Development and initial validation of the localized scleroderma skin damage index and physician global assessment of disease damage: a proof-of-concept study.
OBJECTIVE
To develop and assess the psychometric properties of the Localized Scleroderma (LS) Skin Damage Index (LoSDI) and Physician Global Assessment of disease Damage (PGA-D).


METHODS
Damage was defined as irreversible/persistent changes (>6 months) due to previous active disease/complications of therapy. Eight rheumatologists assessed the importance of 17 variables in formulating the PGA-D/LoSDI. LS patients were evaluated by two rheumatologists using both tools to assess their psychometric properties. LoSDI was calculated by summing three scores for cutaneous features of damage [dermal atrophy (DAT), subcutaneous atrophy (SAT) and dyspigmentation (DP)] measured at 18 anatomic sites. Patient GA of disease severity (PtGA-S), Children's Dermatology Life Quality Index (CDLQI) and PGA-D were recorded at the time of each examination.


RESULTS
Thirty LS patients (112 lesions) and nine patient-visit pairs (18 lesions) were included for inter- and intra-rater reliability study. LoSDI and its domains DAT, SAT, DP and PGA-D demonstrated excellent inter- and intra-rater reliability (reliability coefficients 0.86-0.99 and 0.74-0.96, respectively). LoSDI correlated moderately with PGA-D and poorly with PtGA-S and CDLQI. PGA-D correlated moderately with PtGA-S, but poorly with CDLQI.


CONCLUSIONS
To complete the LS Cutaneous Assessment Tool (LoSCAT), we developed and evaluated the psychometric properties of the LoSDI and PGA-D in addition to the LS Skin Severity Index (LoSSI). These instruments will facilitate evaluation of LS patients for individual patient management and clinical trials. LoSDI and PGA-D demonstrated excellent reliability and high validity. LoSCAT provides an improved understanding of LS natural history. Further study in a larger group of patients is needed to confirm these preliminary findings.
Arkachaisri
Thaschawee
T
Department of Pediatrics, Division of Rheumatology, Children's Hospital of Pittsburgh, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA. thaschawee.arkachaisri@kkh.com.sg
Vilaiyuk
Soamarat
S
Torok
Kathryn S
KS
Medsger
Thomas A
TA
D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D008297:Male; D015588:Observer Variation; D010865:Pilot Projects; D011594:Psychometrics; D011788:Quality of Life; D015203:Reproducibility of Results; D012594:Scleroderma, Localized / Q000175:diagnosis*; D012720:Severity of Illness Index