Visual analogue scale scoring and ranking: A suitable and sensitive method for assessing scar quality?

Background: The field of scar assessment lacks a standard methodology. Previous methods have focused on a wide range of scar types, resulting in poorer sensitivity and diminishing their discriminatory effectiveness. Methods: As part of a clinical trial investigating the scar-improving efficacy of transforming growth factor-beta 3, the authors investigated the use of a visual analogue scale and scar ranking as scar assessment tools. Scar photographic images were assessed using a newly developed computerized scar assessment system by an external lay panel. Results: A total of 4296 scar images were collected for visual analogue scale assessment and 2148 scar pairs were collected for scar ranking. Intrarater consistency was 100 percent for the ranking data, with differences very close to zero for the visual analogue scale consistency data. Reducing the number of assessors in the external panel significantly improved intraclass correlation coefficients. From month 1 to month 12, the correlation coefficients for the difference in visual analogue scale score showed that the assessors reliably noted the changes in the maturing scars. Combining logistic regression with an area under the curve of 0.72 in a receiver operating characteristic curve analysis, the visual analogue scale score was shown to be a highly statistically significant predictor of a good scar. Conclusions: The authors have shown the visual analogue scale scar scoring and scar ranking methods to be consistent, reliable, valid, and feasible. These methods for scar assessment are highly sensitive and capable of reliably measuring differences in scar quality, making them valuable techniques, reaching an unmet clinical need, and enabling investigation of changes in scar quality (e.g., with time or after therapeutic intervention).