Analytical approaches for transplant research, 2004.

This article provides detailed explanations of the methods frequently employed in outcomes analyses performed by the Scientific Registry of Transplant Recipients (SRTR). All aspects of the analytical process are discussed, including cohort selection, post-transplant follow-up analysis, outcome definition, ascertainment of events, censoring, and adjustments. The methods employed for descriptive analyses are described, such as unadjusted mortality rates and survival probabilities, and the estimation of covariant effects through regression modeling. A section on transplant waiting time focuses on the kidney and liver waiting lists, pointing out the different considerations each list requires and the larger questions that such analyses raise. Additionally, this article describes specialized modeling strategies recently designed by the SRTR and aimed at specific organ allocation issues. The article concludes with a description of simulated allocation modeling (SAM), which has been developed by the SRTR for three organ systems: liver, thoracic organs, and kidney-pancreas. SAMs are particularly useful for comparing outcomes for proposed national allocation policies. The use of SAMs has already helped in the development and implementation of a new policy for liver candidates with high MELD scores to be offered organs regionally before the organs are offered to candidates with low MELD scores locally.