title: A prospective evaluation of the influence of three bariatric procedures on insulin resistance improvement. Should the extent of undiluted bile transit be considered a key postoperative factor altering glucose metabolism?
abstract: BACKGROUND
  Insulin resistance (IR), the essential step in development of type 2 diabetes mellitus (T2DM), resolves quickly after bariatric surgery, but the effectiveness depends on the type of the procedure. Although the long-term influence on IR improvement is well documented, the mechanisms of the ultra-fast response after restrictive and bypass procedures require explanation.
  
  
  OBJECTIVE
  To determine IR evolution from the initial preparative period to 6 months after the operation, exposing the rapid postoperative response while comparing the 3 bariatric methods, with the belief that the metabolic effect may be correlated with anatomical combinations.
  
  
  METHODS
  From January to December, 2013, a cohort of severely obese, insulin resistant individuals recruited to the prospective study underwent laparoscopic sleeve gastrectomy (SG-30), Roux-en-Y gastric bypass (RYGB-30) and one-anastomosis gastric bypass (OAGB-30). Main laboratory parameters of glucose metabolism were evaluated in fasting patients preoperatively, 4 days and 1, 3 and 6 months after surgery.
  
  
  RESULTS
  Within the whole observation period the most significant improvement in homeostasis model assessment for IR (HOMA-IR) was observed in the first 4 days after each operation. The decrease of HOMA-IR was higher (p < 0.0001) in gastric bypass groups than in patients after SG (-41%). The difference between bypass groups favors OAGB over RYGB (63 vs. -56%, p = 0.0489).
  
  
  CONCLUSIONS
  Among all bariatric management factors, operation type is the most important in IR improvement. The significant difference in response after SG vs. RYGB and OAGB supports the concept of metabolic competence of duodeno-jejunal exclusion. Altered bile flow after duodeno-jejunal exclusion may be responsible for enhanced glucose metabolism improvement.
authors.affiliation: Department of General, Endocrine and Transplant Surgery, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Łukasz
authors.initials: Ł
authors.lastname: Kaska
authors.affiliation: Department of General, Endocrine and Transplant Surgery, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Monika
authors.initials: M
authors.lastname: Proczko
authors.affiliation: Department of General, Endocrine and Transplant Surgery, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Piotr
authors.initials: P
authors.lastname: Wiśniewski
authors.affiliation: Department of Clinical Nutrition, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Marta
authors.initials: M
authors.lastname: Stankiewicz
authors.affiliation: Department of General, Endocrine and Transplant Surgery, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Derek
authors.initials: D
authors.lastname: Gill
authors.affiliation: Department of General, Endocrine and Transplant Surgery, Medical University of Gdansk, Gdansk, Poland.
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Śledziński
keywords: Roux-en-Y gastric bypass; homeostasis model assessment for insulin resistance; insulin resistance; one-anastomosis gastric bypass; role of bile; sleeve gastrectomy; type 2 diabetes mellitus