The health of living kidney donors 20 years after donation

Pros and cons of live kidney donation in prediabetics: A critical review and way forward

There is shortage of organs, including kidneys, worldwide. Along with deceased kidney transplantation, there is a significant rise in live kidney donation. The prevalence of prediabetes (PD), including impaired fasting glucose and impaired glucose tolerance, is on the rise across the globe. Transplant teams frequently come across prediabetic kidney donors for evaluation. Prediabetics are at risk of diabetes, chronic kidney disease, cardiovascular events, stroke, neuropathy, retinopathy, dementia, depression and nonalcoholic liver disease along with increased risk of all-cause mortality. Unfortunately, most of the studies done in prediabetic kidney donors are retrospective in nature and have a short follow up period. There is lack of prospective long-term studies to know about the real risk of complications after donation. Furthermore, there are variations in recommendations from various guidelines across the globe for donations in prediabetics, leading to more confusion among clinicians. This increases the responsibility of transplant teams to take appropriate decisions in the best interest of both donors and recipients. This review focuses on pathophysiological changes of PD in kidneys, potential complications of PD, other risk factors for development of type 2 diabetes, a review of guidelines for kidney donation, the potential role of diabetes risk score and calculator in kidney donors and the way forward for the evaluation and selection of prediabetic kidney donors.

The National Landscape of Living Kidney Donor Follow-Up in the United States

In 2013, the Organ Procurement and Transplantation Network (OPTN)/ United Network for Organ Sharing (UNOS) mandated that transplant centers collect data on living kidney donors (LKDs) at 6 months, 1 year, and 2 years postdonation, with policy-defined thresholds for the proportion of complete living donor follow-up (LDF) data submitted in a timely manner (60 days before or after the expected visit date). While mandated, it was unclear how centers across the country would perform in meeting thresholds, given potential donor and center-level challenges of LDF. To better understand the impact of this policy, we studied Scientific Registry of Transplant Recipients data for 31,615 LKDs between January 2010 and June 2015, comparing proportions of complete and timely LDF form submissions before and after policy implementation. We also used multilevel logistic regression to assess donor- and center-level characteristics associated with complete and timely LDF submissions. Complete and timely 2-year LDF increased from 33% prepolicy (January 2010 through January 2013) to 54% postpolicy (February 2013 through June 2015) (p < 0.001). In an adjusted model, the odds of 2-year LDF increased by 22% per year prepolicy (p < 0.001) and 23% per year postpolicy (p < 0.001). Despite these annual increases in LDF, only 43% (87/202) of centers met the OPTN/UNOS-required 6-month, 1-year, and 2-year LDF thresholds for LKDs who donated in 2013. These findings motivate further evaluation of LDF barriers and the optimal approaches to capturing outcomes after living donation.

Increasing Use of the Expanded Criteria for Living Kidney Donation and Good Outcomes of Living Kidney Donors in Korea

BACKGROUND

Donor shortage for kidney transplantation may increase the number of expanded-criteria living donors (ECLDs). We investigated recent trends for ECLD use and the long-term outcomes of living kidney donors.

METHODS

We retrospectively analyzed medical records of 1,144 living kidney donors who donated at the Seoul National University Hospital from 1993 to 2015. The expanded criteria for living donation allow the following: age ≥60 years, body mass index >30 kg/m², history of hypertension, estimated glomerular filtration rate <80 mL/min, proteinuria or microscopic hematuria, and fasting glucose >100 mg/dL.

RESULTS

The mean age of donors was 40.7 ± 10.8 years, and there were 600 women (52.4%). A total of 466 donors (40.7%) met the ECLD criteria, and the proportion of ECLDs increased over time. Only 5 donors died after donation over a median follow-up of 7 years. No donor developed end-stage renal disease (ESRD). A urine protein-creatinine ratio ≥0.3 g/gCr was found in 14 patients and was more common in the ECLDs than in the standard-criteria living donors. The follow-up loss rate of donors was 59.3% at 5 years.

