P753 Early perianal abscess recurrence in patients with perianal Crohn's disease on biologic therapy predicts long-term permanent fecal diversion

Abstract Background Generally, it’s difficult to estimate the efficacy of biologics (Bio) for perianal lesions of Crohn’s disease (CD) and lack of evidence. Sometimes, we experience the recurrence of perianal abscess and need to perform re-drainage even after starting 1st Bio. When the 1st bio fails, choosing an accurate 2nd Bio is difficult. The most severe result of this situation is rectal amputation. We wonder if any relationships between recurrence timing and long-term outcomes exist. We reviewed and aimed to know our institute’s perianal CD (pCD) treatment. Methods We retrospectively investigated patients' medical charts with pCD from 1988 to 2022 at Kenseikai Nara Coloproctology Center. We excluded the patients without using Bio or starting Bio after rectal amputation. The cases with missing values are excluded, too. We defined "early" as within two years and compared two cohorts, the early recurrence group (ER) and the no or late recurrence group (non-ER). We use the Kaplan-Meier method for calculating the time to fecal diversion. Results Eighty patients were recruited. The mean current age is 37.5 years old, and the onset of CD is 22.6 years old. The Perianal lesion’s onset is 24.5 years old. The male is 66, and 19 smokers are included. In this part, perianal lesion means only perianal abscess and fistula. Montreal Classification is shown in TABLE1. The Median follow-up duration was 142.5 months. We performed perianal surveillance (PS) for these patients, including EUA, Abscess Drainage, and seton placement, 3.1 times for each person. After the surgical interventions, we treat them with four Bio. After starting Bio, we experienced 33 early recurrences. We observed eight transient stoma creations, nine rectal amputations, and one anorectal cancer. Among them, we calculate the relationships between early recurrence and rectal amputation and find that early recurrence is a risk factor for permanent fecal diversion (HR 6.84 95%CI 1.48-31.7, p=0.0047 FIGURE1). We needed to switch the Bio for 31 patients during the observational period. To know which way of switching is effective for pCD, we calculate the relationships between the practice of switching and any treatment failure. Same class switching and changing MOA are not different for any treatment failure, which means re-abscess drainage and creation of any stoma (HR 0.40 95%CI 0.10-1.57 p=0.19). Conclusion Perianal abscess recurrence as we need to re-incision and drainage within two years after sta