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November 9, 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
ARCHIVES OF INTERNAL MEDICINE NEWS RELEASES
(Embargoed Until: 3 P.M. (CT), Monday, November 9, 2009)
ARCHIVES OF NEUROLOGY NEWS RELEASES
(Embargoed Until: 3 P.M. (CT), Monday, November 9, 2009)
ARCHIVES OF OPHTHALMOLOGY NEWS RELEASES
(Embargoed Until: 3 P.M. (CT), Monday, November 9, 2009)
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. 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 P.M. (CT), MONDAY, November 9, 2009
Mood Improves on Low-Fat, but not Low-Carb, Diet Plan
CHICAGO—After one year, a low-calorie, low-fat diet appears more beneficial to dieters' mood than a low-carbohydrate plan with the same number of calories, according to a report in the November 9 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. Obese individuals who lose weight tend to have an improved psychological state, including a better mood, according to background information in the article. "Despite the consistency of official recommendations advocating a high-carbohydrate, low-fat, energy-restricted diet for obesity treatment, the obesity epidemic has led to widespread interest in alternative dietary patterns for weight management, including very low-carbohydrate 'ketogenic' diets that are typically high in protein and fat (particularly saturated fat)," the authors write. "While recent clinical studies have shown that low-carbohydrate diets can be an effective alternative dietary approach for weight loss, their long-term effects on psychological function, including mood and cognition, have been poorly studied." Grant D. Brinkworth, Ph.D., of Commonwealth Scientific and Industrial Research Organisation-Food and Nutritional Sciences, Adelaide, Australia, and colleagues conducted a randomized clinical trial involving 106 overweight and obese participants who were an average age of 50. Of these, 55 had been randomly assigned to follow a very-low-carbohydrate, high-fat diet and 51 to a high-carbohydrate, low-fat diet for one year. Changes in body weight, mood and well-being, and cognitive functioning (thinking, learning and memory skills) were assessed periodically during and following the one-year intervention. After one year, the overall average weight loss was 13.7 kilograms (about 30.2 pounds), with no difference between the two groups. Both groups initially (after the first eight weeks) experienced an improvement in mood. However, most measurements of mood revealed a lasting improvement in only those following the low-fat diet, while those on the high-fat diet returned to their initial levels (i.e., mood returned toward more negative baseline levels). "This outcome suggests that some aspects of the low-carbohydrate diet may have had detrimental effects on mood that, over the term of one year, negated any positive effects of weight loss," the authors write. Potential explanations include the social difficulty of adhering to a low-carbohydrate plan, which is counter to the typical Western diet full of pasta and bread; the prescribed, structured nature of the diet; or effects of protein and fat intake on brain levels of serotonin, a neurotransmitter related to psychological functioning.
There was no evidence that the nutrient content of either diet was associated with changes in cognitive function, since both groups experienced similar changes in thinking and memory performance over time. "Further studies are required to evaluate the effects of these diets on a wider range of cognitive domains," the authors conclude.
Editor's Note: This study was supported by project grants from the National Heart Foundation of Australia and the National Health and Medical Research Council of Australia. Simplot Australia, Mt. Buffalo Hazelnuts Victoria, Webster Walnuts Victoria, Stahmann Farms Queensland and Scalzo Food Industries Victoria donated foods for this study. 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 P.M. (CT), MONDAY, November 9, 2009
Proportion of Emergency Department Patients Seen Within Recommended Triage Time Frame Appears to Be Declining
