Comparison of pressure ulcer grading scales: a study of clinical utility and inter-rater reliability

Pressure ulcer grading scales are subjective measures of pressure damage. This study measured inter-observer agreement of the Stirling scale (1-digit and 2-digit versions) and the European Pressure Ulcer Advisory Panel Scale, using Cohen's kappa and percentage agreement. Clinical utility was also assessed. Thirty-five observations were made by two Registered Nurses on 30 adult in-patients. The levels of agreement obtained were better than those reported previously and this may be related to the methodology used. The 2-digit Stirling scale gave the best level of chance corrected agreement (kappa=0.457) and was the scale preferred by raters. The 1-digit Stirling scale performed least favourably. Qualitative data identified problems with scale construction relating to visualisation of the base of the wound, discolouration of the skin, abrasions and shallow ulcers. Whilst refinements in scale construction may improve rater reliability, there is a need to develop objective measures of pressure induced tissue damage.