Preface

The Agency for Healthcare Research and Quality (AHRQ), through its Evidence-Based Practice Centers (EPCs), sponsors the development of evidence reports and technology assessments to assist public- and private-sector organizations in their efforts to improve the quality of healthcare in the United States. The National Cancer Institute, the Centers for Medicare & Medicaid Services, and the Centers for Disease Control and Prevention requested and provided funding for this report. The reports and assessments provide organizations with comprehensive, science-based information on common, costly medical conditions and new healthcare technologies. The EPCs systematically review the relevant scientific literature on topics assigned to them by AHRQ and conduct additional analyses when appropriate prior to developing their reports and assessments.

To bring the broadest range of experts into the development of evidence reports and health technology assessments, AHRQ encourages the EPCs to form partnerships and enter into collaborations with other medical and research organizations. The EPCs work with these partner organizations to ensure that the evidence reports and technology assessments they produce will become building blocks for healthcare quality improvement projects throughout the Nation. The reports undergo peer review prior to their release.

AHRQ expects that the EPC evidence reports and technology assessments will inform individual health plans, providers, and purchasers as well as the healthcare system as a whole by providing important information to help improve healthcare quality.

We welcome comments on this evidence report. They may be sent by mail to the Task Order Officer named below at: Agency for Healthcare Research and Quality, 540 Gaither Road, Rockville, MD 20850, or by e-mail to epc@ahrq.gov.

Carolyn M. Clancy, M.D.

Director

Agency for Healthcare Research and Quality

Andrew C. von Eschenbach, M.D.

Director

National Cancer Institute

Julie L. Gerberding, M.D., M.P.H.

Director

Centers for Disease Control and Prevention

Mark B. McClellan, M.D., Ph.D.

Administrator

Centers for Medicare & Medicaid Services

Jean Slutsky, P.A., M.S.P.H

Director, Center for Outcomes and Evidence

Agency for Healthcare Research and Quality

Kenneth S. Fink, M.D., M.G.A., M.P.H.

Director, EPC Program

Agency for Healthcare Research and Quality

Ernestine W. Murray, B.S.N, R.N., M.A.S.

EPC Program Task Order Officer

Agency for Healthcare Research and Quality