Sleep-disordered breathing and obstructive sleep apnoea in asthma: impact on disease control, exacerbation frequency and clinical outcomes – a systematic review and meta-analysis of observational studies

Background Sleep-disordered breathing (SDB), including obstructive sleep apnoea (OSA), is a common but underrecognised comorbidity in asthma that may worsen disease control and clinical outcomes. This systematic review and meta-analysis evaluated associations between OSA/SDB and asthma control, exacerbations, future-risk outcomes and treatment response. Methods: PubMed, Scopus, Embase, Web of Science and the Cochrane Library were searched from inception to March 2025. Observational studies reporting validated asthma outcomes in populations with OSA/SDB were included. Risk of bias was assessed using adapted ROBINS-I domains. Random-effects meta-analyses used restricted maximum likelihood estimation with Hartung-Knapp correction where appropriate. Results Twenty-one studies involving 922,748 participants from 12 countries were included. OSA was associated with persistent asthma symptoms in adults (OR 1.74, 95% CI 1.49-2.02), poor asthma control in children (OR 2.48, 95% CI 1.45-4.23), severe asthma (OR 3.49, 95% CI 1.49-8.15), hospital readmission (IRR 1.09, 95% CI 1.04-1.15), and mechanical ventilation in hospitalised children (OR 6.62, 95% CI 4.29-10.22). The pooled prevalence of OSA/SDB in asthma by objective sleep testing was 62.3% (95% CI 34.7%-83.7%). Asthma independently predicted incident OSA (OR/HR/RR 2.11, 95% CI 1.35-3.29). GRADE certainty was low to very low for most outcomes. Conclusion OSA/SDB is highly prevalent in asthma and consistently associated with poorer asthma control, greater exacerbation risk and increased healthcare utilisation. Routine SDB screening should be considered in poorly controlled asthma. Addressing this overlap supports Sustainable Development Goal 3.