Purpose/Background: Ileocolic resections (ICR) are the most common resections for Crohn’s disease (CD). Historical control groups have often been used for comparison when assessing post-operative recurrence (POR), usually with temporal bias. This study aimed to: (i) report contemporary rates of POR requiring repeat surgery (surgical recurrence at anastomosis[SR-ICR], or at any site[SR-any]) and the rates of endoscopic recurrence(ER) in the ‘biologic era’; and (ii) determine risk factors for SR-ICR and ER. METHODS A retrospective multicentre study involving twelve tertiary Australian centres was performed. Patients (of any age) who had undergone an ICR for CD between 2007-2023 were included. Cox proportional hazards modelling was used to evaluate clinico-pathological risk factors for SR-ICR and ER (defined as Rutgeert’s Grade ³ i2b). RESULTS Overall, 875 patients were included (mean 38.7yrs [SD 15.1], 51% F). Median follow-up was 63.9 months. Rates of SR-ICR were 4.5% (95%CI:2.8%-6.1%) and 12.8% (95%CI:8.8%- 16.5%) at 5- and 10-years, respectively. Rates of SR-any were 5.6% (95%CI:3.8%-7.5%) and 15.1% (95%CI:11.0%-19.1%) at 5- and 10-years, respectively. Early (within 12-months) ER occurred in 24.7%. On multivariable analysis, smoking (aHR 3.49 [95%CI:1.93-6.29]) was the only factor significantly associated with SR-ICR. Smoking, positive microscopic margins and granulomas were associated with ER, and prophylactic therapy and younger age at diagnosis ( <17 yrs) were protective. CONCLUSIONS The rate of SR at the ileocolic anastomosis in this large Australian cohort was low, recorded to be one-in-twenty at 5-years. Smoking remains the strongest risk factor for both ER and SR. Histopathological factors influence ER and should be considered in future risk prediction models.
