finding the evidence

Example:
The first step when looking for evidence is to formulate the question which needs to be answered. Looking at the case study described in the text.  In generally well patients with HIV,  not yet started on antiretrovirals, when is the best time to start antiretroviral therapy?

After formulating the question, follows the identification of possible sources of information.  For most of the questions encountered in general practice, where a swift response is required, the electronic information sources with frequent updates will be the best. This does not, however, render paper sources of information obsolete. It is just that the electronic media is much more accessible, and well indexed, and most importantly is much more up to date. With the internet it is also possible to link to unlimited related and supplementary sources of information.

You may ask: "So I need evidence. Now tell me how and where to find it?"   You find the answer to this question in the following section.

The key aspect of providing evidence-based health care is keeping tabs on the availability, scope as well as the quality of any new resource(s) which might be directly pertinent to your own professional practice.

However, keeping up-to-date means reading journals and this can prove to be very time-consuming. To be able to keep up to date with the current research a doctor will fill his day reading articles and have no time to see patients. This is not possible, but doctors caring for patients need information on what the best treatment for a particular patient may be.

In order to overcome this problem there are several secondary publications available that provide summaries or abstracts of key articles of importance to particular clinical practitioners. 

Some examples of secondary journals include:

• ACP Journal Club
• Evidence-Based Medicine

These secondary publications observe two basic principles in order to make information useful to the user.

1. They use explicit criteria for seeking and selecting the studies that will be featured. It is made very clear to the reader which journals have been covered and how the articles have been selected.
2. They try to report enough information about the methods of the studies ed. This is to enable the reader to judge for themselves the quality and applicability for a particular situation.

where to search
The best sources to search for information will be electronic bibliographic databases such as PubMED/MEDLINE or The Cochrane Library.  These databases cover the health literature and are continually updated as new information is published. The information contained within these is also peer reviewed literature.

how to search
Once the resources to be searched have been identified the search strategy needs to be designed.

This is done by identifying the key concepts within the clinical question. Using our case study it will be ‘antiretroviral therapy’ (ART) and ‘optimal timing’.
Good questions serve as the backbone of both the practice and the teaching of EBM.

The basic steps for acquiring the evidence to support a clinical decision appears in Fig 1.

Figure 1: The steps in acquiring evidence