Biomedical subjects
Publications and source records attributed to Jeffrey L Anderson.
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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.
Although previous studies have demonstrated that various "statins" decrease levels of high-sensitivity C-reactive protein (hs-CRP), the dose-response relation for lowering hs-CRP by the clinically important drug simvastatin compared with lipid lowering is unclear. A 16-week, randomized, double-blind study was performed in patients with stable coronary artery disease and high hs-CRP levels (>3 mg/L). Subjects were randomized to placebo, 20 mg of simvastatin, or 80 mg of simvastatin for 12 weeks. Those currently on a statin first underwent a 4-week washout. Of the 107 total patients randomized, 96 completed the trial, and 89 were able to be evaluated for efficacy. Changes in hs-CRP differed across simvastatin and placebo groups (change score +1.6 vs -0.6 mg/L, p = 0.004), but no dose response was observed when comparing 80 with 20 mg/day (-0.6 vs -0.5 mg/L, respectively). A strong dose response was observed for changes in total (p <0.01) and low-density lipoprotein (p <0.001) cholesterol. hs-CRP changes did not correlate with low-density lipoprotein changes. In conclusion, this randomized trial in patients with chronic stable coronary artery disease showed a strong dose response for simvastatin for total and low-density lipoprotein cholesterol lowering but not for hs-CRP.
The complete blood cell (CBC) count is an inexpensive, frequently obtained blood test whose information content is potentially underused. We examined the predictive ability of the CBC count for incident death in 29,526 consecutive consenting patients who underwent coronary angiography. Subjects were randomly assigned to training (60%) and test (40%) groups and were followed for an average of 4.9 years. Computed and integer risk score models for all-cause death were developed for 30 days and 1, 5, and 10 years using multivariable logistic regressions applied to CBC metrics, age, and gender. The study cohort was an average age of 61 years, 62% were men, and had a 3.3% annual risk of mortality. An integer (scalar) risk score (range 0 to 18) successfully separated patient cohorts into subgroups at markedly different mortality risks (<1% to >14% at 30 days). Predictive fractions (area under risk curve) at 30 days for the CBC-only model and the age- and gender-adjusted CBC model were 0.76 and 0.78, respectively, in the training set and 0.71 and 0.75, respectively, in the test set (all p values <<0.001). The CBC model was markedly more informative than models based only on hematocrit, white blood cell count, or age and gender and was superior to models with all 7 traditional risk factors. In conclusion, in a large, prospectively assembled database, a CBC risk model had high predictive ability for risk of incident mortality. A total CBC score is an important new addition to risk prediction, and it can be easily generated by computer for clinical use at negligible incremental cost.
BACKGROUND: Recent evidence suggests that long-term exposure to particulate air pollution contributes to pulmonary and systemic oxidative stress, inflammation, progression of atherosclerosis, and risk of ischemic heart disease and death. Short-term exposure may contribute to complications of atherosclerosis, such as plaque vulnerability, thrombosis, and acute ischemic events. These findings are inconclusive and controversial and require further study. This study evaluates the role of short-term particulate exposure in triggering acute ischemic heart disease events. METHODS AND RESULTS: A case-crossover study design was used to analyze ischemic events in 12,865 patients who lived on the Wasatch Front in Utah. Patients were drawn from the cardiac catheterization registry of the Intermountain Heart Collaborative Study, a large, ongoing registry of patients who underwent coronary arteriography and were followed up longitudinally. Ambient fine particulate pollution (particles with an aerodynamic diameter < or = 2.5 microm; PM2.5) elevated by 10 microg/m3 was associated with increased risk of acute ischemic coronary events (unstable angina and myocardial infarction) equal to 4.5% (95% confidence interval, 1.1 to 8.0). Effects were larger for those with angiographically demonstrated coronary artery disease. CONCLUSIONS: Short-term particulate exposures contributed to acute coronary events, especially among patients with underlying coronary artery disease. Individuals with stable presentation and those with angiographically demonstrated clean coronaries are not as susceptible to short-term particulate exposure.
