Defining Skin Ulcers in Systemic Sclerosis: Systematic Literature Review and Proposed World Scleroderma Foundation (WSF) Definition

Purpose There is a lack of a valid definition for skin ulcers in systemic sclerosis (SSc) to be used in clinical trials. Our aim was to develop a consensus definition for SSc skin ulcers based on the results of a systematic literature review (SLR) for skin ulcer definitions and expert opinion; and to evaluate its face validity, reliability and feasibility. Methods SLR for skin ulcer definitions was conducted using PubMed, Web of Science, and Cochrane library for articles published from inception to January 1st, 2016. SSc experts were to discuss the definition categories and vote for the relevant terms. Reliability of the definition was tested in a second expert meeting, seven SSc experts evaluated 7 SSc patients with skin lesions twice. Face validity and feasibility were evaluated by sending out case report forms (CRFs) to four SSc experts, who were each asked to use the definition in five patients. Results A total of 3464 abstracts and titles were screened, and 446 articles were fully evaluated. Of these, 66 met eligibility criteria and skin ulcer definitions were extracted. SSc experts discussed, refined, and voted on the consensus definition using nominal process. Kappa for inter-rater agreement was 0.51 and for intra-rater agreement was 0.90. The mean time to decide if the lesion is an ulcer was 7.4 seconds. All investigators endorsed the face validity of the new definition in the CRFs. Conclusions Using an SLR and a nominal technique, we developed a preliminary consensus-based definition of SSc skin ulcers. Face validity, feasibility and reliability were demonstrated for the developed definition.