Quality of health care is the top-rated concern of Americans with regard to changes in the health care system (1). Some employers and other purchasers of health care are also concerned with quality, attempting to spend their health care dollars on high quality health care at the lowest possible cost. For many years, it was assumed that quality was maintained through organizational methods, such as licensure and board certification of physicians and the accreditation of hospitals and other medical facilities. In the last few decades, however, there has been a dramatic expansion in the treatment options available to physicians, without corresponding research on the efficacy of many of these options. This phenomenon has often impeded the development of consensus on proper treatment, resulting in large variation in physician practice patterns. The uncertainty surrounding treatment options and the difficulty in linking treatments to discrete, definable outcomes have made assessment of the quality of health care extremely difficult. The purpose of this article is to present definitions of the concepts of health care quality and outcomes and provide information on how to choose measures of quality and outcomes. We focus primarily on outcomes associated with outpatient care, since the majority of care for rheumatic diseases is provided in the outpatient setting.
370Defining the concepts of health care quality and outcomes Quality of health care is a multidimensional concept that can be viewed narrowly (e.g., clinical efficacy) or broadly (e.g., all attributes of health care that consumers value). The Institute of Medicine defined quality of health care as "the degree to which health services for individuals and populations increase the likelihood of desired health outcomes and are consistent with current professional knowledge" ( 2 ) . Donabedian (3,4) defined 3 types of quality measures: structural measures, such as physician specialty mix, resources available, teaching status, and reimbursement methodology; process measures, or measures of the activities that health care providers perform in caring for patients, such as tests ordered, medications prescribed, and specialty referrals; and outcomes measures, or measures of the effects of health care on health status and consumer satisfaction.Structural measures have historically been used in accreditation processes, and some, such as physician board certification, have been used as indicators of quality, but most current methods to assess health care quality do not focus on structural measures. As medical care has become more complex, structural indicators have proven inadequate to measure and explain variations in practice.Process measures are widely used in evaluations of health care quality; in fact, the majority of the quality indicators recommended by purchaser groups, for example, those specified in HEDIS (the Health Plan Employer Data and Information Set, a managed care-oriented set of data elements for assessing the quality of health plans [51), are process meas...