Preserved Ratio Impaired Spirometry (PRISm) from an Epidemiological Perspective

Background: The term preserved ratio impaired spirometry (PRISm) is defined as post-bronchodilator forced expiratory volume in 1 s (FEV₁) <80% predicted and FEV₁/forced vital capacity (FVC) ratio ≥0.7 or ≥lower limit of normal (LLN). The population prevalence is estimated to be between 3% and 20%. PRISm does not indicate a specific lung disease but is associated with functional limitations, respiratory symptoms, comorbidities, and mortality. The aim of this study is to analyze the PRISm prevalence in an excellently characterized epidemiological study, to obtain better insight into the influence of comorbidities on PRISm development and its impact on overall mortality. Methods: We included 3403 healthy subjects from the Study of Health in Pomerania (SHIP) and 507 individuals with PRISm. Data from lung function testing, cardiopulmonary exercise testing (CPET), and echocardiography were compared in both groups. Comorbidities, as well as cardiovascular and all-cause mortality data, were analyzed. Results: Individuals in the PRISm group reported more often a history of myocardial infarction, hypertension, type 2 diabetes, dyspnea, and lung disease, and had more unfavorable median values for most of the lung function, CPET, and echocardiographic parameters compared to the non-PRISm group. Furthermore, they were older, more often current smokers, and had higher body fat marker values. Likewise, all-cause and cardiovascular death were more frequently observed in the PRISm group. Conclusions: Future studies are warranted to identify the underlying mechanisms and longitudinal progression of PRISm. However, our findings reveal that PRISm is not only associated with cardiovascular comorbidities but also with increased dyspnea, an impaired exercise capacity, and mortality.