CHICAGO—One in four emergency department patients in 2006 waited longer to be evaluated by a clinician than recommended at triage, an increase from one in five in 1997, according to a report in the November 9 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. "Prolonged emergency department (ED) wait time decreases patient satisfaction, limits access, increases the number of patients who leave before being seen and is associated with clinically significant delays in care for patients with pneumonia, cardiac symptoms and abdominal pain," the authors write as background information in the article. Previous analyses have noted an increase in the amount of time ED patients wait to see a clinician. Between 1997 and 2004, median wait times increased 36 percent, from 22 minutes to 30 minutes. However, wait time alone is an imperfect measure of the timeliness of emergency care because it does not take into account the nature of patients' illnesses or injuries. Leora I. Horwitz, M.D., M.H.S., of Yale–New Haven Hospital and Yale University School of Medicine, New Haven, Conn., and Elizabeth H. Bradley, Ph.D., also of Yale University School of Medicine, analyzed data from the National Hospital Ambulatory and Medical Care Survey to examine trends in the percentage of patients seen within the target time recommended during triage (initial process of prioritizing patients for treatment according to the seriousness of their condition). "Emergency departments are increasingly overcrowded, thereby straining resources," the authors write. "Triage assessment is intended to mitigate this strain by ensuring that the most acutely ill patients are prioritized for assessment, regardless of the competing demands on ED physicians' time. Considering wait time within the clinical context of triage assessment therefore allows for a more nuanced understanding of the timeliness of ED care than wait time in aggregate." A total of 151,999 ED visits between 1997 and 2006 were categorized in the database as emergent (recommended that clinicians see in zero to 14 minutes), urgent (see in 15 minutes to 60 minutes), semi-urgent (see in 61 minutes to two hours) or non-urgent (see in more than two to 24 hours). For all categories, the percentage of patients seen within the triage target time declined an average of 0.8 percent per year, from 80 percent in 1997 to 75.9 percent in 2006. The decline was greater-2.3 percent per year-for emergent patients, who had 87 percent lower odds than semi-urgent patients of being seen within the triage target time. "Overall, 56.6 percent of emergent patients were seen within the triage target time compared with 100 percent of non-urgent patients," the authors write. Results did not differ for patients with or without insurance, or for those of different racial or ethnic groups. Many causes likely exist for increased wait times, the authors note. Per capita ED use has increased during the same timeframe, with much of the increase among less acutely ill patients. Moreover, high hospital occupancy rates decrease the number of beds available for patients admitted through the ED.
"The multifactorial nature of prolonged ED wait time lends itself to numerous avenues for improvement," the authors conclude. These include increasing patients' access to alternate sites of care; interventions to improve ED processes; and redesign of the physical environment. "Comparative research into the most effective methods of reducing ED crowding, decreasing ED length of stay and limiting ED wait times is urgently needed to help EDs prioritize their quality improvement activities and maximize their impact."
Editor's Note: This study was supported by Clinical and Translational Science Award grants from the National Center for Research Resources, a component of the National Institutes of Health, and NIH roadmap for Medical Research. Dr. Horwitz is supported by Yale-New Haven Hospital and by the NCRR. Please see the article for additional information, including author contributions and affiliations, financial disclosures, funding and support, etc. Editorial: Variety of Solutions Needed to Solve ED Problems
"Increasing attention, both in the media and in the academic literature, has been placed on emergency department crowding in the past few decades," write Renee Y. Hsia, M.D., M.Sc., and Jeffrey A. Tabas, M.D., of the University of California, San Francisco, in an accompanying editorial. "What are the consequences of ED crowding? Crowding in the ED has been associated with poorer process measures, including delays in treatment of pain, delays in antibiotic treatment for community-acquired pneumonia and decreases in the satisfaction of patients with their ED stay and hospitalization. There is also increasing evidence to suggest that ED crowding is associated with poorer clinical outcomes, such as increased in-hospital morbidity and mortality."
"The problem of ED crowding and wait times is certainly not unique to the United States, and no single solution will solve overcrowding," Drs. Hsia and Tabas conclude. "However, the problem is serious and worsening, and we must implement a variety of solutions in the areas of ED input, throughput and output as well as broader health system reform. Otherwise, our patients will remain waiting, waiting, waiting."
