For a long time, critical care research has focused on mechanism of action studies in the laboratory and on efficacy studies in small groups of patients to explore the effects of specific therapies. With the reorganization in health care financing and delivery, there is a need to understand what works in medicine, and researchers are now asking such questions as does the way intensive care is delivered affect outcome (open versus closed), does a full-time intensivist versus a generalist improve outcome, do different populations access intensive care services differently, does insurance status affect access to critical care services, and are the organizational characteristics of ICUs associated with outcomes.<sup>1 Angus D.C., Linde-Zwirble W.T., Sirio C.A. , e al. The effect of managed care on ICU length of stay: Implications for Medicare JAMA 1996 ;  276 : 1075-1082

Cliccare qui per andare alla sezione Riferimenti, 21 Knaus W.A., Wagner D.P., Zimmerman J.E. , e al. Variations in mortality and length of stay in intensive care units Ann Intern Med 1993 ;  118 : 753-761

Cliccare qui per andare alla sezione Riferimenti, 33 Poses R.M., Smith W.R., McClish D.K. , e al. Controlling for confounding by indication for treatment Are administrative data equivalent to clinical data? Med Care 1995 ;  33 : AS36-AS46

Cliccare qui per andare alla sezione Riferimenti</sup> To explore these types of questions, it is usually inappropriate to conduct a prospective study. Rather, we need to conduct observational outcome studies on existing databases that describe the real world.

Although the major intent of this article is to describe the availability and potential use of large-scale databases, we believe it is essential to first understand the basic principles involved in the conduct and interpretation of observational outcomes studies. Therefore, in this article we briefly overview the design of observational outcomes studies as applied to critical care medicine and then suggest criteria for evaluating data sources and for in-depth reviewing of the available data sources from which these observational studies can be conducted. For further discussion of the role of observational outcomes research in critical care, we refer the reader to the report of the recent American Thoracic Society (ATS) Workshop on Outcomes Research in Critical Care.<sup>36 Romano P.S., Roos L.L., Luft H.S. , e al. A comparison of administrative versus clinical data: coronary artery bypass surgery as an example. Ischemic Heart Disease Patient Outcomes Research Team J Clin Epidemiol 1994 ;  7 : 249-260  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup>