Developing Core Outcome Sets for Vascular Conditions Across Europe, Not as Easy as It Sounds.

Introduction: Most of the outcomes reported in the literature have been chosen by doctors, constituting "traditional" outcome measures such as mortality and re-intervention. Some of the key outcome measures important to patients, families, health providers and other stakeholders may have been overlooked. Core outcome sets, consisting of 6-15 outcomes, can improve representation of all key stakeholders, standardise outcome reporting, and improve future ability to pool results. The aim of this study was to outline the methods and challenges of conducting European core outcome sets.

Report: As an overview, development of core outcome sets follows a multistep iterative process: (1) Systematic review of the literature summarising existing outcome measures, (2) Focus Group meeting with patients and other stakeholders to establish missing outcome measures, (3) Development and piloting of Delphi survey, (4) Delphi consensus study for prioritisation of outcomes and establishing consensus, and (5) European consensus meeting to produce a core outcome set. The challenges include the varying ethical requirements for survey work across Europe and translation for surveys and consensus meetings.

Discussion: There is an increasing need for core outcome sets to complement clinical practice guidelines. As a European vascular community we need to produce these through collaborative efforts. Unfortunately, there are considerable barriers to doing so - the time and energy required to set up a core outcome study is not dissimilar to that of a multicentre randomised trial. Currently only one core outcome set exists for vascular surgery, for critical limb ischaemia, but this was developed in a single country.