Core Outcome Measures in Effectiveness Trials

Developing a core outcome set for in rectovaginal fistula

General Information


Innovations in rectovaginal fistula have led to a proliferation of techniques; however, lack of standardised outcome measures hamper effective analysis and comparison of data. The development of standardised outcome measures can solve these issues and this study defines a core outcome set (COS) for rectovaginal fistula.


In Phase 1, identify a long-list of candidate outcomes that could be measured in rectovaginal fistula trials, and categorise outcomes into domains. This will be done through a systematic review of the literature and patient interviews.

In Phase 2, outcome domains will be presented via a web-based Delphi system to assess key stakeholders’ views on the importance of each domain. Participants will be asked to score each outcome on a nine-point Likert scale based upon how important they felt it was in deciding whether the overall treatment of [their/their patient’s] rectovaginal fistula had worked well. The stakeholders will be identified from (inter)national organisations, and include a range of healthcare professionals and people living with rectovaginal fistula. In round 1 of this process participants will also be given the opportunity

In Phase 3, a face-to-face consensus meeting with all stakeholders will be used to finalise and ratify the core outcome set.


In total, 187/238 (78.5%) of the recruited participants completed phase one (92 outcomes), 176/187 (94.1%) completed phase two (80 outcomes, including five de-novo outcomes) and 183/187 (97.9%) completed phase three (50 outcomes).

The consensus meeting of 41 experts (across all stakeholder groups) generated agreement on an eight domain COS. This constituted three patient-reported outcome domains (quality of life, incontinence and a combined score of patient priorities), five clinician-reported outcome domains (perianal disease activity, development of new perianal abscess/sepsis, new/recurrent fistula, unplanned surgery and faecal diversion).


A COS in fistulating pCD will reduce the heterogeneity of outcome reporting with the overall aim to improve the quality of research to benefit patient care.

Kapil Sahnan - St Mark's Hospital
Phil Tozer - St Mark's Hospital

Further Study Information

Current Stage:
January 2018 - January 2019
Funding source(s):
St Mark's Hospital, Fistula Research Unit

Health Area

Disease Category
Pregnancy & childbirth

Disease Name
Rectovaginal fistula

Target Population

Age Range
18 - 100


Nature / type of Intervention


Consensus conference
Consensus meeting
Delphi process
Literature review
Semi structured discussion
Systematic review

Stakeholders Involved

Clinical experts
Conference participants
Consumers (caregivers)
Consumers (patients)
Patient/ support group representatives

Study Type

COS for clinical trials or clinical research
COS for practice

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