Prevalence and risk factors for COPD in subjects with preserved ratio impaired spirometry

BackgroundChronic obstructive pulmonary disease (COPD) has been found to be caused by impairment of lung development. Preserved ratio impaired spirometry (PRISm) is thought to be a subtype of lung growth impairment and is associated with COPD. PRISm is heterogeneous and the prevalence and progression to COPD are not yet clear. To prove this, we examined the association by using the medical check-up data.MethodsThis retrospective study included medical check-up subjects who visited the Kochi Medical Check-up Clinic at least twice for both period 1 (P1) (2014–2016) for the first visit and period 2 (P2) (2017–2019) for the final visit. The mean duration between visits was 1042±323 days. COPD was defined as a forced expiratory volume in 1 s (FEV1):forced vital capacity (FVC) ratio LLN and per cent forced expiratory volume in 1 s (%FEV1) (FEV1/predicted FEV1) of