Editor's Note: Please see the article for additional information, including 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 P.M. (CT), MONDAY, November 9, 2009
Study Examines Quality and Duration of Primary Care Visits
CHICAGO—Adult primary care visits have increased in quality, duration and frequency between 1997 and 2005, according to a report in the November 9 issue of Archives of Internal Medicine, one of the JAMA/Archives journals. "Two of the most pressing goals for the U.S. health care system are to deliver higher-quality care and to lower costs," according to background information in the article. Primary care physicians are being held to these goals while patient populations have grown older and more complex. Additionally, primary care physicians' net incomes have decreased by more than 10 percent from 1995 to 2003, raising concerns that physicians would respond by shortening the time they spend on each visit in order to see more patients. Research suggests that a higher investment of primary care physicians' time may be required to deliver high-quality care. Lena M. Chen, M.D, M.S., then of the Veterans Affairs Boston Healthcare System and now of the University of Michigan Health System, Ann Arbor, and colleagues conducted a retrospective analysis of 46,250 U.S. visits to primary care physicians by adults age 18 and older between 1997 and 2005. Researchers set out to determine changes in visit duration and if visit duration is associated with quality of care. Quality of care was evaluated using nine medical, counseling or screening quality indicators used in previous studies. From 1997 to 2005, U.S. adult primary care visits to physicians increased by 10 percent, from an estimated 273 million to 338 million annually. The average visit duration increased from 18 minutes to 20.8 minutes. For general medical examinations, visit duration increased by 3.4 minutes and for the three most common primary diagnoses visit duration increased by 4.2 minutes for diabetes mellitus, by 3.7 minutes for essential hypertension and by 5.9 minutes for arthropathies (joint diseases). "Comparing the early period (1997 to 2001) with the late period (2002 to 2005), quality of care improved for one of three counseling or screening indicators and for four of six medication indicators," the authors write. Visits for counseling or screening generally took 2.6 to 4.2 minutes longer than visits in which patients did not receive these services, while providing appropriate medication therapy was not associated with longer visit duration.
"Although it is possible that physicians have become less efficient over time, it is far more likely that visit duration has increased because it takes more resources or time to care for an older and sicker population," the authors conclude. "Improvements in quality of care will likely require a combination of investments in systems such as electronic health records, greater use of other professionals such as nurse practitioners and better reimbursement to primary care physicians for the extra time spent."
Editor's Note: This study was supported by the Massachusetts Veterans Epidemiology Research and Information Center, Veterans Affairs Boston Healthcare System. 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 P.M. (CT), MONDAY, November 9, 2009
Exposure to Several Common Infections Over Time May Be Associated With Risk of Stroke
CHICAGO—Cumulative exposure to five common infection-causing pathogens may be associated with an increased risk of stroke, according to a report posted online today that will appear in the January 2010 print issue of Archives of Neurology, one of the JAMA/Archives journals. Stroke is the third leading cause of death and leading cause of serious disability in the United States, according to background information in the article. Known risk factors include high blood pressure, heart disease, abnormal cholesterol levels and smoking, but many strokes occur in patients with none of these factors. "There is therefore interest in identifying additional modifiable risk factors," the authors write. Some evidence exists that prior infection with pathogens such as herpes viruses promotes inflammation, contributes to arterial disease and thereby increases stroke risk. Mitchell S. V. Elkind, M.D., M.S., of Columbia University Medical Center, New York, and colleagues studied 1,625 adults (average age 68.4) living in the multi-ethnic urban community of northern Manhattan, New York. Blood was obtained from all participants-none of whom had a stroke-and was tested for antibodies indicating prior exposure to five common pathogens: Chlamydia pneumoniae, Helicobacter pylori, cytomegalovirus and herpes simplex virus 1 and 2. A weighted composite index of exposure to all five pathogens was developed. Participants were followed up annually over a median (midpoint) of 7.6 years. During this time period, 67 had strokes. "Each individual infection was positively, though not significantly, associated with stroke risk after adjusting for other risk factors," the authors write. "The infectious burden index was associated with an increased risk of all strokes after adjusting for demographics and risk factors." There were several reasons to investigate these five particular pathogens, the authors note. "First, each of these common pathogens may persist after an acute infection and thus contribute to perpetuating a state of chronic, low-level infection," they write. "Second, prior studies demonstrated an association between each of these pathogens and cardiovascular diseases." Studies examining several of these pathogens individually have suggested some may contribute to stroke risk.
"Our study could have potential clinical implications," the authors conclude. "For example, treatment and eradication of these chronic pathogens might mitigate future risk of stroke. Antibiotic therapy directed against C pneumoniae has been tested in randomized controlled trials without evidence of benefit against heart disease. Whether the same holds true for stroke has not yet been established. More studies will be required to further explore infectious burden as a potential modifiable risk factor for stroke."