CONCLUSIONS

Both mortality and ESRD were very rare in carefully selected living kidney donors. However, living donors should be followed more carefully, because the follow-up loss rate was very high and ECLDs are increasingly used.

Living Kidney Donor Decision Making: State of the Science and Directions for Future Research

Background

The Federal government and transplantation organizations have called for further study of living donation at a time when 3 new living donor protocols are being introduced throughout the United States that promise to significantly increase the donor pool and change the face of living donation. Donation to a once incompatible and sometimes unknown recipient may now occur through the use of plasmapheresis therapy or paired and nondirected living donor protocols.

Objective

To describe the state of the science on living kidney donor decision making, and to provide recommendations for future research to guide donor education and care.

Data Sources

Automated literature search using PubMed and CINAHL scientific literature databases.

Study Data Extraction

Research papers on living donor decision making from 1997 to 2003. Studies available only as abstracts were excluded. Data Synthesis Studies of living kidney donor decision making and outcomes have been limited in scope, with small sample sizes and inconsistent reports of racial and ethnic characteristics of the sample. The retrospective nature of the majority of living donor studies is a significant limitation.

Conclusions

Future prospective studies that are diverse by sex, race, and ethnicity will contribute to our knowledge of factors that influence the decision to be a living kidney donor.

Ethical Analysis of Living Organ Donation

In 2003, the first 3-way living kidney donor-swap was performed at Johns Hopkins Hospital in Baltimore, Md. Three new donor protocols including paired donation now allow unrelated individuals to serve as donors. Some ethicists have suggested that emotionally unrelated individuals not be permitted to donate because they will not experience the same satisfaction that a family member who is a donor experiences. Others who frame living donation as an autonomous choice do not see emotionally unrelated or even nondirected donation as ethically problematic. This article uses an ethical framework of principlism to examine living donation. Principles salient to living donation include autonomy, beneficence, and nonmaleficence. The following criteria are used to evaluate autonomous decision making by living donors, including choices made (1) with understanding, (2) without influence that controls and determines their action, and (3) with intentionality. Empirical work in these areas is encouraged to inform the ethical analysis of the new living donor protocols.

Long-term outcomes of kidney donors

PURPOSE OF REVIEW

Partial renal ablation in laboratory animals leads initially to compensatory glomerular hyperfiltration and progressive, sclerotic kidney disease. In addition, modest declines in kidney function are associated with premature mortality in epidemiological studies. Hence, the long-term safety of living-kidney donation is an important issue. The purpose of this review was to examine existing research on outcomes among living-kidney transplant donors, with a focus on longer term outcomes.

RECENT FINDINGS

Although studies with sibling controls are unavailable, the current evidence base suggests that kidney donors have mortality and end-stage renal disease risks that are equivalent to similar individuals in the general population. Although findings for albuminuria and hypertension vary between studies, risks may be acceptable if donors receive optimal follow-up and care. Parenthetically, viewed as an experimental model of kidney-function loss, the neutrality of outcomes among donors may have major implications for the population at large: the robust associations between modest declines in kidney function and mortality seen in the general population suggest a confounded relationship and finding these confounders could have major implications for future research directions and for public health.

SUMMARY

Long-term outcomes suggest that kidney donation is not a major threat to longevity.

Health outcomes for living kidney donors with isolated medical abnormalities: a systematic review

Individuals with isolated medical abnormalities (IMAs) are undergoing living donor nephrectomy more frequently. Knowledge of health risks for these living donors is important for donor selection, informed consent and follow-up. We systematically reviewed studies with > or = 3 living kidney donors with preexisting IMAs, including older age, obesity, hypertension, reduced glomerular filtration rate (GFR), proteinuria, microscopic hematuria and nephrolithiasis. We abstracted data on study and donor characteristics, perioperative outcomes, longer term renal and blood pressure outcomes and mortality and compared them to those of non-IMA donors. We found 22 studies on older donors (n = 987), 10 on obese donors (n = 484), 6 on hypertensive donors (n = 125), 4 on donors with nephrolithiasis (n = 32), 2 on donors with microscopic hematuria and one study each on donors with proteinuria or reduced GFR. Perioperative outcomes for donors with and without IMAs were similar. Few studies reported longer term (> or = 1 year) rates of hypertension, proteinuria or renal function. Studies were frequently retrospective and without a comparison group. Given the variability among studies and their methodological limitations, uncertainties remain regarding long-term medical outcomes for IMA donors. As transplant centers continue to cautiously screen and counsel potential IMA donors, rigorously conducted, longer term prospective cohort studies are needed.

