Development of a core domain set for nailfold capillaroscopy reporting.

Background: The peripheral microangiopathy may be well evaluated and studied by nailfold capillaroscopy (NFC) which is a safe and non-invasive technique. NFC has been reported to have both diagnostic and prognostic values in patients presenting with Raynaud's phenomenon.

Objective: The overarching objective of this work was to make a consensus on what domains should be included in a capillaroscopy report and that it can be used in daily clinical practice and clinical research in the area of rheumatology.

Methods: A Delphi questionnaire was developed regarding capillaroscopy report from a literature review and expert consensus. The first Delphi round included 14 core areas, its 18 domains with 50 subdomains, derived from a systematic literature review. The level of evidence was determined for each core set using the Oxford Centre for Evidence-based Medicine (CEBM) system. Nine response categories have been set per each item ranging between 1 and 9. Round 2, aimed to reach preliminary consensus "in" or "out" for domains. It included all items that were rated "critical" by at least 80% of the participants as well as any new domains proposed in round 1.

Results: The participants to the first, and second round were 11 experts. Fourteen domains were discussed in the two rounds. At the end of the survey, the final report template of NFC in rheumatology reached a consensus.

Conclusion: A nailfold capillaroscopy report template has been developed by this study, based on outcomes of a Delphi process, by international participants panel. All domains met the 80% voting threshold set in this work. The reporting template can be used for both clinical research as well as day to day practice to provide guidance and standardize the NFC reporting.