Clinical patterns of severe obstructive sleep apnea (OSA): a cluster analysis based on systematic assessment

<bold>Background:</bold> Obstructive sleep apnea (OSA) is a heterogeneous disorder and the severe OSA could lead to cardiovascular and metabolic comorbidities. However, the OSA diagnosis focuses on the respiratory system according to guidelines. In this study, we aim to explore the clinical patterns of severe OSA based on systematic assessment of multiple organs function using cluster analysis. <bold>Methods:</bold> Patients with severe OSA were studied with data of age, sex, anthropometric examination, blood pressure, liver and renal function, lipid levels, fasting blood glucose, AHI, lowest Sao2 during sleep-monitor, and disorders of nonalcoholic fatty liver disease (NAFLD) and carotid atherosclerosis. Cluster analysis was performed using k-medoids algorithm. The characteristics between clusters were analyzed using one-way analysis of variance, Mann-Whitney U test or chi-squared tests. <bold>Results:</bold> Two clusters were identified with 503 subjects. When compared with cluster 2 (n=136), cluster 1 (n=367) showed higher AHI (55.0 vs 49.8), more proportion of males (90.7% vs 28.7%), larger BMI (27.3±2.8 vs 25.2±2.9 kg/m2), larger neck and waist circumferences, higher blood pressure, worse liver function, worse renal function, worse lipid levels, higher fasting blood glucose. Moreover, the prevalence of NAFLD and carotid atherosclerosis in cluster 1 was higher than cluster 2 (NAFLD: 42.2% vs 15.4%; carotid atherosclerosis: 39.8% vs 16.2%). <bold>Conclusions:</bold> The result identified distinct patterns of severe OSA based on systematic assessment. The age and lowest Sao2 during sleep-monitor are not involved into it.