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Eighteen years of fair glycemic control preserves cardiac autonomic function in type 1 diabetes

Jakob R Larsen1, Hans Sjøholm, Tore J Berg

  • 1Diabetes Research Center, Aker and Ulleval University Hospitals, and Department of Pediatrics, Ulleval University Hospital, Oslo, Norway. j.r.larsen@ioks.uio.no

Diabetes Care
|March 30, 2004
PubMed

Insights

Maintaining a mean HbA1c below 8.4% over 18 years preserves cardiac autonomic function in type 1 diabetes patients. Higher HbA1c levels are linked to impaired cardiac autonomic function and dysfunction.

Area of Science:

  • Cardiology
  • Endocrinology
  • Diabetology

Background:

  • Type 1 diabetes management requires long-term glycemic control.
  • Cardiac autonomic neuropathy is a serious complication of diabetes.
  • The impact of sustained glycemic control on cardiac autonomic function needs further investigation.

Purpose of the Study:

  • To investigate the association between long-term mean HbA1c levels and cardiac autonomic function.
  • To assess cardiac autonomic function in type 1 diabetes patients after 18 years of intensive insulin treatment.

Main Methods:

  • A cohort of 39 type 1 diabetes patients was followed for 18 years with annual HbA1c measurements.
  • Cardiac autonomic function was assessed at 18-year follow-up using heart rate variability (HRV) and standard autonomic function tests.
  • Tests included deep breathing, Valsalva maneuver, tilt test, exercise ECG, and nocturnal heart rate monitoring.

Main Results:

  • Patients with mean HbA1c <8.4% demonstrated significantly better cardiac autonomic function across all tested parameters compared to those with HbA1c ≥8.4%.
  • Heart rate variability during deep breathing was 40% in the low HbA1c group versus 19.9% in the high HbA1c group (P=0.005).
  • The low HbA1c group exhibited a higher heart rate increase during maximal exercise (P=0.001) and lower minimal nocturnal heart rate (P=0.039).

Conclusions:

  • Sustained glycemic control, with a mean HbA1c below 8.4%, is associated with preserved cardiac autonomic function in type 1 diabetes.
  • Elevated mean HbA1c (≥8.4%) over 18 years is linked to impaired cardiac autonomic function and dysfunction.
  • Intensive insulin treatment aiming for lower HbA1c levels may protect against diabetic cardiac autonomic neuropathy.
Abstract

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