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April 14, 2009JAMA news releases are made available to the public after 3 pm US Central time on the first 4 Tuesdays of each month. The Archives of Journals news releases are made available to the public after 3 pm Central time on Mondays. We also provide a list of previous news releases. THIS WEEK'S CONTENTS
JAMA NEWS RELEASES (Theme Issue on Diabetes)
(Embargoed for Early Release: 10 a.m. ET Tuesday, April 14, 2009)
JAMA REPORT (VIDEO SCRIPT)
INFORMATION CONTAINED IN THESE NEWS RELEASES IS PROTECTED BY COPYRIGHT. JOURNAL ATTRIBUTION IS REQUIRED. JOURNALISTS CAN NOW ACCESS EMBARGOED JAMA/ARCHIVES STUDIES ON-LINE. Go to www.jamamedia.org for more information and to apply for access. SAVE THE DATE: JAMA will present new research from a theme issue on Diabetes at a media briefing on Tuesday, April 14, from 10 a.m. – 12:15 p.m., at the National Press Club in Washington, D.C. To register, go to www.jamamedia.org and click on the Events tab, or call 312-464-JAMA. Program information will be included in a future email. TV Note: This week's JAMA Report video is on the association between severe hypoglycemia and the risk of dementia for older adults with type 2 diabetes. The report will be fed Tuesday, April 14, from 9:00 - 9:30 a.m. ET and 2:00 - 2:30 p.m. ET, on Galaxy 28 (C-Band), Transponder 19, downlink frequency: 4080 vertical, audio 6.2/6.8. For more information, call 312/464-JAMA. Please Note: The FOR THE MEDIA website now has a search feature to enable media to find previous JAMA/Archives news releases on specific medical topics. This search feature link is located on the home page at www.jamamedia.org EMBARGOED FOR EARLY RELEASE: 10 A.M. (ET) TUESDAY, APRIL 14, 2009
Screening Patients With Type 2 Diabetes for Coronary Artery Disease Does Not Significantly Reduce Risk of Cardiac Events
WASHINGTON, D.C.—Screening for coronary artery disease in patients with type 2 diabetes did not result in a significant reduction in the rate of heart attacks or cardiac death compared to patients who were not screened, according to a study in the April 15 issue of JAMA, a theme issue on diabetes. Frans J. Th. Wackers, M.D., Ph.D., of the Yale University School of Medicine, New Haven, Conn., presented the findings of the study at a JAMA media briefing at the National Press Club in Washington, D.C. Almost 200 million people worldwide have type 2 diabetes. "Coronary artery disease (CAD) is a major health concern and the leading cause of death in individuals with type 2 diabetes. CAD is often asymptomatic [having no symptoms] in these patients until the onset of myocardial infarction [heart attack] or sudden cardiac death," the authors write. There has been substantial interest in the early detection of asymptomatic CAD by screening of patients with type 2 diabetes. However, the potential of routine screening to alter treatment and to prevent cardiac events in persons without clinically apparent CAD is largely unknown, according to background information in the article. Dr. Wackers and colleagues of the Detection of Ischemia in Asymptomatic Diabetics (DIAD) study group tested prospectively whether systematic screening for CAD would identify higher-risk individuals and beneficially affect their risk of heart attack or cardiac death. In the trial, that included 1,123 participants with type 2 diabetes and no symptoms of CAD, patients were randomly assigned to be screened (n = 561) for CAD with the imaging method of adenosine-stress radionuclide myocardial perfusion imaging (MPI), or not be screened (n = 562). The average follow-up was 4.8 years. The overall cumulative 5-year cardiac event rate was 2.9 percent and averaged 0.6 percent per year, lower than anticipated. The researchers found that when analyzed according to randomization, there were 15 events (7 nonfatal heart attacks; 8 cardiac deaths; 2.7 percent ) in the screening group vs. 17 events (10 nonfatal heart attacks; 7 cardiac deaths; 3.0 percent) in the no-screening group. Of those in the screened group, 409 participants (78 percent) with normal results and 50 (10 percent) with small MPI defects had lower event rates than the 33 with moderate or large MPI defects; 0.4 percent per year vs. 2.4 percent per year. Coronary angiography was performed within 120 days after screening in 4.4 percent of 561 participants, including in 15 percent of 33 with moderate or large defects. In comparison, only 3 (0.5 percent) of 562 participants in the no-screening group underwent angiography within 120 days after randomization. The overall rate of coronary revascularization was low in both groups: 5.5 percent in the screened group and 7.8 percent in the unscreened group. During the course of the study there was a significant and equivalent increase in primary medical prevention with aspirin, statins and angiotension-converting enzyme (ACE) inhibitors in both groups. "The strategy of routine screening for CAD in patients with type 2 diabetes is based on the premise that testing could accurately identify a significant number of individuals at particularly high risk and lead to various interventions that prevent cardiac events. However, the results of the DIAD study would appear to refute this notion," the authors write. "… participants had a low cardiac event rate and the identification of participants with abnormal screening results did not serve to eliminate their risk over 5 years of follow-up."
