Sleep position and obstructive sleep apnea (OSA): Do we know how we sleep? A new explorative sleeping questionnaire

Positional obstructive sleep apnea (POSA) has been defined as a difference of 50% or more in Apnea-Hypopnea Index (AHI) between supine and non-supine position. Sleep position is fundamental in the evaluation of obstructive sleep apnea syndrome (OSAS) severity but most tools used in the diagnosis of OSAS are not free from potential bias in the evaluation of usual sleep positions. The aim of this investigation was to evaluate a novel sleep questionnaire with the purpose of exploring sleep habits and evaluating if sleep assessment can identify the usual body position assumed for sleep.

The questionnaire was administered to patients recruited from October to November 2018. Questions concerned sleeping positions and conditions that could influence sleeping positions. Patients who had previously undergone polysomnography (PSG) were asked how they slept during the study night. Whenever present during the examination, the patient's bed partner was also asked about the patient's usual body positions during sleep.

Of 315 patients (211 men) enrolled, 35% were affected by OSAS and 69% of patients with OSAS had POSA. POSA was more prevalent among men (75%) compared to women (43%). The new questionnaire provided a discordant result from PSG recordings about sleeping positions and revealed a difference between usual sleeping position and the position during PSG recording. Reported sleep quality was much worse on PSG than at home suggesting that the "first night effect" is real and may lead to over-estimation of POSA cases.

Information about sleeping positions is fundamental to the assessment of OSAS severity. Knowledge gained from the new questionnaire as described may represent a valuable addendum to develop a more detailed polygraphic report. Such a tool may be used in practice with the aim of better identifying patients with true positional OSAS. Such patients may benefit from targeted positional therapy.