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. 2022 Mar 1;2022(3):CD014067. doi: 10.1002/14651858.CD014067.pub2

Underwood 2009.

Study characteristics
Methods RCT
Participants 90 preterm (< 35 weeks) or low birth weight (750 to 2000 g) infants (most participants very preterm or VLBW)
Interventions [3‐arm trial]
Synbiotics (N = 61): (i) Lactobacillus rhamnosus (5 × 10⁸ cfu) OR (ii) L. acidophilus (1 × 1010 cfu) + Bifidobacterium longum (5 × 10⁸ cfu) + B. bifidum (cfu) +B. infantis (5 × 10⁸ cfu) plus inulin (dose not stated) given twice daily dissolved in saline for 28 days or until hospital discharge
Control (N = 29): placebo (1:30 dilute preparation of elemental formula)
Participating infants were fed with human milk or formula (or both).
Outcomes
  • Stool colonisation with probiotic species (primary outcome)

  • NEC

  • Death

  • Invasive infection

Notes USA (single centre: 2004‐ 06)
Funding: NIH UC Davis K30 Program (#UL1RR024146, MAU) and the Children's Miracle network (CLB).
Risk of bias
Bias Authors' judgement Support for judgement
Random sequence generation (selection bias) Low risk Computer‐generated
Allocation concealment (selection bias) Low risk Pharmacy‐assigned
Blinding of participants and personnel (performance bias)
All outcomes Low risk Masked (placebo‐controlled)
Blinding of outcome assessment (detection bias)
All outcomes Low risk Masked (placebo‐controlled)
Incomplete outcome data (attrition bias)
All outcomes Low risk Complete reporting
Selective reporting (reporting bias) Low risk Unlikely
Other bias Low risk No evidence baseline imbalance

cfu: colony‐forming units;FOS: fructo‐oligosaccharides;GOS: galacto‐oligosaccharides; NEC: necrotising enterocolitis; NIH:National Institutes of Health; RCT: randomized controlled trial; VLBW: very low birth weight