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BACKGROUND: Increased homocysteine (HCY) is associated with increased risk of vascular disease. Whether HCY affects development of congestive heart failure (CHF) independent of coronary artery disease (CAD) is uncertain. We evaluated whether increased HCY predicts low ejection fraction or clinical CHF. METHODS: Patients (n = 2,842) undergoing coronary angiography had HCY measured between 1994 and 1999 and were prospectively studied. Left ventricular dysfunction (LVD) was defined as ejection fraction < or =40%. Multivariable regressions assessed predictive strength of HCY for LVD or LVD/CHF. RESULTS: The average age was 64 +/- 12 years; 69% were men, and 74% had CAD. LVD was present in 12% and the combination of either LVD or clinical CHF was present in 21.9%. Quartiles of HCY were: < or =10.5 (Q1), 10.5-13.2 (Q2), 13.3-17.0 (Q3) and > or =17.1 micromol/l (Q4). LVD and LVD/CHF were more prevalent in Q3 (15, 25%) and Q4 (15, 27%) than in Q1 HCY (8.4, 18%; p < 0.001 vs. Q4). After adjustment, Q3 and Q4 HCY independently predicted LVD (OR = 1.7, 95% CI 1.2-2.5, p = 0.004; OR = 1.8, 95% CI 1.3-2.6, p = 0.002) or LVD/CHF (OR = 1.4, 95% CI 1.04-1.8, p = 0.03; OR = 1.7, 95% CI 1.3-2.2, p < 0.001). Findings did not differ by disease etiology: for Q4 among non-CAD patients, OR = 1.7 for LVD and OR = 1.7 for LVD/CHF. Further, there was no interaction of results with gender. CONCLUSION: High HCY levels (Q3/4 > or =13.3 micromol/l) are associated with LVD and combined endpoint of LVD/clinical CHF. This relationship is independent of CHF etiology and gender. Further research is indicated to distinguish between a causal or noncausal mechanism for this association.
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Heterogeneity of heart failure (HF) phenotypes indicates contributions from underlying common polymorphisms. We considered polymorphisms in the beta(1)-adrenergic receptor (beta(1)AR), a beta-blocker target, as candidate pharmacogenomic loci. Transfected cells, genotyped human nonfailing and failing ventricles, and a clinical trial were used to ascertain phenotype and mechanism. In nonfailing and failing isolated ventricles, beta(1)-Arg-389 had respective 2.8 +/- 0.3- and 4.3 +/- 2.1-fold greater agonist-promoted contractility vs. beta(1)-Gly-389, defining enhanced physiologic coupling under relevant conditions of endogenous expression and HF. The beta-blocker bucindolol was an inverse agonist in failing Arg, but not Gly, ventricles, without partial agonist activity at either receptor; carvedilol was a genotype-independent neutral antagonist. In transfected cells, bucindolol antagonized agonist-stimulated cAMP, with a greater absolute decrease observed for Arg-389 (435 +/- 80 vs. 115 +/- 23 fmol per well). Potential pathophysiologic correlates were assessed in a placebo-controlled trial of bucindolol in 1,040 HF patients. No outcome was associated with genotype in the placebo group, indicating little impact on the natural course of HF. However, the Arg-389 homozygotes treated with bucindolol had an age-, sex-, and race-adjusted 38% reduction in mortality (P = 0.03) and 34% reduction in mortality or hospitalization (P = 0.004) vs. placebo. In contrast, Gly-389 carriers had no clinical response to bucindolol compared with placebo. Those with Arg-389 and high baseline norepinephrine levels trended toward improved survival, but no advantage with this allele and exaggerated sympatholysis was identified. We conclude that beta(1)AR-389 variation alters signaling in multiple models and affects the beta-blocker therapeutic response in HF and, thus, might be used to individualize treatment of the syndrome.
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OBJECTIVES: The primary objective was to determine the effect of statin-fibrate combination therapy on inflammatory biomarkers in patients with diabetes. BACKGROUND: Atherosclerosis is a long-term, chronic inflammatory disease that is exacerbated in patients with diabetes. METHODS: Patients (n = 300) with type II diabetes, mixed dyslipidemia (2 or more of low-density lipoprotein > or =100 mg/dl, triglycerides > or =200 mg/dl, or high-density lipoprotein <40 mg/dl), and no history of coronary heart disease were randomly assigned to receive simvastatin 20 mg, fenofibrate 160 mg, or a combination of simvastatin 20 mg and fenofibrate 160 mg daily. At 12 weeks after randomization, we measured levels of high-sensitivity C-reactive protein (hsCRP) and lipoprotein-associated phospholipase A2 (Lp-PLA(2)). RESULTS: At 12 weeks, median hsCRP was significantly reduced (-14.6%, p = 0.004) from baseline, but the effect did not differ between treatments. The effect was greatest among patients with baseline hsCRP levels >2.0 mg/l (fenofibrate = -18.9%, p = 0.002 vs. baseline; simvastatin = -24.8%, p < 0.0001; combination = -27.3%, p = 0.002). Likewise, median Lp-PLA(2) levels in the overall study population were significantly reduced (-16.8%, p < 0.0001), and the effect did not differ among treatments. This effect also was greatest among patients with increased baseline levels of Lp-PLA(2) greater than the median of 320.9 ng/ml (fenofibrate = -41.3%, p < 0.0001; simvastatin = -47.5%, p < 0.0001; combination = -46.8%, p < 0.0001). CONCLUSIONS: Simvastatin, fenofibrate, and combination therapy each lowered hsCRP and Lp-PLA(2). These anti-inflammatory effects were most pronounced among patients with increased baseline levels. Combination therapy was no more effective than either form of monotherapy. (The DIACOR Study; http://www.clinicaltrials.gov/ct/show/NCT00309712?order=1).
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