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 Table of Contents  
Year : 2020  |  Volume : 6  |  Issue : 4  |  Page : 294-300

The use of calorically dense enteral formulas in adult home enteral nutrition population in a tertiary care center: A retrospective analysis

1 Division of Endocrinology, Diabetes, Metabolism and Nutrition, Mayo Clinic, Rochester, MN, USA
2 Division of Endocrinology, Diabetes, Metabolism and Nutrition, Mayo Clinic; Division of General Internal Medicine, Mayo Clinic, Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN, Division of Gastroenterology, Hepatology and Nutrition, University of Louisville, KY, USA

Date of Submission14-Jul-2020
Date of Acceptance21-Nov-2020
Date of Web Publication24-Dec-2020

Correspondence Address:
Dr. Manpreet S Mundi
Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, 200 First St SW, Rochester, MN 55905
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/IJAM.IJAM_92_20

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Introduction: The prevalence of home enteral nutrition (HEN) has increased dramatically as studies showing clinical benefit have emerged. During this time, the practice of HEN has evolved as well including the availability of diverse formulas ranging in macronutrient distribution and concentration. Despite this availability, there continues to be a paucity of data regarding the efficacy of 2.0 kcal/ml density formulas in the HEN population.
Materials and Methods: A retrospective review of HEN database was conducted for the use of concentrated formula (2.0 kcal/ml). Baseline variables as well as efficacy of formula were assessed.
Results: In the time period evaluated, 32 HEN patients with a mean age of 58 ± 13.4 years met inclusion criteria. A total of 25 (78.1%) patients were male, the most common indication for HEN was dysphagia (53.1%), and the most common diagnosis was head-and-neck cancer (65.7%). The vast majority (87.4%) received concentrated formula through percutaneous gastrostomy (PEG) and were able to receive 93.1% ±19.7% of their goal calories needs as well as 98.5% ±21.7% of their goal protein needs. A total of 9 (28%) patients were initially started on concentrated formula, whereas 23 (72%) were switched from their initial formula with most common indication being the need for additional calories. Twenty-nine patients (90.6%) were able to utilize the formula as their primary source of nutrition with 22 patients (69%) reported no adverse effects.
Conclusions: Our study found that the use of concentrated formula was well tolerated in a diverse cohort of patients, meeting their calorie and protein needs.
The following core competencies are addressed in this article: Medical knowledge, Practice-based learning, Systems-based practice.

Keywords: Home enteral nutrition, nutritional formulation, nutrition support

How to cite this article:
Narasimhan R, Patel JM, Velapati SR, Mohamed Elfadil O, Hurt RT, Mundi MS. The use of calorically dense enteral formulas in adult home enteral nutrition population in a tertiary care center: A retrospective analysis. Int J Acad Med 2020;6:294-300

How to cite this URL:
Narasimhan R, Patel JM, Velapati SR, Mohamed Elfadil O, Hurt RT, Mundi MS. The use of calorically dense enteral formulas in adult home enteral nutrition population in a tertiary care center: A retrospective analysis. Int J Acad Med [serial online] 2020 [cited 2023 Jan 31];6:294-300. Available from: https://www.ijam-web.org/text.asp?2020/6/4/294/304606

  Introduction Top

Over the past two decades, there has been a tremendous rise in the prevalence of home enteral nutrition (HEN), with recent studies estimating an increase from 152,000 patients receiving HEN in the United States in 1992 to 437,882 HEN patients in 2013.[1],[2] A number of factors have led to this increase including multiple studies showing clinical benefits of enteral nutrition such as lower incidence of morbidity, reduction in infection, length of hospital and intensive care unit (ICU) stay, as well as a favorable cost compared to parenteral nutrition.[2],[3] In addition, there has also been a number of major advances in enteral formula specifically reflecting influences of sciences of food, nutrition, and medicine.[4] Over the years, specialized immune-enhancing nutritional formulations have been developed, and their early initiation in ICU patients and patients undergoing gastrointestinal (GI) surgery has demonstrated decreased indexes of inflammation, decreased organ failure, improved cell-mediated immunity, improved outcomes, and reduction in length of stay.[5],[6],[7],[8] Additional advances have also been made in the macronutrient composition and concentration of formulas available. However, despite the availability of a wide variety of formula with concentrations ranging from 1.0–2.0 calories/ml, there is a paucity of data regarding clinical outcomes, especially in the HEN population. This diversity in formulas available does allow HEN to be tailored to the patient's underlying medical conditions and to meet the needs of an increasingly diverse patient population; however, it has led to difficulty in achieving standardization.

