The science of Stewardship: due diligence for kidney donors and kidney function in living kidney donation--evaluation, determinants, and implications for outcomes

Office blood pressure: overcoming the problems of diagnosis and control of arterial hypertension treatment

Some national guidelines since 2017 considered the most common method for diagnosing and controlling hypertension (HTN) (office blood pressure (OBP) measurement) as screening only. Automated OBP (AOBP) measurement claims to be a unique method by obtaining a standardized result, even in primary health care. AOBP improves the reliability of data by reducing the influence of various errors on result. However, although the level of AOBP is on average lower than similar OBP in clinical and research practice and is comparable to the mean 24-hour BP monitoring, at present, all international guidelines emphasize the mandatory use of ambulatory BP measurements for diagnostic purposes. Whether the results of AOBP and the reference level ≥130/80 mm Hg are equivalent with the same OBP level, the use of which is associated with an increase in the prevalence of hypertension and insufficient control of antihypertensive therapy, is a question for research. Compared with conventional OBP, the use of AOBP in conjunction with outpatient measurement leads to a reduction in the proportion and timing of initiation of treatment in patients with masked HTN, whose cardiovascular risk is similar to that of patients with stable HTN. However, the widespread implementation of AOBP is hindered by the high cost and lack of accumulated data. The review analyzes in detail the limitations and advantages of various types of BP measurement, as well as the potential of using AOBP in modern clinical and research practice.

 

Results of the prospective multicenter SoLKiD Cohort Study indicate bio-psycho-social outcome risks to kidney donors 12 months after donation

The outcome after living kidney donation was assumed to be comparable to that of the general population. However, recent register studies reveal negative changes in kidney function, quality of life and fatigue. Avoiding methodological issues of previous studies, the Safety of the Living Kidney Donor (SoLKiD) cohort study analyzed the outcome of donors in a multicenter and interdisciplinary fashion. Donor data were collected pre-donation and two-, six- and 12-months post-donation in 20 German transplantation centers. Primary parameters were kidney function, quality of life, and fatigue. Secondary endpoints were blood pressure, hemoglobin, hemoglobin A1c, body mass index, depression and somatization. Parameters were analyzed with non-parametric statistical tests and a mixed model regression for changes in time, their clinical relevance and interaction encompassing 336 donors with mean age of 52 years. Most of the physical secondary parameters, depression, and quality of life showed little or no changes and regained their pre-donation level. Kidney function decreased significantly with a 37% loss of glomerular filtration rate and an increase of donors with chronic kidney disease stage 3 from 1.5% pre-donation to about 50%. Donors consistently showed increased fatigue and somatization. Mental fatigue increased from 10.6% to 28.1%. The main influencing factors for decreased kidney function and increased fatigue were their respective pre-donation levels, and donor age for kidney function and subject stress level in fatigue. Thus, our study showed that a significant number of donors developed clinically relevant changes in physical and mental health and emphasizes the urgent need to inform potential donors about these risks.

Risk for subsequent hypertension and cardiovascular disease after living kidney donation: is it clinically relevant?

The first successful live donor kidney transplant was performed in 1954. Receiving a kidney transplant from a live kidney donor remains the best option for increasing both life expectancy and quality of life in patients with end-stage kidney disease. However, ever since 1954, there have been multiple questions raised on the ethics of live kidney donation in terms of negative impacts on donor life expectancy. Given the close relationship between reduced kidney function in patients with chronic kidney disease (CKD) and hypertension, cardiovascular disease and cardiovascular mortality, information on the impact of kidney donation on these is particularly relevant. In this article, we review the existing evidence, focusing on the more recent studies on the impact of kidney donation on all-cause mortality, cardiovascular mortality, cardiovascular disease and hypertension, as well as markers of cardiovascular damage including arterial stiffness and uraemic cardiomyopathy. We also discuss the similarities and differences between the pathological reduction in renal function that occurs in CKD, and the reduction in renal function that occurs because of a donor nephrectomy. Kidney donors perform an altruistic act that benefits individual patients as well as the wider society. They deserve to have high-quality evidence on which to make informed decisions.

