Prevalence of PRISm and COPD and associated factors in a university medical centre spirometry unit: a cross-sectional...

Preserved Ratio Impaired Spirometry (PRISm) is a new spirometric entity defined in international guidelines, associated with overall worse outcomes. It remains unclear whether this represents a distinct entity or an early phase of multiple other diseases, such as chronic obstructive pulmonary disease (COPD) and restrictive lung diseases. There is a notable scarcity of data on PRISm, particularly in Lebanon. This study aimed to evaluate the prevalence of PRISm and COPD, and their associated factors, among individuals aged 40 years and above who underwent spirometry in a single university medical centre between 2022 and 2024.

Outpatient Pulmonary Function Tests Laboratory at a Lebanese university medical centre.

All individuals aged 40 years or older who performed spirometry between 2022 and 2024 METHODS: A retrospective analysis of pulmonary function tests (PFTs) and demographics was performed. Patients were classified based on the spirometry patterns that are consistent with COPD (forced expiratory volume in the first second (FEV₁)/forced vital capacity (FVC)<0.7 post bronchodilator), PRISm (FEV₁/FVC≥0.7 and FEV₁<80% post bronchodilator) and normal PFTs (FEV₁/FVC≥0.7 and FEV₁≥80%). A small number of PFTs did not meet the above criteria and were classified as 'others'; they were excluded from the main analysis but retained for descriptive estimation of PRISm and COPD prevalence over the past 3 years. The prevalence and associated risk factors of PRISm and COPD were assessed. Descriptive, bivariate and multinomial regression models were performed using IBM's Statistical Package for the Social Sciences V.29.

A total of 698 PFTs were performed for 639 patients. The prevalence of PRISm and COPD in the centre between 2022 and 2024 was 11% and 17%, respectively. Compared with normal PFTs, subjects with PRISm were older (adjusted OR; aOR (95% CI)=1.03 (1.002 to 1.05); p=0.03) and more likely to be ex-smokers (aOR=2.19 (1.12 to 4.30); p=0.022); patients with COPD were older (aOR 1.09 (1.07 to 1.12); p<0.001), had lower body mass index (aOR 0.95 (0.91 to 0.99); p=0.024) and were more likely to be smokers or ex-smokers.

These findings highlight PRISm as a potentially relevant pattern within chronic airway disease. Within the context of Sustainable Development Goal 3 on non-communicable diseases, they underscore the importance of identifying this subgroup for closer clinical attention. Further longitudinal and multicentre studies are needed to better understand the clinical significance of PRISm and its relationship to chronic airway diseases.