Extracts of the medicinal plant Tripterygium wilfordii Hook F (TwHF) have been used in China for centuries to treat a spectrum of inflammatory diseases.

China's National Free Antiretroviral Treatment Program began in 2002 and, by August 2008, included over 52,000 patients.

The Budd-Chiari syndrome (BCS) is hepatic venous outflow obstruction. What is known about the syndrome is based on small studies of prevalent cases.

Neuraminidase inhibitors (NAIs) are stockpiled internationally for extended use in an influenza pandemic.

Few data are available about the effectiveness of nonpharmaceutical interventions for preventing influenza virus transmission.

A distributed health data network is a system that allows secure remote analysis of separate data sets, each comprising a different medical organization's or health plan's records. Distributed health data networks are currently being planned that could cover millions of people, permitting studies of comparative clinical effectiveness, best practices, diffusion of medical technologies, and quality of care. These networks could also support assessment of medical product safety and other public health needs. Distributed network technologies allow data holders to control all uses of their data, which overcomes many practical obstacles related to confidentiality, regulation, and proprietary interests. Some of the challenges and potential methods of operation of a multipurpose, multi-institutional distributed health data network are described.

The Distributed Ambulatory Research in Therapeutics Network (DARTNet) is a federated network of electronic health data from 8 organizations representing more than 500 clinicians and more than 400 000 patients. DARTNet was designed to increase knowledge of the comparative effectiveness of prescription medications and medical devices. Traditional observational comparative effectiveness research is conducted using large data sets, such as claims databases. Such databases do not provide important clinical information that is critical to understanding comparative effectiveness. By linking electronic health records, laboratory and imaging data, and administrative data from diverse and geographically disparate patients, DARTNet provides important new insight into the comparative effectiveness of oral diabetes medications, and it is ready for expansion to further enable effectiveness research.

Systematic reviews and meta-analyses are essential to summarize evidence relating to efficacy and safety of health care interventions accurately and reliably. The clarity and transparency of these reports, however, is not optimal. Poor reporting of systematic reviews diminishes their value to clinicians, policy makers, and other users. Since the development of the QUOROM (QUality Of Reporting Of Meta-analysis) Statement-a reporting guideline published in 1999-there have been several conceptual, methodological, and practical advances regarding the conduct and reporting of systematic reviews and meta-analyses. Also, reviews of published systematic reviews have found that key information about these studies is often poorly reported. Realizing these issues, an international group that included experienced authors and methodologists developed PRISMA (Preferred Reporting Items for Systematic reviews and Meta-Analyses) as an evolution of the original QUOROM guideline for systematic reviews and meta-analyses of evaluations of health care interventions. The PRISMA Statement consists of a 27-item checklist and a four-phase flow diagram. The checklist includes items deemed essential for transparent reporting of a systematic review. In this Explanation and Elaboration document, we explain the meaning and rationale for each checklist item. For each item, we include an example of good reporting and, where possible, references to relevant empirical studies and methodological literature. The PRISMA Statement, this document, and the associated Web site (www.prisma-statement.org) should be helpful resources to improve reporting of systematic reviews and meta-analyses.

Suggested intervals for postpolypectomy surveillance colonoscopy are currently based on the adenoma findings from the most recent examination.

Results from clinical trials examining the effect of intensive glucose control on cardiovascular disease have been conflicting.