Alterations in the Mineral Bone Metabolism of Living Kidney Donors After Uni-Nephrectomy: Prospective Observational Study

We investigated the dynamic change of mineral bone metabolism and explored factors associated with the alteration of mineral bone metabolism in the living kidney donors (LKDs) after uni-nephrectomy. One-hundred forty-four prospective LKDs who underwent kidney donation between May 2016 and September 2018 were enrolled. Laboratory evaluation regarding mineral bone metabolism including intact parathyroid hormone (iPTH), renal fractional excretion of phosphate (FEPi), and technetium-99m diethylenetriaminepentaacetate (^99mTc-DTPA) scan was performed predonation and 6 months after donation. We divided donors into two groups, the low ΔFEPi and high ΔFEPi groups, according to the change of FEPi after donation, and investigated significant risk factors associated with high ΔFEPi. At 6 months after uni-nephrectomy, estimated glomerular filtration rate (eGFR) significantly declined by 30.95 ml/min/1.73 m² (p < 0.001), but the measured GFR (mGFR) of the remaining kidney by ^99mTc-DTPA scan showed significant increase. Serum phosphorus decreased (p < 0.001), whereas FEPi (13.34–20.23%, p < 0.001) and serum iPTH (38.70–52.20 pg/ml, p < 0.001) showed significant increase. In the high ΔFEPi group, the proportion of preexisting hypertension (HTN) was higher, the baseline FEPi was lower, and the percent decline in eGFR was greater. Moreover, all of these factors were independently associated with high ΔFEPi upon multivariable logistic regression analysis. LKDs showed a significant change in mineral bone metabolism after uni-nephrectomy, especially when the donors had preexisting HTN, lower baseline FEPi, and showed greater loss of kidney function. Hence, strict monitoring of the mineral bone metabolism parameters and bone health may be required for these donors.

Long-term prognosis after kidney donation: a propensity score matched comparison of living donors and non-donors from two population cohorts

Background

Live donor nephrectomy is a safe procedure. However, long-term donor prognosis is debated, necessitating high-quality studies.

Methods

A follow-up study of 761 living kidney donors was conducted, who visited the outpatient clinic and were propensity score matched and compared to 1522 non-donors from population-based cohort studies. Primary outcome was kidney function. Secondary outcomes were BMI (kg/m²), incidences of hypertension, diabetes, cardiovascular events, cardiovascular and overall mortality, and quality of life.

Results

Median follow-up after donation was 8.0 years. Donors had an increase in serum creatinine of 26 μmol/l (95% CI 24–28), a decrease in eGFR of 27 ml/min/1.73 m² (95% CI − 29 to − 26), and an eGFR decline of 32% (95% CI 30–33) as compared to non-donors. There was no difference in outcomes between the groups for ESRD, microalbuminuria, BMI, incidence of diabetes or cardiovascular events, and mortality. A lower risk of new-onset hypertension (OR 0.45, 95% CI 0.33–0.62) was found among donors. The EQ-5D health-related scores were higher among donors, whereas the SF-12 physical and mental component scores were lower.

Conclusion

Loss of kidney mass after live donation does not translate into negative long-term outcomes in terms of morbidity and mortality compared to non-donors.

Trial registration

Dutch Trial Register NTR3795.

Electronic supplementary material

The online version of this article (10.1007/s10654-020-00647-y) contains supplementary material, which is available to authorized users.

Donor-Recipient Relationship and Risk of ESKD in Live Kidney Donors of Varied Racial Groups

RATIONALE & OBJECTIVE

Risk factors for kidney failure are the basis of live kidney donor candidate evaluation. We quantified risk for end-stage kidney disease (ESKD) by the biological relationship of the donor to the recipient, a risk factor that is not addressed by current clinical practice guidelines.

STUDY DESIGN

Retrospective cohort study.

SETTING & PARTICIPANTS

A cohort of 143,750 US kidney donors between 1987 and 2017.

EXPOSURE

Biological relationship of donor and recipient.

OUTCOME

ESKD. Donors' records were linked to national dialysis and transplantation registries to ascertain development of the outcome.

ANALYTIC APPROACH

Donors were observed over a median of 12 (interquartile range, 6-18; maximum, 30) years. Survival analysis methods that account for the competing risk for death were used.

RESULTS

Risk for ESKD varied by orders of magnitude across donor-recipient relationship categories. For Asian donors, risks compared with unrelated donors were 259.4-fold greater for identical twins (95% CI, 19.5-3445.6), 4.7-fold greater for full siblings (95% CI, 0.5-41.0), 3.5-fold greater for offspring (95% CI, 0.6-39.5), 1.0 for parents, and 1.0 for half-sibling or other biological relatives. For black donors, risks were 22.5-fold greater for identical twin donors (95% CI, 4.7-107.0), 4.1-fold for full siblings (95% CI, 2.1-7.8), 2.7-fold for offspring (95% CI, 1.4-5.4), 3.1-fold for parents (95% CI, 1.4-6.8), and 1.3-fold for half-sibling or other biological relatives (95% CI, 0.5-3.3). For white donors, risks were 3.5-fold greater for identical twin donors (95% CI, 0.5-25.3), 2.0-fold for full siblings (95% CI, 1.4-2.8), 1.4-fold for offspring (95% CI, 0.9-2.3), 2.9-fold for parents (95% CI, 2.0-4.1), and 0.8-fold for half-sibling or other biological relatives (95% CI, 0.3-1.6).

