UC Irvine

Aim

The modified Rodnan skin score (mRSS) is a validated outcome measure for skin thickness in systemic sclerosis (SSc). Training has been shown to reduce variability in the measurement of mRSS. Our objective was to assess the inter- and intra-observer variability of mRSS scoring using the proposed recommendations for training by the Scleroderma Clinical Trials Consortium (SCTC) and World Scleroderma Foundation (WSF).

Method

Fifty-two trainees and eight adult SSc patients participated in the SSc skin scoring workshop that was conducted in two sessions by four teachers. Each session, attended by 26 trainees, had a teaching and evaluation phase. The teaching phase comprised of: (a) lecture on mRSS scoring; (b) video demonstration of mRSS scoring; and (c) live demonstration of mRSS on one SSc patient. In the evaluation phase, each trainee independently assessed the mRSS in four SSc patients. For intra-observer reliability, 14 trainees re-assessed the mRSS of two SSc patients whom they had previously examined. We computed the inter- and intra-observer variability using a linear mixed model.

Results

For the evaluation phase, 34 (65.4%) trainees were within five units of the established teachers' score in 3 out of 4 patients. Overall, the whole group had acceptable inter-observer variability (intra-class correlation coefficient [ICC] = 0.71, mean = 8.64 and within-patient standard deviation [SD] = 4.25). The intra-observer ICC was 0.85 and within-patient SD was 2.73.

Conclusion

There was good inter-observer and excellent intra-observer reliability. This is the first study examining the training of assessors using the SCTC/WSF recommendations and our results support the importance of standardized training for skin scoring.