Archive for August, 2008

August 29, 2008 · Filed under Uncategorized · Tagged , , , , ,

Translating Hemoglobin A1c into Average Glucose Values

In stable diabetic patients, each percentage point of HbA1c corresponded to about a 29 mg/dL increment in estimated average glucose.

 

The interpretation of glycosylated hemoglobin (HbA1c) levels is not intuitively obvious to many diabetic patients, who are accustomed to thinking in terms of blood glucose levels. In this international study, researchers explored the relation between HbA1c and average blood glucose levels in 507 people; 86% had stable diabetes, and 14% were not diabetic. Each subject underwent 2 days of continuous glucose monitoring every 4 weeks for 12 weeks (generating 288 glucose readings on each monitored day) and finger-stick capillary glucose monitoring seven times daily on 3 days each week for 12 weeks. HbA1c was measured at 12 weeks.

A significant linear relation between average glucose and HbA1c levels was confirmed and is reported in Table 1.

link to table go to: http://general-medicine.jwatch.org/cgi/content/full/2008/828/1/T1

  Thus, each percentage point of HbA1c corresponded to about a 29 mg/dL increment in estimated average glucose.Comment: The authors propose that laboratories should report the corresponding estimated average glucose when they report HbA1c results; this move presumably would facilitate communication with diabetic patients. Note, however, that the association between average glucose and HbA1c levels exhibits some variability: For example, inspection of a scatter plot in this paper shows that, for HbA1c of 7%, average glucose values for individual patients range from about 120 mg/dL to 180 mg/dL.

— Allan S. Brett, MD

Published in Journal Watch General Medicine August 28, 2008

Citation(s):

Nathan DM et al. Translating the A1C assay into estimated average glucose values. Diabetes Care 2008 Aug; 31:1473.

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Preventing Stroke Recurrence: How Best to Control Hypertension?

August 28, 2008 · Filed under Uncategorized · Tagged , , , , , , , , , , , ,

Preventing Stroke Recurrence: How Best to Control Hypertension?

In a randomized trial, use of an ARB to lower blood pressure in patients with recent stroke did not improve outcomes.

 

In the Perindopril Protection against Recurrent Stroke Study (PROGRESS, JW Cardiol Dec 14 2001), lowering blood pressure with an ACE inhibitor plus a diuretic after a stroke reduced the rate of recurrent stroke. The Prevention Regimen for Effectively Avoiding Second Strokes (PRoFESS) was an industry-sponsored, international study of strategies to reduce the risk for recurrent stroke. In the antihypertensive arm of the trial, 20,332 patients were randomized to receive telmisartan (an angiotensin-receptor blocker) or placebo within 120 days after experiencing an ischemic stroke; additional blood-pressure control agents were allowed at investigators’ discretion. Mean patient age was 66, and about one third were women. At baseline, mean systolic blood pressure was 144 mm Hg, and about three quarters of the patients had histories of hypertension.

As expected, the average systolic blood pressure was lower in the telmisartan group than in the placebo group, by 5.4 mm Hg at 1 month and 4.0 mm Hg at 1 year. At a mean follow-up of 30 months, a first recurrent stroke (the primary outcome) occurred in 8.7% of the telmisartan group and 9.2% of the placebo group (hazard ratio, 0.95; P=0.23). Cardiovascular events occurred in 13.5% of the telmisartan group and 14.4% of the placebo group. Mortality was similar in the two groups. Over the course of the study, more patients in the telmisartan group than in the placebo group discontinued study medications, primarily because of hypotensive symptoms. No interaction was found with the results of the antiplatelet arm of the same trial (JW Cardiol Aug 27 2008).

Comment: These results show yet again that improvement in a risk factor may not translate into patient benefit, and they substantiate the importance of testing specific strategies. In patients with stroke and modest elevations of systolic blood pressure, treatment with telmisartan failed to confer a clinical benefit over 30 months, even though the intervention lowered blood pressure. We also cannot determine from this study whether such outcomes are specific to telmisartan or might be found with all ARBs.

— Harlan M. Krumholz, MD, SM

Published in Journal Watch Cardiology August 27, 2008

To learn about healthy products and savings that can help contribute to the prevention of cardiac problems to go www.shaklee.net/zaranis

Jennifer Zaranis

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Low Serum Vitamin D to Increased Hip Fracture Risk in Postmenopausal Women

August 19, 2008 · Filed under Uncategorized · Tagged , , , , , , , , ,

Low Serum Vitamin D Linked to Increased Hip Fracture Risk in Postmenopausal Women

Low serum vitamin D is associated with increased hip fracture risk, according to a nested case-control study in Annals of Internal Medicine. 

 

 

After adjustment for confounders including age, BMI, and calcium intake, hip fracture risk was significantly higher among women in the lowest quartile of vitamin D relative to those in the highest quartile (odds ratio, 1.7). The vitamin D–hip fracture link persisted even when frailty, physical function, and number of falls were taken into account.

 

The authors list several study limitations — for example, they were unable to test whether bone mineral density mediated the association between low vitamin D and hip fracture.

