Description
When the first edition of this book was published in the 1980s, clinical epidemiology was on the fringes of medicine. Patient-centered research, the kind that should guide patient care decisions, was poorly developed. Epidemiology was so separate from clinical medicine that we were told it would be a bad idea to include “epidemiology” in the title of a book for clinicians.
Now, dinical epidemiology is in the mainstream. Clinicians are more sophisticated consumers of research information. They have a far better understanding of how to find the best information and to judge its validity and generalizability for themselves. Their efforts are now supported by an extraordinary array of dinically useful electronic databases, clinical practice guidelines, systematic reviews, articles selected for their scientific strength and clinical applicability, and courses in research methods and knowledge management. Many dinical practice guidelines are based on rigorous rules of evidence and provide a rationale for rheir recommendations, including grades for scientific strength. Editors of texrbooks, such as UpToDate and AC? Medicine, now expect authors to incorporate into their chapters critical evaluations of evidence and modern, quantitative descriptions of the benefits and risks of treatments.
The dinical research community has bui!t clinical epidemiology into all phases of its work. Grants are judged by study sections guided largely by the principles described in this book. Serious clinical investigators in many different specialties are pursuing formai postgraduate training in research methods, often in departments of epidemiology. Research reams increasingly comprise the full range of expertise in de sign, measurement, and analysis that bears on their work. Clinical epidemiology is the language of journal peer review and “hanging committees” in which decisions are made about research results that should or should not be published and how the completeness and balance of articles can be improved. The National Library of Medicine now includes (in Medline randomized contro!led trial and sensitivity/specificity. ln short, clinical medicine and epidemiology are making common cause. “Healing the schism” is what Kerr White called it.
For these reasons, readers expect more from an entry-level textbook of clinical epidemiology than they did when earlier editions were published. We have made changes in this new edition to take these expectations into account. Many topics are covered in greater depth, such as the credibility of observational studies of treatment effects, gold standards for studies of screening test accuracy, Bayesian reasoning, and large simple trials. Sysrematic reviews (and meta-analyses when warranted) have become an especially powerful way of summarizing the results of individual studies, which often seem to disagree with one another. W e cover systematic reviews more completely in this edition. \Y/e have added a new chapter on knowledge management (Chapter 13) to help clinicians cope more effectively and efficientlywith the vast body of research results. In this chapter, we take into account clinicians’ practical needs for rapid access to information and for delegating to others some of the responsibility of finding information and selecting and summarizing the best studies. We continue to use clinical examples to illustrate concepts. Sorne of the facts in these examples have been modified by subsequent research, as expecred, and we have updated those ex amples. Most underlying concepts have not changed, although some are described in greater depth.
Many clinicians (and even students) have difficulty fin ding adequate time with an uncluttered mind for reading. We have trîed to make their job casier by highlighting key words and listing them at the beginning of each chapter. At the end of each chapter, we provide questions to assist readers who wish to review in this way. We hope the clinical examples throughout the book continue to anchor abstract concepts in real-life application. The publisher has donc its part by creating a more modern, reader-friendly layout, adding color, and choosing a larger trim size and a