Statistical analysis
death, Death
REGRESSION, EVENT
Baseline characteristics were compared by BMI class and assigned treatment. The chi-squared test and the Mann-Whitney U test were used to assess differences in categorical or continuous variables. The presence of a trend was evaluated using the Cochran-Mantel-Haenszel test and the Jonckheere-Terpstra test.The prognostic effect of BMI was evaluated irrespective of assigned treatment from date of randomization onwards. The predictive effect of BMI on the efficacy of 6 versus 3 years of anastrozole was assessed from 3 years after randomization onwards (ie, ‘adapted’ endpoints). Patients with a DFS event or patients who were lost to follow-up within 3 years after randomization were excluded from the adapted analyses.DFS and OS were examined using Kaplan-Meier survival analyses and Cox regression analyses, when adjusting for potential confounders. BCSM and OCM were determined with competing risk methodology, using the Fine and Gray model when adjusting for potential confounders. Differences between BMI classes and treatment groups were assessed with the log-rank test and the Gray’s test. In the absence of an event, patients were censored at the last follow-up visit in all analyses. Death not related to BC was considered a competing event in the analysis of BCSM. BC-related death was considered a competing event in the analysis of OCM. Missing data of confounders were imputed.Prognostic analyses were stratified by age (<60 versus ≥60 years). The cutoff point of 60 years, ie, 57 years at BC diagnosis, was chosen to distinguish younger postmenopausal women from older postmenopausal women, as some younger patients were premenopausal at BC diagnosis (
All statistical analyses were performed with SPSS (version 25) and Stata (version 17).