Association of Preserved-Ratio Impaired Spirometry (PRISm) with All-Cause Mortality: A Longitudinal Cohort Study

Rationale Numerous studies indicate that preserved-ratio impaired spirometry (PRISm) is associated with adverse clinical outcomes. However, the impact of PRISm severity, particularly in regard to forced vital capacity (FVC), on mortality risk remains unclear. Objectives To determine whether PRISm was associated with mortality and to identify specific groups with particularly increased mortality rates. Methods This retrospective study enrolled individuals aged >40 years who underwent comprehensive health screening at the Center for Health Promotion at Samsung Medical Center between 2003 and 2020. PRISm was characterized by a ratio of forced expiratory volume in 1 second to FVC of at least 0.7 and forced expiratory volume in 1 second <80% of predicted values. Participants were classified into three groups: normal lung function, PRISm with normal FVC, and PRISm with low FVC (FVC <80% predicted). We compared all-cause mortality rates using the Kaplan-Meier method and the Cox proportional hazard ratio model. Results Among 106,458 individuals, 86,208 exhibited normal lung function, 6,249 had PRISm with normal FVC, and 14,001 had PRISm with low FVC. Over a median follow-up of 10.1 years, 2,219 participants died. Individuals with PRISm experienced a higher cumulative mortality rate compared with those with normal lung function (39 vs. 16 per 10,000 person-years; adjusted hazard ratio, 1.43; 95% confidence interval [CI], 1.31–1.56). The fully adjusted hazard ratios for all-cause mortality in PRISm with normal and low FVC were 1.25 (95% CI, 1.03–1.52) and 1.47 (95% CI, 1.33–1.62) relative to those with normal lung function, respectively. Conclusions PRISm is associated with an increased risk of death, particularly when accompanied by low FVC.