High versus low medium chain triglyceride content of formula for promoting short-term growth of preterm infants.

BACKGROUND: In-hospital growth of preterm infants remains a challenge in clinical practice. The high nutrient demands of preterm infants often lead to growth faltering. For preterm infants who cannot be fed maternal or donor breast milk or may require supplementation, preterm formulas with fat in the form of medium chain triglycerides (MCTs) or long chain triglycerides (LCTs) may be chosen to support nutrient utilization and to improve growth. MCTs are easily accessible to the preterm infant with an immature digestive system, and LCTs are beneficial for central nervous system development and visual function. Both have been incorporated into preterm formulas in varying amounts, but their effects on the preterm infant's short-term growth remain unclear. This is an update of a review originally published in 2002, then in 2007. OBJECTIVES: To determine the effects of formula containing high as opposed to low MCTs on early growth in preterm infants fed a diet consisting primarily of formula.  SEARCH METHODS: We used the standard search strategy of Cochrane Neonatal to search Cochrane Central Register of Controlled Trials (CENTRAL; 2020, Issue 8), in the Cochrane Library; Ovid MEDLINE Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Ovid MEDLINE(R) Daily, and Ovid MEDLINE(R); MEDLINE via PubMed for the previous year; and Cumulative Index to Nursing and Allied Health Literature (CINAHL), on 16 September 2020. We also searched clinical trials databases and the reference lists of retrieved articles for randomized controlled trials (RCTs) and quasi-RCTs. SELECTION CRITERIA: We included all randomized and quasi-randomized trials comparing the effects of feeding high versus low MCT formula (for a minimum of five days) on the short-term growth of preterm (< 37 weeks' gestation) infants. We defined high MCT formula as 30% or more by weight, and low MCT formula as less than 30% by weight. The infants must be on full enteral diets, and the allocated formula must be the predominant source of nutrition. DATA COLLECTION AND ANALYSIS: The review authors assessed each study's quality and extracted data on growth parameters as well as adverse effects from included studies. All data used in analysis were continuous; therefore, mean differences with 95% confidence intervals were reported. We used the GRADE approach to assess the certainty of evidence. MAIN RESULTS: We identified 10 eligible trials (253 infants) and extracted relevant growth data from 7 of these trials (136 infants). These studies were found to provide evidence of very low to low certainty. Risk of bias was noted, as few studies described specific methods for random sequence generation, allocation concealment, or blinding. We found no evidence of differences in short-term growth parameters when high and low MCT formulas were compared. As compared to low MCT formula, preterm infants fed high MCT formula showed little to no difference in weight gain velocity (g/kg/d) during the intervention, with a typical mean difference (MD) of -0.21 g/kg/d (95% confidence interval (CI) -1.24 to 0.83; 6 studies, 118 infants; low-certainty evidence). The analysis for weight gain (g/d) did not show evidence of differences, with an MD of 0.00 g/d (95% CI -5.93 to 5.93; 1 study, 18 infants; very low-certainty evidence), finding an average weight gain of 20 ± 5.9 versus 20 ± 6.9 g/d for high and low MCT groups, respectively. We found that length gain showed no difference between low and high MCT formulas, with a typical MD of 0.10 cm/week (95% CI -0.09 to 0.29; 3 studies, 61 infants; very low-certainty evidence). Head circumference gain also showed little to no difference during the intervention period, with an MD of -0.04 cm/week (95% CI -0.17 to 0.09; 3 studies, 61 infants; low-certainty evidence). Two studies reported skinfold thickness with different measurement definitions, and evidence was insufficient to determine if there was a difference (2 studies, 32 infants; very low-certainty evidence). There are conflicting data (5 studies) as to formula tolerance, with 4 studies reporting narrative results of no observed clinical difference and 1 study reporting higher incidence of signs of gastrointestinal intolerance in high MCT formula groups. There is no evidence of effect on the incidence of necrotizing enterocolitis (NEC), based on small numbers in two trials. Review authors found no studies addressing long-term growth parameters or neurodevelopmental outcomes. AUTHORS' CONCLUSIONS: We found evidence of very low to low certainty suggesting no differences among short-term growth data for infants fed low versus high MCT formulas. Due to lack of evidence and uncertainty, neither formula type could be concluded to improve short-term growth outcomes or have fewer adverse effects. Further studies are necessary because the results from included studies are imprecise due to small numbers and do not address important long-term outcomes. Additional research should aim to clarify effects on formula tolerance and on long-term growth and neurodevelopmental outcomes, and should include larger study populations to better evaluate effect on NEC incidence.

