The risk factors of future exacerbations and treatment responses among different inhalation therapies of patients with preserved ratio impaired spirometry

Background: Preserved ratio impaired spirometry (PRISm) is closely related to chronic obstructive pulmonary disease (COPD). However, there is a lack of relevant research on the treatment of patients with PRISm. Therefore, this study aimed to investigate the risk factors of future exacerbations and treatment responses among different inhalation therapies of patients with PRISm. Methods: This is a retrospective cohort study. Patients with PRISm were registered in the real-world study on the status of diagnosis and treatment of COPD (RealDTC) study between January 2017 and August 2024. Data on demographics, pulmonary function, symptom scores, number of exacerbations and hospitalisations in the past year, inhalation therapy regimens including long-acting muscarinic antagonist (LAMA), long-acting β2-agonist (LABA) + inhaled corticosteroid (ICS), LABA + LAMA, and LABA + LAMA + ICS, and comorbidities were collected. The number of exacerbations, frequent exacerbations, hospitalisations, and all-cause of mortality were collected during one year of follow-up. Results: A total of 575 patients were included for the final analysis. During one year of follow-up, 144 (25.0%) patients experienced exacerbations. The patients experienced exacerbations had higher age, symptom score, number of exacerbations and hospitalisations in the past year, as well as higher proportion of biofuel exposure and without inhalation therapy. Logistic regression analysis showed that age, number of hospitalisations in the past year, and without inhalation therapy were the independent risk factors for patients experienced exacerbations. Furthermore, after propensity score matching, the patients without inhalation therapy had higher number of exacerbations, frequent exacerbations, and hospitalisations during one year of follow-up. However, there were no significant differences in future exacerbations, frequent exacerbations, hospitalisations, and all-cause of mortality among LAMA, LABA + LAMA, LABA + ICS, and LABA + LAMA + ICS. Conclusions: Patients with PRISm had high risk of future exacerbations. Inhalation therapy could reduce the risk of future exacerbations and clinicians should recommend mono-LAMA to patients with this condition.