The long-term outcome of anti-TNF alpha therapy in perianal Crohn's disease.

BACKGROUND: The aim of the present study was to evaluate the long-term outcomes of anti-tumour necrosis factor alpha therapy in perianal Crohn's disease and identify factors predicting response to treatment.

METHODS: Data from hospital clinical records and coding databases were retrospectively reviewed from a tertiary care hospital in Christchurch, New Zealand. The study included 75 adult patients with perianal Crohn's disease commenced on anti-tumour necrosis factor alpha therapy from January 2000 to December 2012. Response to treatment was determined from records relating to clinical evaluation, magnetic resonance imaging follow-up and whether further surgical intervention was required.

RESULTS: 73% (55) of all patients and 38 of the 57 (67%) patients with perianal fistulas responded to anti-tumour necrosis factor alpha therapy. Patients with complex fistulas were less likely to improve as compared to patients without fistulising disease. Five of the 57 (13%) patients with perianal fistulas demonstrated complete healing on clinical evaluation; however, magnetic resonance imaging confirmed complete healing in only two. Patients that had taken antibiotics and those that had previously required abscess drainage were less likely to respond to treatment [relative risk (RR) = 0.707 and 0.615, respectively; p = 0.03, p = 0.0001]. Responders were less likely to require follow-up surgery (RR = 0.658, p = 0.014) including ileostomy or proctectomy.

CONCLUSIONS: Although anti-tumour necrosis factor alpha tends to improve symptoms of perianal Crohn's disease, in the long term, it rarely achieves complete healing. Perianal fistulising disease, a history of perianal abscess and antibiotic treatment are predictors of poor response to therapy.