among the community adults finally recruited, 9.43% of participants exhibited PRISm, while 90.57% exhibited normal spirometry. Compared with the normal spirometry population, PRISm participants had a higher prevalence of peripheral eosinophilia in individuals aged 40-79 years (27.41% vs 21.37%, p = 0.01), non-Hispanic Whites (29.22% vs 21.32%, p = 0.01), those with a body mass index of 18.5-<25 kg/m2 (25.01% vs 16.75%, p = 0.03), never smokers (23.47% vs 18.65%, p = 0.03), individuals without a history of asthma (26.81% vs 20.67%, p<0.001), and those with FeNO levels <50 parts per billion (p < 0.05). Multivariable regression analysis showed a significant association between participants with eosinophil counts ≥300 cells/µL and PRISm compared to those with counts <150 cells/µL, with an adjusted odds ratio of 1.39 (95% CI: 1.12, 1.72). Peripheral eosinophilia was associated with PRISm in individuals without airflow obstruction. It is necessary to focus on the characteristics of peripheral eosinophils in this population.