Sensitivity to change of the modified Rodnan skin score in diffuse systemic sclerosis--assessment of individual body sites in two large randomized controlled trials.
OBJECTIVE
The modified Rodnan skin score (MRSS) is a standard outcome measure for skin disease in SSc and calculated by summation of skin thickness in 17 different body sites (total score = 51). Our objective was to evaluate the sensitivity of change over time of individual body sites used in the calculation of total MRSS.


METHODS
We analysed two randomized placebo controlled clinical trials investigating the effect of either recombinant human relaxin or type I oral collagen in dcSSc. Both trials used MRSS as the primary outcome measure. We used a change of >10 mm (on a 0-100 VAS) in the patient global assessment (PGA) as the clinically important improvement. We calculated the mean change and the effect size (ES) for each individual body site used in the total MRSS for each study. Magnitude of ES was assessed using Cohen's rule of thumb for ES.


RESULTS
In the relaxin and collagen studies, 71 of 199 patients (36%) and 54 of 129 (42%) of patients had an improvement >10 mm on the PGA at 6 and 12 months, respectively. Total MRSS had large ES in both studies (0.85-0.98); the chest, forearms and hands had moderate ES (0.50-0.74); and the lower extremities, face, abdomen and fingers had small ES (0.16-0.49).


CONCLUSIONS
Certain body sites (hands, forearms and chest) are more sensitive to change compared with other body sites in two randomized clinical trials. It remains to be seen whether decreasing the number of body sites by exclusion of relatively static areas would further increase the sensitivity to change over time of the total MRSS.
Kaldas
Marian
M
UCLA-Olive View, Sylmar, CA, USA.
Khanna
Puja P
PP
Furst
Daniel E
DE
Clements
Philip J
PJ
Kee Wong
Weng
W
Seibold
James R
JR
Postlethwaite
Arnold E
AE
Khanna
Dinesh
D
D000328:Adult; D024042:Collagen Type I / Q000627:therapeutic use; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011994:Recombinant Proteins / Q000627:therapeutic use; D012065:Relaxin / Q000627:therapeutic use; D045743:Scleroderma, Diffuse / Q000188:drug therapy* / Q000473:pathology; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D012867:Skin / Q000473:pathology*; D016896:Treatment Outcome
D024042:Collagen Type I; D011994:Recombinant Proteins; D012065:Relaxin