The levels of reliability and validity of the Waterlow pressure sore risk calculator.

The Waterlow pressure sore risk calculator is widely used in the UK but has not been found to display high levels of reliability and validity. Few evaluative studies have been carried out in the community. This study aimed to evaluate the Waterlow score when used by district nurses to assess elderly patients. The score was not found to display high levels of reliability, and suffered from a lack of operational definitions within risk categories. In line with other studies, it was found to over-predict pressure sore formation. The findings of this small study suggest that the Waterlow score should not be used as the sole basis for decisions concerning the use of pressure sore prevention resources. High Waterlow scores may be a predictor of ill health in elderly people and this hypothesis requires further examination. The findings also indicate that clarification of the role of risk calculators in general is needed, as many mediating factors appear to affect the ability of a tool to predict pressure sore formation.