IntroductionObstructive sleep apnea (OSA) is one of the most important co-morbid conditions related with morbid obesity. Bariatric procedures are associated with significant improvement in OSA. The aim of the current study was to evaluate the effect of bariatric surgery on daytime sleepiness and quality of sleep in patients that had undergone laparoscopic sleeve gastrectomy.MethodsFifty-nine patients were prospectively enrolled in the study. Pre-operative and post-operative (6 months) demographics, medical history, weight, and height of the patients were recorded, and patients were asked to complete Pittsburg Sleep Quality Index (PSQI) and Epworth Sleepiness Scale (ESS) questionnaires. OSA screenings were performed using the STOP-Bang questionnaire.ResultsThe mean age of the patients was 37.1 ± 1.2 years and 76% were female. Pre-operative and post-operative median (range) BMIs were 47 kg/m2 (39–67 kg/m2) and 35 kg/m2 (25–44 kg/m2), respectively (P < 0.001). The mean ± standard deviation excess weight loss was 51.6 ± 13.2%. In univariate analysis, total PSQI, STOP-Bang, and ESS scores were found to significantly improve 6 months after surgery (all P < 0.001). Multivariate mixed-model analysis showed a high correlation between the decrease in BMI and all key predictors. Mixed-model analysis revealed that every 1 kg/m2 decrease in BMI was associated with a 0.32, 0.13, and 0.26 improvements in PSQI, STOP-Bang, and ESS scores, respectively (all P < 0.001).ConclusionLaparoscopic sleeve gastrectomy is associated with rapid weight loss and improvements in sleep quality, daytime sleepiness, and the risk of OSA 6 months after surgery.