Changes in A1C Levels Are Significantly Associated With Changes in Levels of the Cardiovascular Risk Biomarker hs-CRP

Results from SteP Study

  1. William H. Polonsky, PHD7
  1. 1Forschergruppe Diabetes e.V., Helmholtz Center Munich, Munich, Germany
  2. 2Roche Diagnostics Deutschland GmbH, Mannheim, Germany
  3. 3Biostat International, Inc., Tampa, Florida
  4. 4Institute of Medical Biometry and Informatics, University of Heidelberg, Heidelberg, Germany
  5. 5CGParkin Communications, Inc., Boulder City, Nevada
  6. 6Diabetes Center, University of California, San Francisco, San Francisco, California
  7. 7Department of Psychiatry, University of California, San Diego, San Diego, California
  1. Corresponding author: Oliver Schnell, oliver.schnell{at}lrz.uni-muenchen.de.

Abstract

OBJECTIVE The effect of therapeutic strategies on cardiovascular (CV) disease can be evaluated by monitoring changes in CV risk biomarkers. This study investigated the effect of a structured self-monitoring of blood glucose (SMBG) protocol and the resulting improvements in glycemic control on changes in high-sensitivity C-reactive protein (hs-CRP) in insulin-naïve patients with type 2 diabetes.

RESEARCH DESIGN AND METHODS The Structured Testing Program (STeP) study was a prospective, cluster-randomized, multicenter trial in which 483 poorly controlled, insulin-naïve patients with type 2 diabetes were randomized to active control (ACG) or structured testing (STG) that included quarterly structured SMBG. Changes in A1C, hs-CRP, and glycemic variability (STG subjects only) were measured at baseline and quarterly.

RESULTS Reductions in geometric mean hs-CRP values were significantly greater in the STG group at months 3 (P = 0.005), 6 (P = 0.0003), and 12 (P = 0.04) than in the ACG group. STG patients at high CV risk (>3 mg/L) showed significantly greater reductions in hs-CRP levels than ACG patients at high CV risk: −3.64 mg/dL (95% CI −4.21 to −3.06) versus −2.18 mg/dL (−2.93 to −1.43), respectively (P = 0.002). There was a strong correlation between reductions in hs-CRP and A1C in both groups: standardized coefficient (β) was 0.25 for the entire cohort (P < 0.0001), 0.31 for STG (P < 0.0001), and 0.16 for ACG (P = 0.02).

CONCLUSIONS Reductions in hs-CRP level are associated with reductions in A1C but not reductions in lipids or glycemic variability. Comprehensive structured SMBG-based interventions that lower A1C may translate into improvements in CV risk, as evidenced by levels of the biomarker hs-CRP.

  • Received August 23, 2012.
  • Accepted November 19, 2012.

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  1. Diabetes Care
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