Background: A phenotype with insomnia symptoms has been associated with increased prevalence of cardiovascular disease (CVD) in obstructive sleep apnea (OSA). This difference is not explained by the severity of OSA. (Saaresranta et al. Plos One 2016) We hypothesized that the elevated comorbidity in patients with insomnia is mediated by nocturnal hypoxia. Methods: A prospective follow-up ESADA cohort (17365 adult patients) with suspected OSA was divided into clinical phenotypes according to daytime symptoms (excessive daytime sleepiness, EDS) and characteristics suggestive of insomnia (short sleep duration, long sleep latency, hypnotic medication or an insomnia diagnosis). Four phenotypes were labelled as EDS, EDS/insomnia, non-EDS/non-insomnia, or insomnia. Multiple confounders including geographical region were taken into account in the analysis. Results: In logistic regression analysis, higher prevalence of CVD was independently associated with nadir SaO2 in the EDS-insomnia and insomnia groups (Table).
Conclusions: Insomnia-like symptoms and signs of nocturnal hypoxemia should alert clinicians to a high prevalence of CVD in patients with OSA. This finding also emphasizes the importance of clinical phenotyping in the management of OSA.