Editor's Note: This research was supported by National Institutes of Health/National Institute of Neurological Disorders and Stroke grants. 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 P.M. (CT), MONDAY, November 9, 2009
Reduced Muscle Strength Associated With Risk for Alzheimer's Disease
CHICAGO—Individuals with weaker muscles appear to have a higher risk for Alzheimer's disease and declines in cognitive function over time, according to a report in the November issue of Archives of Neurology, one of the JAMA/Archives journals. Alzheimer's disease is characterized by declines in memory and other cognitive (thinking, learning and memory) functions, according to background information in the article. However, it is also associated with other features, such as impaired gait and other motor functions, depression and decreased grip strength. Patricia A. Boyle, Ph.D., and colleagues at Rush University Medical Center, Chicago, studied 970 older adults (average age 80.3) who did not have dementia at their initial evaluation. Each participant underwent a structured initial evaluation that included a medical history, 21 tests of cognitive function, neurologic and neuropsychological evaluations and a composite measure of muscle strength derived from testing in 11 muscle groups. During an average of 3.6 years of follow-up, each participant completed at least one additional identical evaluation. Over the study period, 138 participants (14.2 percent) developed Alzheimer's disease. Muscle strength scores ranged from -1.6 to 3.3 units; for each one-unit increase at the beginning of the study, older adults had about a 43 percent decrease in the risk of developing Alzheimer's disease during follow-up. Those at the 90th percentile of muscle strength had about a 61 percent reduced risk of developing Alzheimer's disease compared with those in the 10th percentile. The association between muscle strength and risk for Alzheimer's disease remained even after other factors, including body mass index and physical activity level, were considered. "Because Alzheimer's disease develops slowly over many years and its hallmark is change in cognitive function, we examined the association of muscle strength with cognitive decline," the authors write. Individuals who were stronger at the beginning of the study experienced a slower rate of decline. "Finally, in an analysis that excluded participants with dementia or mild cognitive impairment at baseline, muscle strength was associated with the risk of developing mild cognitive impairment, the earliest manifestation of cognitive impairment," the authors write. "Overall, these data show that greater muscle strength is associated with a decreased risk of developing Alzheimer's disease and mild cognitive impairment and suggest that a common pathogenesis may underlie loss of muscle strength and cognition in aging."
The basis for this association is unknown, they note. Possibilities include damage to the mitochondria, which produce energy for the body's cells, that may contribute to loss of both muscle strength and cognitive function. Alternatively, decreased strength could result from stroke or other disorders of the central nervous system that also may reveal subclinical Alzheimer's disease.
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 P.M. (CT), MONDAY, November 9, 2009
Cataract Surgery Does Not Appear Associated With Worsening of Age-Related Macular Degeneration
CHICAGO—Age-related macular degeneration does not appear to progress at a higher rate among individuals who have had surgery to treat cataract, contrary to previous reports that treating one cause of vision loss worsens the other, according to a report in the November issue of Archives of Ophthalmology, one of the JAMA/Archives journals. Cataract is the leading cause of blindness worldwide and age-related macular degeneration (AMD) is the leading cause of blindness among Americans age 65 and older, according to background information in the article. Surgery is the most effective and common vision-restoring treatment for cataract. "Because both conditions are strongly age-related, many individuals with cataract also have AMD," the authors write. "There has been a long-standing controversy among clinicians as to whether cataract surgery is contraindicated in eyes with non-neovascular AMD. A major concern has been whether cataract surgery increases the risk of progression to neovascular AMD [an advanced form of the disease involving formation of new blood vessels] in eyes at risk of progression such as those with intermediate AMD." Li Ming Dong, Ph.D., of Stony Brook University School of Medicine, N.Y., and colleagues studied eyes of 108 individuals with non-neovascular AMD who underwent preoperative assessments for cataract surgery between 2000 and 2002. Photographs of the retina were taken and fluorescein angiography, which uses a special dye to investigate blood vessels in the eye, was performed. A total of 86 evaluated eyes had non-neovascular AMD before surgery, and 71 had follow-up assessments between one week and one year after surgery. Neovascular AMD was observed in nine (12.7 percent) of these 71 eyes at one or more follow-up assessments. Five eyes displayed signs of neovascular AMD at the one-week follow-up point; the size and location of the lesions identified indicated that they may have been present before surgery but not visible due to the opaque lens caused by cataract. When these eyes and one eye that did not have one-week follow-up photographs available were excluded, the progression rate between one week and one year decreased to three of 65 eyes (4.6 percent). The rate of progression to neovascular AMD was similar among participants' other, cataract-free eyes over the same time period (one eye, or 3 percent). "Our findings suggest that previous reports of the association or progression of non-neovascular AMD to advanced AMD after cataract surgery could be biased with the absence of immediate pre-operative and postoperative fluorescein angiography to rule out pre-existing neovascular AMD or geographic atrophy," the authors write. "Subtle signs of neovascular AMD or geographic atrophy, even on an angiogram, may be obscured by lens opacity just prior to cataract surgery. In such cases, the neovascular disease or the geographic atrophy may contribute to the individual's vision loss, and this may erroneously be ascribed to the cataract and contribute to a decision to proceed with cataract surgery."
