Body Mass Index, Gender, and Ethnic Variations Alter the Clinical Implications of the Epworth Sleepiness Scale in Patients with Suspected Obstructive Sleep Apnea§

Sean Hesselbacher1, Shyam Subramanian 1, Jerry Allen 2, Sara Surani 2, Salim Surani*, 1, 2, 3, 4
1 Department of Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Baylor College of Medicine, Houston, TX, USA
2 Torr Sleep Center, Corpus Christi, TX, USA
3 Texas A&M University, Corpus Christi, TX, USA
4 CHRISTUS Spohn Hospital, Corpus Christi, TX, USA

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© Hesselbacher et al.; Licensee Bentham Open.

open-access license: This is an open access article licensed under the terms of the Creative Commons Attribution Non-Commercial License ( which permits unrestricted, non-commercial use, distribution and reproduction in any medium, provided the work is properly cited.

* Address correspondence to this author at the Department of Medicine, Section of Pulmonary, Critical Care, and Sleep Medicine, Texas A&M University, 613 Elizabeth Street, Suite 813, Corpus Christi, Texas 78413, USA; Tel: 1-361-885-7722; Fax: 361-850-7563; E-mail:



The Epworth Sleepiness Scale (ESS) is often used in the evaluation of obstructive sleep apnea (OSA), though questions remain about the influence gender, ethnicity, and body morphometry have in the responses to this questionnaire. The aim of this study was to examine differences in ESS scores between various demographic groups of patients referred for polysomnography, and the relationship of these score to sleep-disordered breathing


Nineteen hundred consecutive patients referred for polysomnographic diagnosis of OSA completed questionnaires, including demographic data and ESS. OSA was determined based on a respiratory disturbance index (RDI) ≥15 by polysomnography.


In this high risk population for OSA, the ESS was 10.7 ± 5.6. The highest ESS scores were seen in obese males; non-obese females and non-obese Caucasian males scored the lowest. ESS was weakly correlated with RDI (r = 0.17, P < 0.0001). The sensitivity of ESS for the diagnosis of OSA was 54% and the specificity was 57%. The positive (PPV) and negative (NPV) predictive values were 64% and 47%, respectively. In obese subjects, the sensitivity and specificity were 55% and 53%, compared with 47% and 63% in non-obese subjects. In obese, Hispanic males, the sensitivity, specificity, and PPV were 59%, 54%, and 84%, respectively. In non-obese, Caucasian females, the sensitivity, specificity, and NPV were 43%, 59%, and 72%.


The ESS appears to be affected by many factors, including gender, ethnicity, and body morphometry. The ability of the ESS to predict OSA is modest, despite a significant correlation with the severity of OSA. The test characteristics improve significantly when applied to select populations, especially those at risk for OSA.

Keywords: Ethnicity, gender, obstructive sleep apnea, epworth sleepiness scale, screening..