Imputing variance estimates do not alter the conclusions of a meta-analysis with continuous outcomes: a case study of changes in renal function after living kidney donation

OBJECTIVE

To assess how different imputation methods used to account for missing variance data in primary studies influence tests of heterogeneity and pooled results from a meta-analysis with continuous outcomes.

STUDY DESIGN AND SETTING

Point and variance estimates for changes in serum creatinine, glomerular filtration rate, systolic blood pressure, and diastolic blood pressure were variably reported among 48 primary longitudinal studies of living kidney donors (71%-78% of point estimates were reported, 8%-13% of variance data were reported). We compared the results of meta-analysis, which either were restricted to available data or used four methods to impute missing variance data. These methods used reported P-values, reported nonparametric summaries, results from other similar studies using multiple imputation, or results from estimated correlation coefficients.

RESULTS

Significant heterogeneity was present in all four outcomes regardless of the imputation methods applied. The random effects point estimates and 95% confidence intervals varied little across imputation methods, and the differences were not clinically significant.

CONCLUSIONS

Different methods to impute the variance data in the primary studies did not alter the conclusions from this meta-analysis of continuous outcomes. Such reproducibility increases confidence in the results. However, as with most meta-analyses, there was no gold standard of truth, and results must be interpreted judiciously. The generalization of these findings to other meta-analyses, which differ in outcomes, missing data, or between-study heterogeneity, requires further consideration.

Proteinuria and reduced kidney function in living kidney donors: A systematic review, meta-analysis, and meta-regression

We reviewed any study where 10 or more healthy adults donated a kidney, and proteinuria, or glomerular filtration rate (GFR) was assessed at least 1 year later. Bibliographic databases were searched until November 2005. 31 primary authors provided additional information. Forty-eight studies from 27 countries followed a total of 5048 donors. An average of 7 years after donation (range 1-25 years), the average 24 h urine protein was 154 mg/day and the average GFR was 86 ml/min. In eight studies which reported GFR in categories, 12% of donors developed a GFR between 30 and 59 ml/min (range 0-28%), and 0.2% a GFR less than 30 ml/min (range 0-2.2%). In controlled studies urinary protein was higher in donors and became more pronounced with time (three studies totaling 59 controls and 129 donors; controls 83 mg/day, donors 147 mg/day, weighted mean difference 66 mg/day, 95% confidence interval (CI) 24-108). An initial decrement in GFR after donation was not accompanied by accelerated losses over that anticipated with normal aging (six studies totaling 189 controls and 239 donors; controls 96 ml/min, donors 84 ml/min, weighted mean difference 10 ml/min, 95% CI 6-15; difference not associated with time after donation (P=0.2)). Kidney donation results in small increases in urinary protein. An initial decrement in GFR is not followed by accelerated losses over a subsequent 15 years. Future studies will provide better estimates, and identify those donors at least risk of long-term morbidity.

Medical Risks in Living Kidney Donors: Absence of Proof Is Not Proof of Absence

Living-kidney donation has become increasingly widespread, yet there has been little critical analysis of existing studies of long-term medical outcomes in living donors. This review analyzes issues in study design that affect the quality of the evidence and summarizes possible risk factors in living donors. Virtually all studies of long-term outcomes in donors are retrospective, many with large losses to follow-up, and therefore are subject to selection bias. Most studies have small sample sizes and are underpowered to detect clinically meaningful differences between donors and comparison groups. Many studies compare donors with the general population, but donors are screened to be healthier than the general population and this may not be a valid comparison group. Difficulties in measurement of BP and renal function may underestimate the impact of donation on these outcomes. Several studies have identified possible risk factors for development of hypertension, proteinuria, and ESRD, but potential vulnerability factors in donors have not been well explored and there is a paucity of data on cardiovascular risk factors in donors. Prospective registration of living kidney donors and prospective studies of diverse populations of donors are essential to protect living donors and preserve living-kidney donation.

