The first step in finding an answer to a clinical question is to ask an effective question. This was the subject of the previous installment in this series, in which the PICOT question format was introduced (see The Hospitalist, Nov. 2005, p. 32). This format leads naturally to effective search strategies, so we optimize our chances of finding quality answers if they exist. There are many possible sources of information that can be searched, however, and the type of question asked can provide valuable guidance as to which sources should be first up for review.
Types of Questions and Where to Look for Answers
Many clinical questions pertain to basic medical knowledge rather than cutting-edge current research. These so-called background questions typically involve such issues as the underlying pathophysiology of a disease, the incidence of the disease, the general treatment considerations for the disease, and overall prognosis for patients with the disease. These questions usually do not require evaluation of the most recent medical literature and can often be answered by reviewing sources of established medical knowledge such as medical textbooks, MD Consult, or UpToDate. In fact, searching for basic knowledge in the current research literature can be exhausting because the focus of most papers is necessarily narrow and therefore too restrictive to properly address knowledge of a general nature.
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The main limitation of these more general sources is that it takes years for medical knowledge to become established, so the most current results will seldom be incorporated. For background questions this is usually acceptable, but if a major breakthrough in our understanding of a disease occurs it is unlikely to be found in these sources. An additional limitation is that the statements found in these sources are often not truly evidence-based—at least not in a transparent or reproducible manner. These limitations are becoming less problematic as resources such as UpToDate strive to add evidence-based reviews and quality measures to their summaries, and also begin to update information much more rapidly as online materials become more standard.
In contrast to background clinical questions, foreground clinical questions are more likely to relate to the management of an individual patient in a specific clinical setting, and are therefore too narrow in scope to be addressed well by the sources best suited for background questions. For example, consider the question posed in the last installment of this series, “Among men over the age of 65 with Stage II renal cell carcinoma, does post-resection chemotherapy result in greater five-year survival than nephrectomy alone?” No textbook will answer a question with this narrow focus. To find an answer we need to be able to sift through the current medical research literature.
Searching for the answers to well-constructed clinical questions is obviously a crucial step in the EBM process.
How to Search Research Databases
The number of medical journals has increased dramatically in the past 20 years. As a result, while it may be more likely that your question has been addressed somewhere, it can be more difficult to locate the paper you need. One approach to this problem is to become skilled in developing search strategies. We will return to this, but an alternative is to utilize secondary journals such as ACP Journal Club (www.acponline.org) or prefiltered sources such as the Cochrane Library (www.cochrane.org).
Secondary journals typically screen articles for both clinical relevance and methodologic quality, making them efficient resources for busy clinicians. The Cochrane Library focuses mainly on systematic reviews of controlled trials of therapeutic interventions. The main downside of these sources is that they may not address your particular question. Therefore, one effective search strategy is to first search a secondary journal or prefiltered source and stop if you find what you need. If you don’t find what you are looking for, you will need to enter the world of the large medical research database armed with a search strategy.