Evaluation of Reliability, Validity, and Responsiveness of the CDASI and the CAT-BM

Abstract

Background To properly evaluate therapies for cutaneous dermatomyositis (DM), it is essential to administer an outcome instrument that is reliable, valid, and responsive to clinical change, particularly when measuring disease activity. Objective The purpose of this study is to compare two skin-severity DM outcome measures, the Cutaneous Disease and Activity Severity Index (CDASI) and the Cutaneous Assessment Tool-Binary Method (CAT-BM), with the physician global assessment (PGA) as the ‘gold standard’. Methods Ten dermatologists evaluated fourteen patients with DM using the CDASI, CAT-BM, and PGA scales. Inter-, intra-rater reliability, validity, responsiveness, and completion time were compared for each outcome instrument. Responsiveness was assessed from a different study population, where one physician evaluated 35 patients with 110 visits. Results The CDASI was found to have a higher inter- and intra-rater reliability. Regarding construct validity, both the CDASI and the CAT-BM were significant predictors of the PGA scales. The CDASI had the best responsiveness among the three outcome instruments examined. The CDASI had a statistically longer completion time than the CAT-BM by about 1.5 minutes. Limitations The small patient population may limit the external validity of the findings observed. Conclusions The CDASI is a better clinical tool to assess skin severity in DM.

Validation studies of outcome measures in pemphigus

“…ABSIS = Autoimmune Bullous Skin Disorder Intensity Score; BPDAI = Bullous Pemphigoid Disease Area Index; CDASI = Cutaneous Dermatomyositis Disease Area and Severity Index; CLASI = Cutaneous Lupus Erythematosus Disease Area and Severity Index; EBDASI = Epidermolysis Bullosa Disease Activity and Scarring Index; EASI = Eczema Acvitity and Scarring Index; MCID = minimal clinically-important difference; PASI = Psoriasis Area and Severity Index; PDAI = Pemphigus Disease Area Index; SCORAD = Scoring Atopic Dermatitis. 1 Rahbar et al, 2014; 2 Murrell et al, 2008; 3 Boulard et al, 2016; 4 Shimizu et al, 2014, 5 Pfutze et al, 2007; 6 Gourraud et al, 2012; 7 Puzenat et al, 2010; 8 Tofte et al, 1998; 9 Hanifin et al, 2001; 10 Breuer et al, 2004; 11 Schram et al, 2012; 12 Sartorius et al, 2010; 13 Loh et al, 2014; 14 Jain et al, 2016; 15 Wijayanti et al, 2014, Wijayanti et al, 2016; 16 Murrell et al, 2012; 17 Patsatsi et al, 2012; 18 Lévy-Sitbon et al, 2014; 19 Bonilla-Martinez et al, 2008; 20 Albrecht et al, 2005; 21 Klein et al, 2011; 22 Goreshi et al, 2012; 23 Anyanwu et al, 2015; 24 Stalder et al, 1993; 25 Schram et al, 2012; 26 Angelova-Fischer et al, 2005; 27 Langley and Ellis, 2004; 28 Zhao et al, 2015.…”

213th ENMC International Workshop: Outcome measures and clinical trial readiness in idiopathic inflammatory myopathies, Heemskerk, The Netherlands, 18–20 September 2015

“…In addition, cutaneous damage, which includes poikiloderma and calcinosis, is similarly assessed across the 15 body areas and the hands [74]. The CDASI has good to excellent inter-rater reliability, good construct validity, including good correlation with change in HRQoL, and superior responsiveness compared to other cutaneous assessment tools [75,76]. The clinical interpretability of CDASI scores has also been defined, with CDASI activity ≥ 14 indicative of moderate to severe activity and a 5 point change defined as clinically relevant [77].…”

“…Another cutaneous assessment tool available is the Cutaneous Assessment Tool (CAT), which assesses 17 activity and 11 cutaneous damage items, and is more clinically-usable in binary mode [78,79]. Rater reliability and construct validity are comparable to the CDASI, but it may be less sensitive to change than the CDASI [54,75] (Table 2). …”

Myositis registries and biorepositories

“…We have categorized this listing of myositis research registries into different groups (see Tables 1, 2, and 3) [13**,14,15*,16–28,29*,30*,31–37,38*,39–42,43* 44,45,46*,47–60,61**,62,63*,64*,65, 66*,67,68**,69*,70*,71,72*,73–82,83*,84–90,91*,92–107,108*,109,110**,111** 112–115,116*,117, 118*,119–121, 122**,123–129, 130*,131–133,134*,135,136*, 137–149,150*,151,152,153*,154*] based on the types of myositis included, as well as whether the registries are regional, national, or international in scope. Thirteen registries are international and 33 are national or regional registries.…”

“…Standardized assessment of skin activity and damage in myositis through cutaneous assessment tools [20,72*,73,74] has been developed, and assessment of muscle dysfunction, including exercise intolerance [145,150*], and pulmonary and cardiac involvement [71,146–148], is emerging with the use of new, more sensitive radiographic measures. A focus on capturing patient-reported outcomes, including the severe impact of myositis on health-related quality of life, is now beginning [75,96].…”