Targeting 2.5 versus 4 g/kg/day of amino acids for extremely low birth weight infants: a randomized clinical trial

J Pediatr. 2013 Nov;163(5):1278-82.e1. doi: 10.1016/j.jpeds.2013.06.075. Epub 2013 Aug 12.


Objective: To compare the effect of 2.5 vs 4 g/kg/d of amino acid (AA) in parenteral nutrition of extremely low birth weight infants on metabolic tolerance, short-term growth, and neurodevelopment.

Study design: One hundred thirty-one infants with birth weight between 500 and 1249 g were randomized to 2.5 (standard AA [SAA] group) or 4 (high AA [HAA] group) g/kg/d AA intake, with equal nonprotein energy. The primary outcome was body size at 36 weeks.

Results: One hundred thirty-one patients were randomized and 114 analyzed (58 SAA group and 56 HAA group). Study groups had similar demographics and clinical characteristics. Elevated blood urea (BU >70 mg/dL = BU nitrogen >32.6 mg/dL) occurred in 24% vs 59% (P = .000) and hyperglycemia (>175 mg/dL) in 34% vs 11% (P = .003) of the SAA and HAA patients, respectively. Body weight, length, and head circumference at 36 weeks and 2 years were similar between groups. Bayley Scales of Infant and Toddler Development, Third Edition score was 94 ± 13 in the SAA group and 97 ± 15 in the HAA group (P = .35).

Conclusions: The HAA group had higher BU levels and better glucose control. An extra 8 g/kg of AA over the first 10 days of life did not improve growth and neurodevelopment.

Keywords: AA; Amino acid; BU; BU nitrogen; BUN; BW; Bayley III; Bayley Scales of Infant and Toddler Development, Third Edition; Birth weight; Blood urea; ELBWI; Extremely low birth weight infants; HAA; High amino acid; NPE; Nonprotein energy; PMA; PN; Parenteral nutrition; Postmenstrual age; RCT; Randomized clinical trial; SAA; Standard amino acid.

Publication types

  • Randomized Controlled Trial

MeSH terms

  • Amino Acids / administration & dosage*
  • Birth Weight
  • Body Height
  • Body Weight
  • Female
  • Humans
  • Infant
  • Infant, Extremely Low Birth Weight*
  • Infant, Newborn
  • Infant, Premature
  • Male
  • Nervous System / drug effects
  • Nervous System / growth & development*
  • Nitrogen / therapeutic use
  • Parenteral Nutrition
  • Time Factors
  • Urea / blood
  • Weight Gain / drug effects


  • Amino Acids
  • Urea
  • Nitrogen