Multivariate analysis of factors associated with IBD-related abdominal surgery after infliximab initiation
| Factor | OR | CI for OR | P value |
| TDM never tested | 2.5 | 1.1 to 5.7 | 0.03 |
| Previous exposure to biologic, n (%) | 4.3 | 1.6 to 11.8 | <0.01 |
| Total duration of follow-up | 1.01 | 1.0 to 1.02 | 0.053 |
IBD, inflammatory bowel disease; TDM, therapeutic drug monitoring.