EvidenceBased Diagnosis An Introduction to Clinical Epidemiology

This is a book about diagnostic testing It is aimed primarily at clinicians, particularly those who are academically minded, but it should be helpful and accessible to anyone involved with selection, development, or marketing of diagnostic, screening, or prognostic tests Although we admit to a love of mathematics, we have restrained ourselves and kept the math to a minimum a little simple algebra and only three Greek letters, kappa, alpha, and beta Nonetheless, quantitative discussions in this book go deeper and are more rigorous than those typically found in introductory clinical epidemiology or evidencebased medicine texts Our perspective is that of skeptical consumers of tests We want to make properdiagnoses and not miss treatable diseases Yet, we are aware that vast resources are spent on tests that too frequently provide wrong answers or right answers of little value, and that new tests are being developed, marketed, and sold all the time, sometimes with little or no demonstrable or projected benefit to patients This book is intended to provide readers with the tools they need to evaluate these tests, to decide if and when they are worth doing, and to interpret the results The pedagogical approach comes from years of teaching this material to physicians,mostly fellows and junior faculty in a clinical research training program We have found that many doctors, including the two of us, can be impatient when it comes to classroom learning We like to be shown that the material is important and that it will help us take better care of our patients, understand the literature, andor improve our research For this reason, in this book we emphasize reallife examples Although this is primarily a book about diagnosis, two of the twelve chapters are about evaluating treatments using both randomized trials Chapter 8 and observational studies Chapter 9