title: Body Mass Index-Related Mortality in Patients with Type 2 Diabetes and Heterogeneity in Obesity Paradox Studies: A Dose-Response Meta-Analysis.
abstract: OBJECTIVE
  We conducted a systematic review and meta-analysis of studies to quantify the association between body mass index (BMI) and the risks of all-cause and cardiovascular mortality in patients with type 2 diabetes.
  
  
  METHODS
  We included studies assessing the impact of BMI on all-cause and cardiovascular mortality in patients with type 2 diabetes. Data were combined using a random-effects dose-response model.
  
  
  RESULTS
  Sixteen cohort studies on all-cause mortality (n = 445,125) and two studies on cardiovascular mortality (n = 92,841) were evaluated in the meta-analysis. A non-linear association was observed between BMI and all-cause mortality among patients with type 2 diabetes. With a BMI nadir of 28-30 kg/m2, the risk of all-cause mortality displayed a U-shaped increase. With a BMI nadir of 29-31 kg/m2, the risk of cardiovascular mortality exhibited a gradual non-linear increase for BMI > 31 kg/m2. Subgroup analyses suggested that study location, diabetes duration, and smoking history may have contributed to heterogeneity among the studies.
  
  
  CONCLUSIONS
  An obesity paradox exists for patients with type 2 diabetes with respect to all-cause and cardiovascular mortality. Study location, diabetes duration, and smoking history might contribute to heterogeneity among obesity paradox studies of patients with type 2 diabetes.
authors.affiliation: Department of Family Medicine, Korea University College of Medicine, Seoul, South Korea.|Center for Obesity and Metabolic Diseases, Korea University Anam Hospital, Seoul, South Korea.
authors.forename: Yeongkeun
authors.initials: Y
authors.lastname: Kwon
authors.affiliation: Institute for Evidence-based Medicine, The Korean Branch of Australasian Cochrane Center, Department of Preventive Medicine, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Hyun Jung
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Center for Obesity and Metabolic Diseases, Korea University Anam Hospital, Seoul, South Korea.|Division of Upper Gastrointestinal Surgery, Department of Surgery, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Sungsoo
authors.initials: S
authors.lastname: Park
authors.affiliation: Department of Biostatistics, The Catholic University of Korea College of Medicine, Seoul, South Korea.
authors.forename: Yong-Gyu
authors.initials: YG
authors.lastname: Park
authors.affiliation: Department of Family Medicine, Korea University College of Medicine, Seoul, South Korea.
authors.forename: Kyung-Hwan
authors.initials: KH
authors.lastname: Cho
mesh_terms: D000368:Aged; D000465:Algorithms; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000209:etiology; D002423:Cause of Death; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000150:complications / Q000401:mortality*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D015233:Models, Statistical; D009765:Obesity / Q000150:complications / Q000401:mortality*; D011785:Quality Assurance, Health Care; D012107:Research Design; D012307:Risk Factors