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

Introduction: 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. Materials and Methods: 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/m(2)) or non-obese (BMI <30 kg/m(2)) according to body mass index (BMI). The clinical and polysomnographic results of the patients in both groups were compared. Results: 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). Conclusion: 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.