A Simple Score to Assess the Risk of Rejection Following Orthotopic Heart Transplantation
Background—The aim of this study was to derive and validate a risk score for rejection following orthotopic heart transplantation(OHT).
Methods and Results—The United Network for Organ Sharing(UNOS) registry was used to identify patients undergoing OHT between 1998-2008. A total of 14,265 eligible patients were randomly divided into derivation(80%; n=11,412) and validation(20%; n=2,853) cohorts. The primary outcome was drug-treated rejection within 1-year of OHT. Covariates found to be associated(exploratory univariate p-value <0.2) with rejection were entered into a multivariable logistic regression model. Inclusion of each variable into the model was assessed by improvement in McFadden's pseudo-R2, likelihood ratio test, and c-index. A risk score was then generated using relative magnitudes of the odds ratios from the derivation cohort, and its ability to predict rejection was independently tested in the validation cohort. A 13-point risk score was created incorporating 4 variables(age, race, gender, human leukocyte antigen matching). The mean score in the derivation and validation cohorts was 8.3±2.2 and 8.4±2.1, respectively. Predicted 1-year rejection rates based on the derivation cohort ranged from 16.2%(score=0) to 50.7%(score=13)(p<0.001). In weighted regression analysis, there was a strong correlation between these predicted rates of rejection and actual, observed rejection rates in the validation cohort(r2=0.96, p<0.001). Logistic regression analysis also demonstrated a significant association(OR 1.13, p<0.001). The c-index of the composite score was equivalent in both derivation and validation cohorts(c=0.67).
Conclusions—This novel 13-point risk score is highly predictive of clinically significant rejection episodes within 1-year of OHT. It has potential utility in tailoring immunosuppressive regimens and in research stratification in OHT.
- Received September 8, 2011.
- Accepted April 18, 2012.
- Copyright © 2012, American Heart Association, Inc. All rights reserved. Unauthorized use prohibited