Objectives: To describe the frequency and severity of sleep apnea in obese patients without a primary sleep complaint and to assess the sleep patterns of obese patients without apnea and compare them with the sleep patterns of nonobese controls.
Design and setting: Prospective case series with historical controls in an obesity and sleep disorders clinic.
Subjects: Two hundred obese women and 50 obese men (mean body mass index, 45.3) consecutively referred for treatment of their obesity and 128 controls matched for age and sex.
Main outcome measures: Eight-hour sleep laboratory recording, including electroencephalogram, electro-oculogram, electromyogram, and respirations. Subjectively reported sleep-related symptoms and signs were also recorded.
Results: Twenty men (40%) and six women (3%) demonstrated sleep apnea warranting therapeutic intervention. Another four men (8%) and 11 women (5.5%) showed sleep apneic activity that warranted recommendation for evaluation in the sleep laboratory. In contrast, none of the 128 controls demonstrated sleep apneic activity severe enough for therapeutic intervention. The best clinical predictors of sleep apnea in the obese population were severity of snoring, subjectively reported nocturnal breath cessation, and sleep attacks. Obese patients, both men and women, without any sleep-disordered breathing demonstrated a significant degree of sleep disturbance compared with nonobese controls. Wake time after sleep onset, number of awakenings, and percentage of stage 1 sleep were significantly higher in obese patients than in controls, while rapid eye movement sleep was significantly lower.
Conclusion: Severely or morbidly obese men are at extremely high risk for sleep apnea and should be routinely evaluated in the sleep laboratory for this condition, while for severely or morbidly obese women the physician should include a thorough sleep history in the clinical assessment.