Clinical predictors of obstructive sleep apnea in Asian bariatric patients

Obstructive sleep apnea (OSA) is a common disorder in modern society and closely associated with obesity. Because OSA increases the likelihood of complications in the perioperative period, preoperative recognition is very important for bariatric patients. Polysomnography (PSG) remains the gold standard for diagnosis, but it is a time-consuming and expensive examination. Our study is aimed at identifying practical clinical predictors of OSA for bariatric patients.

From April 2006 to December 2007, 101 morbid obese patients [41 men and 60 women, mean age 30.3 +/- 8.5, mean body mass index (BMI) 43.3 +/- 6.9] who underwent PSG before bariatric surgery were retrospectively studied. The severity of OSA was categorized by the apnea-hypopnea index (AHI) as follows: normal, 0 to 4.9; mild, 5 to 14.9; moderate, 15 to 29.9; and severe, >/=30. Chi-squared tests and linear regression models were used to assess associations between clinical parameters and AHI; P < 0.05 was considered statistically significant.

The mean Epworth sleepiness scale (ESS) score was 8.2 +/- 4.7, and the mean AHI was 28.9 +/- 33.8 per hour. Of 101 patients, 83 patients had OSA; including severe (32.7%), moderate (17.8%), and mild (31.7%) OSA; 18.5% had no OSA. Patients with severe OSA are significantly male predominant and had higher BMI, systolic blood pressure, hemoglobin, neck and waist circumference, and ESS scores. In linear regression model analysis, the parameters which positively correlated with AHI were body weight, BMI, systolic blood pressure, diastolic blood pressure, hemoglobin, waist and neck circumferences, and the scores of ESS. Multivariate analysis confirmed that BMI, neck circumference, and scores of ESS are independent predictors of the increasing of AHI.

OSA is highly prevalent (82.2%) in Asian bariatric patients. BMI, neck circumference, and scores of ESS are independent predictors of OSA in these patients.