Long-term effects of methotrexate monotherapy on UC and CD and to explore the impact of methotrexate tolerance on the need for surgery.

"Effective" will be defined as not escalating to biologic therapy or surgery while treated with cyclosporine. Descriptive statistics will be first performed for clinical characteristics, with continuous variables expressed as medians (25th-75th percentiles); categorical variables expressed as frequencies and percentages. Duration of cyclosporine treatment will be calculated from the start of treatment to the end of treatment and summarized using Kaplan-Meier estimates. The incidence of adverse events will be compared between UC and CD by X2 test. The Cochran-Mantel-Haenszel (CMH) test will be applied to compare the effects of cyclosporine treatment for UC and CD. Comparative effectiveness of cyclosporine between UC and CD will be assessed using multivariate logistic regression with covariates including age at diagnosis, sex, smoking history, treatment chronology, and time from diagnosis to initiation of cyclosporine. The Kaplan-Meier method will be used to assess time to treatment escalation for biologic therapy or surgery. The log-rank test will be used to compare the differences in distribution between UC and CD. Logistic regression models will be applied to explore the correlation between cyclosporine treatment effects and clinical characteristics within UC and CD, using the same covariates as described above but also including disease location. Cox regression model will be applied to explore the correlation between the timing of surgical outcomes and clinical characteristics within UC and CD. A conservative prespecified p-value threshold of less than 0.005 was considered statistically significant. Statistical analysis methods may vary slightly according to the data obtained.