P0498Temporal Sequence of Perianal and Intestinal Symptoms Predicts Distinct Clinical Outcomes in Crohn’s Disease

Abstract Background Perianal fistula is a common complication of Crohn’s disease (CD) and may occur either before or after the onset of intestinal symptoms. However, the differences in clinical characteristics and outcomes among patients with different initial symptom patterns have not been well characterized. Methods This retrospective study included hospitalized patients who were newly diagnosed with CD at the Inflammatory Bowel Disease Center of Sir Run Run Shaw Hospital between May 2018 and September 2022, who were regularly followed at our center. Patients were categorized into three groups based on the temporal sequence of perianal and intestinal symptoms: perianal-first, intestinal-first, and concurrent onset. The clinical features, medications, and prognosis were compared across groups. Results A total of 460 CD patients were included in this study, of whom 28.26% initially presented with perianal symptoms and 54.57% with intestinal symptoms. Compared to the intestinal-first group, the perianal-first group had a significantly higher proportion of males (89.2% vs. 64.9%, P 0.001), a younger age at diagnosis (27.44 vs. 30.05, P = 0.032), a longer diagnostic delay (median 2 years vs. 1 year, P 0.001), and a higher rate of penetrating disease behavior (6.9% vs. 2.0%, P = 0.015). In contrast, the intestinal-first group was characterized by lower hemoglobin levels in males (123.17 g/L vs. 132.03 g/L, P 0.001). The intestinal-first group demonstrated a significantly higher cumulative rate of abdominal operation and disease recurrence. The perianal first group had a higher cumulative rate of perianal operation and persistent and recurrent perianal disease. No significant differences were observed in the cumulative incidence of the use of biologic therapy. However, among patients who had not received biologics, both those with perianal-first onset and those with intestinal-first onset who later developed perianal disease exhibited higher rates of intestinal surgery. Conclusion Initial symptom patterns were associated with distinct disease characteristics and outcomes in CD. Patients with perianal-first onset exhibited longer diagnostic delay and a significantly higher burden of perianal disease, whereas intestinal-first patients more often showed higher abdominal surgery risk. After excluding the biologic therapy, patients with initial perianal symptoms also have poorer intestinal outcomes. The use of biologic therapy may have mitigated the intestinal risks associated with perianal-onset disease. Conflict of interest: Yan, Dong: No conflict of interest Tian, Chuwen: No conflict of interest Huang, Lingjie: No conflict of interest Cao, Qian: No conflict of interest