Multidimensional phenotyping to distinguish among central (CSA), obstructive (OSA) and co-existing central and...

When navigating the landscape of obstructive sleep apnea (OSA), central sleep apnea (CSA) and intersection of the two diseases (co-existing CSA-OSA), there are significant knowledge gaps. Data are scarce regarding the respective prevalence and differences in clinical presentation of the three conditions. One major issue for characterization of the prevalence of the different sleep apnea entities is the scoring of central versus obstructive hypopneas which is not included in the routine practice of many sleep laboratories.

We prospectively assessed multidomain symptoms and collected data on comorbidities, medications and treatment indications in a large monocentric real-life dataset (n > 2400) of patients referred for suspicion of sleep apnea. We have systematically distinguished central versus obstructive hypopneas to define OSA, CSA and co-existing CSA-OSA.

When CSA was defined by the proportion of central apneas (and hypopneas were considered obstructive by default), the prevalence of CSA was 4.59 % (co-existing CSA-OSA: 11.03 %, and OSA: 84.37 %). When the distinction between obstructive and central hypopneas was used to classify the sleep disordered breathing, the prevalence of CSA was fourfold higher at 19.69 % (co-existing: 19.16 %, OSA: 61.16 %). The burden of cardiovascular and metabolic comorbidities was the highest in the CSA and co-existing sleep apnea subgroups. The three sleep apnea groups exhibited different constellations of symptoms but most of the patients with CSA, co-existing and OSA were symptomatic after comprehensive evaluation. The CSA group exhibited the most severe disturbances in sleep architecture on polysomnography. Therapeutic indications differed depending on the subtype of respiratory events.

Our findings imply that not differentiating between central and obstructive hypopneas will underestimate the severity of central sleep disordered breathing abnormalities that mislead therapeutic decisions and might limit improvements in quality of life and sleepiness that are expected in appropriately treated patients with CSA.