Helliwell PS, FitzGerald O, Fransen J, et al. The development of candidate composite disease activity and responder indices for psoriatic arthritis (GRACE project). Ann Rheum Dis. 2013;72:986–91. https://doi.org/10.1136/annrheumdis-2012-201341.

Article  PubMed  Google Scholar 

Mumtaz A, Gallagher P, Kirby B, et al. Development of a preliminary composite disease activity index in psoriatic arthritis. Ann Rheum Dis. 2011;70:272–7. https://doi.org/10.1136/ard.2010.129379.

Article  PubMed  Google Scholar 

Schoels M, Aletaha D, Funovits J, Kavanaugh A, Baker E, Smolen JS. Application of the DAREA/DAPSA score for assessment of disease activity in psoriatic arthritis. Ann Rheum Dis. 2010;69:1441–7. https://doi.org/10.1136/ard.2009.122259.

Article  PubMed  Google Scholar 

Smolen JS, Schoels M, Aletaha D. Disease activity and response assessment in psoriatic arthritis using the Disease Activity Index For Psoriatic Arthritis (DAPSA). A brief review. Clin Exp Rheumatol. 2015;33(93):S48–50.

PubMed  Google Scholar 

Coates LC, Fransen J, Helliwell PJ. Defining minimal disease activity in psoriatic arthritis: a proposed objective target for treatment. Ann Rheum Dis. 2010;69:48–53. https://doi.org/10.1136/ard.2008.102053.

Article  CAS  PubMed  Google Scholar 

Smolen JS, Schols M, Braun J, et al. Treating axial spondyloarthritis and peripheral spondyloarthritis, especially psoriatic arthritis, to target: 2017 update of recommendations by an international task force. Ann Rheum Dis. 2018;77:3–17. https://doi.org/10.1136/annrheumdis-2017-211734.

Article  PubMed  Google Scholar 

Helliwell PS, Kavanaugh A. Comparison of composite measures of disease activity in psoriatic arthritis using data from an interventional study with golimumab. Arthritis Care Res. 2014;66(5):749–56. https://doi.org/10.1002/acr.22204.

Article  CAS  Google Scholar 

Helliwell PS, Deodhar A, Gottlieb AB, et al. Composite measures of disease activity in psoriatic arthritis: comparative instrument performance based on the efficacy of guselkumab in an interventional phase II trial. Arthritis Care Res. 2020;72(11):1579–88. https://doi.org/10.1002/acr.24046.

Article  CAS  Google Scholar 

Coates LC, Smolen JS, Mease PJ, et al. Comparative performance of composite measures from two phase III clinical trials of ixekizumab in psoriatic arthritis. RMD Open. 2022;8:e002457. https://doi.org/10.1136/rmdopen-2022-002457.

Article  PubMed  PubMed Central  Google Scholar 

Tillett W, McHugh N, Orbai AM, et al. Outcomes of the 2019 GRAPPA workshop on continuous composite indices for the assessment of psoriatic arthritis and membership-recommended next steps. J Rheumatol Suppl. 2020;96:11–8. https://doi.org/10.3899/jrheum.200121.

Article  PubMed  Google Scholar 

Tillett W, Fitzgerald O, Coates LC, et al. Composite measures for routine clinical practice in PsA: testing of shortened versions in a UK multicenter study. J Rheumatol Suppl. 2021;97:45–9. https://doi.org/10.3899/jrheum.201675.

Article  PubMed  Google Scholar 

Tillett W, Coates L, Sharaf M, et al. Strong correlation between short- vs long-form composite measures of psoriatic arthritis disease activity in a TNF-IR population treated with guselkumab: data from the phase 3b COSMOS trial. Paper presented at: American College of Rheumatology Convergence; 2022 Nov 10–14; Philadelphia, Pennsylvania.

Tillett W, Coates L, Vis M, et al. Minimal important difference (MID), minimal detectable change (MDC), and disease activity thresholds for two novel composite instruments (3 VAS and 4 VAS) in patients with PsA: Pooled analysis of 3 phase 3 studies. Paper presented at: American College of Rheumatology Convergence; 2022 Nov 10–14; Philadelphia, Pennsylvania.

Tillett W, Coates L, Kishimoto M, et al. Evaluating numeric rating scale versions of the 3- and 4-VAS composite measures in patients with active PsA from the SELECT-PsA program. Paper presented at: American College of Rheumatology Convergence; 2022 Nov 10–14; Philadelphia, Pennsylvania.

Kasiem FR, Kok MR, Luime JL, et al. Construct validity and responsiveness of feasible composite disease activity measures for use in daily clinical practice in patients with psoriatic arthritis. RMD Open. 2023;9:e002972. https://doi.org/10.1136/rmdopen-2022-002972.

Article  PubMed  PubMed Central  Google Scholar 

Wervers K, Luime JL, Tchetverikov I, et al. Comparison of disease activity measures in early PsA usual care. Rheumatology. 2019;58:2251–9. https://doi.org/10.1093/rheumatology/kez215.

Article  PubMed  PubMed Central  Google Scholar 

Leung YY, Tillett W, deWit T, et al. Initiating evaluation of composite outcome measures for psoriatic arthritis: 2022 updates from the GRAPPA-OMERACT working group. J Rheumatol. 2023. https://doi.org/10.3899/jrheum.2023-0530.

