Phenotypes of patients with mild to moderate obstructive sleep apnoea as confirmed by cluster analysis
Article first published online: 21 DEC 2011
© 2011 The Authors. Respirology © 2011 Asian Pacific Society of Respirology
Volume 17, Issue 1, pages 99–107, January 2012
How to Cite
JOOSTEN, S. A., HAMZA, K., SANDS, S., TURTON, A., BERGER, P. and HAMILTON, G. (2012), Phenotypes of patients with mild to moderate obstructive sleep apnoea as confirmed by cluster analysis. Respirology, 17: 99–107. doi: 10.1111/j.1440-1843.2011.02037.x
- Issue published online: 21 DEC 2011
- Article first published online: 21 DEC 2011
- Accepted manuscript online: 17 AUG 2011 07:55AM EST
- Received 24 February 2011; invited to revise 4 April 2011, 7 June 2011; revised 26 May 2011, 8 June 2011; accepted 8 June 2011 (Associate Editor: David Hui).
- obstructive sleep apnoea;
- rapid eye movement sleep;
- sleep stage;
- supine position
Background and objective: Patients with 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 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: The data for 1184 consecutive patients, collected over 24 months, was analysed. Patients with a total AHI of 5–30/h were categorized according to the sleep stage and position in which they were predominantly affected. This categorization was compared with one in which patients were grouped using a K-means clustering technique with log linear modelling and cross-tabulation.
Results: 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: (i) rapid eye movement (REM) predominant OSA, 44.6%; (ii) non-REM predominant OSA, 18.9%; (iii) supine predominant OSA, 61.9%; and (iv) 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: 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.