Phenotypes of patients with mild to moderate obstructive sleep apnoea as confirmed by cluster analysis

Mild-moderate OSA is heterogeneous with respect to AHI but there is limited data on the proportions of patients with varying OSA phenotypes. Patients with mild-moderate OSA were categorized into distinct, overlapping phenotypes that differed significantly. Analyses based on phenotype may increase understanding of the pathophysiology and outcomes of OSA. ABSTRACT: Background and objective:a?? Patients with obstructive sleep apnoea (OSA) manifest different patterns of disease. However, this heterogeneity is more evident in patients with mild-moderate OSA than in those with severe disease and a high total apnoea-hypopnoea index (AHI). We hypothesized that mild-moderate OSA can be categorized into discreet disease phenotypes, and the aim of this study was to comprehensively describe the pattern of OSA phenotypes through the use of cluster analysis techniques. Methods:a?? The data for 1,184 consecutive patients, collected over 24 months, was analyzed. Patients with a total AHI of 5-30 per hour were categorized according to the sleep stage and position in which they were predominantly affected. This categorization was compared to one in which patients were grouped using a K-means clustering technique with log linear modelling and cross-tabulation. Results:a?? Patients with mild-moderate OSA can be categorized according to polysomnographic parameters. This clinical categorization was validated by comparison with a categorization in which patients were grouped by unsupervised K-means cluster analysis. The clinical groups identified were: A) rapid eye movement (REM) predominant OSA, 44.6 : B) non-rapid eye movement predominant OSA, 18.9 ; C) supine predominant OSA, 61.9 ; and D) intermittent OSA, 12.4 . Patients categorized as having both REM and supine predominant OSA showed characteristics of both the REM predominant and supine predominant OSA groups. Conclusions:a?? Patients with mild-moderate OSA show different polysomnographic phenotypes. This approach to categorization more appropriately reflects disease heterogeneity and the likely multiple pathophysiological processes involved in OSA