Higher versus lower protein intake in formula-fed low birth weight infants

Dilute versus full-strength formula in exclusively formula-fed preterm or low birth weight infants

BACKGROUND

Preterm infants have fewer nutrient reserves at birth than full-term infants and often receive artificial formula feeds in the absence of expressed breast milk. Although it is generally agreed that feeding must be initiated slowly and advanced with much greater deliberation than in a healthy, full-term infant, the way in which feeds are introduced and advanced in preterm infants varies widely. This review focuses on whether dilute or full-strength formula is the preferable mode of introducing feeds in preterm infants for whom expressed breast milk is unavailable.

OBJECTIVES

To assess the effects of dilute versus full-strength formula on the incidence of necrotising enterocolitis, feeding intolerance, weight gain, length of stay in hosptial and time to achieve full calorie intake in exclusively formula-fed preterm or low birth weight infants. A secondary objective was to assess the effects of different dilution strategies.

SEARCH METHODS

We used the standard search strategy of Cochrane Neonatal to update the search in the Cochrane Central Register of Controlled Trials (CENTRAL 2018, Issue 9), MEDLINE via PubMed (1966 to 1 October 2018), Embase (1980 to 1 October 2018), and CINAHL (1982 to 1 October 2018).We searched clinical trials' registries for ongoing or recently completed trials (clinicaltrials.gov; the World Health Organization's International Trials Registry and Platform; and the ISRCTN Registry).

SELECTION CRITERIA

Randomised or quasi-randomised trials comparing strengths of formula milk in exclusively formula-fed preterm or low birth weight infants. We excluded studies if infants received formula as a supplement to breast milk.

DATA COLLECTION AND ANALYSIS

We independently assessed studies for inclusion. We collected data using the standard methods of Cochrane Neonatal, with independent assessment of risk of bias and data extraction. We synthesised mean differences using a fixed-effect meta-analysis model. We used the GRADE approach to assess the certainty of evidence.

MAIN RESULTS

We included three studies involving 102 preterm or low birth weight infants in the review. The studies compared dilute (double-volume, half-strength) formula with full-strength (20 kcal/oz (˜ 68 to 70 kcal/100 mL)) formula. We assessed all three studies as having unclear risk of bias due to the likely absence of blinding of study personnel and the potential for selection bias in the largest trial. Data for the primary outcome of necrotising enterocolitis were not reported in any of the studies. We could combine two of the studies (88 infants) in the meta-analysis. The evidence suggests that dilute formula with double-volume (half-strength) may lead to fewer episodes of gastric residuals per day (one study; mean difference (MD) -1.20, 95% confidence interval (CI) -2.20 to -0.20; low-certainty evidence), fewer episodes of gastric residuals per baby until attaining 100 kcal/kg (one study; MD -0.80, 95% CI -1.32 to -0.28; low-certainty evidence), fewer episodes of vomiting per day (one study; MD -0.04, 95% CI -0.07 to -0.01; low-certainty evidence) and fewer occurrences of abdominal distension greater than 2 cm (two studies; MD -0.16, 95% CI -0.19 to -0.13; low-certainty evidence). For the secondary outcomes, data suggest that infants in the dilute formula with double-volume (half-strength) group may have attained an adequate energy intake earlier than infants in the full-strength group (two studies; MD -2.26, 95% CI -2.85 to -1.67; low-certainty evidence). There was no evidence of a difference between groups for weight gain one week after commencement of intragastric feeds (one study; MD 0.05 kg, 95% CI -0.06 to 0.15; low-certainty evidence). Data were not reported for length of hospital stay.

AUTHORS' CONCLUSIONS

There is low-certainty evidence from three small, old trials that use of dilute formula in preterm or low birth weight formula-fed infants may lead to an important reduction in the time taken for preterm infants to attain an adequate energy intake.However, our confidence in this result is limited due to uncertainty over risk of bias and sparsity of available data. Dilute formula may reduce incidence of feeding intolerance, but the clinical significance of the reduction is uncertain. The impact on serious gastrointestinal problems, including necrotising enterocolitis, was not reported in any of the trials. Further randomised trials are needed to confirm these results.

