Preserved ratio impaired spirometry and OSA may contribute to cardio-metabolic complications: evidence from the ESADA cohort

<bold>Background:</bold> Recent studies show Preserved Ratio Impaired Spirometry (PRISm) to be associated with increased risk for mortality due to respiratory and cardiovascular events. <bold>Aims and Objectives:</bold> To assess prevalence, risk factors, and clinical implications of PRISm in the European Sleep Apnea Database (ESADA, supported by ERS as Clinical Research Collaboration) cohort. <bold>Methods:</bold> 7,048 obstructive sleep apnea (OSA) patients (AHI≥5 events/h) diagnosed with PG/PSG and free of acute or chronic respiratory disease underwent pulmonary function tests. Participants with PRISm, defined as FEV1/FVC≥0.7 and FEV1 <80% predicted, were further divided by low FVC into restrictive PRISm (FVC <80%) and non-restrictive PRISm (FVC ≥80%). Multivariate regression analysis examined the effect of both forms of PRISm on OSA severity, arterial blood gases (ABGs) and cardio-metabolic risk, after adjusting for confounders. <bold>Results:</bold> Among all, 888 (13%) patients had PRISm [549 (8%) non-restrictive PRISm and 339 (5%) restrictive PRISm]. BMI, coronary artery disease, diabetes type 2, indices of OSA severity, and ABGs were independently associated with both forms of PRISm (all p<0.001). Male sex, age and cardiac failure were risk factors for restrictive PRISm, whereas current smoking was associated with non-restrictive PRISm. <bold>Conclusion:</bold> PRISm was independently associated with anthropometrics, OSA severity, and cardiometabolic comorbidities. Therefore, PRISm could be a potential marker for disease severity and cardiovascular risk classification in OSA. However, further studies are needed to explore whether PRISm has a causal association and prognostic significance in OSA patients.