Dan Mayer Essential Evidence-based Medicine

The medical literature: an overview 27
techniques in clinical settings. 1 Thus, while this book focuses on clinical
studies, the principles discussed also apply to your critical appraisal of basic science
research studies.
Editorials
Editorials are opinion pieces written by a recognized expert on a given topic.
Most often they are published in response to a study in the same journal issue.
Editorials are the vehicle that puts a study into perspective and shows its usefulness
in clinical practice. They give contextual commentary to the study, but,
because they are written by an expert who is giving an opinion, the piece incorporates
that expert’s biases. Editorials should be well referenced and they should
be read with a skeptical eye and not be the only article that you use to form your
opinion.
Clinical review
A clinical review article seeks to review all the important studies on a given subject
to date. It is written by an expert or someone with a special interest in the
topic and is more up to date than a textbook. Clinical reviews are most useful for
new learners updating their background information. Because a clinical review
is written by a single author, it is subject to the writer’s biases in reporting the
results of the referenced studies. Due to this, it should not be accepted uncritically.
However, if you are familiar with the background literature and can determine
the accuracy of the citations and subsequent recommendations, a review
can help to put clinical problems into perspective. The overall strength of the
review depends upon the strength (validity and impact) of each individual study.
Meta-analysis or systematic review
Meta-analysis or systematic review is a relatively new technique to provide a
comprehensive and objective analysis of all clinical studies on a given topic. It
attempts to combine many studies and is more objective in reviewing these studies
than a clinical review. The authors apply statistical techniques to quantitatively
combine the results of the selected studies. We will discuss the details on
evaluating these types of article in Chapter 33.
Components of a clinical research study
Clinical studies should be reported upon in a standardized manner. The most
important reporting style is referred to as the IMRAD style. This stands for
1 S. T. Bogardus, Jr., J. Concato & A. R. Feinstein. Clinical epidemiological quality in molecular genetic
research: the need for methodological standards. JAMA 1999; 281: 1919–1926.