Evidence and Perspectives for Choline Supplementation during Parenteral Nutrition—A Narrative Review
, Katrin A. Böckmann 1, Michaela Minarski 1, Cornelia Wiechers 1, Annegret Busch 2, Daniela Bach 2, Christian F. Poets 1 and Axel R. Franz 1,3,*Round 1
Reviewer 1 Report
Comments and Suggestions for Authors
MaxiMoM: Individualized Fortification of Human Milk
For Infants Born ≤ 1250 g; a Three Arm Randomized
Clinical Trial
WHAT IS/ARE THE PRINCIPAL RESEARCH QUESTIONS TO BE ADDRESSED?
Primary Research Question:
Does target or blood urea nitrogen (BUN) adjustable fortification of human milk fed during initialhospitalization, compared to Standard fortification, improve cognitive development of infants born ≤1250 g (or <30+0 weeks gestational age and < 1500 g) at 18-24 months CA?
Secondary Research Questions:
Does target or BUN adjustable fortification of human milk fed during initial hospitalization, compared to Standard fortification, of infants born ≤1250 g (or <30+0 weeks gestational age and < 1500 g):
1. Improve language and motor development at 18-24 months CA
2. Improve in-hospital weight, length, head circumference gains
3. Improve body composition
4. Impact mortality/morbidity (NEC, sepsis, chronic lung disease, retinopathy of prematurity [ROP])
5. Show an acceptable cost-effectiveness from a health care sector perspective?
Exploratory Research Questions:
Does target or BUN Adjustable fortification of human milk fed during initial hospitalization, compared to Standard fortification, of infants born <1250 g (or <30+0 weeks gestational age and < 1500 g):
1. Improve the likelihood that recommended energy and nutrient intakes are achieved
Whether maternal diet quality during lactation influences the efficacy of individualized fortification will also be explored.
STUDY DESIGN
This is a three arm, pragmatic, multi-centre, double-blind, randomized clinical trial designed to evaluate the effectiveness of standard versus target versus BUN adjustable fortification on growth, morbidityand neurodevelopment.
Study Day 1 is defined as the day that the infant reaches an enteral intake of 100 ml/kg/d (day fortification commences) and the infant has been randomized to one of the three arms in the study.
Control, Standard Fortification: Infants randomized to the standard fortification group will serve as controls and will receive human milk (mother’s own and donor milk) fortified from Study Day 1 onwards with a standard fixed dose of multi-nutrient fortifier and as appropriate nutrient modulars following the feeding guidelines outlined in Table 2 (found in the full proposal).
Intervention, Target Fortification: Commencing on Study Day 1, infants randomized to target fortification will receive human milk fortified with standard fortification. Once infants reach full enteral feeds (160 ml/kg/d) and for the duration of the feeding intervention, 2x weekly “analyzed” macronutrient values of human milk will be used to fortify enteral feeds using fat and protein modulars. The feeding guidelines for this arm of the study are outlined in Table 3 of the full proposal.
Intervention, BUN Adjustable Fortification: Commencing on Study Day 1, infants randomized to BUN adjustable fortification will receive human milk fortified with standard fortification. Once infants reach full enteral feeds (160 ml/kg/d) and for the duration of the feeding intervention, weekly BUN values will be used to adjust the fortification of enteral feeds using a protein modular. The feeding guidelines for this arm of the study are outlined in Table 4 of the full proposal.
Infants are weaned off the study intervention once any of the following criteria are met:
· Reached 36 weeks 0 days (except where they have not yet achieved 4 weeks in the feeding intervention)
· Is discharged home
· Received two oral feeds without top-up over three consecutive days.
INCLUSION AND EXCLUSION CRITERIA
Inclusion criteria
o ≤1250 g birth weight or GA <30+0 weeks and <1500 g
o Parental/guardian consent to participate.
o Consent for the use of pasteurized donor milk if mother’s milk is not available.
Exclusion criteria
o Infant received fortifier or formula before Study Day 1.
o Study Day 1 to occur after day 21 of life.
o Infants with congenital or chromosomal anomalies that may affect growth or neurodevelopment.
o Enrollment in any other clinical study affecting nutritional management during the feeding intervention.
o Reasonable potential that the infant will be transferred to a NICU before they have completed at least 4 weeks of the feeding intervention where the study protocol will not be continued.