"Our findings do not support the hypothesis that cataract surgery accelerates the progression of AMD," they conclude.
Editor's Note: Please see the article for additional information, including other authors, author contributions and affiliations, financial disclosures, funding and support, etc. Editorial: More Research Needed to Illuminate Potential Link
"Since the late 1980s, there have been several reports of an association between cataract surgery and age-related macular degeneration," writes Barbara E. K. Klein, M.D., M.P.H., of the University of Wisconsin-Madison, in an accompanying editorial. "Some report a cross-sectional association; some, incidence of AMD after surgery; and yet others report progression to more severe AMD. Still, there are some studies that do not find a significant association after controlling for relevant confounders. What might explain the disparate results? In my estimation, the diversity of findings in no small part begins with differences in study design."
Until an ideal study is designed to examine the associations, clinicians will still have to answer difficult questions from patients regarding cataract surgery, Dr. Klein notes. "A straightforward discussion of the inconsistencies of the research findings to date regarding risks of progression of early AMD and development of late AMD and its accompanying risk of severe loss of acuity after cataract surgery would help both the patient and his or her physician to make a more informed decision," she concludes. "Until we have better information regarding the risk of developing AMD in those undergoing cataract surgery, it is the best we can do for our patients."
Editor's Note: This editorial is supported by a National Institutes of Health grant and, in part, by Research to Prevent Blindness. Please see the article for additional information, including author contributions and affiliations, financial disclosures, funding and support, etc.
EMBARGOED FOR RELEASE UNTIL 3 P.M. (CT), MONDAY, November 9, 2009
Laser Surgery Does Not Appear to Have Long-Term Effects on Corneal Cells
CHICAGO—Laser eye surgery to correct vision problems does not appear to be associated with lasting changes to cells lining the inside of the cornea at nine years after the procedure, according to a report in the November issue of Archives of Ophthalmology, one of the JAMA/Archives journals. Two types of laser surgery-photorefractive keratectomy (PRK) and laser in situ keratomileusis (LASIK)-are often used to correct refractive errors such as nearsightedness, according to background information in the article. Little is known about how these procedures affect the cornea, the transparent membrane covering the eye, on the cellular level over the long term. Sanjay V. Patel, M.D., and William M. Bourne, M.D., of Mayo Clinic, Rochester, Minn., studied 29 eyes of 16 patients who had undergone LASIK or PRK. Photographs of the cells lining the cornea (endothelial cells) were taken and analyzed before and nine years after surgery. The annual rate of corneal endothelial cell loss in the eyes of patients who had had surgery was compared with those of 42 eyes that had not undergone either procedure. Nine years after surgery, the density of cells lining the cornea had decreased by 5.3 percent from their preoperative state. However, the average annual rate of cell loss (0.6 percent) was the same in corneas of eyes that were operated on and those that were not. "Our results support the findings of numerous short-term studies that found no significant endothelial cell loss after LASIK and PRK," the authors write.
"The importance of the findings in our study relates to using corneas that have undergone LASIK or PRK as donor tissue," they conclude. "Our findings of no difference in endothelial cell loss after keratorefractive surgery compared with normal eyes suggests that corneas after keratorefractive surgery should be suitable for posterior lamellar keratoplasty," a surgical treatment for corneal dysfunction that involves donor tissue.
Editor's Note: This study was supported by a grant from the National Institutes of Health, by Research to Prevent Blindness Inc., and by the Mayo Foundation. 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. |
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