The Lattice System-Physician Global Assessment, professional-Simplified Psoriasis Index, and the Product of the Investigator Global Assessment and Body Surface Area have higher levels of evidence demonstrating their validity, reliability, and responsiveness for assessing outcomes in psoriasis clinical trials compared with the 5- and 6-point investigator global assessments (IGAs) and patient global assessment (PtGA).
This was according to a systematic review that consisted of studies that reported on the measurement properties of instruments that included an IGA in psoriasis, consisting of a subjective measure of psoriasis severity, or a PtGA, consisting of an overall evaluation of disease severity or a patient’s perspective of the global impact of disease. A total of 15 studies, comprising 9 IGAs and 3 PtGAs, were included in the review. The quality of each study was rated by 3 independent reviewers in accordance with the COnsensus-based standards for the Selection of health Measurement INstruments (COSMIN) checklist.
Across studies, evidence for content validity and feasibility was lacking for most measures. Higher levels of evidence for validity, reliability, and/or responsiveness were observed for the Lattice System-Physician Global Assessment, Product of the Investigator Global Assessment and Body Surface Area, and the professional-Simplified Psoriasis Index compared with the 5- and 6-point IGAs. The only PtGA with evidence for validity, reliability, and responsiveness was the self-assessment-Simplified Psoriasis Index.
The researchers who conducted this literature review suggested that negative results included in the studies may have been under-reported by the authors because of publication bias. In addition, the COSMIN checklist was updated after the review concluded, which may limit the findings from the review.
They concluded that additional studies are essential “to demonstrate the suitability of existing instruments or new tools developed to measure the ‘patient global’ and ‘investigator global’ domains in psoriasis clinical trials.”
Disclosure: Several study authors declared affiliations with the pharmaceutical industry. Please see the original reference for a full list of authors’ disclosures.
Perez-Chada LM, Salame NF, Ford AR, et al. Investigator and patient global assessment measures for psoriasis clinical trials: a systematic review on measurement properties from the International Dermatology Outcome Measures (IDEOM) initiative [published online January 16, 2020]. Am J Clin Dermatol. doi: 10.1007/s40257-019-00496-w.