Clinical parameters in obstructive sleep apnea: are there any correlations?

OBJECTIVE: To assess the correlation between clinical symptoms and examination findings with severity of obstructive sleep apnea (OSA).

DESIGN: Prospective observational study.

SETTING: Otorhinolaryngology sleep clinic in a tertiary referral centre.

PARTICIPANTS: Consecutive patients referred to the sleep clinic with a suspected diagnosis of OSA.

MAIN OUTCOMES MEASURES: Body mass index (BMI), Epworth Sleepiness Scale (ESS) score, tonsil size, modified Mallampati index (MMP), Müller manoeuvre, reflux finding score (RFS), apnea-hypopnea index (AHI), lowest oxygen saturation, and percentage of rapid eye movement sleep.

RESULTS: Eighty patients (14 female, 66 male), with a mean age of 42.9 years (range 22-66), were included in the study. The mean BMI was 27.6 (range 20-39). A correlation was found between ESS score and anteroposterior pharyngeal wall collapse at the level of the soft palate during Müller manoeuvre (r=.3, p=.02). BMI was significantly associated with a history of hypertension (r=.3, p=.01), MMP (r=.3, p=.001), and lateral wall collapse at the level of the soft palate during Müller manoeuvre (r=.4, p=.0001). OSA severity correlated significantly with male gender (p=.02), history of hypertension (r=.5, p<.0001), BMI (r=.2, p=.03), MMP (r=.3, p=.003), and upper airway collapse during Müller manoeuvre.

CONCLUSIONS: Clinical findings in patients with OSA do correlate with the severity of OSA and polysomnographic findings. The degree of upper airway collapse during Müller manoeuvre does correlate with AHI severity. Accuracy in predicting the presence and severity of OSA allows for greater cost-effectiveness in screening patients prior to polysomnography.