title: The effect of intensive diabetes treatment on resting heart rate in type 1 diabetes: the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study.
abstract: OBJECTIVE
  Cardiovascular disease is a major cause of morbidity and mortality in individuals with type 1 diabetes. Resting heart rate (RHR) is a risk factor for cardiovascular disease in the general population, and case-control studies have reported a higher RHR in individuals with type 1 diabetes. In individuals with type 1 diabetes, there is a positive correlation between A1C and RHR; however, no prospective studies have examined whether a causal relationship exists between A1C and RHR. We hypothesized that intensive diabetes treatment aimed to achieve normal A1C levels has an effect on RHR in individuals with type 1 diabetes.
  
  
  METHODS
  A total of 1,441 individuals with type 1 diabetes who participated in the Diabetes Control and Complications Trial (DCCT) had their RHR measured biennially by an electrocardiogram during the DCCT and annually for 10 years during the Epidemiology of Diabetes Interventions and Complications (EDIC) follow-up study.
  
  
  RESULTS
  During the DCCT, intensive treatment was associated with lower mean RHR than conventional treatment, both in adolescents (69.0 vs. 72.0 bpm [95% CI 62.8-75.7 and 65.7-78.9, respectively], P = 0.013) and adults (66.8 vs. 68.2 [65.3-68.4 and 66.6-69.8, respectively], P = 0.0014). During follow-up in the EDIC, the difference in RHR between the treatment groups persisted for at least 10 years (P < 0.0001).
  
  
  CONCLUSIONS
  Compared with conventional therapy, intensive diabetes management is associated with lower RHR in type 1 diabetes. The lower RHR with intensive therapy may explain, in part, its effect in reducing cardiovascular disease, recently demonstrated in type 1 diabetes.
authors.affiliation: Program in Genetics and Genomic Biology, The Hospital for Sick Children, TMDT Building East Tower, Room 15-707, 101 College St., Toronto, ON M5G 1L7, Canada. andrew.paterson@utoronto.ca
authors.forename: Andrew D
authors.initials: AD
authors.lastname: Paterson
authors.forename: Brandy N
authors.initials: BN
authors.lastname: Rutledge
authors.forename: Patricia A
authors.initials: PA
authors.lastname: Cleary
authors.forename: John M
authors.initials: JM
authors.lastname: Lachin
authors.forename: Richard S
authors.initials: RS
authors.lastname: Crow
mesh_terms: D000293:Adolescent; D000328:Adult; D017668:Age of Onset; D003922:Diabetes Mellitus, Type 1 / Q000188:drug therapy / Q000503:physiopathology*; D003925:Diabetic Angiopathies / Q000517:prevention & control*; D004562:Electrocardiography; D005500:Follow-Up Studies; D006339:Heart Rate / Q000187:drug effects*; D006801:Humans; D016018:Least-Squares Analysis; D018579:Patient Selection