Article  PubMed  Google Scholar 

Cauli A, Gladman DD, Mathieu A, et al. Patient’s global assessment in psoriatic arthritis: a multicenter GRAPPA and OMERACT study. J Rheumatol. 2011;38:5. https://doi.org/10.3899/jrheum.100857.

Article  Google Scholar 

Orbai AM, Ogdie A. Patient reported outcomes in psoriatic arthritis. Rheum Dis Clin N Am. 2016;42:265–83. https://doi.org/10.1016/j.rdc.2016.01.002.

Article  Google Scholar 

Cauli A, Gladman DD, Mathieu A, et al. Physicians’s global assessment in psoriatic arthritis: a multicenter GRAPPA study. J Rheumatol. 2018;45:9. https://doi.org/10.3899/jrheum.171183.

Article  Google Scholar 

Tillett W, Dures E, Hewlett S, et al. A multicenter nominal group study to rank outcomes important to patients, and their representation in existing composite outcome measures for psoriatic arthritis. J Rheumatol. 2017;44:1445–52. https://doi.org/10.3899/jrheum.161459.

Article  PubMed  Google Scholar 

Coates LC, Tillett W, Shaddick G, et al. Value of the routine assessment of patient index data 3 in patients with psoriatic arthritis: results from a tight-control clinical trial and an observational cohort. Arthritis Care Res. 2018;70(8):1198–205. https://doi.org/10.1002/acr.23460.

Article  Google Scholar 

Mease PJ, van der Heijde D, Ritchlin CT, et al. Ixekizumab, an interleukin-17A specific monoclonal antibody, for the treatment of biologic-naïve patients with active psoriatic arthritis: results from the 24-randomized, double-blind, placebo-controlled and active (adalimumab)-controlled period of the phase III trial SPIRIT-P1. Ann Rheum Dis. 2017;76:79–87. https://doi.org/10.1136/annrheumdis-2016-209709.

Article  CAS  PubMed  Google Scholar 

van der Heijde D, Gladman DD, Kishimoto M, et al. Efficacy and safety of ixekizumab in patients with active psoriatic arthritis: 52-week results from a phase III study (SPIRIT-P1). J Rheumatol. 2018;45:367–77. https://doi.org/10.3899/jrheum.170429.

Article  CAS  PubMed  Google Scholar 

Nash P, Kirkham B, Okada M, et al. Ixekizumab for the treatment of patients with active psoriatic arthritis and an inadequate response to tumour necrosis factor inhibitors: results from the 24-randomized, double-blind, placebo-controlled period of the SPIRIT-P2 phase 3 trial. Lancet. 2017;389:2317–27. https://doi.org/10.1016/S01460-6736(17)314290-0.

Article  CAS  PubMed  Google Scholar 

Genovese MC, Combe B, Kremer JM, et al. Safety and efficacy of ixekizumab in patients with PsA and previous inadequate response to TNF inhibitors: week 52 results from SPIRIT-P2. Rheumatology. 2018;57:2001–11. https://doi.org/10.1016/S0140-6736(17)31429-0.

Article  CAS  PubMed  PubMed Central  Google Scholar 

Michelsen B, Sexton J, Smolen JS, et al. Can disease activity in patients with psoriatic arthritis be adequately assessed by a modified Disease Activity index for Psoriatic Arthritis (DAPSA) based on 28 joints? Ann Rheum Dis. 2018;77:1736–41. https://doi.org/10.1136/annrheumdis-2018-213463.

Article  CAS  PubMed  Google Scholar 

Ashcroft DM, Wan AL, Williams HC, et al. Clinical measures of disease severity and outcome in psoriasis: a critical appraisal of their quality. Br J Dermatol. 1999;141:185–91. https://doi.org/10.1046/j.1365-2133.1999.02963.x.

Article  CAS  PubMed  Google Scholar 

Rich P, Scher RK. Nail psoriasis severity index: a useful tool for evaluation of nail psoriasis. J Am Acad Dermatol. 2003;49:206–12. https://doi.org/10.1067/S0190-9622(03)00910-1.

Article  PubMed  Google Scholar 

Healy PJ, Helliwell PS. Measuring clinical enthesitis in psoriatic arthritis: assessment of existing measures and development of an instrument specific to psoriatic arthritis. Arthritis Rheum. 2008;59:686–91. https://doi.org/10.1002/art.23568.

Article  PubMed  Google Scholar 

Fries JF, Spitz P, Young DY, et al. The dimensions of health outcomes: the health assessment questionnaire, disability and pain scales. J Rheumatol. 1982;9:789–93.

CAS  PubMed  Google Scholar 

Ware JE, Sherbourne CD. The MOS 36-item short form health survey (SF-36). Conceptual framework and item selection. Med Care. 1992;30:473–83.

Article  PubMed  Google Scholar 

Evans JD. Straightforward statistics for the behavioral sciences. Pacific Grove: Thomson Brooks/Cole; 1996.

Google Scholar 

Ialongo C. Understanding the effect size and its measures. Biochem Med (Zagreb