GLOSSARY OF STUDY VARIABLES AND DEFINITIONS FOR DSMC
o Baseline variables include:
Sex (a/b)
Birth GA =gestational age of infants at birth
SGA = small for gestation age (yes/no)
PDA =patent ductus arteriosus (yes/no)
Birthweight
Birthlength
BirthHeadCircumference
o Progress through the trial metrics include:
Complete_FI =Completed Feeding Intervention (Yes/No)
Days_FI =Days in the Feeding Intervention
Withdrew_from_study  (Yes/No)
o Safety Outcomes to Be Assessed
Death (Yes/No)
NECII_III* (Yes/No)
LOS** (Yes/No) = Late onset sepsis
CLD*** (Yes/No) = Chronic lung disease
Severe ROP+ (Yes/No) = Severe retinopathy of Prematurity
Brain Injury++ (Yes/No)
Growth between study day 1 and end of the feeding intervention
· StudyDay1Weight; LastIntDayWeight
· StudyDay1Length; LastIntDayLength
· StudyDay1HeadCircumfernce; LastIntDayHeadCircumference
· zStudyDay1Weight;  zLastIntDayWeight
· StudyDay1Length;  zLastDAyIntLength
· StudyDay1HeadCircumfernce; zLastDayHead Circumference
*NECII_III
NEC staging system based upon historical, clinical and radiographic data.
o Stage I (Suspect)
a. Any one or more historical factors producing perinatal stress.
b. Systemic manifestations: temperature instability, lethargy, apnea, bradycardia.
c. Gastrointestinal manifestations: poor feeding, increasing pre-gavage residuals, emesis (may be bilious or test positive for occult blood), mild abdominal distension, occult blood may be present in stool (no fissure).
d. Abdominal radiographs show distension with mild ileus.
o Stage II (Definite)
a. Any one or more historical factors.
b. Above signs and symptoms plus persistent occult or gross gastrointestinal bleeding; marked abdominal distension.
c. Abdominal radiographs show significant intestinal distension with ileus; small bowel separation (edema in bowel wall or peritoneal fluid), unchanging or persistent “rigid” bowel loops, pneumatosis intestinalis, portal vein gas.
o Stage III (Advanced)
a. Any one or more historical factors.
b. Above signs and symptoms plus deterioration of vital signs, evidence of septic shock or marked gastrointestinal hemorrhage.
c. Abdominal radiographs may show pneumoperitoneum in addition to others listed in II c.
**LOS = Late onset sepsis
Late onset sepsis defined as a positive culture from blood, cerebrospinal fluid, catheter or suprapubic urine at >5 days of life and treatment with antibiotics.
CLD*** = Chronic lung disease
Need for supplemental O2 at 36 weeks.
Severe_ROP+ = Severe Retinopathy of Prematurity
Sub-total or total retinal detachment or if laser surgery or intraocular treatment is required (Grade 4 or 5 ROP).
Brain injury++
Brain injury defined as the presence of at least one of the following findings on cranial ultrasound scans: echodense intraparenchymal lesions (present in both coronal and saggital views on at least two consecutive head ultrasound scans), periventricular leukomalacia, porencephalic cysts, and ventriculomegaly (>2 SD of reference) with or without intraventricular hemorrhage.
Comments for author File: 
Comments.pdf
Author Response
RESPONSE: We thank the reviewer for assessing our manuscript, and appreciate your comments and suggestions to improve it. Accordingly, we have re-written many parts, particularly with respect to providing more detailed information on clinical studies as requested.
We rephrased the title (omitting the emphasis on critically ill term and preterm infants, because the available data do not permit such an emphasis). The abstract has been partly re-written, and the end of the introduction and the highlighted parts of the discussion. We included a brief information on regular choline intake of (preterm) infants via breast milk and formula, requiring two additional references (89 and 90; lines 401-412)
Other comments:
- The abstract does no emphasize the findings in critically ill term and preterm infants. In fact, premature infants are not mentioned here.
RESPONSE: Because the available data do not allow for emphasising term/preterm infants, we re-phrased the title and now only indicate that growing organisms have higher needs for choline and hence choline deficiency may be more even relevant to infants than adults. Age ranges of study subjects are now indicated throughout our manuscript.
