Reporting of outcomes in randomized controlled trials on nail psoriasis: a systematic review

BackgroundHarmonization of outcome measures is needed to increase the value of clinical trials on nail psoriasis. ObjectivesTo provide the first step in core outcome set (COS) development for nail psoriasis. MethodsA systematic review was performed to identify outcome instruments and corresponding outcome domains used in (ongoing) randomized controlled trials. ResultsIdentified outcome domains included clinical signs, quality of life, symptoms and delivery of care. The Nail Psoriasis Severity Index (NAPSI) was the most commonly used measure to assess clinical signs (74% of studies). Other outcome instruments used included the Nail Area Severity score, composite fingernail score, a Physician's Global Assessment, individual nail features or a combination of these. Heterogeneity in type and reporting (e.g. NAPSI 50, NAPSI 75) of outcome instruments was high and characteristics were often insufficiently reported. In total 43% of studies assessed quality of life, with 3% of studies using a nail psoriasis-specific tool. Assessment of symptoms and delivery of care was limited. ConclusionsHeterogeneity in the type and reporting of nail psoriasis outcome instruments needs to be addressed in the process towards COS development. Sufficient reporting of instrument characteristics should be encouraged. As nail psoriasis is generally assessed secondarily to psoriasis of the skin or joints, collaboration between different research groups in COS development is needed. What's already known about this topic? Heterogeneity in outcomes restricts data comparability between nail psoriasis trials. What does this study add? A limited number of outcome instruments are used, but diversity within these outcome instruments (in subtypes, e.g. target Nail Psoriasis Severity Index; NAPSI) and reporting (e.g. target NAPSI 50) is substantial. Clinical trials do not commonly investigate patient-reported outcomes. Characteristics of outcome instruments are often insufficiently reported. Plain language summary available online