Guidelines, guidelines, guidelines: what are we to do with all of these North American guidelines?

Over the past decade, clinical guidelines for nutrition therapy in the critically ill have been developed by different North American societies. To avoid target audience confusion and uncertainty, there is a need to undergo a review of the content of these guidelines. In this review, the authors compared the grading systems, the levels of evidence used, and the content of North American nutrition clinical guidelines. The 3 clinical guidelines that met their search criteria and hence were included in the comparison are the Canadian Clinical Practice Guidelines, the American Dietetics Association's evidence-based guideline for critical illness, and the Society of Critical Care Medicine and American Society of Parenteral and Enteral Nutrition's joint guideline. Through their comparison, the authors have shown that although there are several topics where there is a similar direction of recommendation across the 3 societies/organizations, there are stark contrasts among many of the recommendations. These major differences can be attributed to the admission of different populations, lower levels of evidence or expert opinion into the guideline production process, lack of clarity in the link between the evidence and the recommendation, and lack of uniformity in the reporting of levels of evidence and grades of recommendation. The authors have identified the need for the North American nutrition organizations to harmonize the development of future nutrition guidelines in a timely way, so that they remain current and up-to-date. Furthermore, guideline users need to be aware of the dissimilarities in these guidelines before applying the recommendations to their daily practice.