Evidence-based medicine: the conundrum of grading systems

To provide a review and commentary of various systems that grade the strength of a body of evidence for evaluating health care recommendations.

A PubMed literature review was conducted between the years 2000 and 2013 using the following key words: evidence, grading systems, health care decisions, evidence quality, GRADE, and GRADE Working Group. The search focused on guidelines, review articles, and descriptive articles from prominent journals.

A total of 50 articles were reviewed, of which 24 were selected for inclusion. Selected articles prior to the year 2000 were included strictly for background information. Articles were included based on the reputation of the journal or publishing body and whether the content addresses the objective of this review.

A large number of varying grading systems exist, and some use numerical grading while others use prose recommendations. These systems help clinicians decipher the evidence; however, evaluating a multitude of grading systems, which are not only inconsistent but also contain their own inherent strengths and weaknesses, makes evaluation complex.

Clinicians face a challenge when deciding which of these grading systems to use. The GRADE (Grading of Recommendations Assessment, Development, and Evaluation) Working Group began in 2000 as an informal collaboration of people with an interest in addressing the shortcomings of present grading systems in health care. Many international organizations have adopted and/or endorsed the GRADE system or modified it for use in practice. Nevertheless, the true effectiveness of the system as a universal methodology for grading evidence still remains to be validated. To date, there has not been any literature-based proof of its validity; therefore, further research should be conducted in this area.