No significant difference in definite late-onset sepsis or all-cause mortality was found , but this probiotic combination reduced NEC of Bell stage 2 or more ( 2.0 % versus 4.4 % ; relative risk 0.46 , 95 % confidence interval 0.23 to 0.93 , P = .03 ; number needed to treat 43 , 95 % confidence interval 23 to 333 ) .