Survival Analysis: Unraveling Factors in Post-Transplant Disease

Abstract

Graft-versus-host disease (GvHD) is a multi-systemic disorder that occurs when a transplanted organ’s immune cells recognize the host as foreign and attack the recipient’s body cells. CGvHD can occur following: 1) allogeneic bone transplantation, 2) following transplantation of solid organs that are lymphoid rich, and 3) after transfusion of un-irradiated blood. Generally, it is diagnosed after symptoms persist or appear 100 days after transplantation.

The objective of this analysis is exploration of the factors which impact the time to chronic graft-versus-host disease (CGVHD) in leukemia patients that received an allogeneic bone marrow transplant as it relates to the following clinical characteristics across clinical sites: age, sex, cytomegalovirus immune status (CMV), waiting time to transplant, and disease group.

Analysis was conducted using Kaplan-Meier method, generalized gamma Accelerated Time Failure (AFT) model using SAS OnDemand for Academics: SAS Studio. It was found that patients at St. Vincent had a 35% higher time in days to CGVHD compared to the reference level. Conversely, patients at Alfred had a 10.3% decreased time to CGVHD in days compared to the reference level.

For patients at OSU, the relative risk of developing CGVHD decreased by 20.4% compared to the reference level. Additionally, leukemia patients who were cytomegalovirus positive had an 11% decrease in time to CGVHD compared to those who were not. Male leukemia patients had a 14% increase in their time to CGVHD compared to female patients across clinical sites. Every one year increase in patient age led to a 0.3% increase in the time to CGVHD. Disease groups also had an impact on the time to CGVHD, with an increase of 15.2% across groups.

All covariates were statistically insignificant, suggesting that they may not play a strong role in time to development of the disease.

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