Coronary Calcium Score Predicts Cardiovascular Mortality in Diabetes

Diabetes Heart Study

  1. Donald W. Bowden, PHD2,7
  1. 1Department of Cardiology, Oakwood Hospital and Medical Center, Dearborn, Michigan
  2. 2Centers for Diabetes Research and Human Genomics, Wake Forest School of Medicine, Winston-Salem, North Carolina
  3. 3Department of Internal Medicine, Section of Cardiology, Wake Forest School of Medicine, Winston-Salem, North Carolina
  4. 4Department of Biostatistics, University of Washington, Seattle, Washington
  5. 5Department of Internal Medicine, Section of Nephrology, Wake Forest School of Medicine, Winston-Salem, North Carolina
  6. 6Departments of Radiology, Public Health, and Translational Science, Wake Forest School of Medicine, Winston-Salem, North Carolina
  7. 7Department of Biochemistry and Internal Medicine, Wake Forest School of Medicine, Winston-Salem, North Carolina
  1. Corresponding author: Donald W. Bowden, dbowden{at}wakehealth.edu.

Abstract

OBJECTIVE In type 2 diabetes mellitus (T2DM), it remains unclear whether coronary artery calcium (CAC) provides additional information about cardiovascular disease (CVD) mortality beyond the Framingham Risk Score (FRS) factors.

RESEARCH DESIGN AND METHODS A total of 1,123 T2DM participants, ages 34–86 years, in the Diabetes Heart Study followed up for an average of 7.4 years were separated using baseline computed tomography scans of CAC (0–9, 10–99, 100–299, 300–999, and ≥1,000). Logistic regression was performed to examine the association between CAC and CVD mortality adjusting for FRS. Areas under the curve (AUC) with and without CAC were compared. Net reclassification improvement (NRI) compared FRS (model 1) versus FRS+CAC (model 2) using 7.4-year CVD mortality risk categories 0% to <7%, 7% to <20%, and ≥20%.

RESULTS Overall, 8% of participants died of cardiovascular causes during follow-up. In multivariate analysis, the odds ratios (95% CI) for CVD mortality using CAC 0–9 as the reference group were, CAC 10–99: 2.93 (0.74–19.55); CAC 100–299: 3.17 (0.70–22.22); CAC 300–999: 4.41(1.15–29.00); and CAC ≥1,000: 11.23 (3.24–71.00). AUC (95% CI) without CAC was 0.70 (0.67–0.73), AUC with CAC was 0.75 (0.72–0.78), and NRI was 0.13 (0.07–0.19).

CONCLUSIONS In T2DM, CAC predicts CVD mortality and meaningfully reclassifies participants, suggesting clinical utility as a risk stratification tool in a population already at increased CVD risk.

  • Received August 1, 2012.
  • Accepted September 13, 2012.

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  1. Diabetes Care
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