IntroductionChronic obstructive pulmonary disease (COPD) is a dynamic disease with a high socioeconomic burden. Using data collected prospectively from the general population, we examined factors related to the transition of at-risk individuals to COPD. MethodsWe used the Korean Genome Epidemiology Study (KoGES) database, defining pre-COPD based on respiratory symptoms and radiological abnormalities suggestive of COPD; the preserved ratio impaired spirometry (PRISm) was defined as a forced expiratory volume in 1s (FEV1)/forced vital capacity ratio≥70% and FEV1<80%, as predicted by spirometry. We determined group differences in the rate of lung function decline, risk of future airflow obstruction (AFO). ResultsThe study included 4762 individuals, and longitudinal analysis revealed distinct trends in pulmonary function indicators. Compared to the normal group, the pre-COPD group showed a more rapid decline in lung function, while the PRISm group showed a slower decline. In the pre-COPD and PRISm groups, 4.4% and 3.5%, and 13.6% and 10.8%, respectively, of patients had progressed to COPD at the first and second visits. Pre-COPD and PRISm contributed to an earlier time to first AFO, but consideration of comorbid cardiovascular disease weakened this relationship in the PRISm group. Multivariate logistic regression showed that pre-COPD and PRISm are significant risk factors for future development of COPD (OR 1.80, p<0.001; OR 4.26, p<0.001, respectively). ConclusionPre-COPD and PRISm patients showed different trends in lung function changes over time and both were significant risk factors for future development of COPD.