2.2 Statistical analysis
Statistical analyses were conducted using Stata v.16.1 software (Stata
Corporation LLC, College Station, USA). Categorical variables were
presented as counts and percentages, and were analyzed using either the
chi-square or Fisher’s exact test. Continuous variables were presented
as means with standard deviations (SD) or medians with interquartile
ranges (IQR), and comparative analyses were performed using either
Student’s T-test or the Mann–Whitney U test. Univariable and
multivariable logistic regression analyses were employed to identify
factors independently associated with R/R HLH. The results were
presented as odds ratios (OR) and 95% confidence intervals (CI).
Receiver operating characteristic (ROC) curve analysis was applied to
determine the optimal cutoff for predicting R/R HLH. Kaplan-Meier
survival analysis and the Log-rank test were utilized to evaluate the
2-year and 5-year overall survival (OS) rates. A p-value of less than
0.05 was considered statistically significant.