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April 27, 2010 — Embargoed ContentJAMA 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. JAMA NEWS RELEASES
Complete Table of Contents
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. TV Note: This week's JAMA Report video is on whether the measure of calcium in the coronary arteries helps predict the risk of heart disease. The report will be fed Tuesday, April 27, from 9:00 - 9:15 a.m. ET and 2:00 - 2:15 p.m. ET, on Galaxy 28 (C-Band), Transponder 15, downlink frequency: 4000 vertical, audio 6.2/6.8. For more information, call 312/464-JAMA. The JAMA Report video is also now available on Pathfire every Tuesday, in VNF Provider A. Please look for the JAMA Report tab. 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 RELEASE UNTIL 3:00 P.M. (CT), Tuesday, April 27, 2010
Adding Measure of Calcium in Coronary Arteries to Traditional Risk Factors Associated With Improved Prediction of Heart Disease Risk
CHICAGO—Use of a score based on the amount of calcium in coronary arteries in addition to traditional risk factors improved the classification of risk for prediction of coronary heart disease events, and placed more individuals in the most extreme risk categories, according to a study in the April 28 issue of JAMA. The coronary artery calcium score (CACS; determined by use of computed tomography by measuring buildup of calcium in plaque on the walls of the arteries of the heart) has been shown in large prospective studies to be associated with the risk of future cardiovascular events. However, the extent to which adding CACS to traditional coronary heart disease (CHD) risk factors improves classification of risk is unclear, according to background information in the article. Tamar S. Polonsky, M.D., of the Northwestern University Feinberg School of Medicine, Chicago, and colleagues conducted a study to determine whether adding CACS to a prediction model based on traditional risk factors improves classification of risk. CACS was measured by computed tomography (a type of imaging method) in 6,814 participants from the Multi-Ethnic Study of Atherosclerosis (MESA), a population-based cohort without known cardiovascular disease. Recruitment of participants began in July 2000, with follow-up through May 2008. Five-year risk estimates for new CHD were categorized as 0 percent to less than 3 percent, 3 percent to less than 10 percent, and 10 percent or more using hazards models. Model 1 incorporated age, race/ethnicity, sex, tobacco use, antihypertensive medication use, systolic blood pressure and total and high-density lipoprotein cholesterol measurements. Model 2 used these risk factors plus CACS. The researchers calculated the net reclassification improvement using model 2 vs. model 1. Among a final group of 5,878 individuals, there were 209 CHD events during a median (midpoint) follow-up of 5.8 years, of which 122 were major events (heart attack, death from CHD, or resuscitated cardiac arrest). The researchers found that model 2 resulted in significant improvements in risk prediction compared with model 1. In model 1, 69 percent of the cohort was classified in the highest or lowest risk categories compared with 77 percent in model 2. With the addition of CACS to the model, an additional 23 percent of those who experienced events were reclassified as high risk and an additional 13 percent of those who did not experience events were reclassified as low risk. Among intermediate-risk individuals, 16 percent were reclassified as high risk while 39 percent were classified as low risk. "The results of this study demonstrate that when CACS is added to traditional risk factors, it results in a significant improvement in the classification of risk for the prediction of CHD events in an asymptomatic population-based sample of men and women drawn from 4 U.S. racial/ethnic groups," the authors write. "Incorporation of an individual's CACS leads to a more refined estimation of future risk of CHD events than traditional risk factors alone."
"The results provide encouragement for moving to the next stage of evaluation to assess the use of CACS on clinical outcomes."
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. Editorial: What Makes a Good Predictor? — The Evidence Applied to Coronary Artery Calcium Score
John P. A. Ioannidis, M.D., of the University of Ioannina School of Medicine, Ioannina, Greece, and Ioanna Tzoulaki, Ph.D., of the Imperial College of Medicine, London, write that despite the exemplary nature of the study by Polonsky et al, determining whether CACS should be used routinely still requires testing in a randomized intervention trial. "Thus, the authors have not yet demonstrated that the added accuracy in risk stratification can actually aid clinicians in better treating patients or improving their clinical outcomes. Therefore, their findings, no matter how promising, do not suffice to recommend this marker for widespread routine use. Moreover, cost and harms may be major issues. Computed tomography costs $200 to $600 and routine implementation at the population level can be very expensive. The lifetime excess cancer risk due to radiation exposure from a single examination at age 40 years is 9 cancers per 100,000 men and 28 cancers per 100,000 women. This risk should be taken into account in formal risk-benefit analyses."
"All of these aspects require careful weighting. The evidence to date suggests that while CACS is a promising tool, the verdict is not in yet as to whether it is ready for routine use, and much more is still left to do."
