This is prospective cohort study. Total 400 obese patients will be enrolled(Sleeve gastrectomy 200 patients, Roux-en-Y gastric bypass 200)~The principal investigator or another clinical investigator in charge will individually inform the patients about the study, before operation at out patient clinic. At that time patient is selected to either sleeve gastrectomy group or Roux-en-Y gastric bypass group. All investigator report to clinical research center about patients BMI and operation method.~About 30-35 obesity patients will be enrolled according to their BMI status. Patients' BMI status is classified into several parts by 2.5 gap started from 27.5.~All patients will undergo periodically anthropometry, laboratory tests, bioelectrical impedance analysis, gastrofiberscopy, polysomnography and abdomen CT before and after surgery.~Patients with hypertension will undergo echocardiography. Patients with polycystic ovary syndrome will be checked hormonal study. Patients with type 2 diabetes mellitus will be performed 75g oral glucose tolerance test test.~Surgical complication include wound morbidities, gastrointestinal leakage or fistula, postoperative bleeding, intra-abdominal abscess, stricture , adhesive ileus, reflux esophagitis, marginal ulceration, dumping syndrome and internal hernia.~Systemic complication which is not associated with the operation field include ling morbidities, heart morbidities, urinary morbidities and others.~Hospital mortality is defined as postoperative death form any cause within 30 days after operation.~All patients will be followed up post operative 1 month, 3 month, 6 month, 12 month, 18 month, 24 month.~All patients' liver tissue, visceral fat and subcutaneous fat will be harvested during operation.~All patients' blood sample will be collected at out patient clinic visit. All patients' urine and face will be collected at out patient clinic visit and will be analyzed to evaluate microbial change throughout pre and post operation period.
Prospective, double-arm, multi-center cohort study on obese patients, for laparoscopic sleeve gastrectomy versus Roux-en Y gastric bypass