title: Relationship of baseline HbA1c, HbA1c change and HbA1c target of < 7% with insulin analogues in type 2 diabetes: a meta-analysis of randomised controlled trials.
abstract: OBJECTIVE
  We performed a meta-analysis of randomised controlled trials (RCTs) with insulin analogues in type 2 diabetes utilising a least-squared regression model in order to assess the relationship between baseline HbA1c, the magnitude of HbA1c decrease and attainment of HbA1c target of < 7%.
  
  
  METHODS
  Randomised controlled trials involving insulin regimens (basal, prandial, biphasic and basal-bolus) were identified through electronic searches (MEDLINE, EMBASE, CINAHL and The Cochrane Library) through September 2010. We included any study arm of RCTs if they were at least 12 weeks in duration; the number of patients in any arm was more than 30 and reported the baseline HbA1c and change from baseline HbA1c.
  
  
  RESULTS
  We found 87 studies, with a total of 135 arms, and 38,803 patients. The weighted R(2) values for the overall analysis assessing the association between baseline HbA1c and absolute change in HbA1c or the proportion of patients at target were 0.485 (p < 0.001) and 0.146 (p < 0.001), respectively. Subanalyses of insulin regimens for the association between basal HbA1c and absolute decrease of HbA1c produced weighted R(2), which were significant for all insulin regimens with the highest association for basal-bolus (R(2) = 0.719, p < 0.001).
  
  
  CONCLUSIONS
  The strong positive relationship between baseline HbA1c and the magnitude of HbA1c change we found in RCTs using insulin analogues in type 2 diabetes should be considered when assessing the clinical efficacy of insulin therapies.
authors.affiliation: Department of Geriatrics and Metabolic Diseases, Second University of Naples, Naples, Italy. dario.giugliano@unina2.it
authors.forename: D
authors.initials: D
authors.lastname: Giugliano
authors.forename: M
authors.initials: M
authors.lastname: Maiorino
authors.forename: G
authors.initials: G
authors.lastname: Bellastella
authors.forename: P
authors.initials: P
authors.lastname: Chiodini
authors.forename: K
authors.initials: K
authors.lastname: Esposito
mesh_terms: D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000188:drug therapy*; D006442:Glycated Hemoglobin / Q000378:metabolism*; D006801:Humans; D007004:Hypoglycemic Agents / Q000627:therapeutic use*; D007328:Insulin / Q000031:analogs & derivatives*; D016032:Randomized Controlled Trials as Topic; D012044:Regression Analysis; D016896:Treatment Outcome
chemical_list: D006442:Glycated Hemoglobin; D007004:Hypoglycemic Agents; D007328:Insulin