Associated Factors and Pulmonary Function Outcomes of Preserved Ratio Impaired Spirometry: A Scoping Review

Preserved ratio impaired spirometry (PRISm) is a common but understudied abnormal pulmonary function state and is strongly associated with poor health outcomes. However, there is a lack of uniformity in defining the factors and pulmonary function outcomes associated with PRISm.

This scoping review aims to elucidate the associated factors and pulmonary function outcomes of PRISm, thereby enhancing healthcare professionals' understanding of PRISm and laying the groundwork for its prevention and treatment.

This scoping review follows the 5-step framework developed by Arksey and O'Malley. Literature on PRISm was systematically searched from databases including PubMed, Embase, CINAHL, the Cochrane Library, Web of Science, CNKI, and Wan Fang, spanning from inception to July 2024. Inclusion and exclusion criteria were applied to enroll relevant studies. Data were extracted, collected, summarized, and reported.

A total of 38 studies were included. The analysis revealed that associated factors for PRISm encompass possible pathogenic factors (older age, female, lower education level, smoking, obesity, etc), comorbidity associations (asthma, diabetes, cardiovascular diseases, etc), and disease characteristic factors (disease burden, physical performance, radiological characteristics, etc). The pulmonary function status of the PRISm population is unstable, making progression to airflow obstruction (AFO) more likely than in the normal population. PRISm exhibits multiple subgroups (incident or stable PRISm, definite PRISm or PRISm with AFO, non-restrictive or restrictive PRISm, etc) and significant differences exist in pulmonary function outcomes among different subgroups.

This scoping review offers a more comprehensive understanding of PRISm. It is recommended that future research focus on a deeper investigation of the pulmonary function of PRISm, elucidating its pathophysiological characteristics, and proposing new strategies for its prevention and treatment. Furthermore, more research is needed in low-income and middle-income economies to understand PRISm comprehensively.