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 about 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 older than 40 years who underwent comprehensive health screening at the Center for Health Promotion, Samsung Medical Center, between 2003 and 2020. PRISm was characterized by FEV₁/FVC ≥ 0.7 and FEV₁ <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, while 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 succumbed. Individuals with PRISm experienced a higher cumulative mortality rate compared to those with normal lung function (39 vs. 16 per 10,000 person-years; adjusted HR 1.43, 95% CI 1.31-1.56). The fully-adjusted HRs 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.