Determining who receives the limited supply of donor organs is one of the greatest challenges facing the transplant community. Severity of illness is the main criterion for hopeful liver recipients; however, it is not the only factor that influences post-transplant survival.
Patients awaiting liver transplantation who also suffer other conditions may face poorer survival after liver transplantation. These conditions have been incorporated into a new modified comorbidity index that helps predict post-transplant survival.
In other medical fields comorbidities have been considered as relevant predictors of survival, but never among the liver transplant community.
Researchers led by Dr. Michael Volk of the Department of Gastroenterology at the U-M Health System sought to determine if the Charlson Comorbidity Index (CCI) would predict long-term survival after liver transplantation.
Their findings are published in the November issue of Liver Transplantation, a journal by John Wiley & Sons. The article also is available online via Wiley Interscience www.interscience.wiley.com/journal/livertransplantation.
Researchers conducted a retrospective study of 624 patients who underwent liver transplantation at U-M Hospital between 1994-2005. They collected demographic, clinical and laboratory data for each patient, but focused on the nine comorbidities comprising the CCI. These include congestive heart failure, coronary artery disease, diabetes mellitus, peripheral vascular disease, cerebral vascular accident, chronic obstructive pulmonary disease (COPD), connective tissue disease, renal insufficiency and malignancy.
Forty percent of the patients had one or more comorbidities prior to transplantation. After statistical analysis, researchers found that coronary disease, diabetes, COPD, connective tissue disease, and renal insufficiency all were independent predictors of poorer post-transplant survival. The researchers then recalibrated the CCI using this information, to create the CCI-OLT. This new index predicted post-transplant survival equally as well as the other available model, which uses recipient characteristics like age, body mass index and the origin of liver disease.
“Our study shows that comorbidities play an important role in determining post-transplant survival,” the authors report. “This information will be useful when counseling patients with comorbidities about outcomes after transplantation.”
The study was limited by the fact that it was a single center, retrospective cohort study and the researchers were not able to determine to what extent the comorbidities were manifestations of advanced liver disease. Still, the researchers demonstrated the usefulness of the modified comorbidity index for predicting post-liver-transplant.
