An exploration of variation in the management of Crohn’s anal fistula

Crohn’s disease has a prevalence of 1 in 650 people in the UK. Of these, 30% will develop an anal fistula. This debilitating condition requires multiple medical and surgical interventions. Treatment goals may be preference sensitive for patients. This thesis assesses the evidence base for treatment of Crohn’s anal fistula, explores clinician preferences, and patient informational needs. Systematic literature review identified 27 trials of pharmacological therapies. Anti-tumour necrosis factors (TNF) drugs were associated with induction (RR, 2.01; 95% CI, 1.36-2.97) and maintenance of response (RR 1.94 CI 1.25-3.02). Review of the surgical literature identified 63 studies, of which three were randomised-controlled trials. Interpretation of the literature was impeded by poor outcome reporting and methodological issues of included studies. A survey of gastroenterologists showed thiopurines and anti-TNF were first-line agents. Variation was noted in time to reassessment following treatment, and selection of subsequent interventions. A survey of colorectal surgeons showed consistency in the treatment in the acute setting, but a wide range in the definitive surgical procedures offered. Clinicians offered consistent indications for faecal diversion. Assessment of treatment pathways across three tertiary centres found the median time to receive anti-TNF agents was 204 days. The study suggested challenges in cross-specialty working. A consensus exercise conducted with colorectal surgeons and agreed a framework for surgical treatment. Semi-structured interviews with 17 patients found that participants wanted to participate in decision-making and suggested information needed to inform decisions. This informed the a survey conducted across 10 centres. Principal component analysis identified three items to inform decisions; immediate aftercare, effect on perianal region, severity of operation. This thesis shows variation in clinical practice. Patients wish to participate in decision-making about their treatment. The items identified may form the basis of a preparedness for decision-making tool. This thesis may form the basis for a patient decision aid.