Annals of Internal Medicine is published by the American College of Physicians on the first and third Tuesday of every month. These highlights are not intended to substitute for articles as sources of information. For a copy of an article, call 1-800-523-1546, ext. 2656, or 215-351-2656, or visit www.annals.org. Past highlights are accessible as well.
A vaccine for H1N1 influenza is anticipated to become available this fall. With the amount and timing of vaccine release still in question, policy makers struggle to set priorities regarding who should be vaccinated when. Using a complex mathematical model, researchers sought to determine the clinical and cost effectiveness of H1N1 vaccination in mid-October to mid-November 2009. The researchers studied a hypothetical sample of 8.3 million persons up to age 100 living in a large U.S.city similar to New York City. The researchers found that vaccinating 40 percent of the population in October or 35 percent in November, as opposed to vaccinating later in the year, would save costs, and could shorten the pandemic. Experts agree that covering the majority of the population with an effective vaccine for H1N1 would prevent the most morbidity and mortality from H1N1. However, the short time frame for vaccine development and projected limited vaccine supply make this strategy infeasible. The researchers analysis suggests that vaccination will be valuable even if it reaches less than half of the population.
The H1N1 pandemic highlights the urgent need for effective strategies to mitigate flu outbreaks. While current focus on H1N1 is warranted, the pandemic potential of the influenza A (H5N1) virus, or avian flu, is among the greatest health concerns of the 21st century because avian flu is highly lethal to humans. Researchers used a complex mathematical model to compare the costs and benefits of three strategies to mitigate an avian flu pandemic in a city closely resembling New York City. The first strategy used non-pharmaceutical interventions (such as social distancing), vaccination, and antiviral drugs in currently available quantities to prevent infection (prophylaxis). The second and third strategies used expanded supplies of either antiviral drugs or expanded vaccination in addition to non-pharmaceutical interventions. The model suggested that expanded vaccination was the most cost-effective mitigation strategy and that expanded antiviral drug prophylaxis would be beneficial while other strategies were implemented.
Growing evidence suggests that health insurance benefits the long-term health of adults with treatable illnesses. Conversely, patients without health insurance often receive suboptimal care that can result in irreversible complications, elevated clinical risks, or delay of costly elective procedures. The disparities in health care and disease management often lessen after patients become eligible for near-universal Medicare coverage after the age of 65. Researchers compared Medicare spending for 2,951 continuously insured adults and 1,616 adults who were intermittently or continuously uninsured before age 65. They analyzed longitudinal survey data and linked Medicare claims data to compare spending. They estimated that Medicare spending for previously uninsured patients was significantly higher ($5,796) compared to previously insured ($4,773) adults. Previously uninsured patients also had higher adjusted annual hospital rates for complications related to cardiovascular disease and diabetes. Researchers conclude that costs of expanded coverage before age 65 may be partially offset by subsequent reductions in Medicare spending after 65 for patients, especially those with common chronic conditions. A separate editorial cautions that the savings to Medicare of expanded coverage before age 65 are unlikley to be as large as the researchers suggest.
In this Issue:
Obstructive sleep apnea, or OSA, is a condition in which a person periodically stops breathing during sleep. Typically, people suffering from OSA experience poor concentration and excessive daytime sleepiness due to the poor quality of their night time rest. Patients with untreated OSA have a two- to seven-fold increased risk for motor vehicle accidents, making the condition a serious public health concern with respect to road safety. Researchers compared the effects of sleep restriction and alcohol consumption on driving simulator performance in 38 patients with untreated OSA and 20 age-matched control patients. Participants were tested under three conditions: unrestricted sleep, sleep restriction, and consumption of alcohol. Compared with controls, simulated driving performance was worse among patients with untreated OSA. These patients also had greater decrements in driving performance after sleep restriction and after alcohol consumption. Researchers advise that people with symptoms of OSA should avoid even legal doses of alcohol or sleep restriction before driving or performing other tasks where safety is a factor.
Coronary heart disease (CHD) is the leading cause of death in adults in the United States. Health care professionals can help reduce a patients risk for death through early identification and treatment of CHD risk factors. Traditionally, physicians use a method called the Framinghamrisk score to stratify patients according to their 10-year risk for a major coronary event. A patients Framinghamscore is based on seven factors: age, gender, total blood cholesterol, HDL cholesterol, smoking status, systolic blood pressure, and whether the patient is on blood pressure medication. Some of the 23 million Americans with no history of cardiovascular disease who are classified as intermediate-risk by the Framinghamscore could actually be at high risk, meaning they could benefit from more aggressive risk reduction. To determine if nontraditional risk factors could also play a role in determining those at high risk for CHD, researchers from the U.S. Preventative Services Task Force reviewed literature since 1996 on 9 proposed markers of CHD risk. These novel risk factors included high-sensitivity C-reactive protein, ankle-brachial index, leukocyte count, fasting blood glucose, periodontal disease, carotid intimal thickness, eloctron-beam computed tomography, homocysteine, and lipoprotein(a). They found insufficient evidence to support routine use of these additional risk factors to screen for CHD.