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Diabetes Watch

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Glycemic Control Decreases Adverse Outcomes in Patients with DM and CKD

In a population-based cohort study, researchers in Canada followed almost 24,000 patients with diabetes mellitus (DM) and impaired renal function (stage 3 and stage 4 chronic kidney disease [CKD]), a group that is often excluded from studies and trials, for a median of 46 months to determine the link between glycemic control (measured by A1C) and development of nephropathy or cardiovascular events.

From this study, it was concluded that increases in A1C levels were associated with greater adverse events overall, including allcause mortality and nonfatal events, such as hospitalizations. The researchers said, “Better glycemic control does help to prevent nephropathy and other microvascular complications of DM in people without CKD.”

The target A1C level as suggested in most current guidelines is approximately 7%, depending on the organization. Although targeting lower A1C levels reduced the risk of nephropathy and other complications, A1C levels that were too high (>8%) or too low (<6.5%) actually increased the risk of all-cause mortality. In addition, decreased renal function has been associated with a greater risk of other adverse events, such as hypoglycemia.

Although overall glycemic control is desirable to prevent other adverse events, a more liberal target level may be appropriate in patients with CKD, because much of the microvascular damage has already been done in this population.

Researchers concluded that although better glycemic control can improve the clinical outcomes of patients with both CKD and DM, overly intensive therapy might actually be harmful, leading to increased cardiovascular mortality and serious hypoglycemic events.

The study was published in the November 28, 2011, issue of Archives of Internal Medicine.

 

Possible Link Between BPA and Diabetes

Bisphenol A (or BPA) is a chemical used extensively in manufacturing polycarbonate plastics (eg, food containers, water bottles) that has recently gained public attention for possible associations with cancer and hormone disruption. Studies have suggested that BPA exposure may also have some role in weight gain, obesity, and the development of diabetes.

A study published in the December 2011 issue of the Journal of Clinical Endocrinology and Metabolism examined the impact of BPA exposure on obesity and insulin resistance in humans. The cross-sectional study examined 3390 adults 40 years and older in Shanghai, China. Study participants’ exposure to BPA was determined using urine samples. Obesity was defined as a body mass index (BMI) of 28 kg/m2 or higher, and overweight was defined as a BMI of 24 kg/m2 to 28 kg/m2. Insulin resistance was defined as greater than 2.5 using the homeostasis model assessment.

The results showed that study subjects with the highest levels of urinary BPA had the highest prevalence of obesity (odds ratio [OR] = 1.5; 95% confidence interval [CI], 1.15-1.97] and insulin resistance (OR = 1.37; 95% CI, 1.06-1.77). In examining participants who were not overweight or obese, the researchers found that higher levels of BPA increased the prevalence of insulin resistance by 94%, though this association was not seen in participants who were overweight or obese.

Although the cross-sectional design of the study does not allow a definitive cause and effect to be inferred, the relationship proposed by these results warrants further investigation. PT

 

Patients with DM and Prior Stroke Benefit from Thrombolytic Therapy

Acute ischemic stroke patients who have DM and/or prior stroke have previously been restricted or excluded from studies on the use of thrombolytic agents such as alteplase due to an unfavorable risk-benefit ratio. Current guidelines do not recommend the use of thrombolytics in these patient populations, though there has not been sufficient evidence to support this conclusion.

In a study conducted by the University of Glasgow, Scotland, and published in the November 22, 2011, issue of Neurology, researchers sought to examine the rationale behind this restriction. They analyzed patient information obtained from both the Safe Implementation of Thrombolysis in Stroke-International Stroke Thrombolysis Register (SITS-ISTR) and the Virtual International Stroke Trials Archive (VISTA), sorting out the subgroups in order to compare outcomes with patients who had either DM, prior stroke, or both conditions.

Data from these analyses support the conclusion that these patients benefit just as much as patients without these conditions from thrombolytic therapy when compared with patients who did not receive thrombolytic therapy. There was also no apparent increase in risk due to interaction between the 2 conditions. This information is especially important because patients with diabetes are at an overall increased risk of cardiovascular complications, including stroke.

Bart Demaerschalk, MD, who wrote the accompanying editorial in Neurology, said, “There appears to be no justification for the continued restriction of these patients from receiving thrombolytic therapy.”