2.4 Statistical analysis
Data were summarized as absolute frequency (percentage) for nominal variables and as mean (standard deviation [SD]) for continuous variables. Percentages were compared with the Chi-square or Fisher’s exact test. Continuous data were compared using the Student’s t-test or Mann-Whitney U-test. Survival curves for DFS and OS were generated using Kaplan-Meier survival curves and compared using the log-rank test. The effect of uterine manipulator type on DFS and OS were evaluated using univariable and multivariable Cox proportional hazards regression analysis, expressed as hazard ratio (HR) and 95% confidence interval (CI). The following baseline variables were added as potential confounders in the multivariable analysis: age at onset, FIGO stage, and presence of LVSI. Also, the type of hospital (academic versus non-academic) was added in the multivariable analyses. A p-value of less than 0.05 was considered significant. Data were analysed with the statistical package STATA/SE (version 14.1; STATA CORP., College Station, Texas, USA).