Statistical analysis
Fisher’s exact test was used for categorical variables. The Mann-Whitney U test was used for continuous variables such as the baseline characteristics and clinical endpoints of the patients. These tests were used to evaluate differences between the scheduled and interrupted groups. OS and EFS were estimated using the Kaplan-Meier method and compared with the log-rank test. The comparison of NRM and cumulative incidence of relapse were evaluated using Gray’s test.
A multivariate logistic regression model was created to identify the statistically significant clinical variables contributing to the incidence of cGVHD. Categorical variables with P -values< 0.1 in the univariate analysis for the factors causing cGVHD were entered into the model. The categorical variables were sequentially eliminated in a stepwise backward fashion. Factors with a significance level of < 0.05 were retained in the final model. A P -value of ≤ 0.05 was considered statistically significant. All statistical analyses were performed with Easy R (EZR), a graphical user interface for R (The R Foundation for Statistical Computing). EZR is a modified version of the T commander designed to add statistical functions frequently used in biostatistics [16].