Effectiveness of Infliximab on Deep Radiological Remission in Chinese Patients with Perianal Fistulizing Crohn's Disease

Background and Aims Information concerning deep radiological healing of perianal fistulas in Chinese patients with CD is limited. The present study aimed to establish the effectiveness of infliximab on CD-related perianal fistulas using magnetic resonance imaging (MRI) and identify predictors of deep radiological remission of fistulas. Methods We retrospectively reviewed patients with CD with draining perianal fistulas treated with infliximab and included only those who underwent clinical assessment and MRI before and after infliximab therapy. Results Among 178 patients who underwent repeated MRI and clinical assessment, 65.2% had complex fistulas. Post-infliximab therapy, 55.1% of patients with perianal fistulizing CD showed clinical remission and 26.4% presented a clinical response; 38.2% had deep radiological remission, and 34.3% had a partial response based on the Ng score; the Van Assche scores decreased obviously compared with baseline. Prolonged infliximab infusion (18 times) presented higher radiological remission rates in patients with CD with complex fistulas. Concomitant treatment with azathioprine increased the fistula healing rate compared with infliximab alone (50% vs. 36.9%,P < 0.001). Younger age at diagnosis of CD, proctitis and requiring perianal surgery were identified as predictors of poor deep radiological remission of fistulas. Eight of ten patients who stopped infliximab and switched to an alternative agent retained a status of fistula healing in the first year of follow-up. Conclusions Infliximab induced deep radiological remission of perianal fistulas in Chinese patients with CD. Routine MRI should be used to monitor fistula healing. Patients with younger age at diagnosis of CD, proctitis, and/or requiring perianal surgery should receive combined therapy and careful monitoring.