Editor's Note: Please see the article for additional information, including 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 RELEASE UNTIL 3:00 P.M. (CT), Tuesday, April 27, 2010
Use and Costs of Diagnostic Imaging Increasing for Patients With Cancer
CHICAGO—From 1999 through 2006 the use of diagnostic imaging for Medicare patients with cancer increased, with use of positron emission tomography (PET) increasing the most significantly, according to a study in the April 28 issue of JAMA. Imaging costs for these patients also increased, outpacing the rate of increase in total costs among Medicare beneficiaries with cancer. Cancer-related expenditures are expected to increase faster than any other area of health care. "Emerging technologies, changing diagnostic and treatment patterns, and changes in Medicare reimbursement are contributing to increasing use of imaging in cancer," the authors write. "The types and costs of imaging, including costly new imaging modalities, among Medicare beneficiaries with cancer have not been examined previously." Michaela A. Dinan, B.S., of the Duke Clinical Research Institute, Durham, N.C., and colleagues examined changes in the use and costs of imaging and how these changes have influenced the cost of cancer care. The study included an analysis of a nationally representative 5 percent sample of claims from the U.S. Centers for Medicare & Medicaid Services. From 1999 through 2006, there were 100,954 new cases of breast cancer, colorectal cancer, leukemia, lung cancer, non-Hodgkin lymphoma, and prostate cancer. The researchers found that in each subset of cancer type, the number of positron emission tomography (PET) scans per beneficiary increased at an average annual rate of 35.9 percent to 53.6 percent. "Patients with lung cancer or lymphoma had the largest increase in PET use, accompanied by an overall reduction of conventional nuclear medicine imaging tests in both cancer types and stabilized computed tomography [CT] in the lymphoma group. Increases also occurred in the use of bone density scans (6.3 percent - 20.0 percent), echocardiograms (5.0 percent - 7.8 percent), magnetic resonance imaging (4.4 percent - 11.5 percent), and ultrasound (0.7 percent - 7.4 percent). Use of CT increased in all cancer subgroups (4.5 percent - 7.6 percent) except lymphoma," the authors write. Use of conventional radiographs decreased or stayed the same in each cancer subgroup but remained the most heavily used imaging modality for all diagnoses, at an average of 4.3 to 12.2 procedures per patient. The authors also found that for all cancer types, average 2-year imaging costs per beneficiary increased between 5.1 percent and 10.3 percent per year, at least double the rate of increase in overall costs (the cost of cancer care increased 1.8 percent to 4.6 percent per year). Imaging costs for all cancers studied also accounted for a larger percentage of total costs in the 2006 group than in all previous years.
"It is unclear whether the rapid increase in use of advanced imaging is a result of the novelty of the technologies, better outcomes, or a shift to new revenue sources after the enactment of the Medicare Prescription Drug, Improvement, and Modernization Act," the authors write.
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 RELEASE UNTIL 3:00 P.M. (CT), Tuesday, April 27, 2010
High Doses of B Vitamins Associated With Increased Decline in Kidney Function for Patients With Kidney Disease From Diabetes
CHICAGO—Patients with diabetic nephropathy (kidney disease caused by diabetes) who received high dose B-vitamin therapy experienced a more rapid decline in kidney function and had a higher rate of heart attack and stroke than patients who received placebo, according to a study in the April 28 issue of JAMA. Diabetic nephropathy typically affects the network of tiny blood vessels in the glomerulus, a key structure in the kidney composed of capillary blood vessels, which is necessary for the filtration of the blood. "In addition to the personal burden, the societal burden of diabetic nephropathy is enormous, exceeding U.S. $10 billion in annual medical expenditures. Despite effective therapies to slow disease progression, approximately 40 percent of the estimated 21 million patients with diabetes in the United States develop overt nephropathy. New treatment approaches to this problem are needed," the authors write. According to background information in the article, several observational studies have shown a significant association between high concentrations of plasma total homocysteine and the risk of developing diabetic nephropathy, retinopathy, and vascular diseases, including myocardial infarction (MI; heart attack) and stroke. B-vitamin therapy (folic acid, vitamin B6, and vitamin B12) has been shown to lower the plasma concentration of homocysteine. Andrew A. House, M.D., of the University of Western Ontario, London, Ontario, and colleagues conducted a study to examine whether B-vitamin therapy would slow the progression of diabetic nephropathy and prevent vascular events in 238 patients with type 1 or 2 diabetes. The randomized, placebo-controlled trial was conducted at five university medical centers in Canada between May 2001 and July 2007. Patients received single tablet of B vitamins containing folic acid (2.5 mg/d), vitamin B6 (25 mg/d), and vitamin B12 (1 mg/d), or matching placebo. The primary outcome was change in radionuclide glomerular filtration rate (GFR; a measure of kidney function) between baseline and 36 months. Other outcomes included dialysis and a composite of heart attack, stroke, revascularization and all-cause death. Plasma total homocysteine was measured. Participants were followed-up for an average of 31.9 months. Among the results, the researchers found that participants assigned to the B-vitamin group had a greater decrease in radionuclide GFR (and subsequently poorer kidney function) compared with the placebo group. Also, participants randomized to receive B vitamins had a significantly greater number of cardiovascular and cerebrovascular events, with the 36-month risk of a composite outcome, including heart attack, stroke, revascularization, and all-cause mortality that was double in the B-vitamin group, compared to the placebo group. There was no difference in requirement of dialysis. Regarding plasma total homocysteine levels, at 36 months, participants in the B-vitamin group had an average decrease while participants in the placebo group had an average increase.
