Prevalence and severity of sleep disordered breathing in a group of morbidly obese patients

Obesity may be complicated by sleep disordered breathing (SDB). The presence of SDB is associated with increased morbidity and mortality. Patient characteristics, pulmonary function tests and daytime arterial blood gas analyses may help to identify patients with SDB. These variables and the prevalence and severity of sleep disordered breathing were studied in a group morbidly obese patients.

Forty-eight patients, 19 men and 29 women who were referred to our clinic of internal medicine because of their obesity were included. Characteristics, pulmonary function tests and daytime arterial blood gas analyses of groups with different grades of SDB were compared.

Male subjects had significantly more apnoeas/hypopnoeas per hour (AHI) (18.4 +/- 20.9 versus 4.8 +/- 9.4) with more desaturation, a lower mean saturation (92.6 +/- 4.1 versus 96.1 +/- 1.6) and a lower saturation nadir (73.8 +/- 12.0 versus 83.1 +/- 6.7). Five (26%) of the male subjects and none of the female subjects had severe SDB (AHI > or = 25). Subjects were divided into three groups according to the severity of their SDB: twenty-nine subjects (23 women and 6 men) with AHI < 5, 14 subjects (6 women and 8 men) with AHI > or = 5 and < 25 and 5 subjects, all men, with AHI > or = 25. Except for gender no significant differences were found between the three groups.

Our study confirms the findings that morbidity obese men have SDB more frequently and more severely than obese women. Patient characteristics other than gender, pulmonary function tests and daytime blood gas analyses have no predictive value.