Evidence Based Medicine for The Hospitalist
Each of us asks dozens of clinical questions every day. Sometimes the answers are clear: If our question is “Which statin is on formulary?” the answer will be provided to us by a patient’s insurance plan or by our own hospital pharmacy. Many times, however, the answers to our questions aren’t so well defined. Further, these are often the questions that most affect patient care: This is precisely why we ask them in the first place. Many of us give little thought to how we state our questions, but the format of a question can have a dramatic effect on whether or not we will be able to locate an answer. There is an art to asking clinical questions in a manner that maximizes our ability to find a meaningful answer in an efficient way.
Consider an example: We are seeing a 72-year-old man newly diagnosed with a stage II (T2M0N0) renal cell carcinoma. We are curious about treatment options, so we might ask, “Should all cancer patients receive chemotherapy?” It is intuitively clear that the answer to this question depends on a multitude of variables not clarified in the question.
For example, different types of cancer respond differently to chemotherapy and there are innumerable chemotherapy regimens, each having differing mechanisms of action. The patient’s age and gender may matter, and the patient’s medical history will almost certainly affect treatment options. As stated the question is essentially impossible to answer.
A better question might be, “Among men over age 65 with stage II renal cell carcinoma, does post-resection chemotherapy prolong survival compared with nephrectomy alone?” This question is far more specific and therefore more relevant to our individual patient. It is also more likely to yield an answer when we search for one. The point of this somewhat extreme example is that a clear, focused clinical question will usually lead to more precise answers. A vague question will often lead only to frustration.
Construct an Effective Clinical Question
How, then, can we phrase questions to optimize our chances of obtaining clinically helpful answers? One approach is to adopt the PICO or PICOT format. (See “Illustration of PICOT Approach to Clinical Questions,” p. 32.) This format provides a structure for question formation that emphasizes the elements most questions are designed to address: the patients of interest, the intervention in question, what it will be compared with, and what outcome we wish to assess.
The first element (P) represents the patient or population of interest. The aim is to define a group of patients similar to the one prompting the question. For example, our patient is a 72-year-old man with stage II renal cell carcinoma, so we would like to find information on patients that at least approximately fit this description.
The second element (I) represents the intervention, which is usually fairly straightforward to determine if the question relates to a choice of treatments. However, this can also be the prognostic factor or exposure of interest, depending on the type of study and specific question. In our example, the intervention is post-resection chemotherapy, and our clinical question needs to incorporate this information.
