Core outcome domains for lichen sclerosus: a CORALS initiative consensus statement.

Background: Lichen sclerosus (LS) is a chronic inflammatory condition mainly affecting genital skin. It causes distressing symptoms that impact daily quality of life (QoL). It causes progressive anatomical changes and a potential risk of cancer. Published randomized controlled trials are of varying methodological quality and difficult to combine in meta-analyses. This is partly due to lack of agreed outcome measures to assess treatment response. Identification of core outcome sets (COSs), which standardize key outcomes to be measured in all future trials, is a solution to this problem.

Objectives: To obtain international agreement on which outcome domains should be measured in interventional trials of genital LS.

Methods: Recommended best practice for COS domain development was followed: (i) identification of potential outcome domains: a long list was generated through an up-to-date LS literature search, including information collected during the LS priority-setting partnership; (ii) provisional agreement of outcome domains: a three-stage multi-stakeholder international electronic-Delphi (e-Delphi) consensus study; (iii) final agreement of outcome domains: online consensus meeting with international stakeholders including anonymized voting.

Results: In total, 123 participants (77 patients, 44 health professionals, 2 researchers) from 20 countries completed three rounds of the e-Delphi study. Eleven outcome domains were rated as 'critical' and were discussed at the online consensus meetings. The first set of consensus meetings involved 42 participants from 12 countries. Consensus was met for 'symptoms' (100% agreed) and 'QoL - LS-specific' (92% agreed). After the second set of meetings, involving 29 participants from 12 countries, 'clinical (visible) signs' also met consensus (97% agreed).

Conclusions: The international community has agreed on three key outcome domains to measure in all future LS clinical trials. We recommend that trialists and systematic reviewers incorporate these domains into study protocols with immediate effect. CORALS will now work with stakeholders to select an outcome measurement instrument per prioritized core domain.