Longitudinal Outcomes and Prognostic Risk of Normalized Airflow Obstruction in a Korean General Population Cohort.

Abstract

Introduction: Some individuals with airflow obstruction later show normalized spirometric values, but the clinical implications of this phenomenon in the general population are unclear.

Methods: Using data from the Korean Genome and Epidemiology Study (KoGES), we examined the characteristics and prognosis of individuals with normalized airflow obstruction (NO), defined as FEV1/FVC <0.7 at baseline that normalized to ≥0.7 during follow-up.

Results: Between 2000 and 2006, 4,807 participants were classified as NO (n=242), fixed obstruction (FO; persistent FEV1/FVC <0.7; n=277), or normal (FEV1/FVC ≥0.7 throughout; n=4,288). Over eight years of follow-up (2007-2014), the NO group contained more men, current smokers, and individuals with lower body mass index than the normal group and showed intermediate lung function between FO and normal groups. Annual FEV1 decline was similar across groups (-48.8 mL/year normal; -48.3 mL/year NO; -45.8 mL/year FO). However, by the end of the 12-year follow-up period, 37.2% of participants in the NO group developed airflow obstruction, with a 4.22-fold higher risk compared with the normal group (95% CI 3.26-5.46). Findings were consistent in a sensitivity analysis excluding individuals with excessive lung function variability. (HR 7.41, 95% CI 5.45-10.07).

Discussion: These findings indicate that NO may represent a distinct and dynamic spirometric phenotype associated with increased risk of future airflow obstruction and highlight the need for early identification and preventive strategies in at-risk populations.