Fig. 3From: Proportions and risk factors of chronic obstructive pulmonary disease and preserved ratio impaired spirometry, and association with small airway disease, in the positive screening older population from China: a cross-sectional studySAF of participants. Abbreviations: COPD:Chronic obstructive pulmonary disease; PRISm:Preserved ratio impaired spirometry; MMEF:Maximal mid-expiratory flow; FEF:Forced expiratory flowBack to article page