The well-designed randomized controlled trial (RCT) is the most powerful tool available for the evaluation of the true benefits of preventive or therapeutic interventions. The RCT has the potential to improve the quality of care and control costs through the careful comparison of alternative treatments.<sup>2 Begg C., Cho M., Eastwood S. , e al. Improving the quality of reporting of randomized controlled trials: The CONSORT statement JAMA 1996 ;  276 (8) : 637-639

Cliccare qui per andare alla sezione Riferimenti, 19 NIH Inventory of Clinical Trials: Fiscal Year 1979, vol I. National Institutes of Health, Division of Research Grants, Research Analysis and Evaluation Branch, Bethesda, MD

Cliccare qui per andare alla sezione Riferimenti</sup> The RCT is the only tool that has the power to improve both the effectiveness and efficiency of care.

Given the importance of the RCT to modern medicine, there are many well-written texts dealing with the design, analysis, and even the reporting of clinical trials aimed at the trialist.<sup>2 Begg C., Cho M., Eastwood S. , e al. Improving the quality of reporting of randomized controlled trials: The CONSORT statement JAMA 1996 ;  276 (8) : 637-639

Cliccare qui per andare alla sezione Riferimenti, 16 Meinart C.L. Single-center versus Multicenter Trials Clinical Trials: Design, Conduct and Analysis New York: Oxford University Press (1986).  23-30

Cliccare qui per andare alla sezione Riferimenti, 20 Pocock S.J. The Size of a Clinical Trial: Multicentre Trials Clinical Trials: A Practical Approach Chichester: John Wiley & Sons (1983).  123-142

Cliccare qui per andare alla sezione Riferimenti</sup> Despite the existence of these extensive methodologic resources, there are numerous reports in the literature documenting design flaws and reporting deficiencies in published clinical trials.<sup>9 Freiman J.A., Chalmers T.C., Smith H. , e al. The importance of beta, the type II error, and sample size in the design and interpretation of the randomized controlled trial: Survey of 71 `negative' trials N Engl J Med 1978 ;  299 : 690-694  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 17 Moher D., Dulberg C.S., Wells G.A. Statistical power, sample size and their reporting in randomized controlled trials JAMA 1994 ;  272 : 122-124

Cliccare qui per andare alla sezione Riferimenti</sup> Because of the RCT's importance to the dissemination and uptake of new therapies, some authors have written users' guides to assist the end user (the clinician) in reading and interpreting published trials.<sup>3 Chalmers T.C., Smith H., Blackburn B. , e al. A method for assessing the quality of a randomized control trial Control Clin Trials 1981 ;  2 : 31-49  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti, 13 Guyatt G.H., Sackett D.L., Cook D.J. Evidence-Based Medicine Working Group: Users' Guides to the Medical Literature II. How to use an article about therapy or prevention A. Are the results of the study valid? JAMA 1993 ;  270 (21) : 2598-2601

Cliccare qui per andare alla sezione Riferimenti, 14 Guyatt G.H., Sackett D.L., Cook D.J. Evidence-Based Medicine Working Group: Users' Guides to the Medical Literature II. How to use an article about therapy or prevention B. What were the results and will they help me in caring for my patients? JAMA 1993 ;  271 (1) : 59-63

Cliccare qui per andare alla sezione Riferimenti, 15 Ingelfinger J.A., Mosteller F., Thibodeau L.A. , e al. Reading a Report of a Clinical Trial Biostatistics in Clinical Medicine New York: McGraw-Hill (1994).  259-279

Cliccare qui per andare alla sezione Riferimenti</sup> Most recently, a version of users' guides has been published specifically for the critical care physician.<sup>4 Cook DJ, Guyatt GH, Heyland DK, et al: How to use an article on therapy or prevention: Pneumonia prevention using subglottic secretion drainage Part II: What are the results and will they help me in patient care? Crit Care Med (in press)

Cliccare qui per andare alla sezione Riferimenti, 5 Cook D.J., Hebert P.C., Heyland D.K. , e al. How to use an article on therapy or prevention: Pneumonia prevention using subglottic secretion drainage Part I: Are the results of the study valid Crit Care Med 1997 ;  25 : 1502-1513  [cross-ref]

Cliccare qui per andare alla sezione Riferimenti</sup>

The most widely used users' guides were published by the Evidence-Based Medicine Working Group<sup>13 Guyatt G.H., Sackett D.L., Cook D.J. Evidence-Based Medicine Working Group: Users' Guides to the Medical Literature II. How to use an article about therapy or prevention A. Are the results of the study valid? JAMA 1993 ;  270 (21) : 2598-2601

Cliccare qui per andare alla sezione Riferimenti, 14 Guyatt G.H., Sackett D.L., Cook D.J. Evidence-Based Medicine Working Group: Users' Guides to the Medical Literature II. How to use an article about therapy or prevention B. What were the results and will they help me in caring for my patients? JAMA 1993 ;  271 (1) : 59-63

Cliccare qui per andare alla sezione Riferimenti</sup> in 1993 and have not changed much in content since then. This article provides a brief overview of the theoretical underpinnings of these users' guides and builds on the original framework by incorporating some important recommendations published in the clinical trials literature since 1993. For a complete listing of the issues to be addressed when appraising a clinical trial.