Fasting blood glucose in the nondiabetic range is a continuous and graded risk factor for CHD

Asymmetric dimethylarginine, cortisol/cortisone ratio, and C-peptide: markers for diabetes and cardiovascular risk?

BACKGROUND

Diabetes and prediabetic conditions are growing cardiovascular risk factors. Better understanding and earlier recognition and treatment of dysglycemia-related risk are health priorities. We assessed the predictive value of 3 proposed new markers for diabetes and cardiovascular risk. We tested whether the plasma levels of (1) asymmetric dimethylarginine (ADMA), (2) cortisol/cortisone (Cl/Cn) ratio, and (3) C-peptide predicted glycemic status, coronary artery disease, and death or myocardial infarction (MI) in a nested case-control cohort (N = 850) with normal fasting glucose (< 110 mg/dL), impaired fasting glucose (110-125), or diabetic (> or = 126) status.

METHODS

High-sensitivity C-reactive protein (hsCRP) served as a control risk marker. Follow-up averaged 2.6 +/- 1.4 years. High-pressure liquid chromatography with pre-column derivitization and fluorescence was used to assay ADMA, liquid chromatography/tandem mass spectrometry for Cl and Cn, and chemiluminescent immunoassay for C-peptide.

RESULTS

Asymmetric dimethylarginine levels were positively associated with glycemic category (P < .001). Quartiles 2 to 4 ADMA also conferred increased risk of death/MI independent of hsCRP and other risk factors (adjusted hazard ratio, 2.1; P = .002). Cortisol/Cortisone ratios (P = .013) and C-peptide (P = .047) were associated with glycemic categories but less strongly than ADMA. Quartiles 2 to 4 Cl/Cn were protective against incident death/MI (adjusted hazard ratio, 0.48; P < .001), whereas C-peptide did not predict outcomes.

CONCLUSIONS

Among a high coronary risk case-control cohort, ADMA (strongly), Cl/Cn (moderately), and C-peptide (weakly) predicted glycemic categories. Asymmetric dimethylarginine and Cl/Cn also predicted clinical outcome independent of and more strongly than hsCRP. Asymmetric dimethylarginine and Cl/Cn represent promising new candidate markers of dysglycemia and associated cardiovascular risk.

Effect of fasting glucose levels on mortality rate in patients with and without diabetes mellitus and coronary artery disease undergoing percutaneous coronary intervention

BACKGROUND

Diabetes mellitus (DM) is predictive of increased mortality for patients with coronary artery disease (CAD). To what extent this risk extends below the diabetic threshold (fasting glucose level [FG] <126 mg/dL) is uncertain.

METHODS

The study objective was to determine the risk associated with FG in a prospectively assembled cohort of 1612 patients with CAD who were undergoing percutaneous coronary intervention (PCI) and had a FG measured or a clinical diagnosis of DM (CDM). Patients were grouped as: CDM; no CDM, but FG > or =126 mg/dL (ADA-DM); impaired FG, 110-125 mg/dL (IFG); or normal FG, <110 mg/dL (NFG). Survival was assessed for 2.8 +/- 1.2 years.

RESULTS

The average patient age was 62 +/- 12 years; 74% of the patients were men. Diagnostic frequencies were: CDM, 24%; ADA-DM, 18%; IFG, 19%; and NFG, 39%. Mortality rates were greater for patients in the CDM (44/394 [11.2%], P <.0001), ADA-DM (27/283 [9.5%], P <.001), and IFG (20/305 [6.6%], P =.04) groups than patients in the NFG group(12/630 [1.9%]). Independent receiver operating characteristic analysis chose FG > or =109 mg/dL as the best cutoff for increased risk (sensitivity, 81%; specificity, 51%). After adjustment with Cox regression analysis, CDM (hazard ratio [HR] = 5.0; 95% CI, 2.6-9.6; P <.001), ADA-DM (HR, 4.1; 95% CI, 2.1-8.2; P <.001), and IFG status (HR, 3.2; 95% CI, 1.5-6.5; P =.002) remained independent predictors of mortality.

CONCLUSIONS

Prognostically significant abnormalities of FG are much more prevalent (61%) than expected in patients with CAD who are undergoing PCI. Despite revascularization, the associated mortality risk of even mild elevations in FG is substantial, emphasizing the importance of early detection and treatment of glycemia-related risk.