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JPEN J Parenter Enteral Nutr. 2016;40(1):8-9.
What Do We Know, How Do We Know It, and How Can We Best Apply It?
August DA.
Department of Surgery, Section of Gastrointestinal Surgical Oncology, Rutgers-Robert Wood Johnson Medical School and the Rutgers Cancer Institute of New Jersey, New Brunswick, New Jersey.
This month's issue of the Journal of Parenteral and Enteral Nutrition contains an article by Brody and colleagues[1] entitled, "Evaluating Evidence-Based Nutrition Support Practice Among Healthcare Professionals With and Without the Certified Nutrition Support Clinician Credential." In this article, the authors report the results of a study in which they surveyed a sample of convenience of American Society for Parenteral and Enteral Nutrition (A.S.P.E.N.) members, asking nutrition support questions about a clinical scenario concerning acute pancreatitis. The hypothesis of the study was that nutrition support practitioners certified by the National Board of Nutrition Support Certification would answer more of the questions in accordance with published nutrition support guidelines. The results of the survey confirmed the hypothesis; the certified practitioners answered a greater proportion of the 8 questions correctly than did noncertified practitioners (77% vs 57%; P < .001). Recognizing the limitations of their methods (knowledge about only a single clinical scenario was assessed, the response rate to the survey was only 9.1%, there was no information about differences between survey responders and nonresponders, and there was no way to determine whether the difference in knowledge base would have any impact on clinical outcomes in patients receiving parenteral nutrition), the authors' conclusions were appropriately measured. They noted, "The findings of this pilot study suggest that professionals holding the CNSC [Certified Nutrition Support Clinician] credential scored significantly higher on a case-based knowledge assessment of guideline recommendations for the nutrition support treatment of pancreatitis compared with those without a credential. Future research should evaluate the benefit of the credential on safe and efficacious nutrition support care by evaluating changes in patient care outcomes in healthcare settings."
The Brody et al[1] article highlights some of the challenges facing the nutrition support professional community. It exposes some of the frustrations we have as nutrition support practitioners as we try to demonstrate the value of nutrition support and our value added as nutrition support experts. Nutrition support (enteral or parenteral) is almost always an adjunctive therapy. It is a replacement for a normal physiologic function—namely, the ingestion of the nutrients necessary to maintain and restore health. The clear value of nutrition support is the prevention of starvation. Less clear is the role of nutrition support in restoring physiologic processes (eg, impaired immune function to fight infection, impaired wound healing, decreased muscle strength to ambulate) necessary to cure ill patients. There are multiple challenges to defining the benefits of nutrition support in specific clinical settings. Perhaps most important is the adjunctive nature of nutrition support. The attributable benefit of nutrition support in most situations (excluding starvation) is expected to be small. It seems obvious that treatment of the underlying disease and restoration of normal physiology through the use of drugs, surgery, and other therapies will have a much greater effect on clinical outcomes than the use of adjunctive therapies such as nutrition support, physical rehabilitation, and psychosocial support. For example, in all but the most malnourished patients with pancreatic cancer, well-executed surgery, meticulous perioperative management, radiation therapy, and chemotherapy are much more likely to affect outcomes than optimal nutrition support. Given the relatively small attributable effect of nutrition support, demonstration of the benefits of nutrition support in even well-executed clinical trials is difficult without large numbers of subjects, narrowly defined inclusion criteria, and great expense. Furthermore, the details of nutrition support therapy (energy goal and source, protein target, route of administration, timing of initiation, control of blood glucose levels, presence and degree of preexisting malnutrition) are thought to have a great influence on the safety and efficacy of the treatment. Almost all negative studies can be criticized over the failure to administer "optimal" nutrition therapy and thus rarely shed light on the true utility of nutrition support.
These uncertainties add further complexity to the question of the role of nutrition support clinicians in providing optimal nutrition therapy and improving patient outcomes. If it is difficult to define and demonstrate the benefits of "optimal" nutrition support, it is even more difficult to determine the role of nutrition support expertise in achieving improved clinical outcomes. The study by Brody et al[1] provides modest insight into this issue but unfortunately also highlights the enormity of the task ahead for our specialty.
Confronted with these challenges, how are we to proceed? First, our colleagues, our professions, and our patients deserve our utmost honesty. We must be realistic about what we do and do not know, as well as how we use our knowledge and experience to make patient care decisions. Second, we must be rigorous about our interpretation of the results of the studies that have been performed. The significance of study findings cannot be overstated, nor should they be extrapolated to situations to which they do not appropriately apply. For instance, while it is tempting to cite the study by Brody et al, to claim that nutrition support certification identifies superior practitioners who provide better patient care, such claims are well beyond the scope of the study (and, to their credit, the authors were very circumspect in confining the conclusions of their study to a limited statement about the knowledge base of certified practitioners). Third, we must look toward "pragmatic" studies to realistically answer questions concerning nutrition support use.[2] Finally, in this era of big data, system biology, data mining, and the ability to share administrative and clinical data from multiple sites, we must look to outcomes research to develop leads and hypotheses to perform high-yield clinical trials to define the use of nutrition support to improve patient outcomes. What do we know? Currently, not enough. How do we know it? Primarily through clinical trials that have not yet provided reliable answers to many of the questions facing us. How can we best apply what we know? Through the development of realistic, high-yield studies to provide more answers to allow us to better serve our patients and our subspecialty.
References
Brody R, Hise M, Marcus AF, Harvey-Banchik L, Matarese LE. Evaluating evidence-based nutrition support practice among healthcare professionals with and without the certified nutrition support clinician credential. JPEN J Parenter Enteral Nutr. 2015;40(1):107-114.
Harvey SE, Parrott F, Harrison DA, et al. Trial of the route of early nutritional support in critically ill adults. N Engl J Med. 2014;371:1673-1684.
PMID: 26679235
DOI: 10.1177/0148607115587950