Abdominal aortic aneurysms (AAAs) occur in 1 of 20 older men, remain asymptomatic for many years, and, if left untreated, cause death from rupture in about one third of patients. Ultrasonography is a suitable screening test for AAA, and elective repair can prevent rupture. Although these features suggest a promising target for a screening program, evidence of benefit from AAA screening has only recently become available. Four randomized trials of ultrasonographic screening involving more than 125 000 men have been reported, and each trial observed a reduction in AAA-related mortality (which was statistically significant in 2 trials), ranging from 21% to 68%. One trial in women found no benefit. Other studies indicate that screening can begin in men older than 65 years of age and does not need to be repeated if results are negative. An AAA larger than 5.5 cm in diameter should be considered for elective open or endovascular repair. Most aneurysms detected at screening are smaller and should be kept under surveillance with periodic imaging measurement. Widespread elective repair of small AAAs could reduce the benefits and increase the costs of screening. No medical treatments have been proven to reduce the enlargement rate. If elective repair is reserved for larger AAAs, one-time ultrasonographic screening for AAA can be recommended for men 65 to 79 years of age who have ever smoked [correction].

Despite enormous energies invested in authoring clinical practice guidelines, the quality of individual guidelines varies considerably. The Conference on Guideline Standardization (COGS) was convened in April 2002 to define a standard for guideline reporting that would promote guideline quality and facilitate implementation. Twenty-three people with expertise and experience in guideline development, dissemination, and implementation participated. A list of candidate guideline components was assembled from the Institute of Medicine Provisional Instrument for Assessing Clinical Guidelines, the National Guideline Clearinghouse, the Guideline Elements Model, and other published guideline models. In a 2-stage modified Delphi process, panelists first rated their agreement with the statement that "[Item name] is a necessary component of practice guidelines" on a 9-point scale. An individualized report was prepared for each panelist; the report summarized the panelist's rating for each item and the median and dispersion of rankings of all the panelists. In a second round, panelists separately rated necessity for validity and necessity for practical application. Items achieving a median rank of 7 or higher on either scale, with low disagreement index, were retained as necessary guideline components. Representatives of 22 organizations active in guideline development reviewed the proposed items and commented favorably. Closely related items were consolidated into 18 topics to create the COGS checklist. This checklist provides a framework to support more comprehensive documentation of practice guidelines. Most organizations that are active in guideline development found the component items to be comprehensive and to fit within their existing development methods.

Since most hip fractures are related to osteoporosis, treating accelerated bone loss can be an important strategy to prevent hip fractures. Thiazides have been associated with reduced age-related bone loss by decreasing urinary calcium excretion.

The relationship between previous antimicrobial treatments and infection with drug-resistant Helicobacter pylori is unknown.

The system of tort liability for medical malpractice is frequently criticized for poorly performing its theoretical functions of compensating injured patients, deterring negligence, and dispensing corrective justice. Working from an actual malpractice case involving serious injury but no apparent negligence, the authors explore these criticisms from the perspectives of both the plaintiff-patient and the defendant-physician. They then examine the tort system through the lens of patient safety and conclude that the tensions between the system and patient safety initiatives suggest a need to reexamine our attachment to adversarial dispute resolution in health care. They propose targeted reforms that could improve the functioning of the system and create incentives to improve safety and quality.

While there are many examples of people who live for 100 years or more with little evidence of a decline in brain function, many others are not so fortunate and experience a neurodegenerative disorder, such as Alzheimer disease or Parkinson disease. Although an increasing number of genetic factors that may affect the risk for neurodegenerative disorders are being identified, emerging findings suggest that dietary factors play major roles in determining whether the brain ages successfully or experiences a neurodegenerative disorder. Dietary factors may interact with disease-causing or predisposing genes in molecular cascades that either promote or prevent the degeneration of neurons. Epidemiologic findings suggest that high-calorie diets and folic acid deficiency increase the risk for Alzheimer disease and Parkinson disease; studies of animal models of these disorders have shown that dietary restriction (reduced calorie intake or intermittent fasting) and dietary supplementation with folic acid can reduce neuronal damage and improve behavioral outcome. Animal studies have shown that the beneficial effects of dietary restriction on the brain result in part from increased production of neurotrophic factors and cytoprotective protein chaperones in neurons. By keeping homocysteine levels low, folic acid can protect cerebral vessels and prevent the accumulation of DNA damage in neurons caused by oxidative stress and facilitated by homocysteine. Although additional studies are required in humans, the emerging data suggest that high-calorie diets and elevated homocysteine levels may render the brain vulnerable to age-related neurodegenerative disorders, particularly in persons with a genetic predisposition to such disorders.

For two decades, treatment guidelines for sexually transmitted diseases (STDs) have recommended empirical co-treatment for chlamydia when patients are treated for gonorrhea. Because the epidemiology of and diagnostic testing for STDs have changed over time, co-treatment may no longer be needed as a clinical or public health strategy.

Although many studies have provided data on erectile dysfunction in specific settings, few studies have been large enough to precisely examine age-specific prevalence and correlates.

Chronic kidney disease is a worldwide public health problem with an increasing incidence and prevalence, poor outcomes, and high cost. Outcomes of chronic kidney disease include not only kidney failure but also complications of decreased kidney function and cardiovascular disease. Current evidence suggests that some of these adverse outcomes can be prevented or delayed by early detection and treatment. Unfortunately, chronic kidney disease is underdiagnosed and undertreated, in part as a result of lack of agreement on a definition and classification of its stages of progression. Recent clinical practice guidelines by the National Kidney Foundation 1) define chronic kidney disease and classify its stages, regardless of underlying cause, 2) evaluate laboratory measurements for the clinical assessment of kidney disease, 3) associate the level of kidney function with complications of chronic kidney disease, and 4) stratify the risk for loss of kidney function and development of cardiovascular disease. The guidelines were developed by using an approach based on the procedure outlined by the Agency for Healthcare Research and Quality. This paper presents the definition and five-stage classification system of chronic kidney disease and summarizes the major recommendations on early detection in adults. Recommendations include identifying persons at increased risk (those with diabetes, those with hypertension, those with a family history of chronic kidney disease, those older than 60 years of age, or those with U.S. racial or ethnic minority status), detecting kidney damage by measuring the albumin-creatinine ratio in untimed ("spot") urine specimens, and estimating the glomerular filtration rate from serum creatinine measurements by using prediction equations. Because of the high prevalence of early stages of chronic kidney disease in the general population (approximately 11% of adults), this information is particularly important for general internists and specialists.

Antioxidant vitamins are thought to play a role in atherosclerosis. Supplementation of these nutrients has been explored as a means of reducing cardiovascular morbidity and mortality.

This statement summarizes the U.S. Preventive Services Task Force (USPSTF) recommendations on routine vitamin supplementation to prevent cancer and cardiovascular disease and the supporting scientific evidence. Part of the information on which this statement is based, including evidence tables and references, is available in the accompanying article on vitamins to prevent cardiovascular disease in this issue. More complete information can be found in the summaries of the evidence on vitamins to prevent cancer and vitamins to prevent cardiovascular disease, available on the USPSTF Web site (http://www.preventiveservices.ahrq.gov) and through the National Guideline Clearinghouse (http://www.guideline.gov). The summaries of the evidence on these topics and the recommendation statement are also available in print through subscription to the Guide to Clinical Preventive Services, Third Edition: Periodic Updates. A subscription costs $60 U.S. and can be ordered through the Agency for Healthcare Research and Quality Publications Clearinghouse (call 800-358-9295 or e-mail mailto:ahrqpubs@ahrq.gov).