Who is the high-risk recipient? Predicting mortality after lung transplantation using pretransplant risk factors

Objectives: The purpose of this study was to create a preoperative risk stratification score (RSS) based on pretransplant recipient characteristics that could be used to predict mortality following lung transplantation. Methods: United Network for Organ Sharing provided deidentified patient-level data. The study population included 8780 adult recipients (age > 12 years) having lung transplantation from January 1, 1999, to December 31, 2006. Multivariate logistic regression (backward, P > .10) was performed. Using the odds ratio for each identified variable, an RSS was devised. The RSS included only pretransplant recipient variables and excluded donor variables. Results: The strongest negative predictors of 1-year survival included extracorporeal membrane oxygenation, decreased estimated glomerular filtration rate, total bilirubin >2.0 mg/dL, recipient age, hospitalization at time of transplant, O₂ dependence, cardiac index <2, steroid dependence, donor:recipient weight ratio <0.7, all non-cystic fibrosis/chronic obstructive pulmonary disease etiologies, and female donor-to-male recipient. Threshold analysis identified 4 discrete groups: low risk, moderate, elevated risk, and high risk. The 1-year actuarial survival was 80.4% for the entire group, compared with 56.8% in the high-risk group (RSS > 7.2, n = 490; 6%). Conclusion: Pretransplant recipient variables significantly influence both early and late survival following lung transplantation. Some patients face a higher than average risk of mortality during their first year posttransplant, which challenges the goals of equitable organ allocation. RSS may improve organ allocation strategies by avoiding the potential negative impact of performing transplantation in extremely high-risk candidates.