PAVFCOS: The development of a core outcome set for pouch anal and vaginal fistula

Aims: The primary aim was to develop a patient-centred core outcome set (COS) for interventional studies in patients with pouch anal and vaginal fistula (PAVF). Method: PAVFCOS was developed using the methodology outlined by the Core Outcome Measures in Effectiveness Trials (COMET). Systematic review and qualitative patient interviews produced a long list of candidate outcomes. An online Delphi exercise was conducted with stakeholders to prioritise and shortlist outcomes. A consensus meeting of patients and clinicians ratified the final core outcome set. Results: A systematic review of the literature and 14 qualitative patient interviews produced a long list of 99 outcomes. These were reduced to 46 outcomes and subjected to two rounds of a Delphi exercise with 70 participants, including patients (45%), colorectal surgeons (31%), radiologists (6%), gastroenterologists (11%) and pouch specialist nurses (7%). Thirty-six outcomes were discussed in a consensus meeting of seven clinicians and seven patients. Seven core outcomes were selected for inclusion: global assessment of continence, pain related to fistula and surrounding area, impact on quality of life of fistula discharge, fistula healing (clinical and radiological), new fistula or abscess, need for rescue intervention (minor or major) and global quality-of-life assessment. Conclusion: PAVFCOS is the first to establish outcomes that are important to patients with pouch anal and vaginal fistula. PAVFCOS should be used in interventional studies to introduce much-needed standardisation of outcome reporting in this challenging condition.