 

Annals of Internal Medicine

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August 19, 2008 · Filed under Uncategorized · Tagged , , , , , , , ,

Prehypertension and Hypertension in Adolescents

An estimated 7% of prehypertensive adolescents develop hypertension annually.

 

Hypertension often goes undiagnosed in children (JW Pediatr Adolesc Med Aug 29 2007). An important question is the extent to which sporadically elevated blood pressure (BP) persists in adolescents. In this study, investigators examined the persistence of hypertension (systolic or diastolic BP ≥95th percentile) or prehypertension (systolic or diastolic BP ≥90th percentile or ≥120/80 mm Hg but lower than the threshold for hypertension) in 8533 adolescents whose BP was measured at age 13, 14, or 15 and repeated 2 and 4 years later.

Initially, 67% of boys and 77% of girls were normotensive; most remained normotensive at 2 years, but 31% and 12% were prehypertensive at 2 years, and 5% and 4% had developed hypertension. Among boys and girls initially classified as prehypertensive (21% and 13%, respectively), 50% and 24% remained prehypertensive at 2 years, and 14% and 12% had developed hypertension. Among those who were initially hypertensive (11% of boys and 10% of girls), 31% and 26% remained hypertensive at 2 years and 47% and 26% were prehypertensive. Among both boys and girls, changes at 4 years were similar to those at 2 years and systolic BP was associated significantly with weight gain.

Comment: Although these data were based on single BP measurements and probably overestimate the prevalence of elevated BP in adolescents, analysis of follow-up measurements suggests that about 7% of prehypertensive adolescents become hypertensive annually. The message is that BP should be measured in adolescents at every healthcare visit.

— Howard Bauchner, MD

Published in Journal Watch Pediatrics and Adolescent Medicine August 13, 2008

Citation(s):

Falkner B et al. Blood pressure variability and classification of prehypertension and hypertension in adolescence. Pediatrics 2008 Aug; 122:238.

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August 15, 2008 · Filed under Uncategorized · Tagged , , , , , , , , , ,

Does Flu Vaccination Lower Risk for Pneumonia in Elders?

In contrast to results of previous studies, flu vaccine did not lower risk in this study.

 

Previous observational studies have shown that influenza vaccination lowers risk for pneumonia in older patients. In a population-based case-control study, conducted during the preinfluenza and influenza seasons of 2000, 2001, and 2002, Seattle investigators studied managed-care records for 1173 older patients (age range, 65–94) with community-acquired pneumonia (CAP) and for 2346 age- and sex-matched controls without CAP. Both groups were equally likely to have been vaccinated (roughly 60% before the CAP index date and 77% by the end of each influenza season).

In unadjusted analyses, vaccinated patients had a 40% lower risk for CAP than unvaccinated patients in the preinfluenza period — when no biologically plausible explanation exists for vaccine benefit — but the difference disappeared when analyses were adjusted for a wide range of chronic diseases and functional impairment. No difference in risk for CAP was observed between vaccinated and unvaccinated groups during the influenza season, whether analyses were adjusted or not, and no difference was observed in risk for CAP that required hospital admission during peak influenza season.

Comment: According to this provocative study, influenza vaccination offered no benefit in broad measures of risk for community-acquired pneumonia. Editorialists noted that this study has several strengths that have been missing in many other studies: It was conducted during seasons when the antigenic match between influenza strains and vaccine was good; CAP was ascertained with chart audit rather than by evaluating administrative data; the analysis was controlled for a wide range of chronic disease and functional status measures; and both inpatient and outpatient cases were identified.

— Thomas L. Schwenk, MD

Published in Journal Watch General Medicine August 12, 2008

Citation(s):

Jackson ML et al. Influenza vaccination and risk of community-acquired pneumonia in immunocompetent elderly people: A population-based, nested case-control study. Lancet 2008 Aug 2; 372:398.

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New Research Claims Link Between Sugary Drinks And Type 2 Diabetes

August 6, 2008 · Filed under Uncategorized · Tagged , , , , , , , , , , , , , ,

Researchers claim that drinking sugary drinks could increase the risk of Type 2 diabetes.

Scientists looked at the link between weight gain, sugary drinks and Type 2 diabetes in 43,960 African American women.

The women completed a questionnaire about the types of drinks they consumed in 1995 and again in 2001. During the ten year follow-up period, 2,713 women developed Type 2 diabetes. Those who drank more non-diet soft drinks and fruit drinks (not including diet drinks, orange juice or grapefruit juice) were more likely to develop Type 2 diabetes than those who drank less.

Women who drank two or more soft drinks per day had a 24 per cent increase in diabetes risk compared with women who drank less than one soft drink per month, and those who drank two or more fruit drinks per day had a 31 per cent increased risk compared with women who drank less than one per month. Diet soft drinks, grapefruit juice and orange juice were not associated with diabetes risk.

Diabetes UK’s response to the findings

“It is very unlikely that drinking more sugary drinks alone increases the risk of developing diabetes,” said Jemma Edwards, Care Advisor at Diabetes UK.

“However, consuming them could lead to weight gain and we know that being over-weight is a risk factor for developing Type 2 diabetes. Other factors include a lack of physical activity and a family history of diabetes.

