Introduction The benefits of immunosuppressant (IS) therapy in IBD have been demonstrated in many controlled trials, however it has been difficult to show that early and widespread use of these drugs have reduced surgical rates in routine practice.

Methods To assess changes in surgical rates in IBD in a population-based cohort of IBD patients diagnosed in Cardiff between 1988 and 2003. Case notes of Crohn's disease (CD), ulcerative colitis (UC) and indeterminate colitis (IC) patients from IBD incidence studies in Cardiff were reviewed retrospectively for disease characteristics and for follow-up information on the use of IS and the need for surgery for IBD. The patients were identified from the incidence studies of CD (1986–2005), UC and IC (1988–2007). We excluded UC and IC patients with isolated proctitis at diagnosis as surgery is rarely performed for isolated proctitis. The study population was divided into two groups (Group A=1988–1995 and Group B=1996–2003) based on the year of diagnosis.

Results 553 IBD patients (Group A=259 and Group B=294) included in the final analysis. There were 309 CD, 214 UC and 30 IC patients. 5-year follow-up was available in 514 patients (93%). No significant difference in patient or disease characteristics in the two groups. Kaplan-Meier (KM) analysis showed a significant increase in cumulative probability of IS use in IBD over time; At 5 years this was 17% (Group A) and 45% (Group B) (p=0.0001). KM analysis also showed a significant decrease in surgical rates over time; At 5 years this was 47% in Group A and 28% in Group B (p=0.0001). Also there was a significant reduction in resection rates in CD (p=0.0001) and UC (p=0.02) over time in the two groups. Cox multivariate analysis of surgical interventions in IBD showed time of diagnosis (p=0.001), early steroid use (within 3 months of diagnosis) (p=0.0001) and thiopurine use within first year of diagnosis (p=0.002) as independent factors predicting resection (see Abstract 093).

Conclusion The decrease in surgical resections in UC and CD in this population-based cohort over the past 18 years is most likely due to the increased and earlier use of IS therapy.