IntroductionRoux-en-Y gastric bypass (RYGB) is considered the gold standard bariatric procedure with documented safety and effectiveness. Laparoscopic sleeve gastrectomy (LSG) is a newer procedure being done with increasing frequency. Randomized comparisons of LSG and other bariatric procedures are limited. We present the results of the first prospective randomized trial comparing LSG and RYGB in the Polish population.AimTo assess the efficacy and safety of LSG versus RYGB in the treatment of morbid obesity and obesity-related comorbidities.Material and methodsSeventy-two morbidly obese patients were randomized to RYGB (36 patients) or LSG (36 patients). Both groups were comparable regarding age, gender, body mass index (BMI) and comorbidities. The follow-up period was at least 12 months. Baseline and 6 and 12 month outcomes were analyzed including assessment of percent excess weight lost (%EWL), reduction in BMI, morbidity (minor, major, early and late complications), mortality, reoperations, comorbidities and nutritional deficiencies.ResultsThere was no 30-day mortality and no significant difference in major complication rate (0% after RYGB and 8.3% after LSG, p > 0.05) or minor complication rate (16.6% after RYGB and 10.1% after LSG, p > 0.05). There were no early reoperations after RYGB and 2 after LSG (5.5%) (p > 0.05). Weight loss was significant after RYGB and LSG but there was no difference between both groups at 6 and 12 months of follow-up. At 12 months %EWL in RYGB and LSG groups reached 64.2% and 67.6% respectively (p > 0.05). There was no significant difference in the overall prevalence of comorbidities and nutritional deficiencies.ConclusionsBoth LSG and RYGB produce significant weight loss at 6 and 12 months after surgery. The procedures are equally effective with regard to %EWL, reduction in BMI and amelioration of comorbidities at 6 and 12 months of follow-up. Laparoscopic sleeve gastrectomy and RYGB are comparably safe techniques with no significant differences in minor and major complication rates at 6 and 12 months.