In This Issue...
eGDR Linked to Complications in Type 1 Diabetes
Low estimated glucose disposal rate (eGDR) is associated with micro- and macro-diabetic complications in patients with type 1 diabetes, suggesting that eGDR could be useful in identifying patients who would benefit most from early, aggressive prevention strategies (Diabetes Care 2013 doi:10.2337/dc12-1693).
A formula based on HbA1c, presence of hypertension, and waist circumference, eGDR is an alternate method of estimating insulin sensitivity and has been validated in patients with type 1 diabetes. It also is more practical than the accepted standard for measuring insulin sensitivity, the euglycemic-hyperinsulinemic clamp. Al-though insulin resistance is a hallmark of type 2 diabetes, in populations with high prevalence of type 2 diabetes and obesity, individuals with type 1 diabetes may share genetic and environmental factors that result in reduced insulin sensitivity, a phenomenon sometimes called double-diabetes, according to the authors.
Researchers at Montefiore Medical Center in New York City wanted to explore the distribution of eGDR in type 1 diabetics and the association between eGDR and diabetes complications, because the hospital's surrounding community has the highest rates of type 2 diabetes and obesity in New York City and among the highest in the country.
In a cohort of 207 white, black, or Hispanic adults with type 1 diabetes, the authors found that ethnicity was strongly associated with eGDR, with African-Americans having significantly lower eGDR than Hispanics or whites. In comparison to patients with the highest eGDR, those with the lowest eGDR had a significantly greater risk of any diabetic complication, with an odds ratio of 3.1.
Displaying Fees Leads to Fewer Test Orders
Merely displaying the Medicare allowable fee for diagnostic laboratory tests at the time of order entry can influence physician ordering behavior, even without any other type of educational intervention (JAMA Intern Med 2013 doi:10.1001/jamainternmed.2013.232). These findings suggest that this simple measure might reduce the number of inappropriately ordered diagnostic tests.
Researchers at Johns Hopkins Hospital in Baltimore were interested in evaluating whether an uncomplicated method to reduce lab test ordering would actually result in fewer tests ordered. From a total of 70 tests representing the 35 most frequently ordered and the 35 most expensive, the authors randomly selected 61 tests for the study: 31 in the control arm, without charges displayed, and 30 in the active arm with charges displayed.
During a 6-month baseline period, the authors collected data about usage of the tests in question. During a subsequent 6-month intervention period, charges for tests in the active arm were displayed alongside the test name in Johns Hopkins' physician order entry system. Physicians were not informed about why fees for only certain tests were displayed; if any physician asked the investigators about the charge display, they were told it was for a research effort, but not the specifics of the study.
In comparing the baseline and intervention periods, the authors found a 9.1% reduction in tests ordered in the active arm, but a 5.1% increase in tests ordered in the control arm. This resulted in a net charge reduction >$400,000.
Galectin-3 Associated With Negative Outcomes in Heart Failure Patients
Galectin-3 is elevated in a substantial portion of patients with heart failure, especially those with more severe disease and renal dysfunction. In addition, in patients who received the angiotensin receptor blocker valsartan, researchers found a significant reduction in hospitalizations for heart failure only in those with galectin-3 levels below the median of 16.2 ng/mL (Eur J Heart Fail 2013;15:511–8), suggesting that galectin-3 might predict response to therapy.
The Valsartan Heart Failure Trial (Val-HeFT) evaluated the efficacy of valsartan in 5,010 patients with symptomatic heart failure. Researchers measured galectin-3 and other biomarkers such as high-sensitivity C-reactive protein, high-sensitivity troponin, and B-type natriuretic peptide at three time points in a subpopulation of the trial patients. The time points were at baseline and 4- and 12-months after randomization.
The median baseline galectin-3 level in 1,650 patients was 16.2 ng/mL, and levels increased significantly from baseline at both 4- and 12-months post-randomization, with 1.0 ng/mL and 2.2 ng/mL increases, respectively. After multivariate adjustment, each 1 ng/mL increase in galectin-3 was associated with an estimated 2.9% higher risk of mortality, 2.1% increased risk of first morbid event, and 2.2% greater risk of heart failure hospitalization. Including the change in other measurements, such as left-ventricular ejection fraction, serum sodium, and uric acid, the change in galectin-3 from baseline to 4-months and baseline to 12-months remained significantly associated with all endpoints. However, because of the smaller number of events, the association with heart failure hospitalization was no longer significant.
Valsartan was not associated with a beneficial effect on any outcome in the subset of Val-HeFT subjects who provided baseline galectin-3 levels. However, in patients with baseline galectin-3 levels below the median, use of valsartan was associated with a significant decrease in hospitalizations for heart failure.
Scalp Cortisol Measurements Associated With Cardiovascular Disease
Elevated long-term cortisol levels measured in scalp hair are associated with a history of cardiovascular disease (CVD), equivalent to the effect of traditional CVD risk factors (J Clin Endocrinol Metab 2013;doi:10.1210/jc.2012-3663). The findings suggest that long-term elevated cortisol might be an important CVD risk factor.
The impact of chronic stress on CVD has been studied by measuring the stress hormone cortisol in serum and saliva. However, these one-time measurements poorly reflect long-term cortisol levels due to factors such as the diurnal pattern of cortisol secretion and acute stress. Elevated hair cortisol levels previously have been associated with chronic stress, so the authors sought to investigate whether high long-term cortisol levels in scalp hair were associated with CVD.
The study involved a subset of 283 participants in a larger cohort study of predictors and consequences of changes in physical, cognitive, emotional, and social function in older adults. The authors used a commercial enzyme-linked immunosorbent assay kit for cortisol to measure levels in hair samples cut as close to the scalp as possible. They extracted cortisol from the hair using an overnight methanol incubation.
The investigators found significantly higher hair cortisol levels in men than in women, with a median of 26.3 pg/mg hair versus 21.0 pg/mg, respectively. In comparison to subjects in the lowest quartile of cortisol levels, those in the highest quartile had a 2.7-fold increased risk of CVD and a 3.2-fold higher risk of type 2 diabetes. The authors found no association between hair cortisol levels and non-CVD diseases.