Measuring disease activity and damage in discoid lupus erythematosus.
BACKGROUND
Discoid lupus erythematosus (DLE) is a disfiguring inflammatory skin disease. There is no specific tool for measuring disease severity.


OBJECTIVE
To determine the features needed in a score measuring activity and damage in DLE and to investigate the score's reliability and its correlation with the physician's global assessment of disease severity and the patient-reported Dermatology Quality of Life Index (DLQI).


METHODS
The content of the score was determined following a peer review, pilot work in patients and a preliminary inter-rater reliability study. The Score of Activity and Damage in DLE (SADDLE) measures severity of activity (erythema, scale, induration) and damage (scarring/atrophy and dyspigmentation) attributable to DLE. Summed scores range between 0 and 195. Inter- and intrarater reliability of the score was tested using six assessors and nine patients with DLE. Intraclass correlation coefficients (ICCs) > 0.7 were considered evidence of good inter- and intrarater agreement.


RESULTS
The mean +/- SD SADDLE score of nine patients in the inter-rater reliability study was 47 +/- 22 (range 14-102). There was good inter-rater agreement for the total score [ICC 0.82; 95% confidence interval (CI) 0.61-0.95] and for the activity and damage scales, the individual physical signs and the total scores at individual body sites. The total score demonstrated excellent intrarater reliability (ICC 0.98; 95% CI 0.86-1.00). Although there was poor inter-rater agreement for global assessments (ICC 0.28; 95% CI 0.06-0.66), a good correlation was demonstrated between total scores and global assessments (r = 0.7). A weaker positive correlation was observed between disease activity scores and DLQI (r = 0.4).


CONCLUSIONS
The SADDLE measures activity and damage in patients with DLE. It demonstrates good inter- and excellent intrarater agreement, over and above that for global assessment. It correlates well with global assessment scores. Further studies are required to investigate SADDLE's responsiveness to change with therapy.
Wahie
S
S
Dermatological Sciences, Institute of Cellular Medicine, Newcastle University, Newcastle upon Tyne NE2 4HH, UK. shyamalwahie@ncl.ac.uk
McColl
E
E
Reynolds
N J
NJ
Meggitt
S J
SJ
D001291:Attitude of Health Personnel; D005246:Feedback; D006801:Humans; D008179:Lupus Erythematosus, Discoid / Q000175:diagnosis* / Q000473:pathology; D015588:Observer Variation; D011788:Quality of Life; D015203:Reproducibility of Results; D012720:Severity of Illness Index