"However, rather than viewing this study as a negative screening study, clinicians might consider the results as a positive message: patients with type 2 diabetes without symptoms to suggest CAD, receiving contemporary medical care, close follow-up, and appropriate diagnostic evaluation for symptoms of ischemia have relatively favorable outcomes in the current era."
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org. EMBARGOED FOR EARLY RELEASE: 10 A.M. (ET) TUESDAY, APRIL 14, 2009
Severe Hypoglycemia Associated With Increased Risk of Dementia for Older Adults With Type 2 Diabetes
WASHINGTON, D.C.—Having hypoglycemic (low blood sugar level) episodes that are severe enough to require hospitalization are associated with a greater risk of dementia for older adults with type 2 diabetes, according to a study in the April 15 issue of JAMA, a theme issue on diabetes. Rachel A. Whitmer, Ph.D., of Kaiser Permanente, Oakland, Calif., presented the findings of the study at a JAMA media briefing at the National Press Club in Washington, D.C. Hypoglycemic episodes may include dizziness, disorientation, fainting or seizures. While most hypoglycemia is mild and self-managed, more severe hypoglycemia can require hospitalization. Although some studies have reported an association between history of hypoglycemia and impaired cognitive functioning in children and young adults with type 1 diabetes, no studies have evaluated whether or to what extent hypoglycemic episodes are a risk factor for the development of dementia in populations of older patients, who are more likely to have type 2 diabetes than type 1. "With the increasing prevalence of type 2 diabetes worldwide, and potentially of hypoglycemia and dementia among patients with diabetes, the relationship between these conditions should be evaluated," the authors write. Dr. Whitmer and colleagues conducted a study to determine whether prior episodes of hypoglycemia that required hospitalization or emergency department (ED) visits are associated with an increased risk of dementia. The study, that included 22 years (1980-2002) of follow-up for hypoglycemic episodes and more than 4 years (starting in 2003) of follow-up for diagnosis of dementia, included 16,667 patients with type 2 diabetes (average age, 65 years). The researchers found that a total of 1,822 patients (11 percent) had a diagnosis of dementia and 1,465 patients (8.8 percent) had at least 1 episode of hypoglycemia; 250 patients had both dementia and at least 1 episode of hypoglycemia (16.95 percent). Age-adjusted incidence rates of dementia by frequency of hypoglycemic episodes were significantly elevated for patients with at least 1 episode compared with patients with no episodes. "Specifically, we observed a 2.39 percent increase in absolute risk of dementia per year of follow-up for patients with history of hypoglycemia, compared with patients without a history. Although this 1-year absolute risk difference is modest, the cumulative effects would be sizeable," the authors write. Compared with patients with no hypoglycemia, patients with single or multiple episodes had a graded increase in risk of dementia. Patients with 1 hypoglycemic episode had a 26 percent increased risk; 2 episodes, an 80 percent increased risk; and 3 or more hypoglycemic episodes were associated with nearly double the risk for dementia. "Our results suggest that hypoglycemic episodes severe enough to require hospitalization or an ED visit are associated with increased risk of dementia, particularly for patients who have a history of multiple episodes," the researchers write.