Such a scenario exists regarding the use of concentrated formulas (2 calories/ml). Currently, most HEN programs initiate feeding with standard polymeric formulas (SPF), typically providing 1.0–1.5 calories/ml. However, some patients need a significant volume of SPF to meet their calorie needs, which can lead to GI intolerance, volume overload, and reduced compliance.[9] In addition to those needing significant calories, another cohort that may benefit from higher concentration formulas includes those who are volume sensitive and need fluid restriction such as those with congestive heart failure or renal failure. Despite the theoretical benefit of using concentrated formulas in these cohorts, clinical trials evaluating the safety and efficacy of concentrated formulas remain sparse.


This study was conducted to determine the outcome of energy dense formula (2 kcal/ml) in adults receiving HEN and to assess their efficacy in comparison to standard feeding formulas. The primary aim of the study was to assess the percent calorie and protein goals attained from providing an energy-dense formula, and the secondary aim was to evaluate its GI tolerance based on reporting of symptoms after initiation of the formula.

  Methods Top

Study sample and design

A thorough review of our prospectively maintained HEN database was conducted for patients on enteral tube feeds between March 1st, 2016, and March 31st, 2018.


The population of interest was adults (≥18 y/o) who received >90% of their nutritional needs through enteral nutrition and were on concentrated formula (2 kcal/ml) for at least a period of 3 weeks.


Baseline variables including patient demographics, primary illness, and indication for HEN were retrieved from electronic medical records. HEN data including nutritional status, body mass index (BMI), HEN regimen, nutritional requirement, symptoms of intolerance, and follow-up data were also collected. Harris–Benedict Formula was used to determine patients' daily energy needs. For the study population, all variables were reviewed for all patients; however, the reason for switching from initial formula to energy-dense formula was missing in nine entries.


The Center for Disease Control and Prevention definitions of Adult Overweight and Obesity were followed to describe the nutritional status of patients as malnourished if BMI is <18.5 kg/m2 and obese if BMI is >30 kg/m2.[10]

Statistical analysis

Baseline and follow-up categorical variables are provided in frequencies and percentages, whereas continuous variables are provided as means and standard deviations. Duration of tube feeding was reported as median with an interquartile range. Statistical analyses were performed using JMP Pro 14 software 2018 (SAS Institute, Cary, NC; USA, www.jmp.com), and a P < 0.05 (two-tailed) was set to be statistically significant.

Patient consent and standard protocol approvals

The study was approved by the Institutional Review Board of Mayo Clinic, Rochester. Since our study is of a passive nature, all the participants who had signed the Minnesota Research Authorization were included.

  Results Top

Study sample characteristics

After excluding samples with missing data points, a total of 32 HEN patients with a mean age of 58 ± 13.4 years met the inclusion criteria during the study period [Figure 1]. Most patients were male (78.1%, n = 25/32) [Table 1] and 65.7% (21/32) of patients had head-and-neck cancer, and with the second largest group of patients presenting with other carcinomas: esophageal cancer, meningioma, Hodgkin's lymphoma, and squamous cell carcinoma of the lung [Table 1]. The primary indications for tube feeding were dysphagia (53.1%) and malnutrition (22%). The vast majority (n = 21/32, 65.6%) of patients were started on the enteral feeds in an outpatient setting and 87.4% (n = 28/32) of patients received HEN through percutaneous gastrostomy (PEG). Only two patients (6.3%) received feeds through percutaneous jejunostomy (PEJ) and 2 patients (6.3%) received HEN through transgastric jejunal tube (TGJ). All patients received >90% of their daily requirement through tube feeds. The median length of feeding was 116 ± 248 days. None of the patients had congestive heart failure (0%) and 2 (6.3%) had acute kidney injury.
Figure 1: Flow chart depicting a selection of the study sample

