Generalizability of Clinical Studies Conducted at Tertiary Care Medical Centers

A Population-Based Analysis

Published in: Journal of Clinical Epidemiology, v. 49, no. 8, Aug. 1996, p. 835-841

Posted on on August 01, 1996

by Peter Layde, Steven K. Broste, Norman A. Desbiens, Marilyn Follen, Joanne Lynn, Douglas J. Reding, Humberto Vidaillet

Read More

Access further information on this document at Journal of Clinical Epidemiology

This article was published outside of RAND. The full text of the article can be found at the link above.

The Marshfield Epidemiologic Study Area (MESA), a geographically defined population registry at one of the participating sites in SUPPORT (a multicenter study of the care of seriously ill hospitalized patients) permitted assessment of generalizability in that study. On the basis of age- and sex-specific rates of enrollment of SUPPORT patients in MESA, we estimate that about 400,000 patients per year would fulfill SUPPORT eligibility criteria in the United States. However, an estimated 925,000 patients, particularly the elderly and those with impairments in their activities of daily living (ADLs), have SUPPORT-like illnesses annually, but do not receive the aggressive care required for study enrollment. The absence of patients not interested in aggressive care in tertiary care-based studies is compounded by the overrepresentation of patients referred from distant areas to the tertiary care center. Such patients tended to be older and to have different diseases than patients in MESA. Care should be taken in generalizing results from clinical and epidemiologic studies conducted at tertiary care centers.

This report is part of the RAND Corporation External publication series. Many RAND studies are published in peer-reviewed scholarly journals, as chapters in commercial books, or as documents published by other organizations.

Our mission to help improve policy and decisionmaking through research and analysis is enabled through our core values of quality and objectivity and our unwavering commitment to the highest level of integrity and ethical behavior. To help ensure our research and analysis are rigorous, objective, and nonpartisan, we subject our research publications to a robust and exacting quality-assurance process; avoid both the appearance and reality of financial and other conflicts of interest through staff training, project screening, and a policy of mandatory disclosure; and pursue transparency in our research engagements through our commitment to the open publication of our research findings and recommendations, disclosure of the source of funding of published research, and policies to ensure intellectual independence. For more information, visit

The RAND Corporation is a nonprofit institution that helps improve policy and decisionmaking through research and analysis. RAND's publications do not necessarily reflect the opinions of its research clients and sponsors.