LIMITATIONS

Insufficient sample size in some race and relationship groups. Absence of data for family history of kidney disease for donors biologically unrelated to their recipients.

CONCLUSIONS

Marked differences in risk for ESKD across types of donor-recipient relationship were observed for Asian, black, and white donors. These findings warrant further validation with more robust data to better inform clinical practice guidelines.

Diagnostic Performance of Blood Pressure Measurement Modalities in Living Kidney Donor Candidates

BACKGROUND AND OBJECTIVES

Precise BP measurement to exclude hypertension is critical in evaluating potential living kidney donors. Ambulatory BP monitoring is considered the gold standard method for diagnosing hypertension, but it is cumbersome to perform. We sought to determine whether lower BP cutoffs using office and automated BP would reduce the rate of missed hypertension in potential living donors.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We measured BP in 578 prospective donors using three modalities: (1) single office BP, (2) office automated BP (average of five consecutive automated readings separated by 1 minute), and (3) ambulatory BP. Daytime ambulatory BP was considered the gold standard for diagnosing hypertension. We assessed both the Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and Treatment of High Blood Pressure (JNC-7) and the American College of Cardiology/American Heart Association (ACC/AHA) definitions of hypertension in the cohort. Empirical thresholds of office BP and automated BP for the detection of ambulatory BP-diagnosed hypertension were derived using Youden index, which maximizes the sum of sensitivity and specificity and gives equal weight to false positive and false negative values.

RESULTS

Hypertension was diagnosed in 90 (16%) prospective donors by JNC-7 criteria and 198 (34%) prospective donors by ACC/AHA criteria. Masked hypertension was found in 3% of the total cohort by JNC-7 using the combination of office or automated BP, and it was seen in 24% by ACC/AHA guidelines. Using Youden index, cutoffs were derived for both office and automated BP using JNC-7 (<123/82 and <120/78 mm Hg) and ACC/AHA (<119/79 and <116/76 mm Hg) definitions. Using these lower cutoffs, the sensitivity for detecting hypertension improved from 79% to 87% for JNC-7 and from 32% to 87% by ACC/AHA definition, with negative predictive values of 95% and 87%, respectively. Missed (masked) hypertension was reduced to 2% and 4% of the entire cohort by JNC-7and ACC/AHA, respectively.

CONCLUSIONS

The prevalence of hypertension was higher in living donor candidates using ACC/AHA compared JNC-7 definitions. Lower BP cutoffs in the clinic improved sensitivity and led to a low overall prevalence of missed hypertension in prospective living kidney donors.

Impact of errors of creatinine and cystatin C equations in the selection of living kidney donors

Background

Reliable determination of glomerular filtration rate (GFR) is crucial in the evaluation of living kidney donors. Although some guidelines recommend the use of measured GFR (mGFR), many centres still rely on estimated GFR (eGFR) obtained through equations or 24-h creatinine clearance. However, eGFR is neither accurate nor precise in reflecting real renal function. We analysed the impact of eGFR errors on evaluation and decision making regarding potential donors.

Methods

We evaluated 103 consecutive living donors who underwent mGFR via iohexol plasma clearance and eGFR by 51 creatinine- and/or cystatin C-based equations. The cut-off for living donation in our centre is GFR > 80 mL/min for donors >35 years of age or 90 mL/min for those <35 years of age. We analysed the misclassification of donors based on the cut-off for donation-based eGFR.

Results

Ninety-three subjects (90.3%) had mGFR values above (donors) and 10 [9.7% (95% confidence interval 5.4-17)] below (non-donors) the cut-off. In non-donors, most of the equations gave eGFR values above the cut-off, so donation would have been allowed based on eGFR. All non-donors were female with reduced weight, height and body surface. In donors, up to 32 cases showed eGFR below the cut-off, while mGFR was actually higher. Therefore an important number of donors would not have donated based on eGFR alone.

Conclusion

The misclassification of donors around the cut-off for donation is very common with eGFR, making eGFR unreliable for the evaluation of living kidney donors. Whenever possible, mGFR should be implemented in this setting.

Long-Term Consequences of Complex Living Renal Donation: Is It Safe?

INTRODUCTION

As there is a paucity of literature regarding the long-term outcomes of complex living donors, we conducted this study to assess the effect of kidney donation on the complex living kidney donor.

