A new nomogram score for predicting surgery-related pressure ulcers in cardiovascular surgical patients

Abstract

The aim of this study was to build a new nomogram score for predicting surgery-related pressure ulcers (SRPU) in cardiovascular surgical patients. We performed a prospective cohort study among consecutive patients with cardiovascular surgery between January 2015 and December 2015. Univariate and multivariate logistic regression was used to analyse the risk factors for SRPU. A nomogram-predicting model was built based on the logistic regression model. Then, calibration and discrimination were tested. A total of 149 patients with cardiovascular surgery were included in the study. Thirty-seven patients developed SRPUs, with an incidence rate of 24·8% (95%CI: 18·1-32·6%). The logistic regression model for predicting SRPU with four risk factors was Logit(P) = (1·861 × VDH, OR 2·174 × CAD, OR 1·747 × TAA) - 0·029 × weight + 0·005 × surgery duration + 1·241 × perioperative corticosteroids administration (P = 0·003, R² = 0·1181). The goodness-of-fit test (Pearson χ² = 150·69, P = 0·217) indicated acceptable calibration, and the C-index (0·725) indicated moderate discrimination. When the probability cut-off is 0·25 (total score 12), the nomogram model has the best sensitivity and specificity in predicting SRPU. We established a new nomogram model that can provide an individual prediction of SRPU in cardiovascular surgical patients. When the probability is more than 0·25 (total score 12), the cardiovascular surgery patients should be considered at high-risk.

Keywords: Calibration; Cardiovascular surgery; Discrimination; Nomogram score; Surgery-related pressure ulcer.