Data analysis
anxiety
To assess differential response between allocated groups, comparisons of available demographic and clinical characteristics were made between: (a) women in the BC-Predict and standard NHSBSP groups who were invited to complete questionnaires, and (b) women who responded to questionnaires in the BC-Predict and standard NHSBSP groups. Analyses employed The main analyses focussed on comparing the responses of women offered BC-Predict with women offered standard NHSBSP at both follow-up timepoints. ANCOVA was used, with baseline responses to the same variables, age and IMD deciles as covariates. Analyses were conducted on all questionnaire measures at 3 months and 6 months, with the 6-month state anxiety measure being the a priori primary outcome for this study [A similar approach was used to compare the responses of women in the BC-Predict group who accepted the offer of BC-Predict at follow-up, compared with women who declined this offer.ANCOVA was also used to compare responses of the four groups of women in the BC-Predict group provided with different risk estimates (i.e., high, moderate, average and below average) at follow-up. These analyses for each variable controlled for baseline responses to the same variables with age and IMD deciles as covariates. Initial omnibus tests assessed whether differences in groups were statistically significant, and where these omnibus tests were significant, post hoc pairwise comparisons with all four groups were conducted.Satisfaction with information received was compared between the four groups of women in the BC-Predict group provided with different risk estimates (i.e., high, moderate, average and below average) using ANOVA, as there was no baseline measure of this variable for the BC-Predict group and was not measured in the standard NHSBSP group.All statistical tests were two-sided and used an a priori alpha level of 5%. A “completer only” analysis strategy was generally employed. However, given the dropout levels, the a priori primary outcome (comparison of 6-month outcome scores at six months between BC-Predict and standard NHSBSP groups) was repeated using a last occasion carried forward approach to missing data at 6 months, as a sensitivity analysis.