title: Glycemic control and all-cause mortality risk in type 1 diabetes patients: the EURODIAB prospective complications study.
abstract: BACKGROUND
  Glycemic targets and the benefit of intensive glucose control are currently under debate because intensive glycemic control has been suggested to have negative effects on mortality risk in type 2 diabetes patients.
  
  
  OBJECTIVE
  We examined the association between glycated hemoglobin (HbA1c) and all-cause mortality in patients with type 1 diabetes mellitus.
  
  
  METHODS
  A clinic-based prospective cohort study was performed in 2764 European patients with type 1 diabetes aged 15-60 years enrolled in the EURODIAB Prospective Complications Study.
  
  
  METHODS
  Possible nonlinearity of the association between HbA1c and all-cause mortality was examined using multivariable restricted cubic spline regression using three (at HbA1c 5.6%, 8.1%, and 11.8%) and five knots (additionally at HbA1c 7.1% and 9.5%). Mortality data were collected approximately 7 years after baseline examination.
  
  
  RESULTS
  HbA1c was related to all-cause mortality in a nonlinear manner after adjustment for age and sex. All-cause mortality risk was increased at both low (5.6%) and high (11.8%) HbA1c compared with the reference (median HbA1c: 8.1%) following a U-shaped association [P overall effect = .008 and .04, P nonlinearity = .03 and .11 (three and five knots, respectively)].
  
  
  CONCLUSIONS
  Results from our study in type 1 diabetes patients suggest that target HbA1c below a certain threshold may not be appropriate in this population. We recognize that these low HbA1c levels may be related to anemia, renal insufficiency, infection, or other factors not available in our database. If our data are confirmed, the potential mechanisms underlying this increased mortality risk among those with low HbA1c will need further study.
authors.affiliation: School of Population Health (D.A.J.M.S.), University of Queensland, Brisbane, 4006 Queensland, Australia; Department of Diabetes, la Pitié Hospital and University Pierre et Marie Curie, 75013 Paris, France; INSERM CESP (D.S.), U-1018, 94805 Villejuif, France; National Heart and Lung Institute (N.C.), Imperial College London, London W2 1PG, United Kingdom; Department of Epidemiology and Public Health (J.H.F.), University College London, London WC1E 6BT, United Kingdom; and Division of Human Nutrition (S.S.S.-M.), Wageningen University, 6700 EV Wageningen, The Netherlands.
authors.forename: Danielle A J M
authors.initials: DA
authors.lastname: Schoenaker
authors.forename: Dominique
authors.initials: D
authors.lastname: Simon
authors.forename: Nish
authors.initials: N
authors.lastname: Chaturvedi
authors.forename: John H
authors.initials: JH
authors.lastname: Fuller
authors.forename: Sabita S
authors.initials: SS
authors.lastname: Soedamah-Muthu
mesh_terms: D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000187:drug effects*; D002423:Cause of Death; D015331:Cohort Studies; D003922:Diabetes Mellitus, Type 1 / Q000097:blood / Q000150:complications* / Q000401:mortality*; D005060:Europe / Q000453:epidemiology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016019:Survival Analysis; D055815:Young Adult
chemical_list: D001786:Blood Glucose