The clinical and polysomnographic differences between obese and non-obese patients with obstructive sleep apnea

Abstract

Obesity has been considered to be one of the important risk factor for obstructive sleep apnea (OSA). We aimed to investigate the clinical and polysomnographic differences of obese and non-obese OSA patients and how these differences, if any, can be reflected in our daily clinical practice. The polysomnographic data of 157 consecutive patients that underwent a sleep study were analyzed. Ninety-nine adult patients with a diagnosis of OSA [apnea-hypopnea index (AHI) ≥ 5/hour] were retrospectively assesed in two groups in respect of obese (BMI ≥ 30 kg/m2) or non-obese (BMI <30 kg/m2) according to body mass index (BMI). The clinical and polysomnographic results of the patients in both groups were compared. Between 2010 and 2011, 99 (31 K/68 M) of 157 patients underwent polysomnography were diagnosed with OSA (AHI ≥ 5/hour). Thirthy six patients with OSA (36.4%) were non-obese and 63 patients (63.6%) were obese. There were no differences in the symptoms related to OSA between two groups (p> 0.05). Although there was no statistical significance, the age of the obese patients (50.5 ± 12.7 years) was lower than those of the non-obese (54.9 ± 10.0 years) in polysomnography their total sleep time was shorter and sleep latency later, and sleep efficiency, arousal index, N3%, and REM% were lower and N1% was higher (p> 0.05). While in the obese OSA patients the AHI and Epworth Sleepiness sclae were higher (respectively; p= 0.028, p= 0.01), average oxygen saturation at sleep was lower (p<0.001). While obese OSA patients had similar ratio of hypertension and atherosclerotic heart disease with non-obese OSA patients, whereas diabetes mellitus was higher in obese OSA group (p= 0.036). The use of antidepressant drug was more common in the non-obese patients than the obese patients (p= 0.011). Although obese OSA patients have a more severe disease compared to nonobese OSA patients, there were no significant differences in clinical and polysomnographics findings between two groups. Should be noted that OSA may occur in non-obese patients.