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Table 1: Baseline demographics

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Metabolic requirements

The estimated mean calorie requirement as calculated using Harris–Benedict Calculator was 2126.2 ± 594.7 kcal and calories provided from formula at goal were 1953.1 ± 642.7 kcal.[11] Hence, the percent calorie provided at the goal rate was 93.1% ± 19.7%. The estimated mean protein requirement was 83.8 ± 21.7 g/day, and the protein provided from formula at goal was 82.0 ± 27.0 g/day. The percent protein provided at the goal rate was 98.5% ± 21.7%.

Enteral formula

Nutren® 2.0 (Nestlé Health Science, Bridgewater, New Jersey, USA) was the predominant concentrated formula used by our institution and 90.6% (29/32) of patients utilized it as their primary source of nutrition until the end of their HEN regimen [Table 2]. The other three patients (9.4%) had significant enough intolerance symptoms (nausea and vomiting) to be transitioned to other formula or oral intake: one patient was partially transitioned to a 1.5 kcal/ml energy-dense formula (Nutren® 1.5, Nestlé Health Science), while another patient was completely transitioned to the same 1.5 kcal/ml energy-dense formula, and the third patient was transitioned to oral nutrition. A total of 9 (28%) patients were started on Nutren® 2.0 at the initiation of HEN, while 23 (72%) patients were switched from their primary formula. The most common reason for the switch was the requirement of additional calories in 17 patients (53.2%) while on Nutren® 1.5 and 2 patients (6.3%) on Isosource® 1.5 (Nestlé Health Science, Bridgewater, NJ, USA) [Figure 2]. Symptoms of intolerance caused the switch to Nutren 2.0 (Nestlé Health Science, Bridgewater, NJ, USA) in the remaining patients. One patient reported diarrhea on Osmolite® 1.5 (Abbott Laboratories, Abbott Park, IL, USA), another had constipation and volume intolerance on Fibersource® HN (Nestlé Health Science, Bridgewater, NJ, USA), the third had hyperkalemia with multiple low-calorie formulas, and the last patient had significant nausea and dry heaves on Boost® VHC (Very High Calorie, Nestlé Health Science, Bridgewater, NJ, USA). Symptoms of intolerance resolved following the switch in all four patients.
Figure 2: Reason for the switch to concentrated formula

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Table 2: Home Enteral Nutrition characteristics

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Intolerance symptoms

The vast majority of patients (69%, n = 22/32) tolerated Nutren® 2.0 without any adverse effects [Table 2], while some patients (18.8%, n = 6/32) reported nausea and vomiting. Of these, two were partially/completely transitioned to Nutren® 1.5, one was transitioned to oral nutrition and the other three had resolution of symptoms following conservative measures (antiemetics, slower administration of formula, or usage of infusion pump). Four 12.5% (4/32) patients reported either diarrhea or a negative change in stool consistency [Figure 3]. Of these, one patient was fed through PEJ tube, and the other three were through PEG tube. Patients were able to meet goal feeds in 90.6% of patients and maintained weight. The mean weight of the population at the time of Nutren® 2.0 initiation was 68.6 ± 20.7 kg. The baseline BMI of the population was 22.5 ± 5.4 kg/m2. At the end of tube feeding, mean weight was 67.4 ± 18.2 kg and BMI was 22.3 ± 4.7 kg/m2. Further analysis of the cohort revealed that weight loss occurred mainly in obese patients (n = 5), while 75% (6/9) of malnourished patients (BMI <18.6 kg/m2) gained weight, and 66.7% (12/18) of patients were able to maintain or increase their weight.
Figure 3: Symptoms of intolerance on concentrated formula

