The impact of comorbid asthma on obstructive sleep apnoea outcomes

<bold>Background:</bold> Asthma and obstructive sleep apnoea (OSA) are common disorders which can complicate each other. However, whilst OSA can worsen asthma control and exacerbation rate, the evidence is less strong how asthma and their medications affect insomnia, daytime sleepiness and common comorbidities associated with OSA. <bold>Aim:</bold> The aim of this service evaluation project was to understand the impact of asthma on OSA outcomes. <bold>Methods:</bold> We analysed the results of 261 patients with OSA who attended our service. One hundred and eight of these patients had asthma, their medications included inhaled corticosteroids (ICS) in 99, long-acting beta agonist (LABA) in 82, long-acting muscarinic antagonists (LAMA) in 41, short-acting beta agonist (SABA) in 100, and montelukast in 26 cases. Symptoms and comorbidities were compared with logistic regression adjusted for age, sex, body mass index and apnoea-hypopnoea index between the groups. <bold>Results:</bold> Patients with OSA and asthma had similar prevalence of comorbidities as patients with OSA but without asthma. Their Epworth Sleepiness Scale (ESS) and insomnia symptoms did not differ either (all p>0.05). Patients taking montelukast commonly complained about parasomnia (62 vs. 31%, p=0.03) and insomnia (70 vs. 39%, p=0.03) symptoms. Patients taking LABA had higher ESS (12.3±5.3 vs. 10.8±6.4, p=0.02) and patients taking LAMA had higher rates of anxiety (33 vs. 20%, p=0.03). Taking ICS or SABA did not affect the outcomes. <bold>Conclusions:</bold> Adjusted for relevant covariates, asthma in general does not affect outcomes of OSA. However, the relationship between some asthma medications and symptoms as well as comorbidities warrants further analysis.