Systematic reviews and their role in evidence-informed health care.

Systematic reviews are defined as convenient evidential summaries for clinicians which serve as a powerful tool for patient care decisions. They are considered to be the basis for guidelines of medical practice suggesting directions for new research. These scientific reviews, constructed through well-defined methods, have key role in Evidence-Informed Health Care which means to apply new therapies and treatments, which are proved to be effective for a particular treatment by authentic and quality researches, in clinical practice. The art of medicine requires for practice a very sound and up to date clinical knowledge by means of which clinicians can conquer the different challenges. However, a clinician can not depend on the result of a single study for making decisions in clinical practice. The solution to this dilemma is systematic reviews as they provide a precise summary of a topic and have many advantages over narrative reviews. Meta-analysis is a technique which plays an important role in increasing the precision of systematic reviews. Steps of preparation of a systematic review include: 1- Defining the review question, 2- Search and selection of studies, 3- Critical evaluation of studies for biases, 4- Data Collection, 5- Data analysis and presentation of results, 6- Interpretation of results and drawing conclusions, 7- Improving and updating reviews. A reader should first be able to evaluate the quality of a systematic review before practicing the evidence provided by it as it helps to practice the provided evidence more effectively.