Living kidney donor decision making: state of the science and directions for future research

BACKGROUND

The Federal government and transplantation organizations have called for further study of living donation at a time when 3 new living donor protocols are being introduced throughout the United States that promise to significantly increase the donor pool and change the face of living donation. Donation to a once incompatible and sometimes unknown recipient may now occur through the use of plasmapheresis therapy or paired and nondirected living donor protocols.

OBJECTIVE

To describe the state of the science on living kidney donor decision making, and to provide recommendations for future research to guide donor education and care.

DATA SOURCES

Automated literature search using PubMed and CINAHL scientific literature databases. STUDY DATA EXTRACTION: Research papers on living donor decision making from 1997 to 2003. Studies available only as abstracts were excluded.

DATA SYNTHESIS

Studies of living kidney donor decision making and outcomes have been limited in scope, with small sample sizes and inconsistent reports of racial and ethnic characteristics of the sample. The retrospective nature of the majority of living donor studies is a significant limitation.

CONCLUSIONS

Future prospective studies that are diverse by sex, race, and ethnicity will contribute to our knowledge of factors that influence the decision to be a living kidney donor.

Blood pressure evaluation among older living kidney donors

With more patients reaching end-stage renal disease, the demand for living kidney donation is increasing rapidly. Many potential donors are now in older age groups. The effects of increasing BP with age and the measurement criteria for hypertension in this group are not well defined. A total of 238 potential donors between 18 and 72 yr of age were prospectively studied, with a comparison of "clinic" BP values measured in the outpatient clinic with an oscillometric recorder (Dinamap; Critikon), ambulatory BP monitoring (ABPM) findings, and standardized BP values determined by nurses using American Heart Association criteria. Renal function was evaluated on the basis of iothalamate clearance (GFR) and urinary protein and microalbumin excretion. Ninety-six percent of subjects were Caucasian. All subjects exhibited normal GFR and urinary protein excretion. Three age groups were defined (group I, </=35 yr, n = 64; group II, 36 to 49 yr, n = 109; group III, >/= 50 yr, n = 65). BP increased with age, as determined with all methods. Subjects >/= 50 yr of age exhibited the highest clinic readings (145 +/- 2/83 +/- 1 mmHg, compared with 129 +/- 2/76 +/- 1 mmHg for group I, P < 0.01). Awake ABPM and nurse-determined BP measurements were lower than clinic readings, including those for group III (131 +/- 2/80 +/- 1 mmHg, compared with 145 +/- 2/83 +/- 1 mmHg in the clinic, P < 0.001). With the use of systolic BP values of >140 mmHg and/or diastolic BP values of >90 mmHg, 36.7% of subjects were initially considered hypertensive; this proportion decreased to 11% overall with awake ABPM findings (>135/85 mmHg). Measurement variability (SD in ABPM) and the effects of misclassification were greatest for donors >/= 50 yr of age. Multivariate regression indicated that GFR of both donors and recipients decreased with age, but regression identified no independent effect of BP. Recipient outcomes for up to 2 yr were equally good for donor kidneys considered normotensive or hypertensive on the basis of clinic BP measurements. These data indicate that higher arterial BP with age can lead to misclassification of many older living kidney donors. Sixty-two subjects with excellent kidney function were misclassified as hypertensive with clinic oscillometric measurements alone. Detailed evaluations of ABPM findings, GFR, and urinary protein levels are warranted for Caucasian subjects with high clinic BP readings who are otherwise suitable potential donors.