Szajewska 2004.

Study characteristics
Methods	RCT
Participants	Preterm infants, body weight < 2500 g with ≥ 1 first‐degree relative with atopy
Interventions	Extensively (n = 26) or partially hydrolysed whey‐casein preterm formula* (n = 32) Standard preterm formula* (n = 32)
Outcomes	Allergic disease in infancy Feed intolerance
Notes	Primary aim: to assess effects on allergy and atopic disease In‐hospital feed tolerance, growth, and adverse outcomes not reported. We contacted corresponding author in December 2016 to seek these data * Energy content of both formulas: 80 kcal/100 mL 33% "dropout" before assessment at 4 to 5 months post term
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised schedule generated ‐ unspecified how
Allocation concealment (selection bias)	Low risk	Sealed numbered envelopes ‐ not stated whether opaque, but codes concealed from investigators until trial completed
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	"Double‐blind" but study and control formulas not identical in texture and smell
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	"Double‐blind" but study and control formulas not identical in texture and smell
Incomplete outcome data (attrition bias) All outcomes	Low risk	Outcomes reported for all participants
Selective reporting (reporting bias)	Unclear risk	Protocol not available
Other bias	Unclear risk	Funded by Ovita Nutricia Research Foundation

n: number of infants. 
RCT: randomised controlled trial.