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Br J Dermatol. 2015 Oct;173(4):969-74. doi: 10.1111/bjd.13915. Epub 2015 Aug 11.

Validation of the Cutaneous Dermatomyositis Disease Area and Severity Index: characterizing disease severity and assessing responsiveness to clinical change.

Author information

1
Philadelphia Veterans Affairs Medical Center, Philadelphia, PA, U.S.A.
2
Department of Dermatology, University of Pennsylvania School of Medicine, Philadelphia, PA, U.S.A.
3
Division of Immunology and Rheumatology, Department of Dermatology and Medicine, Stanford University School of Medicine, Stanford, CA, U.S.A.
4
Department of Biostatistics and Epidemiology, University of Pennsylvania, Philadelphia, PA, U.S.A.

Abstract

BACKGROUND:

The Cutaneous Dermatomyositis Disease Area and Severity Index (CDASI) was developed for use in clinical trials and longitudinal patient assessment.

OBJECTIVES:

To characterize disease severity using the CDASI and assess the responsiveness of this instrument to clinically meaningful changes in disease activity.

METHODS:

Patients with cutaneous dermatomyositis at the University of Pennsylvania (UPenn, n = 93) and Stanford University (Stanford, n = 106) were prospectively evaluated using the CDASI, physician global assessment (PGA) Likert scales and a visual analogue scale (VAS). Data was analysed using logistic regression models and receiver operating characteristic curves to select cut-offs.

RESULTS:

Baseline CDASI activity scores for the patients evaluated at UPenn ranged from 0 to 47 (median 17), and baseline PGA VAS scores ranged from 0 to 9·6 (median 1·1). At UPenn a CDASI activity score of 19 differentiated mild from moderate and severe disease. At Stanford baseline CDASI scores ranged from 0 to 48 (median 21), baseline PGA VAS scores ranged from 0 to 9·7 (median 4·2) and CDASI activity scores of 14 or less characterized mild disease. When a 2-cm change in the PGA VAS was regarded as a clinically significant improvement, a 4-point (UPenn) or 5-point (Stanford) change in CDASI reflected a minimal clinically significant response.

CONCLUSIONS:

The CDASI is a valid and responsive measure that can be used to characterize cutaneous dermatomyositis severity and detect improvement in disease activity. Variations in cut-offs may be due to differences in disease severity between the two populations or inter-rater variations in the use of the external gold measures.

PMID:
25994337
PMCID:
PMC4878996
DOI:
10.1111/bjd.13915
[Indexed for MEDLINE]
Free PMC Article

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