MATERIALS AND METHODS

This retrospective study was conducted in Narayan Health Hospital, Kolkata, Eastern India. The cohort consisted of complex living kidney donors who donated kidneys between the years 2007 and 2012. All donors were 60 years old or older, or were younger than 60 years and had comorbidities like hypertension and obesity. After a minimum follow-up of 5 years, all donors underwent evaluation. Data pertaining to hypertension, new-onset diabetes, body mass index (BMI), estimated glomerular filtration rate (eGFR) and albuminuria, and cardiac events were compared from the time of donation till 5 years post-transplant.

RESULTS AND DISCUSSION

We found a statistically significant increase in blood pressure, number of antihypertensives used, and mean BMI at follow-up. Diabetes mellitus was developed in 22.3% of donors. The mean GFR also decreased significantly at follow-up. There were 42 elderly donors (≥60 years) and 23 ≤ 59 years of age. There was a significant fall of eGFR in both groups, but the percentage fall was similar in both groups. A significant percentage of donors developed proteinuria, the majority being hypertensives.

CONCLUSION

Procurement of kidneys from marginal donors should be done cautiously, and donors should be assessed for morbidity and mortality in the future, as we found a statistically significant deterioration in renal function, blood pressure, and BMI over long-term follow-up.

Investigation of the physical and psychosocial outcomes after living kidney donation - a multicenter cohort study (SoLKiD - Safety of Living Kidney Donors)

Background

Over the last years, living kidney donation (LKD) has been established for patients with endstage renal failure as an alternative to post mortem donation, which is limited by organ scarcity and long lasting waiting periods. From an ethical perspective, the increase in LKD requires that donors’ physical, psychological, and social harm has to be minimized as much as possible and the risk should not exceed the generally expected consequences of nephrectomy. Despite of numerous, mainly retrospective studies about the postoperative outcome of LKD over the last years from different countries, it becomes apparent that there is a lack of comprehensive prospective multicenter research in this field worldwide. Therefore, the main aim of the study is to examine the physical and psychosocial outcome of living kidney donors in a prospective design before and after transplantation in an interdisciplinary approach (surgery, nephrology, psychosocial medicine).

Methods/design

The goal of the study is to investigate such aspects as the impact of gender- and age-specific factors on LKD outcome, donor outcome in correlation to the health status of the recipient, the medical and psychosocial risk of a healthy subject undergoing the LKD procedure. The study is carried out as a nationwide multicenter study. All adult living kidney donors with sufficient knowledge in the German, Russian, or Turkish language, informed consent, and place of residence in Germany are included. In a naturalistic design (cohort study), clinical data and self-report measures (questionnaires) of 320 donors are collected before and 8 weeks, 6 and 12 months after donation. Primary outcome parameters are the kidney function (estimated GFR) and the quality of life (SF-36) of the donor. Secondary outcome parameters are data about physical (e.g., wound healing, blood pressure) and psychosocial (fatigue, depression, anxiety, somatization) outcome after donation.

Discussion

Previous studies on the postoperative outcome of living kidney donors have methodological limitations and/or were carried out in countries with different healthcare systems, e.g. United States, Norway, Canada, United Kingdom. Thus, results cannot be generalized and are not particularly applicable to the risks of mainly caucasian living kidney donors in the German healthcare system. The study design overcomes these disadvantages in that it provides a prospective multicenter design.

Trial registration

German Clinical Trials Register DRKS00006552 (22 September 2014).

KDIGO Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors

The 2017 Kidney Disease: Improving Global Outcomes (KDIGO) Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors is intended to assist medical professionals who evaluate living kidney donor candidates and provide care before, during and after donation. The guideline development process followed the Grades of Recommendation Assessment, Development, and Evaluation (GRADE) approach and guideline recommendations are based on systematic reviews of relevant studies that included critical appraisal of the quality of the evidence and the strength of recommendations. However, many recommendations, for which there was no evidence or no systematic search for evidence was undertaken by the Evidence Review Team, were issued as ungraded expert opinion recommendations. The guideline work group concluded that a comprehensive approach to risk assessment should replace decisions based on assessments of single risk factors in isolation. Original data analyses were undertaken to produce a "proof-in-concept" risk-prediction model for kidney failure to support a framework for quantitative risk assessment in the donor candidate evaluation and defensible shared decision making. This framework is grounded in the simultaneous consideration of each candidate's profile of demographic and health characteristics. The processes and framework for the donor candidate evaluation are presented, along with recommendations for optimal care before, during, and after donation. Limitations of the evidence are discussed, especially regarding the lack of definitive prospective studies and clinical outcome trials. Suggestions for future research, including the need for continued refinement of long-term risk prediction and novel approaches to estimating donation-attributable risks, are also provided.In citing this document, the following format should be used: Kidney Disease: Improving Global Outcomes (KDIGO) Living Kidney Donor Work Group. KDIGO Clinical Practice Guideline on the Evaluation and Care of Living Kidney Donors. Transplantation. 2017;101(Suppl 8S):S1-S109.

