Comparison of supine-only and REM-only obstructive sleep apnoea.

OBJECTIVES

The effect of body position and sleep state on sleep apnoea have major clinical implications in the management of patients, yet are infrequently reported in the scientific literature. The aim of this study was to compare and contrast the prevalence and severity of supine-only and rapid eye movement (REM)-only obstructive sleep apnoea (OSA) in a population.

METHODS

Prospective cohort analysis of the influence of supine body position and REM sleep on the severity of apnoea in 100 consecutive patients with OSA (apnoea-hypopnoea index [AHI]>5) using attended polysomnography with continuous digital monitoring in an accredited sleep laboratory. Supine-only OSA was defined as a supine:non-supine AHI ratio of >2:1 and non-supine AHI <5 events/h. REM-only OSA was defined as an REM:non-REM ratio of >2:1 and non-REM AHI <5events/h.

RESULTS

Supine sleep time represented a greater proportion of total sleep time than REM sleep time (40% vs 13%). The prevalence of supine-only OSA was more than twofold greater than that of REM-only OSA (23% and 10%, respectively). The supine-only group had greater overall AHI (mean 12.6±6.1 vs 7.2±2.2 events/h; P<0.01) than the REM-only group. No significant differences in gender, age, or sleepiness were found between the two groups.

CONCLUSIONS

Supine-only OSA is more common and is associated with a greater AHI than REM-only OSA.