556841
research-article2015
PENXXX10.1177/0148607114556841Journal of Parenteral and Enteral Nutrition
Letters to the Editor
Full-Feeding With Enteral Nutrition Is Not Always “Full-Feeding” in Research and Clinical Practice DOI: 10.1177/0148607114556841
Dr Choi and colleagues1 recently published a meta-analysis to compare the effect of initial underfeeding with full feeding from enteral nutrition (EN) alone on mortality and other clinical outcomes in critically ill adults. The investigators concluded that “none of the analyzed clinical outcomes were significantly influenced . . . by the calorie intake of the initial EN.” We believe this conclusion to be flawed due to the study selection criteria used for the “full-feeding” group and due to the nature of the few available randomized trials on this topic. In our opinion, the fundamental difficulty in comparing studies of calorie intake relates to the inability to provide sufficient EN to meet calorie goals, even in research settings, and problems with accurate determination of calorie goals in this population. The authors attempted to identify a full-feeding group in their analysis by finding trials that sought to reach 90%–100% of predicted caloric requirements. However, the proportion of predicted caloric requirements actually delivered in the included studies ranged from 71.4% to 95%. Aside from the study that achieved 95% of requirements, we consider this still to be underfeeding. Hence the majority of the full-feeding patient group was still underfed, which may explain the lack of clinical outcome difference. Inability to meet calorie goals when using EN is a common clinical practice issue, with literature suggesting that on average only 45% of caloric goals are met.2 The other issue impacting this meta-analysis is the accurate prediction of calorie requirements. Three of the 4 trials included in the full-feeding group used a fixed prescription estimate method, and 1 trial used the Harris Benedict equation with adjusted stress factors to estimate calorie goals.1 These calorie estimation methods have been shown to be considerably inaccurate, either overestimating or underestimating compared with measured calorie goals.3 In our experience with indirect calorimetry, in practice and in research, we believe underfeeding to be more common than overfeeding when predictive equation estimates are used, meaning that the percentage of actual requirements provided to patients in these reported trials is highly likely to be less than reported. This would mean that the full-feeding group in the included trials may even be more underfed than reported. We have also noted that Figure 2 appears to be incorrectly labeled; the top part of this figure appears to pertain to the studies belonging to the “one-third to two-thirds of the standard caloric requirement” analysis and the middle pertains to the “lower onethird,” rather than how it was labeled in the publication.
Journal of Parenteral and Enteral Nutrition Volume 39 Number 4 May 2015 383–384 © 2015 American Society for Parenteral and Enteral Nutrition jpen.sagepub.com hosted at online.sagepub.com
We commend the authors for attempting to answer this question with what appears to be a methodologically robust meta-analysis; however, we don’t believe the study selection criteria for the full-feeding group allow this question to be answered satisfactorily. Clinicians’ inability to either determine or meet calorie goals for critically ill adults in both research and clinical practice requires further study. Emma Ridley, BNutriDiet, MPH Andrew Davies, FRACP David (Jamie) Cooper, BMBS, MD, FRACP, FCICM ANZIC Research Centre, Monash University, Melbourne, Australia
References 1. Choi EY, Park DA, Park J. Calorie intake of enteral nutrition and clinical outcomes in acutely critically ill patients: a meta-analysis of randomized controlled trials [published online July 30, 2014]. JPEN J Parenter Enteral Nutr. 2. Cahill NE, Dhaliwal R, Day AG, Jiang X, Heyland DK. Nutrition therapy in the critical care setting: what is “best achievable” practice? An international multicenter observational study. Crit Care Med. 2010;38(2):395-401. 3. Walker RN, Heuberger RA. Predictive equations for energy needs for the critically ill. Respir Care. 2009;54(4):509-521.
