The Edmonton Obesity Staging System (EOSS) is a more comprehensive measure of obesity-related diseases and predictor of mortality than BMI or waist circumference. The aim of this study is to determine whether the EOSS is also important in predicting post - operative outcome and 30-day mortality after metabolic surgery.

From October 2014 to December 2015 the investigators conducted a prospective data collection on patients undergoing either laparoscopic sleeve gastrectomy (LSG) or laparoscopic Gastric Bypass (Laparoscopic Roux-en-Y-Gastric Bypass (LRYGB) and Omega-Loop-Gastric-Bypass (LOLGB)), being the first surgical treatment for severe obesity. Preoperative EOSS by Sharma et al. was applied to all patients by two different evaluators. Data collection included the following: gender, age, body mass index, waist circumference, waist to hip ratio, comorbidities, early - postoperative complications, readmission rates and 30 - day mortality. Follow-up was performed in all patients up to 1 month after surgery.

Inclusion Criteria:

• patients undergoing either LSG or LRYGB, being the first surgical treatment for severe obesity

Exclusion Criteria:

• bariatric surgery in the anamnesis

Patients undergoing either LSG, LRYGB or LOLGB, being the first surgical treatment for severe obesity