- Lines 47-50. The necessity for supplements of DHA in preterm infants remains controversial, and this controversy would apply to choline supplementation in preterm infants which is the point of this paper. Would reword these sentences.
RESPONSE: This part has been rewritten as suggested (Lines 48-52).
- Results section. This section lacks the customary figure showing the flow diagram of the studies included in this narrative review, starting with the total number of articles identified and ending with the number of papers relevant to preterm and critically ill term infants.
RESPONSE: A flow diagram has been included and the text adapted (line 96f; New Fig. 1).
- Line 98. Clearly state here how many interventional studies were RCT’s and whether any included preterm and /or critically ill infants.
RESPONSE: These aspects are now clearly stated (Lines 102-104).
- Line 111. Delete the word “subsequently” and identify the subjects of this report-- adult (?) rats? (?) rats?
RESPONSE: “Subsequently” has been eliminated and the animal model (adult New Zealand rabbits) specified (Lines 120&121).
- Delete the bullet point for lines 140-145 and replace with a summary paragraph of the results of this section. Consider emphasizing any studies in newborn rats.
RESPONSE: Bullet points have now been eliminated and the para been re-written. (Lines 150-157)
- Line 147. Are these adult patients?
RESPONSE: Yes, thank you. Their age range has now been included (Line 159)
- Lines 158-159. Does this study include any critically ill term infants or preterm infants? What is included in “pediatric” patients?
RESPONSE: There were no critically ill term or preterm infants studied, and the age range is now specified. (Lines 170-172).
- Lines 171-177. Did either of these studies include critically ill term infants or premature infants?
RESPONSE: There were no critically ill patients, and their age ranges were specified. (Lines 184-190).
- Line 199—should probably state “post partum women” here.
RESPONSE: This statement is indeed on non-pregnant women having participated in the study, not on mothers of the newborns after delivery or any other post-partum mothers.
- Line 214. Not clear in this section if any studies included critically ill term infants or preterm infants. See comment #3 above.
RESPONSE: The patient characteristics, particularly their ages and that patients were in stable condition, is now specified (Lines 229-268).
- Line 235—how many adult patients were in this study?
RESPONSE: As stated, these were adult patients, and their age range and numbers are included. (Line 251-252)
- Lines 246-254. Not clear how many children/infants in this study are critically ill term infants or preterm infants?
RESPONSE: The number of patients, and that all were stable, has now been specified. (Line 261-273)
- Lines 256-257. In the 14 cited reviews, how many reviews were there in human subjects? Did these reviews include animal studies? This reviewer would suggest limiting the reviews to those including human data and state this here.
RESPONSE: The reviews are now clearly defined (all but one also referred (at least in part) to human data). However, we would prefer to leave ref. 66 within the text, as mouse models are instructive to understand human choline deficiency-related liver disease. (Line 276-282)
- Lines 304-305 Spell out these abbreviations for various groups. Note the new designation for IOM.
RESPONSE: We have spelled out all abbreviations of the groups now. (Line 330-336)
Reviewer 2 Report
Comments and Suggestions for Authors
Re-inventing the Wheel: Evidence for Parenteral Choline Supplementation in Critically Ill Term and Preterm Infants
The review by Bernhard et al is focused on reviewing the literature regarding choline intervention in critical infants (human and animal models). Overall, the review highlights several significant methodological weaknesses that compromise the final quality of the article, as summarized below:
1. In the title of the paper, what do you mean by "reinventing the wheel"?
2. In the introduction, the authors write the importance of choline for metabolism under homeostatic conditions. However, the specific role of this nutrient in preterm neonates or children in TPN is not clear. Furthermore, the aim of this review is also unclear: is the primary objective to investigate the prevalence of choline deficiency in critically ill pediatric patients or to examine the effects of adding choline to parenteral nutrition in pediatric patients?
3. In the methods section, the inclusion and exclusion criteria were not described. Additionally, there was no mention of a peer review process, as recommended for systematic literature reviews. The authors included various types of studies with significantly disparate methodologies (e.g., letters to the editor, pre-clinical studies, clinical studies, literature reviews, etc.). Due to the clear methodological differences among the included studies, it seems unlikely that these findings can be included in a systematic literature review. There does not appear to have been a systematic search with pre-defined methodological criteria for screening the studies to be included in the results.
