Predictive validity of the Braden scale for assessing risk of developing pressure ulcers and dependence-related lesions

Abstract

Objective: In 2014, a new theoretical model explained the mechanism of the development of pressure ulcers (PUs) and that of seven types of lesions known as dependence-related lesions (DRL). The aim of this study was to calculate the incidence of DRL that have been classified as PUs and to check the predictive validity of the Braden scale for assessing DRL in accordance with the new theoretical model in an intensive care unit (ICU). Method This longitudinal, prospective study was conducted in a Spanish ICU. The patients were monitored for 14 days in the ICU until they developed DRL, died, or were discharged. The patients' risk of developing DRL was assessed each day using the Braden scale. The following parameters were taken as reference for validating the scale: sensitivity (Se), specificity (Sp), positive and negative predictive values (PPV and NPV, respectively), relative risk (RR) and the area under the receiver operating characteristic (ROC) curve.

Results: Of the 295 patients included in the study, 27.5% developed DRL, which 50.6% were categorised as PUs, 17.3% caused by moisture, and 13.6% caused by friction. The rest were categorised as caused by a combination of factors. Risk according to the Braden scale was greater in the group of patients with DRL than in the group of patients without. The highest risk score provided the best predictive validity parameters for the DRL (Se 0.90, Sp 0.26, PPV 0.31, NPV 0.78 and RR 3.15 [confidence interval (CI) 95%: 1.42-6.96]). These vaules show the individuals at risk are well detected, although it is at the expense of generating a number of false positive cases.

Conclusions: The Braden scale has demonstrated a moderate capacity for predicting PUs and DRL caused by moisture, but no capacity for predicting DRL caused by friction.

Keywords: Braden scale; dependence-related lesions; intensive care units; nursing care; pressure ulcers.