Table 2.

Effects of Bifidobacterium animalis subsp. lactis on NEC risk and/or duration of hospitalization (DOH).

Study	Country	NEC (Bell stage ≥ II) frequency (no. with event divided by no. in treatment arm)		Average duration of hospitalization (days)		Registered	Sequence generation & Allocation concealment	Data collectors/outcome assessors blinded	Year last enrolled participant	Primary Outcome(s)	Comments1
		Treatment	Control	Treatment	Control
Stratiki et al.135	Greece	0/41	3/36	NA	NA	No	Low risk	Clinical staff were blinded as to treatment status, but blinding of outcome assessors not specified in text.	2005	Intestinal permeability	NEC stated as secondary outcome
Mihatsch et al.134	Germany	2/91	4/89	31.1	30.8	No	Low risk	Blinding of caregivers and investigators not specified in text.	2003	Nosocomial infections	NEC stated as secondary outcome
Dilli et al.114	Turkey	2/100*	18/100*	37*	50*	Yes (NCT01807858)‡	Low risk	The study is described as double blind in the methods, and the authors provide assurance that the staff and families were not aware of the treatment or control status of the infants. However, they also state that “ … the only personnel who knew of the infants’ group assignments were the investigators,” but do not provide specific assurance that the treatment assignment was concealed to the outcome assessors.	2014	NEC	DOH stated as secondary outcome
Hays et al.136	France	2/50	3/52	“The mean duration of hospitalization was 50.4 ± 17.4 days, which was similar for both treatment groups.”		Yes (NCT01379417)‡	Low risk	The investigators knew infants’ group assignments.	2010	Short-term postnatal growth and body composition	Outcome category unclear but not primary; secondary outcome was safety of probiotic administration

NA = not available.

*Difference in outcome between treatment and control arms was significant.