Prevalence of obstructive sleep apnoea in patients with difficult-to-treat asthma

<bold>Introduction:</bold> Obstructive sleep apnoea (OSA) and asthma are the most common chronic respiratory conditions. Comorbid OSA may contribute to poor symptom control in patients with difficult-to-treat asthma. This study aimed to assess the prevalence of OSA in patients with difficult-to-treat asthma. <bold>Methods:</bold> This prospective single-centre study was performed at the University Clinic Golnik. Patients were recruited from the outpatient clinic with a multidisciplinary management approach for patients with difficult-to-treat asthma. All consecutive patients were approached to participate in the study from August 2022 to October 2023. Polysomnography was conducted during clinical stability. <bold>Results:</bold> Of the 108 participants (57.9±12.6 years old; 51% men), we confirmed OSA in 50%: 3 (3%) mild OSA and ESS>10, 24 (22%) moderate, and 27 (25%) severe OSA, respectively. Patients with OSA were older (60.6±10.6 vs. 55.2±14 years, p=0.026), more often men (33 (61%) vs. 19 (41%), p=0.034), and obese (31 (57%) vs. 11 (20%), p<0.001). More patients with OSA had arterial hypertension (AH) (30 (56%) vs. 12 (24%), p=0.001), reported snoring (22 (41%) vs. 12 (22%), p=0.032) and breathing pauses (20 (37%) vs. 10 (18%), p=0.032), and had more often ESS>10 (7 (13%) vs 1 (2%) p=0.024). In multivariate logistic regression analysis adjusted to gender, age, AH, obesity, snoring, breathing pauses, ESS>10, gender (OR 3.9, CI 1.4-11), age (OR 1.06, CI 1.0-1.1), obesity (OR 9.9, CI 3.1-32.3), and ESS>10 (OR 32.6, CI 2.5-423), predicted OSA. <bold>Conclusions:</bold> Clinically important OSA was present in 50% of patients with difficult-to-treat asthma. Male sex, higher age, obesity, and ESS>10 predicted OSA in this patient group.