"A large body of evidence suggests that individuals with diabetes are at an increased risk of dementia, yet exact mechanisms are not known; our study suggests a potentially modifiable mechanism. Pharmacologically induced severe hypoglycemia may be associated with neurological consequences in an older population already susceptible to dementia. More scientific studies examining hypoglycemia and cognitive performance and brain-imaging sequelae in populations of older patients with type 2 diabetes are needed."
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org. EMBARGOED FOR EARLY RELEASE: 10 A.M. (ET) TUESDAY, APRIL 14, 2009
Stem Cell Transplantation Helps Patients With Type 1 Diabetes Achieve Long-Term Insulin Independence, Improves Beta-Cell Function
WASHINGTON, D.C.—The majority of patients with type 1 diabetes who underwent a certain type of stem cell transplantation became insulin free, several for more than three years, with good glycemic control, and also increased C-peptide levels, an indirect measure of beta-cell function, according to a study in the April 15 issue of JAMA, a theme issue on diabetes. Richard K. Burt, M.D., of the Northwestern University Feinberg School of Medicine, Chicago, presented the findings of the study at a JAMA media briefing at the National Press Club in Washington, D.C. Clinical evidence indicates that there is an inverse association between beta-cell (a type of cell in the pancreas that secretes insulin) preservation and function and chronic complications of type 1 diabetes mellitus (DM), and the higher the C-peptide levels (a byproduct of insulin production, made up of amino acids), the lower the incidence of some types of complications of type 1 DM. A previous study found that autologous nonmyeloablative hematopoietic stem cell transplantation (HSCT) in 15 patients with newly diagnosed type 1 DM resulted in the majority of patients becoming insulin free during the follow-up, which averaged about 19 months. "However, it was suggested that subsequent insulin independence was a prolonged honeymoon period due to dietary and exercise changes associated with close posttransplant medical observation," the authors write, and it was not known if this change was because of an improvement in beta-cell preservation. HSCT, which uses a patient's own blood stem cells, involves the removal and treatment of the stem cells, and their return to the patient by intravenous injection. Dr. Burt and colleagues conducted a study to determine if posttransplant insulin independence was due to improved beta-cell function by monitoring the C-peptide levels of 23 patients who underwent stem cell transplantation. The patients, with type 1 DM, were ages 13-31 years. Of the 23 patients, 20 experienced time free from insulin (12 continuously and 8 transiently). Patients remained continuously insulin free for an average time of 31 months (range, 14-52 months). One patient had more than 4 years with no exogenous (produced outside the body) insulin use, 4 patients for at least 3 years, 3 patients for at least 2 years, and 4 patients for at least 1 year. Eight patients relapsed and resumed insulin use at low doses. The majority of patients achieved good glycemic control. In the continuously insulin-free group, average area under the curve (AUC; a type of measurement) of C-peptide levels before transplantation (225.0 ng/mL per 2 hours) showed a significant increase at 24 months after transplantation (785.4 ng/mL per 2 hours) and at 36 months after transplantation (728.1 ng/mL per 2 hours). In the transient insulin–independent group, average AUC of C-peptide levels also increased from 148.9 ng/mL per 2 hours pretransplantation to 546.8 ng/mL per 2 hours at 36 months, which was sustained at 48 months. In this group, 2 patients regained insulin independence after treatment with the antihyperglycemic drug sitagliptin, which was associated with an increase in C-peptide levels. Two patients developed pneumonia in the hospital, 3 patients developed late endocrine dysfunction, and 9 patients developed oligospermia (sperm deficiency). There were no deaths.
