In response to a request by the Health Care Financing Administration (HCFA), the Institute of Medicine proposed a study to examine definitions of serious or complex medical conditions and related issues. A seven-member committee was appointed to address these issues. Throughout the course of this study, the committee has been aware of the fact that the topic addressed by this report concerns one of the most critical issues confronting HCFA, health care plans and providers, and patients today. The Medicare+Choice regulations focus on the most vulnerable populations in need of medical care and other services-those with serious or complex medical conditions. Caring for these highly vulnerable populations poses a number of challenges. The committee believes, however, that the current state of clinical and research literature does not adequately address all of the challenges and issues relevant to the identification and care of these patients.

This User’s Guide is intended to support the design, implementation, analysis, interpretation, and quality evaluation of registries created to increase understanding of patient outcomes. For the purposes of this guide, a patient registry is an organized system that uses observational study methods to collect uniform data (clinical and other) to evaluate specified outcomes for a population defined by a particular disease, condition, or exposure, and that serves one or more predetermined scientific, clinical, or policy purposes. A registry database is a file (or files) derived from the registry. Although registries can serve many purposes, this guide focuses on registries created for one or more of the following purposes: to describe the natural history of disease, to determine clinical effectiveness or cost-effectiveness of health care products and services, to measure or monitor safety and harm, and/or to measure quality of care. Registries are classified according to how their populations are defined. For example, product registries include patients who have been exposed to biopharmaceutical products or medical devices. Health services registries consist of patients who have had a common procedure, clinical encounter, or hospitalization. Disease or condition registries are defined by patients having the same diagnosis, such as cystic fibrosis or heart failure. The User’s Guide was created by researchers affiliated with AHRQ’s Effective Health Care Program, particularly those who participated in AHRQ’s DEcIDE (Developing Evidence to Inform Decisions About Effectiveness) program. Chapters were subject to multiple internal and external independent reviews.