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Relationship of hemoglobin A1C and mortality in heart failure patients with diabetes

David Aguilar1, Biykem Bozkurt, Kumudha Ramasubbu

  • 1Winters Center for Heart Failure Research and Section of Cardiology, Department of Medicine, Baylor College of Medicine, 1709 Dryden Street-BCM 620, Suite 500, Box 13, Houston, Texas 77030, USA. daguilar@bcm.edu

Journal of the American College of Cardiology
|July 25, 2009
PubMed

Insights

Glycosylated hemoglobin (HbA1C) levels show a U-shaped association with mortality in diabetic patients with heart failure (HF). Optimal outcomes were observed with modest glucose control, suggesting a need for personalized treatment goals.

Area of Science:

  • Cardiology
  • Endocrinology
  • Geriatrics

Background:

  • Diabetes mellitus and heart failure (HF) frequently coexist.
  • Previous research on the association between glycosylated hemoglobin (HbA1C) and adverse outcomes in diabetic patients with HF has yielded inconsistent results.
  • This study addresses the limited and conflicting data by examining HbA1C's impact on mortality and HF hospitalizations.

Purpose of the Study:

  • To investigate the relationship between glycosylated hemoglobin (HbA1C) levels and adverse clinical outcomes in a cohort of diabetic patients with established heart failure (HF).
  • To determine if specific HbA1C ranges are associated with increased risk of death or HF hospitalization.
  • To identify potential optimal glycemic control targets for patients with both diabetes and HF.

Main Methods:

  • A retrospective analysis was conducted on a national cohort of 5,815 veterans diagnosed with both HF and diabetes.
  • Patients were stratified into quintiles (Q1-Q5) based on their HbA1C levels.
  • The study assessed the association between HbA1C quintiles and the risk of all-cause mortality and HF hospitalization over a 2-year follow-up period, with adjustments for confounders.

Main Results:

  • Mortality rates at 2 years showed a U-shaped pattern across HbA1C quintiles: Q1 (≤6.4%) 25%, Q2 (6.4%-7.1%) 23%, Q3 (7.1%-7.8%) 17.7%, Q4 (7.8%-9.0%) 22.5%, and Q5 (>9.0%) 23.2%.
  • The middle quintile (Q3, HbA1C 7.1%-7.8%) demonstrated significantly reduced mortality compared to the lowest quintile (Q1) after adjusting for confounders (aHR: 0.73; 95% CI: 0.61-0.88; p=0.001).
  • HF hospitalization rates increased with higher HbA1C quintiles, but this trend was not statistically significant after adjusting for confounders.

Conclusions:

  • The association between HbA1C and mortality in diabetic patients with HF exhibits a U-shaped curve.
  • The lowest risk of death was observed in patients with modest glycemic control, specifically HbA1C levels between 7.1% and 7.8%.
  • Further prospective research is warranted to establish precise optimal glycemic control targets for this patient population.
Abstract

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