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Hemoglobin A1c level and future cardiovascular events among women

Gavin J Blake1, Aruna D Pradhan, JoAnn E Manson

  • 1Cardiovascular Division, the Center for Cardiovascular Disease Prevention, and the Division of Preventive Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Mass, USA. blake_gj@yahoo.com

Archives of Internal Medicine
|April 14, 2004
PubMed

Insights

Hemoglobin A1c (HbA1c) levels correlate with cardiovascular risk in women without diabetes, but this association is mainly due to other risk factors. Diabetes mellitus itself is a significant independent predictor of cardiovascular events.

Area of Science:

  • Cardiology
  • Endocrinology
  • Preventive Medicine

Background:

  • Hemoglobin A1c (HbA1c) levels, a measure of blood glucose control, are being investigated for their role in cardiovascular risk.
  • Previous data suggest a link between HbA1c and cardiovascular disease (CVD) in the general population, but prospective data in women without diabetes are limited.

Purpose of the Study:

  • To prospectively evaluate the association between HbA1c levels and incident cardiovascular events in women without pre-existing cardiovascular disease or diabetes mellitus.

Main Methods:

  • A nested case-control study was conducted within the Women's Health Study cohort.
  • 464 women with incident myocardial infarction, stroke, or coronary revascularization were matched with 928 controls free of cardiovascular events.
  • Follow-up averaged 7 years.

Main Results:

  • Among women without diabetes or elevated baseline HbA1c, higher HbA1c levels were significantly associated with increased future cardiovascular events (crude RR 2.25 for highest vs. lowest quartile).
  • This association was attenuated and became non-significant after adjusting for other cardiovascular risk factors.
  • In contrast, diabetes mellitus remained a strong independent predictor of cardiovascular risk, irrespective of HbA1c levels.

Conclusions:

  • HbA1c is associated with future cardiovascular risk in women without diabetes, but this is largely explained by its correlation with other risk factors.
  • Diabetes mellitus is a potent independent determinant of cardiovascular risk, even when HbA1c levels are considered.
Abstract

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