Risks of Mortality and Airflow Limitation in Japanese Individuals with Preserved Ratio Impaired Spirometry

RATIONALE: Several Western studies have reported that participants with preserved ratio impaired spirometry (PRISm) have higher risks of airflow limitation (AFL) and death. However, evidence in East Asian populations is limited. OBJECTIVES: To investigate the relationship between PRISm and the risks of death and incident AFL in a Japanese population. METHODS: A total of 3,032 community-dwelling Japanese participants aged ⩾40 years were seen in follow-up for a median of 5.3 years by annual spirometry examinations. Participants were classified into lung function categories at baseline as follows: normal spirometry (FEV(1)/FVC ⩾0.70 and FEV(1) ⩾80% predicted), PRISm (⩾0.70 and <80%), AFL Global Initiative for Chronic Obstructive Lung Disease 1 (<0.70 and ⩾80%), and AFL Global Initiative for Chronic Obstructive Lung Disease 2–4 (<0.70 and <80%). Hazard ratios (HRs) and their 95% confidence intervals were computed using a Cox proportional hazards model. MEASUREMENTS AND MAIN RESULTS: During the follow-up period, 131 participants died, 22 of whom died of cardiovascular disease, and 218 participants developed AFL. When examining the prognosis of each baseline lung function category, participants with PRISm had higher risks of all-cause death (HR, 2.20; 95% confidence interval, 1.35–3.59) and cardiovascular death (HR, 4.07; 1.07–15.42) than those with normal spirometry after adjusting for confounders. Moreover, the multivariable-adjusted risk of incident AFL was greater in participants with PRISm than in those with normal spirometry (HR, 2.48; 1.83–3.36). CONCLUSIONS: PRISm was associated with higher risks of all-cause and cardiovascular death and a greater risk of the development of AFL in a Japanese community.