Association of Preserved Ratio Impaired Spirometry and Mortality Outcomes Compared With Normal Spirometry: A Meta-Analysis

Background: One of the leading causes of death in the United States is chronic lung disease, with COPD being the most common. One of the hallmarks of COPD is spirometric obstruction as evidenced by a reduced FEV₁/FVC ratio. Preserved ratio impaired spirometry (PRISm) is a spirometric pattern characterized as a low FEV₁ coupled with a preserved FEV₁/FVC ratio. This systematic review and meta-analysis sought to understand better the relationship between PRISm and cardiovascular, respiratory, and all-cause mortality. Methods: We systematically searched PubMed and clinicaltrials.gov for articles published between 2014 and 2023, providing data regarding the association of PRISm compared with normal spirometry in terms of morality outcomes. The generic inverse variance method was used to assess the pooled hazard ratio value at a 95% CI, and forest plots were created using RevMan for analysis. P < .05 was considered to be significant. Results: Our analysis included 690,015 subjects from four prospective studies and three retrospective studies. The pooled hazard ratio for all-cause, cardiovascular, and respiratory-related mortality was 1.70, 1.95, and 5.70 for all prospective studies, respectively, and 1.62, 1.66, and 3.35, in combined prospective and retrospective studies, respectively, which were statistically significant in the random effect model (P < .001). However, 76% heterogeneity was observed in respiratory-related mortality (P = .009). After excluding studies associated with publication bias, a "leave-out" sensitive analysis resulted in a significant pooled hazard ratio of 1.98 with a high significance (P < .001). Conclusions: PRISm, often labeled as GOLD-U, is associated with mortality outcomes and should not be overlooked while treating patients with chronic lung diseases. This meta-analysis provides a stronger correlation of PRISm with all-cause mortality, cardiovascular mortality, and respiratory mortality compared with normal spirometry.