"In conclusion, autologous nonmyeloablative HSCT was able to induce prolonged and significant increases of C-peptide levels associated with absence of or reduction of daily insulin doses in a small group of patients with type 1 DM," the researchers write. "At the present time, autologous nonmyeloablative HSCT remains the only treatment capable of reversing type 1 DM in humans. Randomized controlled trials and further biological studies are necessary to confirm the role of this treatment in changing the natural history of type 1 DM."
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org. EMBARGOED FOR EARLY RELEASE: 10 A.M. (ET) TUESDAY, APRIL 14, 2009
Use of Pancreatic Islets Show Promise in Diabetes Research, Treatments
WASHINGTON, D.C.—The use of pancreatic islets (hormone-producing cells) is increasing in diabetes research and may play an important role in future treatments, according to an article in the April 15 issue of JAMA, a theme issue on diabetes. John S. Kaddis, B.S., of the City of Hope National Medical Center, Duarte, Calif., presented the findings of the article at a JAMA media briefing at the National Press Club in Washington, D.C. "The primary objective of islet-based research is to cure diabetes. Perhaps the most prominent clinical application of this research is currently in the form of cell replacement therapy. With the exception of 1 report in a type 2 diabetic cohort, islet transplantation has been used exclusively for a subset of individuals with type 1 diabetes mellitus and was shown, at least temporarily, to improve glucose control and, in a few cases, to lead to insulin independence," writes Mr. Kaddis and colleagues. With this procedure, pancreatic islets are transplanted from a donated pancreas to a person with diabetes as a means of restoring beta-cell function. The destruction of beta cells in the pancreas is the cause of type 1 diabetes. "Although islet transplantation has been shown to offer both protection against long-term complications of the disease and significant improvement in quality of life, several obstacles remain, such as limited engraftment [acceptance of the islets within the recipient], chronic immunosuppression, and inconsistent supply of human islets. These issues must be addressed if the procedure is to be used as a standard of care for qualified individuals," they write. According to the authors, investigators seeking to understand the biology of human islets have approached the problem in a variety of ways. "Some have used surrogate beta cells and cell lines while others have focused on pancreas-derived isolated islets from human or nonhuman sources. Islets and islet-like cells have been used experimentally and clinically to increase beta-cell mass." The demand for pancreatic islets for research and treatment has been increasing, with the production of human islets contingent on the availability of pancreata (plural for pancreas). One of the barriers to islet production is the cost of acquiring organs, with data from the Islet Cell Resource (ICR) consortium showing that for 665 pancreata acquired from 2001 to 2008, standard acquisition charges ranged from a low of $600 to a high of $39,800. To help address the supply and demand issues faced by islet laboratories and clinical and laboratory scientists, islet sharing networks have been established. "These distribution networks have had a global influence on diabetes research but face economic obstacles in preserving the availability of human islets in a growing research community." Data indicate that 297.6 million islets were produced by 14 ICR laboratories between September 2001 and August 2008, with 67 percent used for basic science research and 31 percent for clinical purposes. "The importance of human pancreatic islets, clinically or for basic science research, is substantiated by the number and quality of studies being performed that rely on these preparations. Data available through the ICR as of August 2008 indicate that a total of 151 national and international scientists received human islets for use in both intramural research performed by the consortium as well as 182 clinical and basic science projects submitted to the consortium for support," they write.
"Human pancreatic islets will be critical for restoration of beta-cell function in patients with diabetes. Even given adequate funding levels, the ongoing challenges to supplying human islets must be addressed for the successful exploration of therapeutic options for this chronic and debilitating disease," the authors conclude.
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. For more information, contact JAMA/Archives media relations at 312/464-JAMA (5262) or e-mail mediarelations{at}jama-archives.org.
JAMA REPORTS
VIDEO: Windows Media | Quicktime
DEMENTIA A DANGER FOR PEOPLE WITH TYPE 2 DIABETES WHO HAVE SUFFERED FROM SEVERELY LOW BLOOD SUGAR
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