Individualized versus standard diet fortification for growth and development in preterm infants receiving human milk.

BACKGROUND: Human milk as compared to formula reduces morbidity in preterm infants but requires fortification to meet their nutritional needs and to reduce the risk of extrauterine growth failure. Standard fortification methods are not individualized to the infant and assume that breast milk is uniform in nutritional content. Strategies for individualizing fortification are available; however it is not known whether these are safe, or if they improve outcomes in preterm infants. OBJECTIVES: To determine whether individualizing fortification of breast milk feeds in response to infant blood urea nitrogen (adjustable fortification) or to breast milk macronutrient content as measured with a milk analyzer (targeted fortification) reduces mortality and morbidity and promotes growth and development compared to standard, non-individualized fortification for preterm infants receiving human milk at < 37 weeks' gestation or at birth weight < 2500 grams. SEARCH METHODS: We used the standard search strategy of Cochrane Neonatal to search the Cochrane Central Register of Controlled Trials (CENTRAL; 2019, Issue 9), in the Cochrane Library; Ovid MEDLINE(R) and Epub Ahead of Print, In-Process & Other Non-Indexed Citations, Daily and Versions(R); and the Cumulative Index to Nursing and Allied Health Literature (CINAHL), on September 20, 2019. We also searched clinical trials databases and the reference lists of retrieved articles for pertinent randomized controlled trials (RCTs) and quasi-randomized trials. SELECTION CRITERIA: We considered randomized, quasi-randomized, and cluster-randomized controlled trials of preterm infants fed exclusively breast milk that compared a standard non-individualized fortification strategy to individualized fortification using a targeted or adjustable strategy. We considered studies that examined any use of fortification in eligible infants for a minimum duration of two weeks, initiated at any time during enteral feeding, and providing any regimen of human milk feeding. DATA COLLECTION AND ANALYSIS: Data were collected using the standard methods of Cochrane Neonatal. Two review authors evaluated the quality of the studies and extracted data. We reported analyses of continuous data using mean differences (MDs), and dichotomous data using risk ratios (RRs). We used the GRADE approach to assess the certainty of evidence. MAIN RESULTS: Data were extracted from seven RCTs, resulting in eight publications (521 total participants were enrolled among these studies), with duration of study interventions ranging from two to seven weeks. As compared to standard non-individualized fortification, individualized (targeted or adjustable) fortification of enteral feeds probably increased weight gain during the intervention (typical mean difference [MD] 1.88 g/kg/d, 95% confidence interval [CI] 1.26 to 2.50; 6 studies, 345 participants), may have increased length gain during the intervention (typical MD 0.43 mm/d, 95% CI 0.32 to 0.53; 5 studies, 242 participants), and may have increased head circumference gain during the intervention (typical MD 0.14 mm/d, 95% CI 0.06 to 0.23; 5 studies, 242 participants). Compared to standard non-individualized fortification, targeted fortification probably increased weight gain during the intervention (typical MD 1.87 g/kg/d, 95% CI 1.15 to 2.58; 4 studies, 269 participants) and may have increased length gain during the intervention (typical MD 0.45 mm/d, 95% CI 0.32 to 0.57; 3 studies, 166 participants). Adjustable fortification probably increased weight gain during the intervention (typical MD 2.86 g/kg/d, 95% CI 1.69 to 4.03; 3 studies, 96 participants), probably increased gain in length during the intervention (typical MD 0.54 mm/d, 95% CI 0.38 to 0.7; 3 studies, 96 participants), and increased gain in head circumference during the intervention (typical MD 0.36 mm/d, 95% CI 0.21 to 0.5; 3 studies, 96 participants). We are uncertain whether there are differences between individualized versus standard fortification strategies in the incidence of in-hospital mortality, bronchopulmonary dysplasia, necrotizing enterocolitis, culture-proven late-onset bacterial sepsis, retinopathy of prematurity, osteopenia, length of hospital stay, or post-hospital discharge growth. No study reported severe neurodevelopmental disability as an outcome. One study that was published after our literature search was completed is awaiting classification. AUTHORS' CONCLUSIONS: We found moderate- to low-certainty evidence suggesting that individualized (either targeted or adjustable) fortification of enteral feeds in very low birth weight infants increases growth velocity of weight, length, and head circumference during the intervention compared with standard non-individualized fortification. Evidence showing important in-hospital and post-discharge clinical outcomes was sparse and of very low certainty, precluding inferences regarding safety or clinical benefits beyond short-term growth.