“This research was carried out on black women only and we already know that people of black or South Asian origin are four to five times more at risk of developing Type 2 diabetes than the general population.

“Diabetes UK recommends a healthy, balanced diet that is low in fat, salt and sugar, and includes at least five portions of fruit and vegetables a day.”

The study was carried out at the Slone Epidemiology Center, Boston University.

Diabetes UK

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August 4, 2008 · Filed under Uncategorized

Specialties Disagree on Need for ECG Evaluations Before Prescribing ADHD Drugs

The American Academy of Pediatrics disagrees with an earlier American Heart Association recommendation that children routinely be given electrocardiograms before receiving drugs for attention deficit/hyperactivity disorder.

 

The AHA made the recommendation in April because of concerns that stimulants such as Ritalin may increase the risk for sudden cardiac death in children with congenital heart disease.

 

Then in May, the AHA and the AAP released a joint statement, saying that it was “reasonable” for a physician to obtain an ECG before starting therapy, but it was at the physician’s discretion.

 

The AAP’s latest response, published online in Pediatrics, contends there’s no compelling evidence that children treated for ADHD have an elevated risk for sudden death or that ECG screening will lower it. Instead, the pediatrics academy encourages physicians to assess all children for cardiac abnormalities by using history and physical assessment and to treat children with ADHD without obtaining ECGs.

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August 1, 2008 · Filed under Uncategorized · Tagged , , , , , , , , , , , , , , , , , ,

Scientists Figure Out How The Immune System And Brain Interact To Control Disease

In a major step in understanding how the nervous system and the immune system interact, scientists at The Feinstein Institute for Medical Research have identified a new anatomical path through which the brain and the spleen communicate.

The spleen, once thought to be an unnecessary bit of tissue, is now regarded as an organ where important information from the nervous reaches the immune system. Understanding this process could ultimately lead to treatments that target the spleen to send the right message when fighting human disease.

Mauricio Rosas-Ballina, MD, working with colleagues in the laboratory of Kevin J. Tracey, MD, figured out that macrophages in the spleen were making tumor necrosis factor, a powerful inflammation-producing molecule. When they stimulated the vagus nerve, a long nerve that goes from the base of the brain into thoracic and abdominal organs, tumor necrosis factor (TNF) production in the spleen decreased. This study complements previous research performed in Dr. Tracey’s laboratory, which showed that stimulation of the vagus nerve increases survival in laboratory models of sepsis.

The findings were published in the Proceedings of the National Academy of Sciences. Many laboratories at The Feinstein Institute study the immune system in health and in disease. Every year, about 500,000 people develop severe sepsis, a syndrome triggered when the body’s immune system wages an attack on the body that is well beyond its normal response to an invader. Sepsis kills about 225,000 deaths in the United States each year.

A hundred years ago, the spleen (located in the upper quadrant of the abdomen) was thought to be only reservoir for blood. It has only been in recent years that scientists discovered that the spleen is a manufacturing plant for immune cells, and a site where immune cells and nerves interact. The spleen defends the body against infection, particularly encapsulated bacteria that circulate through the blood.

The hope is to modulate other immune functions like antibody production through the spleen (via vagus nerve stimulation) as a way to modify the course of infections and possibly some autoimmune disorders.

Dr. Rosas-Ballina began following the winding path of the vagus nerve to establish the route it follows to reach the spleen. He was trying, without much luck, to find fibers of the vagus nerve in this organ. And then he went a little further south to the splenic nerve, the nerve that innervates the spleen. Their results indicate that the vagus nerve inherently communicates with the splenic nerve to suppress TNF production by macrophages in the spleen.

According to the prevailing paradigm, the autonomic nervous system is anatomically and functionally divided in sympathetic and parasympathetic branches, which act in opposition to regulate organ function.

“The division between the parasympathetic and sympathetic nervous systems is not clear cut,” said Dr. Rosas-Ballina, explaining that the vagus nerve (the major parasympathetic nerve) acts through the splenic nerve to modulate immune function.

He said that results of this study suggest that there may be two separate ways the brain communicates with the spleen to regulate immune function. This points the way to a possible solution for treating sepsis. It may be more effective to take advantage of the central nervous system to control cells of the spleen. This way, “you know where the treatment is going,” said Dr. Rosas-Ballina.

About The Feinstein Institute for Medical Research

Headquartered in Manhasset, NY, The Feinstein Institute for Medical Research is home to international scientific leaders in Parkinson’s disease, Alzheimer’s disease, psychiatric disorders, rheumatoid arthritis, lupus, sepsis, inflammatory bowel disease, diabetes, human genetics, leukemia, lymphoma, neuroimmunology, and medicinal chemistry.

The Feinstein Institute, part of the North Shore-LIJ Health System, ranks in the top 6th percentile of all National Institutes of Health grants awarded to research centers. Feinstein researchers are developing new drugs and drug targets, and producing results where science meets the patient. For more information, please visit www.FeinsteinInstitute.org or http://feinsteininstitute.typepad.com/feinsteinweblog

Jennifer Zaranis

Independent Shaklee Distributor

www.shaklee.net/zaranis

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