Curr Diab Rep (2015) 15:15 DOI 10.1007/s11892-015-0590-9
OBESITY (J MCCAFFERY, SECTION EDITOR)
Bariatric Surgery: Prevalence, Predictors, and Mechanisms of Diabetes Remission George Argyropoulos
# Springer Science+Business Media New York 2015
Abstract Type 2 diabetes is a chronic disease that can be treated with pharmacologic and/or lifestyle interventions, but in most cases it does not get cured. One of the few interventions, however, that can remit diabetes is the Roux-en-Y gastric bypass (RYGB) surgery. Approximately 63 % of patients undergoing RYGB surgery experience diabetes remission, but the underlying mechanisms are poorly understood. Some studies implicate enterohepatic pathways with bile acids, fibroblast growth factor 19 (FGF19), and glucagon-like peptide 1 (GLP-1) being the primary components. Here, we discuss these enterohepatic changes and highlight the roles of bile acids, FGF19, and GLP-1 in diabetes remission. We also describe how we can now actually predict, prior to surgery, the probability for remitting diabetes after RYGB surgery by using the DiaRem score. Deeper understanding of the mechanisms of diabetes remission by RYGB surgery could provide the basis for developing more effective interventions for curing the disease. Keywords Diabetes remission . RYGB . Bile acids . FGF19 . CYP7A1 . DiaRem score
Introduction Type 2 diabetes (BT2D^ or Bdiabetes^ herein) is a metabolic disease with significant health and socioeconomic implications [1]. In 2007, nearly 26 million people in the USA had diabetes, 7 million of whom were undiagnosed and unaware This article is part of the Topical Collection on Obesity G. Argyropoulos (*) Institute of Obesity, Geisinger Health System, 100 North Academy Avenue, Danville, PA 17822, USA e-mail: [email protected]
of their condition. In adults, with the age of 20 years and older, more than one in every ten people suffered from diabetes, and in seniors (65 years and older), that figure increased to more than one in every four people. Many of the risk factors for T2D are influenced by lifestyle decisions, and thus could be eliminated or reduced with time and effort. Cases of diagnosed diabetes cost the USA an estimated $174 billion in 2007, or roughly 10 % of the total health care costs, a figure that is expected to rise with the increasing number of diagnosed individuals [2]. The above figures were indeed revised upwards in the National Diabetes Statistics Report for 2014 with 29.1 million (9.3 %) of the U.S. population having diabetes of whom 8.1 million (27.8 %) were undiagnosed [3]. This trend provides evidence that the incidence of diabetes worldwide is in the increase and possible will continue to rise, as also predicted by others [1]. Diabetes, overall, presents an enormous health challenge. Bariatric surgery, and in particular Roux-en-Y gastric bypass (RYGB) surgery, appears to be the most effective intervention available today for not just treating diabetes but rather rendering the disease into long-term remission. Here, the effects of bariatric surgery, and in particular Roux-en-Y gastric bypass (RYGB), on diabetes remission will be discussed along with our current understanding of the underlying mechanism. The underlying mechanisms of other bariatric approaches (e.g., sleeve gastrectomy and lap band) that also improve insulin sensitivity to various degrees will not be discussed here due to space limitations. Definitions of Diabetes and Diabetes Remission Consistent definitions of diabetes and diabetes remission help to avoid variations across studies. The American Diabetes Association (ADA) has established definitions for both diabetes and diabetes remission after bariatric surgery. Diabetes is defined by fasting glucose>126 mg/dL (7.0 mmol/L) or
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HbA1c>6.5 % [4]. Prediabetes is the condition that precedes full scale diabetes and is defined by fasting glucose between 100 and 125 mg/dL (6.9 mmol/L) or by HbA1c levels between 5.7 and 6.4 %. Values of fasting glucose below 100 mg/dL (5.6 mmol/L) or HbA1c below 5.7 % indicate the absence of diabetes or prediabetes. The definition of diabetes remission refers to two categories described as Bpartial^ or Bcomplete^ remission [5]. For partial remission, fasting blood glucose levels are 100– 125 mg/dL (5.6–6.9 mmol/L) and HbA1c levels are
