The Bariatric surgery has been defined as the only effective means for treating severe obesity on a long term basis and metabolic surgery is recommended as one of the most effective treatment for the patients of type 2 diabetes mellitus with class I obesity. So called, Bariatric and metabolic surgery has effect on both conditions as well as other metabolic diseases. Nowadays, almost countries and medical societies have agreed metabolic and bariatric surgery as one of best tools for treating severe obesity and obese type 2 diabetes and along with this situation, Korean Government approved to cover metabolic and bariatirc surgery with national insurance since Jan. 2019. Therefore, the demand for metabolic surgery is increasing and the it is needed immediately to evaluate the safety, effectiveness, adverse effects, complications, cost analysis in Korean patients because these diseases are recognized to have the different presentation by their race. Also, These diseases need long term results. 
We are planning a multi-institute prospective cohort study of Korean patients who have the conditions for the criteria for insurance coverage and be receives the laparoscopic gastric bypass and laparoscopic sleeve gastrectomy, both of which are the most common metabolic and bariatric surgery in the world, collect long term clinical data and human biological materials and analyze them. 
1. We try to evaluate the relevance of the criteria on insurance coverage of Korean Government, complications of the surgery, and to propose the better surgery for Korean patients, preventive method for complications. 2. Additionally, we collect the patients derived materials such as serum, urine, stool, fat tissue and high quality data for the study of mechanisms in Korean patients with obesity and diabetes, which are diseases with racial differences, and for follow-up studies to search for various predictors.

Cohort/Group Label

Metabolic surgery treatment group

Cohort/Group Description

severely obese patient with consent who received gastric bypass or sleeve gastrectomy. After bariatric surgery, we will assess and investigate the change of body weight and quality of life as well as the change of co-morbidities such as type 2 diabetes, hypertension, hyperlipidemia, fatty liver, sleep apnea, polycystic ovarian syndrome. As for the study of weight change, we include waist and hip circumference and as for Quality of Life, EuroQuality of Life five dimensions questionnaire (EQ-5D) , Impact of Weight on Quality of Life-Lite Questionnaire (IWQOL-Lite), Obesity-related Psychosocial Problems scale (OP scale), Bariatric Analysis and Reporting Outcome System (BAROS) will be used. As for co-morbidities, as follows: for type 2 Diabetes Mellitus, HbA1C, oral glucose tolerance test, change of medications / for hypertension, blood pressure and medications / for hyperlipidemia, lipid profile and medicaitons / for fatty liver, change of Housefield unit on CT / for sleep apnea, change of polysomnography / for polycystic ovarian syndrome, change of the hormone profile.

: DNA Collect & Archive: Sample without DNA

Serum, Subcutaneous fat tissue, Visceral fat tissue, Liver tissue, Urine, Stool

inclusion and exclusion criteria
patients aged 20–65 years with a body mass index of ≥35 kg/m2 alone or a body mass index of ≥30 kg/m2 plus comorbidities (hypertension, glucose intolerance, dyslipidaemia and sleep apnea) or type 2 diabetes with body mass index  over 27.5 kg/m2

agreement for informed consent
Non-probablity sampling : purposive sampling

Gender

Age

Description

①  The patients aged 20–65 years with a body mass index of ≥35 kg/m2 alone or a body mass index of ≥30 kg/m2 plus comorbidities (hypertension, glucose intolerance, dyslipidaemia and sleep apnea) or type 2 diabetes with body mass index over 27.5 kg/m2, who visit the participating out patient clinics to consider bariatric surgery 
② ASA score (American society of anesthesiology) : class I - III 
③  agreement for informed consent after full explanation

① previous bariatric or metabolic surgery 
② malignancy in 5 years 
③ vulnerable study participiants 
④ paticipients for other studies within 3 months

rate of weight loss(%), rate of waist circumference (%)

postoperative 48 week

remission or improvement of type 2 diabetes, hypertension, hyperlipidemia, sleep apnea, polycystic ovary syndrome

postoperative 48 week

rate of morbidity and mortality

postoperative 48 week