Investigator and Patient Global Assessment Measures for Psoriasis Clinical Trials: A Systematic Review on Measurement Properties from the International Dermatology Outcome Measures (IDEOM) Initiative
Background and Objective
The International Dermatology Outcome Measures (IDEOM) has defined a core set of domains to be measured in all psoriasis clinical trials. This set comprises the following domains: skin manifestations, psoriasis and psoriatic arthritis symptoms, health-related quality of life, investigator global, patient global, and treatment satisfaction. The next step is to define how to measure these domains. The objective of this article was to evaluate the quality of available instruments to assess ‘investigator global’ and ‘patient global’ domains to identify the most appropriate instruments.
Reviewers conducted a systematic literature review to retrieve studies on the measurement properties of instruments including either an investigator global assessment or a patient global assessment. Following the COnsensus based standards for the Selection of health Measurement INstruments (COSMIN) checklist, three independent reviewers rated the quality of each study. We then performed a qualitative synthesis of the evidence.
We identified nine investigator global assessments and three patient global assessments, reflecting substantial variability in global assessment instruments. Overall, most measures lacked evidence for content validity and feasibility. The Lattice System-Physician Global Assessment, Product of the Investigator Global Assessment and Body Surface Area, and the professional-Simplified Psoriasis Index had higher levels of evidence for validity, reliability, and/or responsiveness than the 5- and 6-point investigator global assessments. The self-assessment-Simplified Psoriasis Index was the only patient global assessment with evidence for validity, reliability, and responsiveness.
The 5- and 6-point investigator global assessments, which are the most widely used investigator global assessments in registered clinical trials, have less evidence for measurement properties as compared with the Lattice System-Physician Global Assessment, professional-Simplified Psoriasis Index, and the Product of the Investigator Global Assessment and Body Surface Area. However, all instruments lack evidence for content validity and feasibility. Further validation studies of investigator global assessments and patient global assessments are required to recommend the best global measure for psoriasis clinical trials.
Compliance with Ethical Standards
International Dermatology Outcome Measures (IDEOM) funded the conduct of this study.
Conflict of interest
Dr. Garg is a consultant/advisor for Abbvie, Pfizer, UCB, and Asana Biosciences and received a grant from UCB. Dr. Gottlieb is an advisor/consultant for Janssen Inc., Celgene, Beiersdorf, BMS, Abbvie, UCB, Novartis, Incyte Corporation, Lilly, Reddy Labs, Valeant, Dermira, Allergan, Sun Pharmaceutical Industries, XBiotech, Leo, Avotres Therapeutics, and Boeringer Ingelheim. She received research/educational grants from Janssen, Incyte Corporation, XBiotech, Novartis, Boeringer Ingelheim, and UCB. In addition, she participated in the development of the National Psoriasis Foundation Psoriasis Score, an instrument discussed in the present study. John Latella is an advisor for Boehringer Ingelheim and Glaxo Smith Kline. Dr. Duffin serves as an advisory board/consultant/investigator for Amgen, Abbvie, Celgene, Novartis, Lilly, Pfizer, Stifle, Janssen, Ortho Dermatologic, and Boehringer Ingelheim. In addition, she has participated in validation studies of the IGA×BSA, an instrument discussed in the present study. Dr. Merola has served as a consultant/investigator/advisory board for Merck, AbbVie Eli Lilly, Incyte, Janssen, UCB, Almirall, Pfizer, Sun Pharma, Novartis, and Burrage Capital Mgmt. In addition, he received grants from Aclaris, Novartis, Leo, Celgene, and Dermavent. Dr. Armstrong serves as a consultant/advisor/investigator for Leo Pharma, Novartis, Delmira, UCB, Abbvie, Janssen, Eli Lilly, Regeneron and Sanofi, Science 37, Modernizing Medicine, Merck, Parexel, Celgene, Ortho Dermatologics, and Pfizer. Drs. Perez-Chada, Salame, and Ford have no conflicts of interest that are directly relevant to the content of this article.