OBESITY (J MCCAFFERY, SECTION EDITOR)
Bariatric Surgery: Prevalence, Predictors, and Mechanisms of Diabetes Remission George Argyropoulos
# Springer Science+Business Media New York 2015
Abstract Type 2 diabetes is a chronic disease that can be treated with pharmacologic and/or lifestyle interventions, but in most cases it does not get cured. One of the few interventions, however, that can remit diabetes is the Roux-en-Y gastric bypass (RYGB) surgery. Approximately 63 % of patients undergoing RYGB surgery experience diabetes remission, but the underlying mechanisms are poorly understood. Some studies implicate enterohepatic pathways with bile acids, fibroblast growth factor 19 (FGF19), and glucagon-like peptide 1 (GLP-1) being the primary components. Here, we discuss these enterohepatic changes and highlight the roles of bile acids, FGF19, and GLP-1 in diabetes remission. We also describe how we can now actually predict, prior to surgery, the probability for remitting diabetes after RYGB surgery by using the DiaRem score. Deeper understanding of the mechanisms of diabetes remission by RYGB surgery could provide the basis for developing more effective interventions for curing the disease. Keywords Diabetes remission . RYGB . Bile acids . FGF19 . CYP7A1 . DiaRem score
Introduction Type 2 diabetes (BT2D^ or Bdiabetes^ herein) is a metabolic disease with significant health and socioeconomic implications [1]. In 2007, nearly 26 million people in the USA had diabetes, 7 million of whom were undiagnosed and unaware This article is part of the Topical Collection on Obesity G. Argyropoulos (*) Institute of Obesity, Geisinger Health System, 100 North Academy Avenue, Danville, PA 17822, USA e-mail: [email protected]
of their condition. In adults, with the age of 20 years and older, more than one in every ten people suffered from diabetes, and in seniors (65 years and older), that figure increased to more than one in every four people. Many of the risk factors for T2D are influenced by lifestyle decisions, and thus could be eliminated or reduced with time and effort. Cases of diagnosed diabetes cost the USA an estimated $174 billion in 2007, or roughly 10 % of the total health care costs, a figure that is expected to rise with the increasing number of diagnosed individuals [2]. The above figures were indeed revised upwards in the National Diabetes Statistics Report for 2014 with 29.1 million (9.3 %) of the U.S. population having diabetes of whom 8.1 million (27.8 %) were undiagnosed [3]. This trend provides evidence that the incidence of diabetes worldwide is in the increase and possible will continue to rise, as also predicted by others [1]. Diabetes, overall, presents an enormous health challenge. Bariatric surgery, and in particular Roux-en-Y gastric bypass (RYGB) surgery, appears to be the most effective intervention available today for not just treating diabetes but rather rendering the disease into long-term remission. Here, the effects of bariatric surgery, and in particular Roux-en-Y gastric bypass (RYGB), on diabetes remission will be discussed along with our current understanding of the underlying mechanism. The underlying mechanisms of other bariatric approaches (e.g., sleeve gastrectomy and lap band) that also improve insulin sensitivity to various degrees will not be discussed here due to space limitations. Definitions of Diabetes and Diabetes Remission Consistent definitions of diabetes and diabetes remission help to avoid variations across studies. The American Diabetes Association (ADA) has established definitions for both diabetes and diabetes remission after bariatric surgery. Diabetes is defined by fasting glucose>126 mg/dL (7.0 mmol/L) or
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HbA1c>6.5 % [4]. Prediabetes is the condition that precedes full scale diabetes and is defined by fasting glucose between 100 and 125 mg/dL (6.9 mmol/L) or by HbA1c levels between 5.7 and 6.4 %. Values of fasting glucose below 100 mg/dL (5.6 mmol/L) or HbA1c below 5.7 % indicate the absence of diabetes or prediabetes. The definition of diabetes remission refers to two categories described as Bpartial^ or Bcomplete^ remission [5]. For partial remission, fasting blood glucose levels are 100– 125 mg/dL (5.6–6.9 mmol/L) and HbA1c levels are
