NATIONAL CENTER Series 4 For HEALTH STATISTICS I Number 11 VITAL amd HEALTH STATISTICS DOCUMENTS AND COMMITTEE REPORTS PROPERTYOF THE PUBLICATIONS8F?ANC~ EDITORIAL LIBMY use of hospital data for Epidemiologicand Medical-Care Research A Report of the United States National Committee on Vital and Health Statistics How hospital data may be used for epidemiologic and medical- care research is discussed with examples of past applications. U.S. DEPARTMENT OF HEALTH, EDUCATION, AND WELFARE Public Health Service Health Services and Mental Health Administration Washington, D. Cl. June 1969 Public Health Service Publication No. 1000-Series 4 -No. 11 For sale by the Superintendent of Documents, U.S. Government Printing Office Washington, D. C., 20402- Price 25 cents NATIONAL CENTER FOR HEALTH STATISTICS THEODORE D. WOOLSEY, Director PHILIP S.LAWRENCE, SC.D., Associate Director OSWALD K. SAGEN, PH.D.>, Assistant Director for Health Statistics Development WALT R. SIMMONS, M.A., Assistant Director for Research and Scientific Development ALICE M. WATERHOUSE, M.D., Medical Consultant JAMES E. KELLY, D. D. S., Dental Advisor EDWARD E. MINTY, Executive O//icer MARGERY R. CUNNINGHAM, Information O//icer OFFICE OF HEALTH STATISTICS ANALYSIS IWAO M.MORIYAMA,Ph.D.,Di~ector DEAN E. KRUEGER, Deputy Directo~ Public Health Service Publication No. 1000-Series 4-No. 11 Library of Congress Catalog Card Number 70-600272 FOREWORD This report, prepared by a Subcommittee of the U.S. National Committee on Vital and Health Statistics, views the development of hospital data in the United States and discusses how they may be used for epidemiologic studies of chronic disease, for disease surveillance purposes, and for medical-care research. The full potential of mor­ bidity and other data in hospital records needs to be exploited for epidemiologic and medical-care research. Robert L. Berg, M. D., Chairman U.S. National Committee on Vital and Health Statistics ... Ill U.S. NATIONAL COMMITTEE ON VITAL AND HEALTH STATISTICS Robert L. Berg, M. D., Chairman Charles E. Lewis, M.D. Professor and Chairman, Department of Professor and Chairman, Department of Preventive Medicine and Community Health Preventive Medicine and Community Health The Medical Center University of Kanaas Medical Center The University of Rochester Kansas City, Kansas Rochester, New York Forrest E. Linder, Ph.D. Department of Biostatistics Iwao M. Moriyama, Ph. D., Executive Secretary School of Public Health Director, Office of Health Statistics Analyais University of North Carolina National Center for Health Statistics Chapel Hill, North Carolina Public Heslth Service* Washington, D.C. Robert Parke, Jr. Program Planning Officer Bureau of the Census Donald J. Davids U.S. Department of Commerce Chief, Records and Statistics Section Washington, D.C. Colorado State Department of Public Health John R. Philp, M.D. Denver, Colorado Health Officer County of Orange Health Department Clyde V. Kiaer, Ph.D. Santa Ana, California Senior Member, Technical Staff Donovan J. Thompson, Ph.D. Milbank Memorial Fund Department of Preventive Medicine New York, New York School of Medicine University of Washington Herbert E. Klarman, Ph.D. Seattle, Washington Department of Public Health Administration Theodore D. Woolsey, ex officio School of Hygiene and Public Health Director, National Center for Health Statistics The Johns Hopkins University Public Health Service* Baltimore, Maryland Washington, D.C. SUBCOMMITTEE ON EPIDEMIOLOGIC USE OF HOSPITAL DATA Paul M. Denaen, SC.D., Chairman Alfonse T. Masi, M. D., Dr. P.H. Director, Center for Community Health Department of Medicine and Medical Care The University of Tennessee School of Public Health and Medical Memphis, Tennessee School Harvard University Robert W. Miller, M.D. Bostcm, Msssachuaetts “ Chief, Epidemiology Branch National Cancer Institute National Institutes of Health Warren Winkelstein, Jr., M. D., Secretary Public Health Service* Professor, Department of Epidemiology Bethesda, Maryland School of Public Health University of California Robert Ivf. Sigmond Berkeley, California Executive Director Hospital Planning Association of Allegheny County Jacob E. Bearman, Ph.D. Pittsburgh, Pennsylvania Professor, Biometry Division School of Public Health Vergil N. SIee, M.D. College of Medical Sciences Director, Commission on Professional and University of Minnesota Hospital Activities Minneapolis, Minnesota Ann Arbor, Michigan Alexander D. Langmuir, M.D, Paul F. Wehrle, M.D. Chief, Epidemiology Program Chief Physician National Communicable Disease Center Pediatrics and Communicable Disease Health Services and Mental Health Services Administration, Public Health Service* Los Angeles County General Hospital .4tlanta, Georgia Los Angeles, California *Depmtmentof