Prospective cohort study of routine use of risk assessment scales for prediction of pressure ulcers

Abstract

Objective: To evaluate whether risk assessment scales can be used to identify patients who are likely to get pressure ulcers.

Design: Prospective cohort study.

Setting: Two large hospitals in the Netherlands.

Participants: 1229 patients admitted to the surgical, internal, neurological, or geriatric wards between January 1999 and June 2000.

Main outcome measure: Occurrence of a pressure ulcer of grade 2 or worse while in hospital.

Results: 135 patients developed pressure ulcers during four weeks after admission. The weekly incidence of patients with pressure ulcers was 6.2% (95% confidence interval 5.2% to 7.2%). The area under the receiver operating characteristic curve was 0.56 (0.51 to 0.61) for the Norton scale, 0.55 (0.49 to 0.60) for the Braden scale, and 0.61 (0.56 to 0.66) for the Waterlow scale; the areas for the subpopulation, excluding patients who received preventive measures without developing pressure ulcers and excluding surgical patients, were 0.71 (0.65 to 0.77), 0.71 (0.64 to 0.78), and 0.68 (0.61 to 0.74), respectively. In this subpopulation, using the recommended cut-off points, the positive predictive value was 7.0% for the Norton, 7.8% for the Braden, and 5.3% for the Waterlow scale.

Conclusion: Although risk assessment scales predict the occurrence of pressure ulcers to some extent, routine use of these scales leads to inefficient use of preventive measures. An accurate risk assessment scale based on prospectively gathered data should be developed.

Figure

Receiver operating characteristic curves for Norton, Braden, and Waterlow risk assessment scales in the first week, including all patients (top) and for all weeks combined, in subpopulation excluding surgical patients and patients with preventive measures who did not develop pressure ulcers (bottom)