Body composition profiles and metabolic vulnerability in comorbid insomnia and sleep apnea (COMISA): A large-scale...

Comorbid insomnia and sleep apnea (COMISA) presents a greater clinical burden than obstructive sleep apnea (OSA) alone. We investigated the association between body composition and insomnia to identify the body composition phenotype of COMISA.

This cross-sectional study included 2915 patients with moderate-to-severe OSA (apnea-hypopnea index ≥15) who underwent polysomnography and body composition analysis. Participants were categorized into OSA (Insomnia Severity Index [ISI] < 15) and COMISA (ISI ≥15). Skeletal muscle mass (SMM), visceral fat area (VFA), and the SMM/VFA ratio were assessed via bioelectrical impedance analysis.

Of the participants, 865 (29.7%) were classified as COMISA. Compared to the OSA-only group, COMISA patients were older, more frequently female, and exhibited poorer sleep parameters, namely shorter total sleep time, prolonged sleep onset latency, increased wake after sleep onset, and lower sleep efficiency, despite comparable body mass index and apnea-hypopnea index. Notably, the COMISA group showed lower SMM, alongside higher VFA. The SMM/VFA ratio was inversely associated with ISI scores (β = -0.08, p = 0.001) and COMISA status (OR = 0.29, p = 0.004), particularly in males. These associations persisted across confounder adjustments and strengthened progressively with stepwise increments in depression severity thresholds.

Patients with COMISA exhibit a more vulnerable body composition profile, characterized by lower muscle-to-fat ratios, compared with those with OSA alone. These findings suggest that clinicians should consider detailed body composition assessments to stratify insomnia risk during the evaluation of patients with OSA.