Kidney Donor Outcomes Cohort (KDOC) Study

Kidney transplantation extends and improves the lives of adults with end-stage renal disease
(ESRD). Live donor kidney transplantation (LDKT) has many advantages over deceased donor
transplantation for the recipient, including shorter or no dialysis exposure, immediate graft
function, lower perioperative morbidity and mortality, and better long-term graft and patient
survival. Also, it yields significant cost savings to the healthcare system overall. These
relative advantages and other advances in the field (e.g., laparoscopic techniques, paired
kidney exchanges) have led transplant candidates and programs to more proactively embrace
LDKT as the primary treatment option. Living kidney donors now account for 40% of all kidney
transplants performed in the United States during the past 10 years, and more than 90,000
adults have undergone living donor nephrectomy in the United States over the last 20 years.

Worldwide there have been few large-scale studies examining the short- and long-term outcomes
of living kidney donation, and many have been limited by retrospective, cross-sectional,
and/or single-center designs with no appropriate control group. Despite efforts to enhance
understanding of donor outcomes, it is clear that we have more knowledge in some areas (e.g.,
surgical and short-term medical complications) than in others (e.g., long-term medical
complications, psychological outcomes, financial impact). The relative paucity of multisite,
prospective outcome studies is concerning, especially considering the expanding donor
eligibility criteria used by transplant programs today. Over the past decade, criteria for
acceptance of a living donor candidate has changed: some donor candidates who would not have
been considered 15 years ago (e.g., those with hypertension, obesity, or no prior
relationship with the recipient) are now readily evaluated by many programs.

Recently, the transplant community and changes in federal regulations have brought attention
to the need for more systematic study of living donor outcomes. While reporting outcomes over
a 2-yr period is now mandated by the Organ Procurement and Transplantation Network (OPTN) and
the United Network for Organ Sharing (UNOS), most transplant programs do not systematically
collect donor outcome data. The lack of such data is an important problem because, without
it, we will continue to have considerable variability in informed consent processes for
living donors and their recipients, as well as limited data to inform clinical practice and
policy development. This study directly addresses several of the recommendations made by the
U.S. Department of Health and Human Services' Advisory Committee on Organ Transplantation.

A. Design Overview

This is a six center, prospective observational cohort study. A total of 280 living kidney
donors, 280 LDKT recipients, and 160 healthy comparison subjects meeting all eligibility
criteria will be enrolled. Participants will complete the assessment protocol at 5 time
points: prior to surgery (Baseline, T1), 1 month after surgery (T2), 6 months after surgery
(T3), 12 months after surgery (T4), and 24 months after surgery (T5). The rationale for
selecting these time points is that they correspond to the assessment intervals currently
required by the OPTN/UNOS for living donor follow-up, which were selected by the Living
Donation Committee as the most appropriate time points for gathering short- and long-term
follow-up data.

B. Study Participants

A total of 280 living kidney donors, 280 LDKT recipients, and 160 healthy comparison subjects
meeting all eligibility criteria will be enrolled.

We will enroll both English and Spanish speaking participants into the study. All
questionnaire outcomes will be translated into Spanish using conventional translational
procedures and we will ensure that an interviewer at BIDMC is fluent in Spanish. It is
important to emphasize that not all of the questionnaires used in this study have been
validated in Spanish or with Hispanic patients. While this is an important limitation, we
feel that this limitation is outweighed by the potential benefits of including primarily
Spanish-speaking participants in the study.

The primary focus of the study is on assessing donor outcomes. The rationale for including
the recipient is to examine the role that recipient factors play in predicting donor
outcomes. There is preliminary evidence that some aspects of the recipient's functioning
(e.g., graft survival, QOL) are associated with certain functional and psychological outcomes
in living donors.7,8,88 The inclusion of transplant recipients in the study permits further
examination of this association over time and allows us to include other recipient variables
that heretofore have been neglected (e.g., perceptions of the donor-recipient relationship).
Also, we will recruit a healthy, non-donor comparison group. A healthy comparison group
allows us to address the question, "What if I had not donated my kidney?" - a question that
is often considered by donors. These will be adults who completed one or more parts of the
donor evaluation, but who did not proceed further for various reasons (although none of them
medical).

C. Participant Recruitment and Retention

The first participant will be enrolled into the study in September 2011. Recruitment time is
scheduled for 24 months. The last study assessment, therefore, will be completed in August
2015. Target recruitment for each site is 47 donor-recipient pairs and 27 healthy
comparisons.

Importantly, we will recruit living donors into the study regardless of their recipient's
participation status. Even in the absence of the recipient's participation, we will obtain
valuable data about donor outcomes. However, because this is first-and-foremost a study
evaluating donor outcomes, if a donor does not consent to participate in the study, we will
not approach their recipient about study participation.

Non-directed donors will be recruited into the study. If it's an anonymous donation, their
recipient will not be approached about the study. In the case, only the donor will be
enrolled. If the non-directed donor has established a relationship (albeit a new one) with
the intended recipient, then we will attempt to enroll both the donor and the recipient into
the study, just like any other donor-recipient pair.

Donors participating in a paired kidney donation program (KPD) will be recruited into the
study. In this instance, we will enroll KPD donors and their intended recipient (i.e., the
recipient with whom they are incompatible, not the recipient of their specific kidney).

For each transplant recipient enrolled in the study, we will determine if s/he had other
potential donors who were initially screened or evaluated but who did not progress to
donation surgery. This initial screening or evaluation may include an initial health history,
ABO testing, and/or other preliminary tests. To qualify as a control subject, the non-donor
may or may not have completed the entire evaluation, but none of the studies performed will
have excluded them from donation. If an enrolled donor has more than one potential health
control subject, we will attempt to recruit them all into the study.

Inclusion Criteria:

- at least 18 years old

- residential or cell phone service

- written informed consent

- medically cleared for donor nephrectomy (donor)

- medically cleared for transplant surgery (recipient)

- did not progress to donation, although medically eligible (control)

- completed preliminary labs (control)

Exclusion Criteria:

- inability or unwillingness to provide informed consent

- inability to speak and read English or Spanish