4. In the discussion, as well as in the introduction, the authors mention that this is a "narrative review of a systematic review" (lines 79 and 349). Such a study type does not exist. It is either a narrative review or a systematic review. In any case, the presented work does not meet the criteria of a systematic review (due to the aforementioned methodological weaknesses) and cannot be a narrative review because the results are summarized as in a systematic review. Furthermore, the title and introduction of the article suggest that the evaluated population will be pediatric. However, upon evaluating the studies included in this review, it is observed that there are studies in adult populations as well as models of NAFLD and guidelines on this topic.
Author Response
RESPONSE: Dear reviewer – thank you for taking the time to review our manuscript, we appreciate your thoughtful comments and suggestions helping to improve this manuscript!
- In the title of the paper, what do you mean by "reinventing the wheel"?
RESPONSE: The intention was to highlight the fact that we report data that was acquired several decades ago – but the medical community failed to perform pivotal trials and (if successful) to integrate the knowledge into clinical care.
We have now deleted this phrase from the title (Line 2&3)
- In the introduction, the authors write the importance of choline for metabolism under homeostatic conditions. However, the specific role of this nutrient in preterm neonates or children in TPN is not clear. Furthermore, the aim of this review is also unclear: is the primary objective to investigate the prevalence of choline deficiency in critically ill pediatric patients or to examine the effects of adding choline to parenteral nutrition in pediatric patients?
RESPONSE: The aim of the review is to summarize available knowledge of the (potential) role of choline supplementation during parenteral nutrition for hepatic health and overall growth and development. We re-phrased the last para of the introduction. (Line 77-83)
- In the methods section, the inclusion and exclusion criteria were not described. Additionally, there was no mention of a peer review process, as recommended for systematic literature reviews. The authors included various types of studies with significantly disparate methodologies (e.g., letters to the editor, pre-clinical studies, clinical studies, literature reviews, etc.). Due to the clear methodological differences among the included studies, it seems unlikely that these findings can be included in a systematic literature review. There does not appear to have been a systematic search with pre-defined methodological criteria for screening the studies to be included in the results.
RESPONSE: We agree: this is not a systematic review with meta-analysis. It is “a narrative review based on a systematic literature search” as stated at the end of the introduction. (not “a narrative review of a systematic review” as quoted by the reviewer). The search terms used and the database screened are clearly defined in the methods. Moreover, the original complete search results (85 hits) are now provided as a supplementary table (Table S1). To be absolutely clear, we added “-a narrative review” to the title. (Line 3)
We clarified that there were no in-/exclusion criteria beyond “relevance to the topic” (choline supplementation during parenteral nutrition). And the majority of studies and reports retrieved during the search were hence included.
We did not limit the search/review to e.g. randomized interventional trials in humans or animals reporting any pre-defined outcomes, as we expected the paucity of trials would only result in the statement “there is insufficient data to draw any conclusions”, instead we aimed to provide a full account of the available data relevant to the topic. However, as appropriate given the lack of data that could be systematically summarized, we did not perform any meta-analysis – as stated by the reviewer. The result of our primary Pubmed search and the selection criteria are included as a flow diagram (Fig. 1) and an additional electronic file (Table S1). (Lines 93-104)
- In the discussion, as well as in the introduction, the authors mention that this is a "narrative review of a systematic review" (lines 79 and 349). Such a study type does not exist. It is either a narrative review or a systematic review. In any case, the presented work does not meet the criteria of a systematic review (due to the aforementioned methodological weaknesses) and cannot be a narrative review because the results are summarized as in a systematic review. Furthermore, the title and introduction of the article suggest that the evaluated population will be pediatric. However, upon evaluating the studies included in this review, it is observed that there are studies in adult populations as well as models of NAFLD and guidelines on this topic.
RESPONSE: We agree with the reviewer: there are narrative reviews or systematic reviews. Consequently, we did not write "narrative review of a systematic review". Instead we wrote “narrative review of a systematic literature search" in our manuscript. As above: this is a narrative review. This narrative review based on a systematic literature search with clearly defined search strategy (clearly defined database and search terms used) - so that everybody can reproduce the search – or identify deficiencies of the literature search and selection according to supplement Table S1 - and ensuring that we did not limit the review to publications that supported the authors’ own opinion (which one of the major limitations of narrative reviews).
