The usual method of estimating survival probabilities, namely the Kaplan-Meier method, is suboptimal in the analysis of deaths on the transplant waiting list.
Death, transplantation, and withdrawal from list must all be considered.
Dr Ray Kim and colleagues from Rochester applied the competing risk analysis method.
This method allows evaluating these end points individually and simultaneously.
It also enables the comparison of the risk of waiting list death across era, blood types, liver disease diagnosis, and severity.
The researchers assessed 861 patients registered on the waiting list at Mayo Clinic Rochester between 1990 and 1999.
Of these patients, 76% underwent transplantation, 10% died while waiting, 5% withdrew from the list, and 9% patients were still waiting as of 2002.
The research team noted that the risk of death at 3 years was 10% by the competing risk analysis.
|The risk of death was increased in those with higher MELD scores|
During the study period, the median time to transplantation increased from 45 to 517 days.
In univariate analyses, the team found no significant difference in the risk of death by era of listing or blood type.
However, the team observed that the risk of death was significantly higher in patients with alcohol-induced liver disease.
The risk of death was also increased in those with higher Model for End-stage Liver Disease (MELD) scores.
A multivariable analysis showed that after adjusting for MELD, blood type, and diagnosis, patients listed in the latter era had higher mortality.
Dr Ray Kim's team concludes, “The competing risk analysis method is useful in estimating the risk of death among patients awaiting liver transplantation.”