Clinical subtypes of co-morbid insomnia and obstructive sleep apnea (COMISA): results of a cluster analysis

Variations in the bidirectional relationship between obstructive sleep apnea (OSA) and insomnia in co-morbid insomnia and OSA (COMISA) may form distinct subtypes of COMISA, which have not been previously characterized. This study aims to identify and characterize subtypes of COMISA. From a community-recruited COMISA cohort 256 individuals who met diagnosis for COMISA were used to identify subtypes using a two-step clustering methodology. Demographics and multidimension clinical characteristics were collected and compared among obtained subtypes. Logistic models were used to evaluate whether these subtypes were associated with cardiometabolic and mental disorders. A clinical cohort of 1816 COMISA patients was used to validate the determined clusters applying the same two-step clustering methodology. Cluster analysis yielded three clusters (COMISA subtypes): “moderate OSA and moderate insomnia” (cluster 1), “moderate OSA and severe insomnia” (Cluster 2) and “severe OSA and moderate insomnia” (Cluster 3), consisting of 58.2%, 21.9% and 19.9% of the entire cohort, which was validated using the clinical COMISA cohort. The clusters differed significantly on a variety of clinical measurements, including blood indicators related to cardiometabolic risk, inflammation and liver function, depression symptoms, and encephalogram (EEG) spectral power. Cluster 2 was associated with elevated risk of moderate-to-severe depression symptoms, while Cluster 3 was associated with increased risk of CVD and metabolic syndrome. These findings provide important preliminary evidence of the existence of phenotypes of COMISA which are likely to have clinical relevance and provide a foundation in precision medicine for treatment of COMISA.