Associations of pre-COPD indicators with lung function decline and their longitudinal transitions

Initial chronic bronchitis and consistent FEV₁ <80% predicted, sSAD, and low PEF are associated with excessive lung function decline among smokers, while consistent chronic bronchitis and sSAD are associated with excessive lung function decline among non-smokers. Initial sSAD accounts for a larger proportion of incident COPD than initial chronic bronchitis, PRISm, and low PEF.