Prevalence and severity of sleep apnea in a group of morbidly obese patients

Obesity is the most important risk factor for obstructive sleep apnea. It is estimated that 70% of sleep apnea patients are obese. In the morbidly obese, the prevalence may reach 80% in men and 50% in women. The aim of this study was to determine the prevalence and severity of sleep apnea in a group of morbidly obese patients, leading to bariatric surgery.

In a cross-sectional study developed in Bahia, northeastern Brazil. 108 patients (78 women and 30 men) from the Obesity Treatment and Surgery Center--"Núcleo de Tratamento e Cirurgia da Obesidade" underwent standard polysomnography. Patients with an apnea-hypopnea index (AHI) > or = 5 events/hour were considered apneic.

Mean +/- SD for age and BMI were 37.1 +/- 10.2 years and 45.2 +/- 5.4 kg/m2, respectively. The calculated AHI ranged widely from 2.5 to 128.9 events/hour. Sleep apnea was detected in 93.6% of the sample, wherein 35.2% had mild, 30.6% moderate and 27.8% severe apnea. Oxyhemoglobin desaturation was directly related to the AHI and was more severe in men.

There was a high frequency of sleep apnea in this group of morbidly obese patients, for whom it was very important to request polysomnography, thus enabling therapeutic management and prognostication.