Preserved Ratio Impaired Spirometry: Prevalence and Characteristics in an Outpatient Setting

Abstract Background: Preserved ratio impaired spirometry (PRISm) is a spirometric pattern characterized by reduced forced vital capacity (FVC) and preserved forced expiratory volume in 1 s (FEV1)-to-FVC ratio. The clinical significance, prevalence, and subtypes of PRISm remain underexplored, particularly in specialized pulmonary care settings. Methods: We conducted a retrospective analysis of patient data from a tertiary care pulmonary outpatient department, identifying cases with PRISm. Spirometric data were analyzed, and patients were categorized based on clinical features, comorbidities, and demographic factors. Associations with respiratory symptoms and other outcomes were also assessed. Results: PRISm was observed in 25.5% of symptomatic patients. Participants with PRISm showed associations with factors such as obesity, age, smoking history, underlying respiratory diseases, and spirometric features. Spirometric features differed significantly between identified subtypes. Conclusions: PRISm is a prevalent but heterogeneous condition in tertiary care pulmonary practice. Identifying distinct PRISm subtypes may aid in tailoring patient management strategies and improving outcomes in this unique patient population. Further studies are needed to clarify long-term implications.