Trajectory of Preserved Ratio Impaired Spirometry: Natural History and Long-Term Prognosis

Rationale: Natural history of preserved ratio impaired spirometry (PRISm), often defined as FEV1/FVC ⩾lower limit of normal and FEV1 <80% of predicted value, is not well described. Objectives: To investigate the natural history and long-term prognosis of the following PRISm trajectories: persistent PRISm trajectory (individuals with PRISm both young and middle-aged), normal to PRISm trajectory (individuals developing PRISm from normal spirometry...