The Hidden Burden of COMISA: Clinical Implications and Treatment Challenges

Insomnia disorder and obstructive sleep apnea (OSA) are two of the most common sleep disorders in the general population. Their coexistence, referred to as comorbid insomnia and sleep apnea (COMISA), exacerbates nighttime disturbances, increases daytime dysfunction, and further diminishes overall quality of life. COMISA is also associated with elevated cardiovascular and mental health risks, including resistant hypertension, heart failure, stroke, depression, and anxiety. Despite its clinical importance, COMISA often remains underdiagnosed, and its management poses notable challenges.

This narrative review article aims to provide a comprehensive overview of the current understanding of COMISA, focusing on its definition, epidemiology, pathophysiological mechanisms, clinical presentation, diagnostic challenges and treatment approaches, including the diagnostic decision-making process and criteria for selecting appropriate therapeutic strategies.

Literature review of published studies with different designs, including peer-reviewed observational studies, randomized controlled trials, meta-analyses, and international clinical guidelines, was conducted. Databases used included PubMed, Scopus, and Web of Science, and they covered epidemiological, clinical, and therapeutic topics focusing on COMISA. Emphasis was placed on the cardiovascular, psychological, and therapeutic outcomes, as reported in the cited literature.

Patients diagnosed with COMISA typically present with symptoms such as greater sleep fragmentation, prolonged sleep latency, persistent daytime fatigue, cognitive deficits, and elevated psychological distress, compared with individuals with insomnia or OSA alone. COMISA is also associated with a threefold increased risk of resistant hypertension and heightened cardiovascular mortality. Despite the fact that continuous positive airway pressure (CPAP) remains the cornerstone of OSA treatment, its effectiveness is often limited by comorbid insomnia, making combined cognitive behavioral therapy for insomnia (CBT-I) and CPAP interventions more promising, as well as emerging pharmacotherapies, such as dual orexin receptor antagonists. Patients with significant insomnia-related impairment or suboptimal CPAP adherence may benefit from these combined or alternative approaches.

COMISA represents a complex clinical entity that is associated with impairments in clinical outcomes and quality of life, requiring a multidisciplinary, personalized approach to simultaneously address sleep-disordered breathing and insomnia symptoms. Early recognition, individualized treatment strategies, and long-term monitoring are essential to improve prognosis and therapeutic success in this high-risk population.