Evidence Report/Technology Assessment

Number 32

Prepared for:
Agency for Healthcare Research and Quality
Department of Health and Human Services
U.S. Public Health Service
2101 East Jefferson Street
Rockville, MD 20852

www.ahrq.gov

Contract No. 290-97-0020

Prepared by:
ECRI, Plymouth Meeting, PA
Health Technology Assessment Group

AHRQ Publication No. 01-E048

June 2001

ISBN 1-58763-051-6
ISSN 1530-4396