How to Read a Paper: The Basics of Evidence-Based Medicine by Trisha Greenhalgh

Author:Trisha Greenhalgh [Greenhalgh, Trisha]
Language: eng
Format: epub, pdf
ISBN: 9781118800966
Amazon: 1118800966
Publisher: BMJ Books
Published: 2014-04-06T16:00:00+00:00

You may have worked out by now that anyone who is thinking about doing a clinical trial of an intervention should first do a meta-analysis of all the previous trials on that same intervention. In practice, researchers only occasionally do this. Dean Fergusson and colleagues of the Ottawa Health Research Institute published a cumulative meta-analysis of all randomised controlled trials carried out on the drug aprotinin in peri-operative bleeding during cardiac surgery [16]. They lined up the trials in the order they had been published, and worked out what a meta-analysis of ‘all trials done so far’ would have shown (had it been performed at the time). The resulting cumulative meta-analysis had shocking news for the research communities. The beneficial effect of aprotinin reached statistical significance after only 12 trials—that is, back in 1992. But because nobody did a meta-analysis at the time, a further 52 clinical trials were undertaken (and more may be ongoing). All these trials were scientifically unnecessary and unethical (because half the patients were denied a drug that had been proved to improve outcome). Figure 9.4 illustrates this waste of effort.

Figure 9.4 Cumulative meta-analysis of randomised controlled trials of aprotinin in cardiac surgery [16]. Reproduced with permission of Clinical Trials.

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