Comorbid Insomnia is Associated with Enhanced Blood Pressure Reduction with CPAP Therapy in Patients with Obstructive Sleep Apnea: A Prospective Cohort Study.

Abstract

Comorbid insomnia and obstructive sleep apnea (COMISA) is prevalent among patients with obstructive sleep apnea (OSA) and is linked to poorer blood pressure (BP) control. However, its impact on the BP response to continuous positive airway pressure (CPAP) therapy remains unclear. Does the presence of comorbid insomnia modulate the antihypertensive effect of short-term CPAP therapy in patients with OSA? In this prospective cohort study, 71 adults with OSA and elevated BP underwent 4 weeks of auto-CPAP therapy. Participants were stratified into COMISA (n=22) and OSA-alone (n=49) groups based on DSM-5 criteria. The primary outcome was a clinically meaningful 24-hour systolic BP (SBP) reduction (decrease ≥ 5 mmHg). Secondary outcomes included absolute changes in 24-hour, daytime, and nocturnal SBP and diastolic BP. After 4 weeks of CPAP, the COMISA group achieved a significantly greater reduction in 24-hour SBP compared to the OSA-alone group (-6.0 ± 8.2 mmHg vs. -0.3 ± 6.5 mmHg, p=0.002), with consistent benefits in daytime and nocturnal SBP. Insomnia symptoms were independently associated with the primary outcome (adjusted OR 5.62, 95% CI 1.50-21.15). Associations with secondary outcomes (24-hour, daytime and nocturnal SBP reductions) did not remain significant after Bonferroni adjustment (α=0.017). COMISA identifies a clinical phenotype with an enhanced SBP-lowering response to CPAP, particularly for achieving clinically meaningful 24-hour SBP reduction. Insomnia is an independent factor associated with this benefit, suggesting that addressing both sleep disorders may optimize cardiovascular outcomes. Strategies to improve CPAP adherence in COMISA are crucial. Chinese Clinical Trial Registry (ChiCTR2300067728).