title: HbA1c below 7% as the goal of glucose control fails to maximize the cardiovascular benefits: a meta-analysis.
abstract: OBJECTIVE
  Whether lowering glycosylated haemoglobin (HbA1c) level below 7.0% improves macro-vascular outcomes in diabetes remains unclear. Here, we aimed to assess the effect of relatively tight glucose control resulting in a follow-up HbA1c level of less or more than 7.0% on cardiovascular outcomes in diabetic patients.
  
  
  METHODS
  We systematically searched Medline, Web of science and Cochrane Library for prospective randomized controlled trials published between Jan 1, 1996 and July 1, 2015 that recorded cardiovascular outcome trials of glucose-lowering drugs or strategies in patients with type 2 diabetes mellitus.
  
  
  RESULTS
  Data from 15 studies involving 88,266 diabetic patients with 4142 events of non-fatal myocardial infarction, 6997 of major cardiovascular events, 3517 of heart failure, 6849 of all-cause mortality, 2084 of non-fatal stroke, 3816 of cardiovascular death were included. A 7% reduction of major cardiovascular events was observed only when relatively tight glucose control resulted in a follow-up HbA1c level above 7.0% (OR 0.93, 95% CI 0.88-0.98; I(2) = 33%), however, the patients can benefit from reduction incidence of non-fatal myocardial infarction only when the follow-up HbA1c value below 7.0% (OR 0.85, 95% CI 0.74-0.96). Apart from the HbA1c value above 7.0% (OR 1.22, 95% CI 1.06-1.40), the application of thiazolidinediones (OR 1.39, 95% CI 1.14-1.69) also increased the risk of heart failure, while the gliptins shows neutral effects to heart failure (OR 1.14, 95% CI 0.97-1.34).
  
  
  CONCLUSIONS
  Relatively tight glucose control has some cardiovascular benefits. HbA1c below 7.0% as the goal to maximize the cardiovascular benefits remains suspended.
authors.affiliation: Department of Endocrinology, Affiliated ZhongDa Hospital of Southeast University, No. 87 DingJiaQiao Road, Nanjing, 210009, People's Republic of China. wangpin542@126.com.|Department of Endocrinology, Sichuan Academy of Medical Science and Sichuan Provincial People's Hospital, East District, No. 32, Section 2, 1st Ring Road (West), Chengdu, 610072, Sichuan, People's Republic of China. wangpin542@126.com.
authors.forename: Pin
authors.initials: P
authors.lastname: Wang
authors.affiliation: Department of Endocrinology, Affiliated ZhongDa Hospital of Southeast University, No. 87 DingJiaQiao Road, Nanjing, 210009, People's Republic of China. huangrong0914@yeah.net.
authors.forename: Rong
authors.initials: R
authors.lastname: Huang
authors.affiliation: Department of Intensive Care Unit, Sichuan Academy of Medical Science and Sichuan Provincial People's Hospital, No. 32, Section 2, 1st Ring Road (West), Chengdu, 610072, Sichuan, People's Republic of China. lu.sen.cool@163.com.
authors.forename: Sen
authors.initials: S
authors.lastname: Lu
authors.affiliation: Department of Endocrinology, Affiliated ZhongDa Hospital of Southeast University, No. 87 DingJiaQiao Road, Nanjing, 210009, People's Republic of China. wen_qing_xia@126.com.
authors.forename: Wenqing
authors.initials: W
authors.lastname: Xia
authors.affiliation: Department of Endocrinology, Affiliated ZhongDa Hospital of Southeast University, No. 87 DingJiaQiao Road, Nanjing, 210009, People's Republic of China. sunshine_9092@163.com.
authors.forename: Haixia
authors.initials: H
authors.lastname: Sun
authors.affiliation: Department of Endocrinology, Affiliated ZhongDa Hospital of Southeast University, No. 87 DingJiaQiao Road, Nanjing, 210009, People's Republic of China. jie_sun19890321@163.com.
authors.forename: Jie
authors.initials: J
authors.lastname: Sun
authors.affiliation: Department of Endocrinology, Affiliated ZhongDa Hospital of Southeast University, No. 87 DingJiaQiao Road, Nanjing, 210009, People's Republic of China. rongrong19900710@163.com.
authors.forename: Rongrong
authors.initials: R
authors.lastname: Cai
authors.affiliation: Department of Endocrinology, Affiliated ZhongDa Hospital of Southeast University, No. 87 DingJiaQiao Road, Nanjing, 210009, People's Republic of China. gyjwsh@163.com.
authors.forename: Shaohua
authors.initials: S
authors.lastname: Wang
mesh_terms: D002318:Cardiovascular Diseases / Q000453:epidemiology* / Q000401:mortality; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy* / Q000378:metabolism; D054873:Dipeptidyl-Peptidase IV Inhibitors / Q000627:therapeutic use; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006333:Heart Failure / Q000453:epidemiology; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D009203:Myocardial Infarction / Q000453:epidemiology; D045162:Thiazolidinediones / Q000627:therapeutic use
chemical_list: D054873:Dipeptidyl-Peptidase IV Inhibitors; D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D045162:Thiazolidinediones; C517652:hemoglobin A1c protein, human