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  Discussion Top

We retrospectively reviewed our prospectively maintained HEN database to evaluate our use of concentrated formulas including an indication of use and as efficacy. We noted that 32 patients were placed on concentrated formula during the study period and were able to meet their calorie and protein goals, leading to weight maintenance. The majority of patients tolerated the formula without any symptoms. Patients who did not tolerate the formula were switched to a lower calorie formula or oral nutrition, following which their symptoms subsided. We had originally assumed that concentrated formulas would more likely be utilized in volume-sensitive patients; however, we noted that only two patients had renal insufficiency and no patients in our cohort had congestive heart failure. The vast majority of patients were either placed on concentrated formula at the initiation of HEN or transitioned to concentrated formula due to the inability to meet calorie needs on lower concentrated formulas. Some patients were transitioned from other formulas due to intolerance and those symptoms resolved after transition.

The theoretical advantages of high caloric dense formula feeding are multifold; however, much of the previous literature has concentrated on the critically ill population. The early versus delayed enteral nutrition (EDEN) randomized control trial looked into the benefits of initial lower volume enteral feeding versus full feeds in patients with acute lung injury.[12] They observed that those on lower volume feeds had a decreased incidence of GI intolerance (1.7% vs. 2.2% for vomiting) and nosocomial infections (aspiration pneumonia). Although critiqued for examining low-risk patients, these findings substantiate ours in a similarly low-risk population. Enteral nutrition providing >50%–65% of goal energy has shown to improve gut integrity, mediate stress, and diminish intestinal permeability and in turn reduce mortality.[13],[14] In the Tight Caloric Control Study (TICACOS), repeated indirect calorimetry measurements were used to modify nutrition prescription. This resulted in patients in the intervention arm receiving significantly more calories than the control group (2086 ± 460 vs. 1480 ± 356 kcal/day; P = 0.01) and resulted in significantly improved clinical outcomes, evidenced by lower hospital mortality in the study group. Mean measured Resting Energy Expenditure was not significantly different in both groups.[15] Similar to our approach, a 2.0 kcal/ml enteral nutrition formula was preferentially used as the initial enteral formula in patients whose energy target was >1500 kcal/day. This study, although focusing on patients in the ICU setting, sets a precedent for studying similar outcomes in patients in the outpatient setup, especially in patients with high calorie needs.

Due to a paucity of data regarding the use of high-calorie formula in the HEN setting, our study is likely the first in exploring the efficacy and benefits of administering such enteral formula in the HEN cohort. Similar to the ICU setting, the use of high-calorie formula does have a number of theoretical benefits for the HEN patients. We initially theorized that the majority of concentrated formulas would be used in those requiring volume restrictions, such as individuals with renal disease or heart failure as that seemed to be the most logical indication. However, in our cohort, only ~5% of the patients on concentrated formula had these indications. Instead, in the majority of cases, concentrated formula was utilized in patients who were unable to meet their nutritional needs with the use of SPF. In these patients, further increasing the volume of SPF would lead to intolerance and decreased compliance due to the volume required to meet their nutrition needs. This was a similar approach to the TICACOS study and tended to apply to patients requiring more than 1500 kcal/day.

In addition to meeting nutritional needs, the use of concentrated formulas has also been shown to reduce GI symptoms in many cases. Internationally, in some countries, it is quite common to add soluble fiber or polysaccharide thickeners to enteral formula in an effort to reduce GI symptoms.[16],[17] As an example, compared to liquid formula, semi-solid formula created with the addition of thickener led to a significant decrease in gastroesophageal reflux as measured with scintigraphy.[17] Theoretically, the use of a more concentrated formula would have the same effect. This could have a significant impact on clinical outcomes as pneumonia resulting from aspiration of gastric contents has been closely associated to regurgitation resulting from enteral nutrition.[18]

