Longitudinal changes in forced expiratory volume in 1 s in patients with eosinophilic chronic obstructive pulmonary disease.

BACKGROUND: Data on changes in lung function in eosinophilic chronic obstructive pulmonary disease (COPD) are limited. We investigated the longitudinal changes in forced expiratory volume in 1 s (FEV1) and effects of inhaled corticosteroid (ICS) in Korean COPD patients. METHODS: Stable COPD patients in the Korean COPD subgroup study (KOCOSS) cohort, aged 40 years or older, were included and classified as eosinophilic and non-eosinophilic COPD based on blood counts of eosinophils (greater or lesser than 300 cells/µL). FEV1 changes were analyzed over a 3-year follow-up period. RESULTS: Of 627 patients who underwent spirometry at least twice during the follow up, 150 and 477 patients were classified as eosinophilic and non-eosinophilic, respectively. ICS-containing inhalers were prescribed to 40% of the patients in each group. Exacerbations were more frequent in the eosinophilic group (adjusted odds ratio: 1.49; 95% confidence interval: 1.10-2.03). An accelerated FEV1 decline was observed in the non-eosinophilic group (adjusted annual rate of FEV1 change: - 12.2 mL/y and - 19.4 mL/y for eosinophilic and non-eosinophilic groups, respectively). In eosinophilic COPD, the adjusted rate of annual FEV1 decline was not significant regardless of ICS therapy, but the decline rate was greater in ICS users (- 19.2 mL/y and - 4.5 mL/y, with and without ICS therapy, respectively). CONCLUSIONS: The annual rate of decline in FEV1 was favorable in eosinophilic COPD compared to non-eosinophilic COPD, and ICS therapy had no beneficial effects on changes in FEV1.