Disappointing durable remission rates in complex Crohn's disease fistula.

BACKGROUND: Despite potent drugs and surgical techniques, the treatment of perianal fistulizing Crohn's disease (CD) remains challenging. We assessed treatment strategies for perianal fistulizing CD and their effect on remission, response, and relapse.
METHODS: Patients with perianal fistulizing CD visiting the Erasmus MC between January 1, 1980 and January 1, 2000 were identified. Demographics, fistula characteristics, and received treatments aimed at the outcome of these strategies were noted.
RESULTS: In total, 232 patients were identified (98 male; 42.2%). Median follow-up was 10.0 years (range, 0.5-37.5 yr). Complex fistulas were present in 78.0%. Medical treatment (antibiotics, steroids, immunosuppressants, and anti-tumor necrosis factor) commenced in 79.7% of the patients and in 53.2%, surgery (colectomy, fistulectomy, stoma, and rectum amputation) was performed. Simple fistulas healed more often than complex fistulas (88.2% versus 64.6%; P < 0.001). Rectum involvement was not associated with a lower remission rate, and anti-tumor necrosis factor therapy did not increase complete fistula healing rates in simple and complex fistula. Initially, healed fistulas recurred in 26.7% in case of simple fistulas and in 41.9% in case of complex fistulas (P = 0.051). Only 37.0% of the complex fistulas were in remission at the end of follow-up compared with 66.7% of the simple fistulas (P < 0.001).
CONCLUSIONS: Only the minority of CD complex perianal fistulas were in remission after conventional treatment strategies after a median follow-up of 10 years. Simple fistulas were more likely to heal than complex fistulas, and less of these healed fistulas relapsed. However, more than 3 quarters of the patients had complex perianal fistulas.