Certainly, the use of more concentrated formula can be associated with symptoms of intolerance as well. As an example, diarrhea has been shown to occur with the rapid administration of highly osmolar formula, especially when directly fed into the small intestine (jejunum). This did not occur in all patients as we noted that only one of the two patients who received feedings through a PEJ, developed diarrhea substantiating prior studies.[19] Davies et al. found no difference in clinical outcomes, especially nutrient delivery and mortality between patients who had gastric versus jejunal access.[20] We did find that, in the four patients who were switched to concentrated formula due to intolerance of SPF, all four had resolution of their symptoms. However, with our current study, the number of patients receiving concentrated formula directly to the intestines is too limited to make any significant conclusions.


Because the data for the study is pulled from a prospectively maintained database, this study provides an insight on how enteral formulas are used in real-world settings. Despite this benefit, our study has a few additional limitations. First, the sample size of our study is small, thereby lowering our statistical power. This limited our ability to make conclusions regarding whether concentrated formulas could be beneficial when compared to SPF with regard to GI symptoms. However, since our findings are biologically significant, this pilot study could be utilized to design future randomized, placebo-controlled clinical trials. Second, the allocation of concentrated formula to patients was at the discretion of the treating provider, and this could lead to selection bias. However, future guidelines could be dictated regarding the implementation of high caloric enteral feeds in low-risk/non-ICU patients. Third, the lack of a comparison group with a similar distribution of demographic and clinical characteristics on standard treatment limits our knowledge to only one set of participants. Finally, our inclusion criterion was restricted to those adults on high caloric enteral feeds for at least a minimum of 3 weeks. We have not explored this phenomenon in the pediatric subpopulation due to a substantial lack of evidence and have looked into the GI tolerance of patients for a considerable time period.

  Conclusions Top

Our study notes that the use of concentrated formulas is well tolerated in a diverse set of participants, and their calorie requirements were suitably met. Based on these findings, the use of concentrated formula should be considered in patients who require >1500 kcal/day. Further randomized control trials will assist in determining additional benefits such as improvement in GI symptoms, as well other clinical outcomes.

Financial support and sponsorship

This study was performed with funding from Nestle Health Science.

Conflicts of interest

There are no conflicts of interest.

Research quality and ethics statement

The authors of this manuscript declare that this scientific work complies with reporting quality, formatting, and reproducibility guidelines set forth by the EQUATOR Network. The authors also attest that this clinical investigation was determined to require Institutional Review Board/Ethics Committee review, and the corresponding protocol/approval number is 19-012648.

