Date of Award


Document Type


Degree Name

Doctor of Philosophy (PhD)



Research Advisor

Donna Hathaway, Ph.D.


Patricia Cowan, Ph.D. Carolyn Driscoll, Ph.D. Wendy Likes, DNSc. Jim Wan, Ph. D.


Renal transplant, Quality of life, centile ranges, benchmarks


The purpose of this study was to create time-related centile ranges that could be
used as benchmarks for evaluating and monitoring quality of life (QoL) following kidney transplantation. QoL is commonly viewed as an important indicator of successful outcomes in chronic disease including kidney transplantation. Despite extensive research documenting the value of QoL, routine measurement of QoL outcomes in clinical practice as a means of patient evaluation to augment clinical care has not been widely accepted. Lack of benchmarks for interpreting QoL scores may contribute to the reluctance to incorporate QoL measures into clinical care. The research question and study aim were: Do QoL outcomes differ for patients by gender and race at four separate time intervals following renal transplantation? Based on this analysis which demographic groups or combination of groups would be required to accurately represent QoL outcomes through time-related centile ranges?

A convenience sample was drawn from the surveys housed by the national Patient
Outcomes Registry for Transplant Effects on Life (PORTEL). To be included in the
study, surveys must have been completed by Caucasian or African American recipients of one kidney transplantation who were between 18 and 65 years of age and who were greater than 14 days post-transplant. SF-12 and Memphis Survey scores were extracted as the QoL measures for creation of time-related centile ranges. Data were analyzed using nonparametric statistical methods. Time-related centile ranges were constructed depicting the 5th through the 95th percentile scores on the QoL outcome measures.

The analysis included 943 surveys bracketed into four time groups, less than 4
months, 4 to 19 months, 19-36 months and greater that 36 months from transplantation. Kruskal-Wallis analyses demonstrated a strong degree of homogeneity among racial and gender groups with only 2 of 16 QoL outcome measures differing significantly; SF-12 PCS scores at 19-36 months and Memphis Frequency scores at less than 4 months. Variation in means across the groups was small and the centile ranges were large leading to the conclusion that negligible clinical differences exist for these QoL outcomes by racial and gender subgroups in this sample. Therefore, one time-related centile range was constructed for each QoL outcome measure for this cohort of kidney transplant recipients
which will be graphically presented.

These time-related centile ranges have immediate clinical utility as a tool for
educating patients regarding QoL expectations and for monitoring post transplant QoL outcomes. They can also provide a means for transplant recipients to compare their QoL to a reference range that is derived from a like population and serve as a catalyst for discussion regarding interventions to enhance QoL for kidney transplant recipients.