Application of acute physiology and chronic health evaluation IV in predicting the prognosis of patients after liver transplantation

Abstract

Objective To explore the value of acute physiology and chronic health evaluation (APACHE) Ⅳ in predicting mortality during hospital stay and intensive care unit (ICU) length of stay (LOS) of patients after orthotopic liver transplantation (OLT). Methods Clinical data of 195 patients [171 males, 24 females, mean age of (48±11) years old] who underwent OLT from February 2006 to July 2009 in Liver Transplantation Center, the Third Affiliated Hospital of Sun Yat-sun University were studied retrospectively.The informed consents of all patients were obtained and the ethical committee approval was received. The required parameters for APACHE IV, actual ICU LOS and mortality during hospital stay were collected. The APACHE Ⅳ scores, actual mortality, estimated ICU LOS, estimated mortality were calculated and receiver operating characteristic (ROC) curve of predicting the patients' mortality was drawn. The survival, mortality and APACHE Ⅳ scores of patients during hospital stay were observed. The ability of APACHE Ⅳ in predicting mortality during hospital stay was analyzed using ROC curve, and the accuracy of APACHE Ⅳ in predicting mortality during hospital stay was analyzed using Hosmer-Lemeshow goodness-of-fit test. The actual ICU LOS and estimated ICU LOS of the survivals during hospital stay were compared using Wilcoxon rank sum test. The correlation between them was studied using Spearman rank correlation analysis. Results There were 168 survivals and 27 deaths with the mortality of 13.8%. The mean APACHE Ⅳ score was (41±22) for all the patients, was (36±16) for the survivals and(75±25) for the death. The area under the curve(A) value of APACHE Ⅳ in predicting mortality during hospital stay was 0.937. The predictive cutoff point was 56 with the sensitivity 0.85, specificity 0.91 and the Youden index 0.76. The actual mortality of the patients was 13.8% and the estimated mortality by APACHE Ⅳ was 3.8%. The actual mortality was underestimated by APACHE Ⅳ in the overall score, 30-60 scores and >60 scores groups. The Hosmer-Lemeshow goodness-offit of APACHE Ⅳ in predicting mortality during hospital stay was good with a high calibration (χ2=1.568, P>0.05) . The median of actual ICU LOS was 3.7(2.4, 5.5)d, and the median of estimated ICU LOS was 3.2(2.4, 4.8)d. The actual ICU LOS was evidently longer than the estimated ICU LOS, and significant difference was observed between them (Z=3.760, P<0.05). There was positive correlation between the actual ICU LOS and the estimated ICU LOS by Spearman rank correlation analysis (r=0.467, P<0.05). Conclusions APACHE Ⅳ has a certain value in predicting mortality of patients after OLT during hospital stay, but it underestimates the mortality and ICU LOS. Key words: Liver transplantation; Acute physiology and chronic health evaluation; Hospital mortality; Intensive care