Effect of preoperative prognostic nutritional index on prognosis of patients with extensive burns

Abstract

Objective To investigate the prognostic value and clinical significance of preoperative prognostic nutritional index （PNI） in patients with extensive burns. Methods Clinical data of 56 patients with extensive burns were retrospectively analyzed，and they were divided into the survival group （n=37） and death group （n=19） according to clinical outcomes. Baseline data and relevant laboratory indexes at preoperative 1 d were collected. PNI was calculated using the following equation： serum albumin level （g/L） +5×total lymphocyte count （×109/L）. Clinical data were statistically compared between two groups. The influencing factors of clinical prognosis were identified by univariate and multivariate Logistic regression analyses. The predictive value of preoperative PNI for clinical prognosis of patients with extensive burns was evaluated by the ROC curve. The area under the ROC curve （AUC） represents the accuracy of prediction. All patients were divided into the high and low PNI groups according to the optimal cut-off value of preoperative PNI. The survival curve was drawn by Kaplan Meier method to predict the differences in 90-d survival rate between two groups. Results Among 56 patients，19 （33.93%） died within postoperative 90 d. There were significant differences in burn area，lymphocyte count and preoperative PNI between the death and survival groups （all P<0.05）. In the death group，burn area was larger，lymphocyte count and preoperative PNI were lower than those in the survival group. There were no significant differences in age，sex，CRP，white blood cell count，creatinine，PLR，albumin levels and the incidence of respiratory tract injury between two groups. Univariate Logistic regression analysis showed that burn area，lymphocyte count and preoperative PNI were the risk factors of death. Multivariate Logistic regression analysis indicated that burn area and preoperative PNI were the independent risk factors for death. The optimal cut-off value of preoperative PNI to predict death in patients with extensive burns was 34.45. The 90-d survival rate of patients with PNI≤34.45 was significantly lower than that of their counterparts with PNI>34.45. Conclusions Preoperative PNI is associated with 90-d death rate in patients with extensive burns. The 90-d survival rate of patients with low PNI is lower than that of those with high PNI. These findings indicate that it is of significance to identify preoperative PNI for patients with extensive burns，which can provide reference for selecting the optimal timing for surgery，accelerate wound healing and reduce the death rate of patients with extensive burns.

Keywords

• burn|prognostic nutritional index|extensive burn|death rate|nutrition