Abstract
This short, well-written, easy to read guide to clinical trials sets out to provide a broad coverage of the area for the non-expert. It succeeds and perhaps could usefully form baseline reading for clinicians either starting off in clinical trials or for those with more experience who want to refresh themselves with regard to the basic and some not so basic issues.
The tone of the book is well set by the Foreword, written by Professor Enkin, McMaster University, Canada, who begins by remarking on perhaps the earliest recorded clinical trial, in 600 BC by Daniel of Judah (1). The health effects of a vegetarian diet and those of a royal Babylonian diet were compared over a 10-day period. The results were stunning and I will return to their formal interpretation below.
The book is set out as a series of questions which makes it very digestible and readable in small portions. The author starts with a description of what a randomized trial is and what the virtues of randomization are for clinical trials. The author explains basic trial designs, parallel, cross-over and factorial, and some issues of trial size. The ‘n-of-1’ trial is explicitly discussed as is the sequential trial that Diener and Ferrari have recently pioneered in headache circles. A description of the phases of drug development is given, although whether phase II need by definition be non-randomized in all settings is perhaps for discussion.
A large chapter outlines the issues surrounding bias and I found this very interesting reading. As the author remarks, much of this is common sense but the evidence is cited and the considerations expansive. No doubt many readers have considered the implications of prestigious journal bias vs. non-prestigious journal bias as they plan to send manuscripts to journals. Similarly, most authors who have published anything have at least once experienced what is labelled as belligerence bias.
Chapter 4 is a good discussion of assessing trials, reminding us of the key elements of good presentation and remarking on the CONSORT guidelines (2) in more detail in Chapter 5. The author then extends into meta-analyses and the role of the Cochrane Collaboration before an all important chapter on translating clinical trial outcomes into practice, which brings the book full circle to the Foreword.
After reading the book I am left to ask other readers what form of bias, 43 are listed in Chapter 3, prevented publication of Daniel of Judah's trial for 400 years? Was it geographical, language or perhaps prestigious journal. Remarkably the publication has remained influential for nearly 2 millennia, which cynics may attribute to ‘flashy title’ bias or even prominent author bias (l)!