Predictors of moderate to severe obstructive sleep apnea: identification of sex differences

Purpose Home sleep apnea tests are recommended only for patients at high risk of moderate to severe obstructive sleep apnea (OSA, apnea-hypopnea index [AHI] >= 15/h). We evaluated 14 factors known to be associated with OSA and identified sex differences in predictors of moderate to severe OSA. Methods Retrospective analysis was done on 545 subjects who completed sleep questionnaires and underwent diagnostic polysomnogram at a tertiary sleep center. Univariate and multivariate analysis was conducted separately in males and females to determine which variables were independent predictors of moderate to severe OSA. Results Overall, physical traits were stronger predictors in both males and females. For each sex, only 3 variables were found to be independently predictive of moderate to severe OSA. In order of predictive strength, this included body mass index (BMI) >= 38 kg/m(2) (aOR 5.80, p < 0.001), neck circumference (NC) >= 17 in. (aOR 2.52, p = 0.002), and Epworth sleepiness scale (ESS) >= 13 (aOR 2.22, p = 0.015) for males and age >= 50 years (aOR 4.19, p < 0.001), NC >= 14.5 in. (aOR 3.13, p = 0.003), and report of morning headaches (aOR 2.00, p = 0.039) for females. Applying the Bonferroni correction, BMI and NC remained significant for males, and age and NC remained significant for females. Conclusions In a subject population referred for sleep evaluation at a tertiary care center only a few variables are independently predictive of moderate to severe OSA, and these variables differed between males and females. Only BMI, NC, and a high ESS were independently predictive of moderate to severe OSA in males, whereas age, NC, and morning headaches were independently predictive in females.