ORIGINAL ARTICLE Influence of the right- versus left-sided sleeping position on the apnea-hypopnea index in patients with sleep apnea Ozcan Ozeke & Ozcan Erturk & Mutlu Gungor & Serap Bılen Hızel & Dilek Aydın & Mehmet Kutlu Celenk & Hazim Dıncer & Gurler Ilıcın & Fuat Ozgen & Can Ozer Received: 26 April 2011 /Revised: 27 May 2011 /Accepted: 8 June 2011 /Published online: 16 June 2011 # Springer-Verlag 2011 Abstract Purpose Sleep and sleep position have a significant impact on physical, cardiac and mental health, and have been evaluated in numerous studies particularly in terms of lateral sleeping positions and their association with dis- eases. We retrospectively examined the relationship be- tween the sleeping position and position-specific apnea- hypopnea index (AHI) in obstructive sleep apnea-hypopnea (OSA) patients. Methods We assessed the sleeping body position and the body position-specific AHI score in patients who were referred for suspected OSA and underwent diagnostic nocturnal polysomnography. In order to eliminate inter- individual differences, only those who had a similar percentage of time spent in the LSSP and RSSP for each patient were enrolled. To provide this validity, only subjects that had a similar percentage of left and right lateral sleep time (±10%) were included in the analysis. Results A total of 864 patients had nocturnal diagnostic PSG. Of them, 131 patients met the inclusion criteria. The percent rate spent in the supine sleeping position (SSP) was 31.3±18.7%, in the LSSP was 31.8±10% and in the RSSP was 32.6±10.8%. Whereas the SSP-specific AHI score was the highest with 60.4±36.2/h among all the sleeping position-specific AHI scores (p<0.001), the LSSP-specific AHI score was statistically higher than that for RSSP (30.2 ±32.6/h vs. 23.6±30.1/h; p<0.001). When comparing individuals sub-grouped based on OSA severity, there was a statistically significant difference between the LSSP- specific AHI score and RSSP-specific AHI score in patients with severe (p=0.002) and moderate (p=0.026), but not mild (p=0.130) OSA. Conclusion We found that the sleeping position had a significant influence on apneic events and RSSP decreased the frequency of obstructive respiratory events in patients with moderate and severe disease. Keywords Sleep . Sleeping position . Sleep apnea Introduction Sleep, in which the average human spends one-third of life, is an active, dynamic physiological process that has a critical impact on many aspects of health and daytime functioning [1]. Sleeping position in healthy or specific patient groups also can have a significant impact on physical and mental health, and has been evaluated in numerous studies particularly on lateral sleeping positions and their association with diseases [2–18]. Although many articles have examined the influence of sleeping position, either supine or lateral, on the severity of sleep apnea, very few have examined whether sleeping on the left or right side can influence its severity. It has been established that OSA severity as measured by the apnea- hypopnea index (AHI; number of apneas and hypopneas per hour of sleep) is increased in the supine sleeping O. Ozeke : M. Gungor : M. K. Celenk : H. Dıncer : G. Ilıcın : C. Ozer Department of Cardiology, Bayindir Hospital, Ankara, Turkey O. Erturk : S. B. Hızel : D. Aydın : F. Ozgen Sleep Disorder Center, Bayindir Hospital, Ankara, Turkey O. Ozeke (*) Kardiyoloji Klinigi, Bayındır Hastanesi Sögütözü, Sögütözü, 06520 Ankara, Turkey e-mail: ozcanozeke@gmail.com Sleep Breath (2012) 16:617–620 DOI 10.1007/s11325-011-0547-4