Strategies of Increased Protein Intake in ELBW Infants Fed by Human Milk Lead to Long Term Benefits

Objective: The aim of this observational study was to evaluate the effects of two different protein intake regimes on feeding tolerance, in-hospital growth, anthropometric data and psychomotor outcome up to 24 months corrected age (CA) in extremely low birth-weight (ELBW; birth weight <1000 g) infants. Methods: During the period 2008-2013, 52 ELBW infants admitted at birth to two Neonatal Intensive Care Units of Emilia Romagna (Italy) were fed according to different protocols of protein fortification of human milk: an estimated protein intakes at maximum fortification levels of 3.5 gr/kg/day in the Standard Nutrition Population-SNP group (n = 26) and 4.8 g/kg/day in the Aggressive Nutrition Population-ANP group (n = 26). During hospitalization, infants' growth, biochemical indices of nutritional status, enteral intake, feeding tolerance, clinical history and morbidity were evaluated. After discharge, anthropometric data and psychomotor outcome, evaluated by Revised Griffiths Mental Development Scales (GMDS-R) 0-2 years, were assessed up to 24 months CA. Results: During hospitalization, the ANP group showed significantly higher weight (18.87 vs. 15.20 g/kg/day) and head circumference (0.70 vs. 0.52 cm/week) growth rates compared to SNP, less days of parenteral nutrition (7.36 ± 2.7 vs. 37.75 ± 29.6) and of hospitalization (60.0 ± 13.3 vs. 78.08 ± 21.32). After discharge, ANP infants had a greater head circumference compared to SNP (45.64 ± 0.29; 46.80 ± 0.31). Furthermore, the General Quotient of GMDS-R mean scores in the SNP group significantly decreased from 12 to 24 months CA, while no difference was seen in the ANP group. Conclusions: Increased protein intake may provide short and long term benefits in terms of growth and neurodevelopment in human milk-fed ELBW infants.

Dilute versus full strength formula in exclusively formula-fed preterm or low birth weight infants

BACKGROUND

Preterm infants have fewer nutrient reserves at birth than full term infants and often receive artificial formula feeds in the absence of expressed breast milk. Although it is generally agreed that feeding must be initiated slowly and advanced with much greater deliberation than in a healthy, full term infant, the way in which feeds are introduced and advanced in preterm infants varies widely. This review focuses on whether dilute or full strength formula is the preferable mode of introducing feeds in preterm infants.

OBJECTIVES

To assess the effects of dilute versus full strength formula on the incidence of necrotising enterocolitis, feeding intolerance, weight gain, length of stay and time to achieve full calorie intake in exclusively formula-fed preterm or low birth weight infants. A secondary objective was to assess the effects of different dilution strategies.

SEARCH METHODS

We used the standard search methods of the Cochrane Neonatal Review Group. This included searches of the Cochrane Central Register of Controlled Trials (The Cochrane Library 2013, Issue 1), MEDLINE (1946 to February 2013) and EMBASE (1974 to February 2013).

SELECTION CRITERIA

Randomised or quasi-randomised trials comparing strengths of formula milk in exclusively formula-fed preterm or low birth weight infants. Studies were excluded if infants received formula as a supplement to breast milk.

DATA COLLECTION AND ANALYSIS

We independently assessed studies for inclusion. We collected data using the standard methods of the Cochrane Neonatal Review Group, with independent assessment of risk of bias and data extraction. We synthesised mean differences using a fixed-effect meta-analysis model.

MAIN RESULTS

Three studies involving 102 preterm or low birth weight infants were included in the review. The studies compared dilute (double volume, half strength) formula with full strength (20 kcal/oz) formula. We assessed all three studies as being at unclear risk of bias due to the likely absence of blinding of study personnel and the potential for selection bias in the largest trial. Data for the primary outcome of necrotising enterocolitis were not reported in any of the studies. Two of the studies (88 infants) could be combined in the meta-analysis. Infants in the dilute formula with double volume (half strength) group had significantly fewer episodes of feeding intolerance. Infants in the dilute formula with double volume (half strength) group had fewer episodes of gastric residuals per day (one study, mean difference (MD) -1.20, 95% confidence interval (CI) -2.2 to -0.2), fewer episodes of gastric residuals per baby until attaining 100 kcal/kg (one study, MD -0.80, 95% CI -1.32 to -0.28), fewer episodes of vomiting per day (one study, MD -0.04, 95% CI -0.07 to -0.01) and fewer occurrences of abdominal distension greater than 2 cm (two studies, MD -0.16, 95% CI -0.19 to -0.13). For the secondary outcomes, infants in the dilute formula with double volume (half strength) group attained an adequate energy intake significantly earlier than infants in the full strength group (two studies, MD -2.26, 95% CI -2.85 to -1.67). For weight gain one week after commencement of intragastric feeds, the difference between groups was not statistically significant (one study, MD 0.05 kg, 95% CI -0.06 to 0.15). Data were not reported for length of hospital stay.

AUTHORS' CONCLUSIONS

There is evidence from three small, old trials at unclear risk of bias that use of dilute formula in preterm or low birth weight formula-fed infants leads to an important reduction in the time taken for these infants to attain an adequate energy intake. There was no evidence of important differences in feeding intolerance. The impact on serious gastrointestinal problems, including necrotising enterocolitis, was not reported. Further randomised trials are needed to confirm these results.