A regression analysis of the Waterlow score in pressure ulcer risk assessment

Abstract

OBJECTIVE: To explore the predictive value of the Waterlow score, and the subscores of age and gender. DESIGN: Logistic regression analysis was conducted on the two subscores of the Waterlow score, and the residual Waterlow score with gender and age removed. Receiver operating characteristic (ROC) analysis gave a quantitative measure of the classification ability of the Waterlow score. SETTING: Burton, UK. SUBJECTS: All admissions over a five-year period to the District General Hospital, a total of 150,015 admissions of 82,691 patients. INTERVENTIONS: None. MAIN OUTCOME MEASURES: Area under the ROC curve for significant (as determined by logistic regression) variables. RESULTS: Data were inaccurate in at least 44.7% of the records, and analysis was conducted on the 43,735 records for which no errors were apparent. Nine hundred and fifty-four patients had a pressure ulcer on admission (2.1%); 277 developed a pressure ulcer (0.6%). The Waterlow score was predictive of pressure ulcers. Age was predictive, and gender was not found to be a significant predictor. CONCLUSIONS: The Waterlow score may be improved and simplified by removing gender from the scoring system.