How do you know what to believe when it comes to medical research studies? What sources of information should you trust? What about statistics? Is evidence based medicine the sollution?
1. How to Evaluate New Medical Treatments Mark Perloe, M.D. www.ivf.com
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Hinweis der Redaktion
The costs of medical care are rising sharply, yet we know that not all common or expensive procedures are necessary, and some may be harmful. Wide variations in the outcomes of medical care have been observed between different centres and different individual clinicians. Patients and their advocates are becoming more informed, more aware that they have (or should have) choices, and more vocal in seeking to make informed choices. Clinicians, health care managers, and, increasingly, lawyers, acknowledge that decision making in health care should involve the patient and be based on best evidence of effectiveness and harm. Comprehensive lists of published research papers, indexed electronically and accessible via standard search techniques, have become available at little or no cost over the internet. Statistical tools, especially those of meta-analysis, are better understood and more widely used. Hence, precise and cumulative estimates of effectiveness and harm tend now to be published soon after the relevant trials are complete. The discipline of critical appraisal (evaluating research papers for their validity and relevance) has evolved and become both more rigorous and more accessible to the non-expert through the publication of basic guides and structured checklists.
Assignment of individuals is randomized RCT: Individuals similar at the beginning RCOT: Prospective analytical, susceptible to bias if carry over effects occur Observational: allocation or assignement is not under investigator control; weaker potential evidence; potential for large confounding variables Cohort: prospective, follow-up period to determine effect of exposure and outcome, stronger than case-control but more expensive Case-Control: retrospective, secondary data from chart review, useful for rare conditions, inexpensive, many forms of bias Cross-Sectional: descriptive study of relationship between factors at one point in time Case-Series: series of cases, lack of comparability, source of hypothesis, most common study type Case-Report: anecdotal evidence,
Scientific enquiry has never been, and never will be, independent of prevailing political, ideological, economic and technological forces