Prevalence of preserved ratio impaired spirometry: A systematic review and meta-analysis.

Objective: To summarise the prevalence of preserved ratio impaired spirometry (PRISm), intending to inform prevention strategies and clinical management.

Methods: We systematically searched PubMed, Embase, Web of Science, and the Cochrane Library databases for cohort studies investigating the prevalence of PRISm. The quality of included studies was assessed with appropriate tools for evaluating risk of bias in prevalence studies. Publication bias was assessed using funnel plots and Egger's test.

Results: After deduplication, 24 of the 33 initially eligible studies were included in the meta-analysis. The pooled prevalence of PRISm was 10% (95% CI: 0.08, 0.12). Smoking was a significant risk factor for PRISm, while no significant association was found with respiratory symptoms. PRISm was significantly associated with comorbidities including hypertension, diabetes, cardiovascular disease, and stroke. Moreover, individuals with PRISm had higher all-cause mortality (OR 1.84, 95% CI: 0.99, 3.41) and cardiovascular mortality (OR 1.82, 95% CI: 1.35, 2.44). Lung function trajectories were heterogeneous, with 10-50% reverting to normal, 20-60% remaining stable, and 6-53% progressing to chronic obstructive pulmonary disease (COPD).

Conclusions: PRISm is associated with a high prevalence, smoking, cardiometabolic comorbidities, increased all-cause and cardiovascular mortality, and heterogeneous lung function trajectories, underscoring its clinical importance beyond COPD.