Health, Education, nnd Welfare. iv CONTENTS ... Foreword ------------------------------------------------------------ m Introduction ---------------------------------------------------------- 1 Epidemiologic Research ----------------------------------------------- 1 Retrospective (case-control) Studies -------------------------------- --- 2 Prospective (cohort) Studies ------------------------------------------ 3 Epidemiologic Surveillance --------------------------------------------- 5 Medical-Care Research ----------------------------------------------- 6 Influence of Dia~oses Per Se----------------------------------------- 6 Influence of Organizational Structure for Providing Medical Care and of Type of Physician ------------------------------------------------ 7 Influence of the Physician's Characteristics ---------------------------- 7 Influence of Various Types of Case Management ------------------------- 7 Confidentiality -------------------------------------------------------- 8 References ----------------------------------------------------------- 8 v IN THIS REPORT a Subcommittee of the U.S. National Committee on Vital and Health Statistics considers the potential value, the available methods, and the problems of using hospital data fov epidemiolo~”c studies. Increasing standardization of diagnostic procedures improves the reli­ ability of hospital diagnoses. Increasing utilization of hospitals veduces the difference between the medical expedience of the hospitalized and the geneval populations. Both trends enhance the potential of hospital data fov epidemiolo~”c study. Hospitil vecovds provide access to large num km of cases of specific diseases which would be difficult to identify in general population suvveys. Techniques ave descvibed, pvoblems are identified, and examples ave given for several types of hospital studies: ~etvospective (usually case- control) studies of specific diseases or conditions; prospective (coho~t) studies with either analytical or clinical- tvial objectives; disease sur­ veillance intended to identify changes in levels of incidence; and med­ ical- care veseavch which is concerned with relationships between utilization and the chavacte-vistics of physicians, hospitals, and case management as well as the specific diagnosis. Opportunities fov hypothesis testing ave pointed out, along with ~equive­ ments, in terms of procedures for vecovding data and the selection of conhol groups. vi USE OF HOSPITAL DATA FOR EPIDEMIOLOGIC AND MEDICAL-CARE RESEARCH INTRODUCTION tional studies of data from chronic disease and psychiatric hospitals and from nursing homes At the suggestion of the Epidemiology Section will sometimes be necessary because short-term of the American Public Health Association made general hospitals are utilized primarily by pa­ during its 1964 meeting in New York City, the tients with acute illnesses and with surgical prob­ Subcommittee on Epidemiologic Use of Hospital lems. Data was constituted by the U.S. National Com­ The three areas in which the information in mittee on Vital and Health Statistics. The task of hospital records can contribute are epidemiologic this Subcommittee was to make a study of the uses research, disease surveillance, and medical-care of diagnostic and other data on hospital patients, research. Each of these areas will be briefly re- including statistics needed for epidemiologic and viewed with respect to the role of the hospital medical-care research, studies of current ther­ record. apeutic practices, and for health surveillance. With the increased standardization of diag­ EPIDEMIOLOGIC RESEARCH nostic tests and criteria, hospital data have be- come more reliable in recent years. The fact that While data on hospital patients have, in the the general hospital is being regarded more and past, provided a resource for testing hypotheses more as the hub of a complex of facilities provid­ on disease causation, it is anticipated that this ing medical care—inpatient and outpatient, pre­ resource will be increasingly useful in the future. ventive and curative—increases the possibility y This is due to the increasing availability of hos­ that hospital data will provide a useful indicator pital care through the extension of private and of the medical experience of the general popula­ governmental support as well as to the increased tion. This opens up the possibility of utilizing di­ recognition of the hospital as a technological agnostic information in hospital records for pur­ center. Masil has pointed out the potential uses poses other than the treatment of patients. Indeed of hospital data for epidemiologic research as the subcommittee believes that the full potential well as their limitations. While some problems of information in hospital records