"Given the recent large-scale clinical trials showing no treatment benefit, and our trial demonstrating harm, it would be prudent to discourage the use of high-dose B vitamins as a homocysteine-lowering strategy outside the framework of properly conducted clinical research," 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. EMBARGOED FOR RELEASE UNTIL 3:00 P.M. (CT), Tuesday, April 27, 2010
Study Examines Global Use and Availability of Treatment Involving Transplantation of Blood Stem Cells
CHICAGO—An examination of the world-wide use of hematopoietic stem cell transplantation (HSCT), which involves transplantation of blood stem cells derived from the bone marrow or blood, finds that there are significant differences in transplant rates between countries and continental regions by indication and donor type, and that HSCT is most frequently used in countries with higher gross national incomes and governmental health care expenditures, according to a study in the April 28 issue of JAMA. "HSCT has become the standard of care for many patients with defined congenital or acquired disorders of the hematopoietic system [pertaining to the formation of blood cells] or with chemosensitive, radiosensitive, or immunosensitive malignancies. Over the last 2 decades, HSCT has seen rapid expansion in use and a constant evolution in its technology," the authors write. "It requires significant infrastructure and a network of specialists from all fields of medicine. Hence, information on indications, use of specific technologies, and trends in the application of HSCT is essential for correct patient counseling and for health care agencies to prepare the necessary infrastructure and to avoid planning errors." Little is known about HSCT use and the factors associated with it on a global level. Alois Gratwohl, M.D., of University Hospital Basel, Switzerland, and colleagues conducted a study to assess differences in the application of HSCT on a global level and to examine associations of various factors with transplant rates. The study included patients receiving allogeneic (genetically different) and autologous (derived from the same individual) HSCTs for 2006, collected by 1,327 centers in 71 participating countries of the Worldwide Network for Blood and Marrow Transplantation. The regional areas used in this study were (1) the Americas (the corresponding World Health Organization regions are North and South America); (2) Asia (Southeast Asia and the Western Pacific Region, which includes Australia and New Zealand); (3) Europe (includes Turkey and Israel); and (4) the Eastern Mediterranean and Africa. A total of 50,417 first HSCTs were reported for 2006; 43 percent were allogeneic, 57 percent autologous. Most of the autologous HSCTs occurred in the Americas and Europe. The most frequent malignant disease for an allogeneic HSCT was acute myeloid leukemia (33 percent); the most frequent nonmalignant disease was bone marrow failure syndrome (6 percent); and the most frequent indication for an autologous HSCT was a plasma cell disorder (41 percent). "Use of allogeneic or autologous HSCT, unrelated or family donors for allogeneic HSCT, and proportions of disease indications varied significantly between countries and regions. In linear regression analyses, government health care expenditures, HSCT team density (indicates the number of transplant teams per one million inhabitants), human development index, and gross national income per capita showed the highest associations with HSCT rates," the authors write. Most of the 50,417 HSCTs were performed in Europe (48 percent), followed by the Americas (36 percent), Asia (14 percent), and the Eastern Mediterranean and Africa (2 percent). The median (midpoint) HSCT rates (per 10 million inhabitants) varied between the continental regions and between participating countries, from 48.5 in the Americas, 184 in Asia, 268.9 in Europe, and 47.7 in the Eastern Mediterranean and Africa. No HSCTs were performed in countries with less than 300,000 inhabitants, smaller than 960 km2, or having less than U.S. $680 gross national income per capita.
"In conclusion, this global overview on HSCT activity demonstrates that it is an accepted therapy worldwide, with different needs and priorities in different regions. Transplant activity is concentrated in countries with higher health care expenditures, higher gross national income per capita, and higher team density; hence, the availability of resources, governmental support, and access to a transplant center determine regional HSCT activity," the researchers write.
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
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CORONARY ARTERY CALCIUM SCORE AIDS PHYSICIANS IN BETTER CLASSIFYING HEART DISEASE RISKS
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