An evaluation of serum albumin and the sub-scores of the Waterlow score in pressure ulcer risk assessment

Abstract

Background From previous work serum albumin is predictive of pressure ulcers over and above the Waterlow score. However the sub-scores of the Waterlow score were not available, and the accuracy of calculation of the total score was poor. This study has used sub-scores and is an order of magnitude larger. Objectives To compare serum albumin with Waterlow score as a predictive measure for pressure ulcers. Design Retrospective analysis of hospital information support system. Settings A district general hospital in Staffordshire. Participants Adult non-elective in-patients. Methods Logistic regression and receiver operating characteristic. Results The sub-scores of the Waterlow score were explored. While they constitute a multi-dimensional dataset, many were not found relevant to pressure ulcer risk in this population (non-elective in-patients). Some sub-scores were not recorded correctly, and body mass index (BMI) was particularly badly reported. Age was found to be as predictive of pressure ulcer as the more complex Waterlow score. Serum albumin was at least as good as the Waterlow score in risk assessment of pressure ulcers. Matching patients with pressure ulcers to patients with none, who had identical Waterlow sub-scores, confirmed serum albumin as a robust predictive value in pressure ulcers. Conclusion Risk assessing patients based on their age is as good as the more complex Waterlow score. Additional risk information can be gained from knowing the serum albumin value.