We added “- a narrative review” to the title and completed the results as described above. (Line 3; lines 81 & 380; flow diagram, Fig. 1; line 97)
Reviewer 3 Report
Comments and Suggestions for Authors
Dear Authors,
I have revised the submitted manuscript entitled "Re-inventing the Wheel: Evidence for Parenteral Choline Supplementation in Critically Ill Term and Preterm Infants". The novelty and the need of the current study are of high importance; however, I do consider that the present paper needs minor improvements prior publication.
Minor comments:
1. What about the cultural and socioeconomic factors related to this subject? Examining the impact of cultural, socioeconomic, and healthcare system factors on the accessibility and compliance with choline supplementation protocols would enhance the implementation of the proposed solution. Please add a specific sub-section related to this subject.
2. In the results section, I recommend eliminating the bullets as they alter the article structure as narrative approach.
3. In the discussion section, I recommend to critically debate also the following gaps related to this subject, namely: optimal dosage and formulation, long-term outcomes (cognitive and developmental impacts), interaction with other nutrients, maternal influence (investigating how maternal choline status and supplementation during pregnancy and lactation affect neonatal outcomes, especially in preterm births).
Comments on the Quality of English Language
Minor editing of the English language is required
Author Response
RESPONSE: Dear reviewer – thank you for taking the time to review our manuscript, we appreciate your thoughtful comments and suggestions helping to improve this manuscript!
Minor comments:
- What about the cultural and socioeconomic factors related to this subject? Examining the impact of cultural, socioeconomic, and healthcare system factors on the accessibility and compliance with choline supplementation protocols would enhance the implementation of the proposed solution. Please add a specific sub-section related to this subject.
RESPONSE: Dear reviewer – thank you for this very important and thoughtful comment. We fully agree, cultural as well as socioeconomic impact on diet as well as genetic background have impact on choline intake and choline pools. In the context of pregnancy and fetal development/preterm birth/lactation it is of course maternal diet that will impact on fetal choline stores and content in breast milk. We will take your suggestion into account and are planning to do an appropriate literature search and write a separate and new manuscript on this issue, which we agree is of importance!
However, because the manuscript is very long already, we did not integrate this topic (cultural and socioeconomic impact) here, as the focus is on parenteral choline supplementation where cultural dietary preferences are less important and access to parenteral nutrition is an inherent prerequisite. Moreover, there are already recent publications addressing the topic of maternal choline supply (e. g. Obeid et al. 2024. A Narrative Review on Maternal Choline Intake and Liver Function of the Fetus and the Infant; Implications for Research, Policy, and Practice. Nutrients16(2):260. doi: 10.3390/nu16020260.). The issue of genetic polymorphisms likely impacting on choline needs also during parenteral nutrition was mentioned in the original manuscript already.
- In the results section, I recommend eliminating the bullets as they alter the article structure as narrative approach.
RESPONSE:
The bullets have been eliminated throughout.
- In the discussion section, I recommend to critically debate also the following gaps related to this subject, namely: optimal dosage and formulation, long-term outcomes (cognitive and developmental impacts), interaction with other nutrients, maternal influence (investigating how maternal choline status and supplementation during pregnancy and lactation affect neonatal outcomes, especially in preterm births).
RESPONSE: Thank you again! We re-phrased / clarified the sections related to dose, proposed formulation and potential interaction with other nutrients in parenteral nutrition solutions. We added a sentence on potential longer-term outcomes (cognitive and developmental impacts) (Lines 51-52). Changes of the discussion were made, and additional information on dosages is provided (403-414).
However, as stated above, to keep the focus on parenteral nutrition in an already complex manuscript, we did not add the additional chapter on maternal diet (including cultural background) and fetal choline stores – but we will happily do so in a different manuscript.
Comments on the Quality of English Language - Minor editing of the English language is required
RESPONSE: We carefully revised the manuscript for proper use of the English language.
Round 2
Reviewer 2 Report
Comments and Suggestions for Authors
The authors have complied with the requested corrections.