Response to Ridley et al DOI:10.1177/0148607114556842
We appreciate Ridley and colleagues’ interest in our article “Calorie Intake of Enteral Nutrition and Clinical Outcomes in Acutely Critically Ill Patients: A Meta-Analysis of Randomized Controlled Trials.”1 Your question might have originated from a matter of word choice. However, we do not believe that a term such as “full feeding” is incorrect. Your concept of full feeding is extremely ideal. As you know, there is no absolute standard of “full feeding” in adults. All 4 studies in our meta-analysis used different names for the full-feeding group: the immediate optimal-flow group, target feeding, full-energy feeding group, and full-feeding group, respectively. The term “full feeding” indicates the intention to reach the predicted caloric requirements as soon as possible,
Downloaded from pen.sagepub.com at FUDAN UNIV LIB on May 16, 2015
research-article2015
PENXXX10.1177/0148607114556841Journal of Parenteral and Enteral Nutrition
Letters to the Editor
Full-Feeding With Enteral Nutrition Is Not Always “Full-Feeding” in Research and Clinical Practice DOI: 10.1177/0148607114556841
Dr Choi and colleagues1 recently published a meta-analysis to compare the effect of initial underfeeding with full feeding from enteral nutrition (EN) alone on mortality and other clinical outcomes in critically ill adults. The investigators concluded that “none of the analyzed clinical outcomes were significantly influenced . . . by the calorie intake of the initial EN.” We believe this conclusion to be flawed due to the study selection criteria used for the “full-feeding” group and due to the nature of the few available randomized trials on this topic. In our opinion, the fundamental difficulty in comparing studies of calorie intake relates to the inability to provide sufficient EN to meet calorie goals, even in research settings, and problems with accurate determination of calorie goals in this population. The authors attempted to identify a full-feeding group in their analysis by finding trials that sought to reach 90%–100% of predicted caloric requirements. However, the proportion of predicted caloric requirements actually delivered in the included studies ranged from 71.4% to 95%. Aside from the study that achieved 95% of requirements, we consider this still to be underfeeding. Hence the majority of the full-feeding patient group was still underfed, which may explain the lack of clinical outcome difference. Inability to meet calorie goals when using EN is a common clinical practice issue, with literature suggesting that on average only 45% of caloric goals are met.2 The other issue impacting this meta-analysis is the accurate prediction of calorie requirements. Three of the 4 trials included in the full-feeding group used a fixed prescription estimate method, and 1 trial used the Harris Benedict equation with adjusted stress factors to estimate calorie goals.1 These calorie estimation methods have been shown to be considerably inaccurate, either overestimating or underestimating compared with measured calorie goals.3 In our experience with indirect calorimetry, in practice and in research, we believe underfeeding to be more common than overfeeding when predictive equation estimates are used, meaning that the percentage of actual requirements provided to patients in these reported trials is highly likely to be less than reported. This would mean that the full-feeding group in the included trials may even be more underfed than reported. We have also noted that Figure 2 appears to be incorrectly labeled; the top part of this figure appears to pertain to the studies belonging to the “one-third to two-thirds of the standard caloric requirement” analysis and the middle pertains to the “lower onethird,” rather than how it was labeled in the publication.
Journal of Parenteral and Enteral Nutrition Volume 39 Number 4 May 2015 383–384 © 2015 American Society for Parenteral and Enteral Nutrition jpen.sagepub.com hosted at online.sagepub.com
We commend the authors for attempting to answer this question with what appears to be a methodologically robust meta-analysis; however, we don’t believe the study selection criteria for the full-feeding group allow this question to be answered satisfactorily. Clinicians’ inability to either determine or meet calorie goals for critically ill adults in both research and clinical practice requires further study. Emma Ridley, BNutriDiet, MPH Andrew Davies, FRACP David (Jamie) Cooper, BMBS, MD, FRACP, FCICM ANZIC Research Centre, Monash University, Melbourne, Australia
References 1. Choi EY, Park DA, Park J. Calorie intake of enteral nutrition and clinical outcomes in acutely critically ill patients: a meta-analysis of randomized controlled trials [published online July 30, 2014]. JPEN J Parenter Enteral Nutr. 2. Cahill NE, Dhaliwal R, Day AG, Jiang X, Heyland DK. Nutrition therapy in the critical care setting: what is “best achievable” practice? An international multicenter observational study. Crit Care Med. 2010;38(2):395-401. 3. Walker RN, Heuberger RA. Predictive equations for energy needs for the critically ill. Respir Care. 2009;54(4):509-521.
Response to Ridley et al DOI:10.1177/0148607114556842
We appreciate Ridley and colleagues’ interest in our article “Calorie Intake of Enteral Nutrition and Clinical Outcomes in Acutely Critically Ill Patients: A Meta-Analysis of Randomized Controlled Trials.”1 Your question might have originated from a matter of word choice. However, we do not believe that a term such as “full feeding” is incorrect. Your concept of full feeding is extremely ideal. As you know, there is no absolute standard of “full feeding” in adults. All 4 studies in our meta-analysis used different names for the full-feeding group: the immediate optimal-flow group, target feeding, full-energy feeding group, and full-feeding group, respectively. The term “full feeding” indicates the intention to reach the predicted caloric requirements as soon as possible,
Downloaded from pen.sagepub.com at FUDAN UNIV LIB on May 16, 2015
