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).

Patients with hepatitis C virus (HCV) are at increased risk for hepatocellular carcinoma. Although serum alpha-fetoprotein (AFP) is often used to detect hepatocellular carcinoma in HCV-infected individuals, its utility is unclear.

Persons with atopic dermatitis or eczema, regardless of disease severity or activity, may develop eczema vaccinatum if they or their close contacts receive the smallpox vaccine. According to current recommendations, a preexposure vaccination program should identify these persons and exclude them from participating.

Dementia is a large and growing problem but is often not diagnosed in its earlier stages. Screening and earlier treatment could reduce the burden of suffering of this syndrome.

Clinical trials have demonstrated that angiotensin-converting enzyme (ACE) inhibitors, beta-blockers, and spironolactone improve survival in patients with heart failure. Because patients with heart failure and renal insufficiency have been underrepresented in these trials, little evidence is available to guide clinicians in the optimal management of patients with both conditions. Approximately one third to one half of patients with heart failure have renal insufficiency (estimated glomerular filtration rate [GFR] <60 mL/min per 1.73 m2), and renal insufficiency is among the strongest predictors of mortality in patients with heart failure. Evidence supports the use of ACE inhibitors to improve survival in patients with moderate renal insufficiency (GFR, 30 to 60 mL/min per 1.73 m2), but there is little evidence with which to weigh the risks and benefits in patients with more advanced renal dysfunction. beta-Blockers improve survival in patients with heart failure, and their beneficial effect is unlikely to differ according to renal function. Spironolactone improves outcomes in patients with advanced heart failure, but renal insufficiency appears to increase risk for hyperkalemia and limits the use of the drug in patients with severe renal insufficiency. Future clinical trials in heart failure should include a representative number of patients with renal insufficiency to improve the evidence base and outcomes in this vulnerable population.

Common methods of benchmarking clinical performance rarely, if ever, account for admission source and, in particular, the effect of a patient being transferred from one medical center to another. Small biases in comparisons of observed versus expected deaths can substantially affect how high-quality institutions compare with peer hospitals. With the most sophisticated and validated set of case-mix measures available for patients, the intensive care unit is an ideal setting in which to study the effect of a patient's being transferred from another hospital.

Etanercept and infliximab are U.S. Food and Drug Administration-approved tumor necrosis factor (TNF) antagonists.

Rofecoxib and celecoxib (coxibs) effectively treat chronic arthritis pain and reduce ulcer complications by 50% compared with nonselective nonsteroidal anti-inflammatory drugs (NSAIDs). However, their absolute risk reduction is small and the cost-effectiveness of treatment is uncertain.

There have been many proposals for objective standards designed to optimize training, testing, and maintaining competency in interpretation of electrocardiograms (ECGs). However, most of these recommendations are consensus based and are not derived from clinical trials that include patient outcomes.

This paper is part 1 of a 2-part series on interpretation of 12-lead resting electrocardiograms (ECGs). Part 1 is a position paper that presents recommendations for initial competency, competency assessment, and maintenance of competency on ECG interpretation, as well as recommendations for the role of computer-assisted ECG interpretation. Part 2 is a systematic review of detailed supporting evidence for the recommendations. Despite several earlier consensus-based recommendations on ECG interpretation, substantive evidence on the training needed to obtain and maintain ECG interpretation skills is not available. Some studies show that noncardiologist physicians have more ECG interpretation errors than do cardiologists, but the rate of adverse patient outcomes from ECG interpretation errors is low. Computers may decrease the time needed to interpret ECGs and can reduce ECG interpretation errors. However, they have shown less accuracy than physician interpreters and must be relied on only as an adjunct interpretation tool for a trained provider. Interpretation of ECGs varies greatly, even among expert electrocardiographers. Noncardiologists seem to be more influenced by patient history in interpreting ECGs than are cardiologists. Cardiologists also perform better than other specialists on standardized ECG examinations when minimal patient history is provided. Pending more definitive research, residency training in internal medicine with Advanced Cardiac Life Support instruction should continue to be sufficient for bedside interpretation of resting 12-lead ECGs in routine and emergency situations. Additional experience or training in ECG interpretation when the patient's clinical condition is unknown may be useful but requires further study.

Positron emission tomography (PET) with 18-fluorodeoxyglucose (FDG) is a potentially useful but expensive test to diagnose solitary pulmonary nodules.