Investigating the intra- and inter-rater reliability of a panel of subjective and objective burn scar measurement tools

•Subjective scar measures have poor reliability unless repeated by more than one assessor.•Objective scar measures have been demonstrated to have good to excellent reliability.•Physical symptoms of scars such as pain and itch were found to be more important to patients compared to surface, area and colour although this finding was not sustained when corrected for multiple comparisons. Research into the treatment of hypertrophic burn scar is hampered by the variability and subjectivity of existing outcome measures. This study aims to measure the inter- and intra-rater reliability of a panel of subjective and objective burn scar measurement tools. Three independent assessors evaluated 55 scar and normal skin sites using subjective (modified Vancouver Scar Scale [mVSS] & Patient and Observer Scar Assessment Scale [POSAS]) and objective tools. The intra-class correlation coefficient was utilised to measure reliability (acceptable when >0.70). Patient satisfaction with the different tools and scar parameter importance were assessed via questionnaires. The inter-rater reliabilities of the mVSS and POSAS were below the acceptable limit. For erythema and pigmentation, all of the Scanoskin and DSM II measures (except the b* value) had acceptable to excellent intra and inter-rater reliability. The Dermascan ultrasound (dermal thickness, intensity) had excellent intra- and inter-rater reliability (>0.90). The Cutometer R0 (firmness) had acceptable reliability but not R2 (gross elasticity). All objective measurement tools had good overall satisfaction scores. Patients rated scar related pain and itch as more important compared to appearance although this finding was not sustained when corrected for multiple comparisons. The objective scar measures demonstrated acceptable to excellent intra- and inter-rater reliability and performed better than the subjective scar scales.