Abstract Introduction Obstructive sleep apnea (OSA) is a heterogeneous disorder with regards to the disease presentation and cardiovascular (CV) consequences. On one hand, prior studies have linked Co-Morbid Insomnia and Sleep Apnea (COMISA), characterized by substantial overlap of chronic insomnia and OSA, to elevated CV risk. On the other, studies in community-based and clinical populations have described symptom-based subtypes of obstructive sleep apnea (OSA), including excessively sleepy, moderately sleepy, disturbed sleep, and minimally symptomatic subgroups, and have demonstrated that the excessively sleepy subtype (not the disturbed sleep subtype) carries the highest CV risk. We explored the extent to which this “paradox” between the findings from research on COMISA and symptom subtypes is explained by underlying excessive sleepiness among patients with COMISA. Methods We utilized data from the Sleep Apnea Global Interdisciplinary Consortium (SAGIC) to compare the overlap between COMISA and OSA symptom subtypes. COMISA was defined as an apnea-hypopnea index (AHI)≥15/hour and insomnia by qualitative (problems initiating sleep, staying asleep or waking too early ≥3x/week for ≥3 months) and/or quantitative criteria (average sleep onset latency and/or wake after sleep onset exceeding 31 minutes, with symptoms persisted for at least 3 months). We used descriptive statistics to understand the proportion of each symptom subtype within patients with COMISA. Results We included 1,929 subjects with OSA (AHI≥5 events/hour), of whom 1,321 (68.5%) had moderate-severe disease (AHI≥15). Among those moderate-severe OSA, 382 (28.9%) subjects had COMISA (19.8% of the full cohort with any OSA). The largest fraction of the patients with COMISA fell into the excessively sleepy subtype (n=179 47%), with most of the remaining falling into the disturbed sleep subtype (n=142 37%) and 10% in either the minimally symptomatic (n=31 8.1%) or moderately sleepy (n=30 7.9%) subtypes. Conclusion Nearly half of patients with COMISA in this international, clinical sample had the excessively sleepy OSA symptom subtype previously associated with increased CV risk. Further studies with longitudinal data should investigate whether the elevated CV risk in patients with COMISA is driven by excessive sleepiness. Support (if any) National Institutes of Health Grant P01 HL160471.
Lam et al. (Fri,) studied this question.