Abstract

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.

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Revised 18 July 2008