- 1.Williamson PR, Altman DG, Bagley H, Barnes KL, Blazeby JM, Brookes ST et al. The COMET Handbook: version 1.0. Trials. 2017;18(Suppl 3):280. 10.1186/s13063-017-1978-4.Google Scholar
- 2.Gottlieb AB, Levin AA, Armstrong AW, Abernethy A, Duffin KC, Bhushan R, et al. The International Dermatology Outcome Measures Group: formation of patient-centered outcome measures in dermatology. J Am Acad Dermatol. 2015;72(2):345–8. https://doi.org/10.1016/j.jaad.2014.11.002.CrossRefPubMedGoogle Scholar
- 7.Langley RG, Feldman SR, Nyirady J, van de Kerkhof P, Papavassilis C. The 5-point Investigator's Global Assessment (IGA) Scale: A modified tool for evaluating plaque psoriasis severity in clinical trials. J Dermatol Treat. 2015;26(1):23–31. https://doi.org/10.3109/09546634.2013.865009.CrossRefGoogle Scholar
- 10.Nikiphorou E, Radner H, Chatzidionysiou K, Desthieux C, Zabalan C, van Eijk-Hustings Y, et al. Patient global assessment in measuring disease activity in rheumatoid arthritis: a review of the literature. Arthritis Res Ther. 2016;18(1):251. https://doi.org/10.1186/s13075-016-1151-6.CrossRefPubMedPubMedCentralGoogle Scholar
- 11.Talli S, Etcheto A, Fautrel B, Balanescu A, Braun J, Canete JD, et al. Patient global assessment in psoriatic arthritis—what does it mean? An analysis of 223 patients from the Psoriatic arthritis impact of disease (PsAID) study. Joint Bone Spine Revue du rhumatisme. 2016;83(3):335–40. https://doi.org/10.1016/j.jbspin.2015.06.018.CrossRefGoogle Scholar
- 12.Mokkink LB, Terwee CB, Knol DL, Stratford PW, Alonso J, Patrick DL, et al. The COSMIN checklist for evaluating the methodological quality of studies on measurement properties: a clarification of its content. BMC Med Res Methodol. 2010;10:22. https://doi.org/10.1186/1471-2288-10-22.CrossRefPubMedPubMedCentralGoogle Scholar
- 13.Terwee CB, Mokkink LB, Knol DL, Ostelo RW, Bouter LM, de Vet HC. Rating the methodological quality in systematic reviews of studies on measurement properties: a scoring system for the COSMIN checklist. Qual Life Res. 2012;21(4):651–7. https://doi.org/10.1007/s11136-011-9960-1.CrossRefPubMedGoogle Scholar
- 18.Berth-Jones J, Grotzinger K, Rainville C, Pham B, Huang J, Daly S, et al. A study examining inter- and intrarater reliability of three scales for measuring severity of psoriasis: Psoriasis Area and Severity Index, Physician's Global Assessment and Lattice System Physician's Global Assessment. Br J Dermatol. 2006;155(4):707–13. https://doi.org/10.1111/j.1365-2133.2006.07389.x.CrossRefPubMedGoogle Scholar
- 19.Simpson MJ, Chow C, Morgenstern H, Luger TA, Ellis CN. Comparison of three methods for measuring psoriasis severity in clinical studies (Part 2 of 2): use of quality of life to assess construct validity of the Lattice System Physician's Global Assessment, Psoriasis Area and Severity Index and Static Physician's Global Assessment. JEADV. 2015;29(7):1415–20. https://doi.org/10.1111/jdv.12861.CrossRefPubMedGoogle Scholar
- 20.Chow C, Simpson MJ, Luger TA, Chubb H, Ellis CN. Comparison of three methods for measuring psoriasis severity in clinical studies (Part 1 of 2): change during therapy in Psoriasis Area and Severity Index, Static Physician's Global Assessment and Lattice System Physician's Global Assessment. JEADV. 2015;29(7):1406–14. https://doi.org/10.1111/jdv.13132.CrossRefPubMedGoogle Scholar
- 21.Walsh JA, McFadden M, Woodcock J, Clegg DO, Helliwell P, Dommasch E, et al. Product of the Physician Global Assessment and body surface area: a simple static measure of psoriasis severity in a longitudinal cohort. J Am Acad Dermatol. 2013;69(6):931–7. https://doi.org/10.1016/j.jaad.2013.07.040.CrossRefPubMedGoogle Scholar
- 32.Tugwell P, Boers M, D’Agostino M-A, Beaton D, Boonen A, Bingham CO et al. Updating the OMERACT filter: implications of filter 2.0 to select outcome instruments through assessment of “truth”: content, face, and construct validity. J Rheumatol. 2014:jrheum. 131310.Google Scholar
- 34.Robinson A, Kardos M, Kimball AB. Physician Global Assessment (PGA) and Psoriasis Area and Severity Index (PASI): why do both? A systematic analysis of randomized controlled trials of biologic agents for moderate to severe plaque psoriasis. J Am Acad Dermatol. 2012;66(3):369–75. https://doi.org/10.1016/j.jaad.2011.01.022.CrossRefPubMedGoogle Scholar