Randomized, controlled trials using the Metro Firm System.

The Firm System at MetroHealth Medical Center was begun almost two decades ago to foster improved continuity of patient care and teaching of medical students and residents in Internal Medicine. For the past 8 years, these parallel teams of providers and patients also have been used to conduct clinical, educational, and health care delivery research. Randomized, controlled trials are made possible by ongoing random assignment of patients and providers to the three teams, or small group practices. Each group practice has equivalent inpatient and outpatient areas supported by nonrotating nursing, paramedical, and clerical staff. The system's current relationships were established after a controlled trial established both decreased costs and increased effectiveness of the "group practice model" as compared to more traditional approaches to patient care by residents in an academic medical center. Other trials, both on the inpatient and outpatient settings, have been used to guide ongoing institutional change. The unique advantages of the randomized controlled trial are high-lighted by contrasting the results of within-group changes during an intervention with results that incorporate control group changes. A variety of methodologic and logistical issues must be addressed when conducting controlled trials that use ongoing randomization within a single institution. These include determination that the groups are equivalent for all important parameters preintervention, choosing an analytic approach that accounts for potential differences among providers and patients, and, in trials designed to affect behavior, assurance that a "steady state" exists prior to initiating another trial designed to affect similar behavior. Consideration also must be given to the possibilities of cross-team contamination, the Hawthorne effect, the "dominant attending effect," and ethical issues related to informed consent. Clinical trials in a single institution may be performed for common problems and those with well defined stages of severity. Since the costs of maintaining the ongoing randomization are relatively small, the incremental costs of conducting randomized controlled trials are low by comparison to traditional approaches. The establishment of analogous systems at other institutions will permit multisite trials for less common clinical problems, enhance the generalizability of findings, and permit new types of health services research, including the rigorous evaluation of practice guidelines.