The Cutaneous Assessment Tool: development and reliability in juvenile idiopathic inflammatory myopathy.
OBJECTIVE
Clinical care and therapeutic trials in idiopathic inflammatory myopathies (IIM) require accurate and consistent assessment of cutaneous involvement. The Cutaneous Assessment Tool (CAT) was designed to measure skin activity and damage in IIM. We describe the development and inter-rater reliability of the CAT, and the frequency of lesions endorsed in a large population of juvenile IIM patients.


METHODS
The CAT includes 10 activity, 4 damage and 7 combined lesions. Thirty-two photographic slides depicting IIM skin lesions were assessed by 11 raters. One hundred and twenty-three children were assessed by 11 paediatric rheumatologists at 10 centres. Inter-rater reliability was assessed using simple agreements and intra-class correlation coefficients (ICC).


RESULTS
Simple agreements in recognizing lesions as present or absent were generally high (0.5-1.0). ICCs for CAT lesions were moderate (0.4-0.75) in both slides and real patients. ICCs for the CAT activity and damage scores were 0.71 and 0.81, respectively. CAT activity scores ranged from 0 to 44 (median 7, potential range 0-96) and CAT damage scores ranged from 0 to 13 (median 1, potential range 0-22). The most common cutaneous lesions endorsed were periungual capillary loop changes (63%), Gottron's papules/sign (53%), heliotrope rash (49%) and malar/facial erythema (49%).


CONCLUSIONS
Total CAT activity and damage scores have moderate to good reliability. Assessors generally agree on the presence of a variety of cutaneous lesions. The CAT is a promising, semi-quantitative tool to comprehensively assess skin disease activity and damage in IIM.
Huber
A M
AM
IWK Health Centre, Dalhousie University, Halifax, Nova Scotia, Canada. adam.huber@iwk.nshealth.ca
Dugan
E M
EM
Lachenbruch
P A
PA
Feldman
B M
BM
Perez
M D
MD
Zemel
L S
LS
Lindsley
C B
CB
Rennebohm
R M
RM
Wallace
C A
CA
Passo
M H
MH
Reed
A M
AM
Bowyer
S L
SL
Ballinger
S H
SH
Miller
F W
FW
Rider
L G
LG
D002648:Child; D003882:Dermatomyositis / Q000175:diagnosis*; D006801:Humans; D015588:Observer Variation; D015203:Reproducibility of Results; D012720:Severity of Illness Index