2.5.2. IGSQ
The IGSQ total score at each visit was analysed using a linear mixed model for repeated measurements, with the visit (from V2 to V4), the infant formula group, the interaction between visit and infant formula group, and the sex as fixed effects, and the subject and centre as random effects. For the specific analysis of individual questions of the IGSQ at each visit, a mixed logistic ordinal model (for repeated measurements) with the same variables for fixed and random effects as the IGSQ total score analysis was used.Furthermore, a post-hoc analysis was performed in order to assess any effect of medications or products which may positively influence GI tolerance. In the subgroup of infants who did not receive such products, a mixed linear model (for repeated measurements) was used to compare eHF and CF with regard to IGSQ total score at each visit (the same model as for main statistical analyses). Additionally, to study the differences between the two subgroups (of infants who did or who did not receive medications or products intended to improve GI tolerance), a three-way interaction term with the infant formula group, the visit, and the subgroup was introduced in the previous mixed linear model.