An estimated 42.7 million Americans (15% of the population) had some form of arthritis in 1995 and, due to the increasing average age of the population, this total is expected to rise to 59.4 million (18.2%) by the year 2020(1,2). Consistent with this, it was recently estimated that, since 1990, the prevalence of arthritis has increased by 750,000 cases per year(3). The estimated total economic cost to the United States of arthritis is over finger pain causes of kidney pain $65 billion annually(4). Although the medical and economic consequences of arthritis are of great concern to researchers and clinicians, this disease also affects an individual's capacity to live a full and active life. Thus, it has increasingly become clear that the problems associated with arthritis are not simply medical ones; it also appears to have a substantial impact on a person's functional capacity and quality of life(5). (top of page) Definitions of Quality pain abdominal causes of kidney pain of Life Many terms are used interchangeably (e.g., quality of life, health status, health-related quality of life) to discuss the effect of diseases, such as arthritis, on functioning and sense of well-being. At the broadest level, quality of life refers not only to health status, but also to environmental and economic factors (e.g., income, educational attainment) that can substantially influence well-being. Thus, different conceptual frameworks guide how quality of life is defined and measured(6). For forms of arthritis causes of kidney pain example, investigators who are interested in the evaluation of the quality of medical care outcomes tend to place greater emphasis on the development of measures that focus on overall well-being. In contrast, those operating from a medical ethics perspective tend to develop measures assessing the importance that an individual places upon his/her quality of life. As a result, there are hundreds of tests purporting to measure different aspects of quality of life(7). However, when the causes of kidney pain causes of kidney pain focus is on