  References Top

Howard L, Ament M, Fleming CR, Shike M, Steiger E. Current use and clinical outcome of home parenteral and enteral nutrition therapies in the united states. Gastroenterology 1995;109:355-65.  Back to cited text no. 1
Mundi MS, Pattinson A, McMahon MT, Davidson J, Hurt RT. Prevalence of home parenteral and enteral nutrition in the united states. Nutr Clin Pract 2017;32:799-805.  Back to cited text no. 2
Klek S, Szybinski P, Sierzega M, Szczepanek K, Sumlet M, Kupiec M, et al. Commercial enteral formulas and nutrition support teams improve the outcome of home enteral tube feeding. JPEN J Parenter Enteral Nutr 2011;35:380-5.  Back to cited text no. 3
Campbell SM. An anthology of advances in enteral tube feeding formulations. Nutr Clin Pract 2006;21:411-5.  Back to cited text no. 4
Marik PE, Zaloga GP. Early enteral nutrition in acutely ill patients: A systematic review. Crit Care Med 2001;29:2264-70.  Back to cited text no. 5
Heyland DK, Novak F, Drover JW, Jain M, Su X, Suchner U, et al. Should immunonutrition become routine in critically ill patients? A systematic review of the evidence. JAMA 2001;286:944-53.  Back to cited text no. 6
Marimuthu K, Varadhan KK, Ljungqvist O, Lobo DN. A meta-analysis of the effect of combinations of immune modulating nutrients on outcome in patients undergoing major open gastrointestinal surgery. Ann Surg 2012;255:1060-8.  Back to cited text no. 7
Osland E, Hossain MB, Khan S, Memon MA. Effect of timing of pharmaconutrition (immunonutrition) administration on outcomes of elective surgery for gastrointestinal malignancies: A systematic review and meta-analysis. JPEN J Parenter Enteral Nutr 2014;38:53-69.  Back to cited text no. 8
Gea Cabrera A, Sanz-Lorente M, Sanz-Valero J, López-Pintor E. Compliance and adherence to enteral nutrition treatment in adults: A Systematic review. Nutrients 2019;11:2627.  Back to cited text no. 9
Defining Adult Overweight and Obesity | Overweight & Obesity | CDC. Available from: https://www.cdc.gov/obesity/adult/defining.html. [Last accessed on 2019 Jul 07].  Back to cited text no. 10
Harris JA, Benedict FG. A biometric study of human basal metabolism. Proc Natl Acad Sci U S A 1918;4:370-3.  Back to cited text no. 11
National Heart, Lung, and Blood Institute Acute Respiratory Distress Syndrome (ARDS) Clinical Trials Network, Rice TW, Wheeler AP, Thompson BT, Steingrub J, Hite RD, et al. Initial trophic vs full enteral feeding in patients with acute lung injury: The EDEN randomized trial. JAMA 2012;307:795-803.  Back to cited text no. 12
Jabbar A, Chang WK, Dryden GW, McClave SA. Gut immunology and the differential response to feeding and starvation. Nutr Clin Pract 2003;18:461-82.  Back to cited text no. 13
Hiesmayr M, Schindler K, Pernicka E, Schuh C, Schoeniger-Hekele A, Bauer P, et al. Decreased food intake is a risk factor for mortality in hospitalised patients: The Nutrition Day survey 2006. Clin Nutr 2009;28:484-91.  Back to cited text no. 14
Singer P, Anbar R, Cohen J, Shapiro H, Shalita-Chesner M, Lev S, et al. The tight calorie control study (TICACOS): A prospective, randomized, controlled pilot study of nutritional support in critically ill patients. Intensive Care Med 2011;37:601-9.  Back to cited text no. 15
Wakita M, Masui H, Ichimaru S, Amagai T. Determinant factors of the viscosity of enteral formulas: Basic analysis of thickened enteral formulas. Nutr Clin Pract 2012;27:82-90.  Back to cited text no. 16
Nishiwaki S, Araki H, Shirakami Y, Kawaguchi J, Kawade N, Iwashita M, et al. Inhibition of gastroesophageal reflux by semi-solid nutrients in patients with percutaneous endoscopic gastrostomy. JPEN J Parenter Enteral Nutr 2009;33:513-9.  Back to cited text no. 17
Heyland DK, Drover JW, MacDonald S, Novak F, Lam M. Effect of postpyloric feeding on gastroesophageal regurgitation and pulmonary microaspiration: Results of a randomized controlled trial. Crit Care Med 2001;29:1495-501.  Back to cited text no. 18
Niv E, Fireman Z, Vaisman N. Post-pyloric feeding. World J Gastroenterol 2009;15:1281-8.  Back to cited text no. 19
Davies AR, Morrison SS, Bailey MJ, Bellomo R, Cooper DJ, Doig GS, et al. A multicenter, randomized controlled trial comparing early nasojejunal with nasogastric nutrition in critical illness. Crit Care Med 2012;40:2342.  Back to cited text no. 20


  [Figure 1], [Figure 2], [Figure 3]

  [Table 1], [Table 2]

This article has been cited by
1 Growing use of home enteral nutrition: a great tool in nutrition practice toolbox
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Current Opinion in Clinical Nutrition & Metabolic Care. 2021; 24(5): 446
[Pubmed] | [DOI]


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