Long-Term Body Mass Index Trends After Living-Donor Nephrectomy

OBJECTIVES

As the demand for kidney transplant allografts has increased, many centers are expanding the upper limit of acceptable body mass index for kidney donors. However, obesity is a risk factor for developing renal disease. Our goal was to quantify body mass index trends in donor nephrectomy patients and to institute nutrition counseling to promote sustainable weight loss to reduce the risk of metabolic syndrome-derived renal dysfunction.

MATERIALS AND METHODS

Ninety patients who underwent donor nephrectomy between 2007 and 2012 consented to having height and weight data collected at multiple time points. After data collection, each patient underwent a standardized nutrition counseling session. One year later, body mass index was reassessed.

RESULTS

Preoperatively, 52% of the patients were overweight or obese. The percentage of overweight and obese patients remained stable for 2 years after surgery. However, at 3, 4, and 5 years after surgery, these rates increased to 59%, 69%, and 91%. Each patient was counseled about obesity-related comorbidities and provided information about lifestyle modification. One year later, 94% of previously overweight patients and 82% of previously obese patients had a decrease in mean body mass index from 27.2 ± 4.0 kg/m2 to 25.1 ± 3.6 kg/m2.

CONCLUSIONS

Living-donor nephrectomy patients are at risk of developing obesity, similar to the adult population. Nutrition counseling may be beneficial to help normalize body mass index in patients who have become overweight or obese to potentially prevent obesity-related comorbidities. All patients were evaluated by a nutrition specialist after surgery to review our donor nephrectomy nutrition brochure. Body mass index monitoring and primary care follow-up appear to be appropriate surveillance methods.

Recipient Outcomes Following Transplantation of Allografts From Live Kidney Donors Who Subsequently Developed End-Stage Renal Disease

Live kidney donors have an increased risk of end-stage renal disease (ESRD) compared with nondonors; however, it is unknown whether undetected, subclinical kidney disease exists at donation that subsequently contributes to this risk. To indirectly test this hypothesis, the authors followed the donated kidneys, by comparing the outcomes of 257 recipients whose donors subsequently developed ESRD with a matched cohort whose donors remained ESRD free. The compared recipients were matched on donor (age, sex, race/ethnicity, donor-recipient relationship), transplant (HLA mismatch, peak panel-reactive antibody, previous transplantation, year of transplantation), and recipient (age, sex, race/ethnicity, body mass index, cause of ESRD, and time on dialysis) risk factors. Median recipient follow-up was 12.5 years (interquartile range 7.4-17.9, maximum 20 years). Recipients of allografts from donors who developed ESRD had increased death-censored graft loss (74% versus 56% at 20 years; adjusted hazard ratio [aHR] 1.7; 95% confidence interval [CI] 1.5-2.0; p < 0.001) and mortality (61% versus 46% at 20 years; aHR 1.5; 95% CI 1.2-1.8; p < 0.001) compared with matched recipients of allografts from donors who did not develop ESRD. This association was similar among related, spousal, and unrelated nonspousal donors. These findings support a novel view of the mechanisms underlying donor ESRD: that of pre-donation kidney disease. However, biopsy data may be required to confirm this hypothesis.

Pregnancy Outcome in Patients with Solitary Kidney

BACKGROUND

Solitary kidney may be congenital or as a result of nephrectomy. There is a lot of literature available on quality of life in these patients, but there is limited data on pregnancy outcome.

OBJECTIVES

To study pregnancy outcome in patients with solitary kidney either congenital or due to nephrectomy.

MATERIALS AND METHODS

Study Design This is a retrospective observational study conducted at tertiary health center in Ahmedabad, from 2011 to 2014. Sample Size There were 164 patients of solitary kidney, out of which two patients had congenital solitary kidney and the remaining had solitary kidney due to nephrectomy. Among 164 patients, 96 (58.53 %) patients had completed family, 37 (22.56 %) patients did not try for pregnancy, 15 (9.14 %) patients have conceived, 12 (7.3 %) were lost to follow up and 4 (2.43 %) patients were infertile. Method Patients in reproductive age group (20-40 years), with solitary kidney either congenital or due to nephrectomy, were included. Maternal and fetal outcome was studied, and patients were followed up till 2 years postpartum. Exclusion Criteria Patients with solitary kidney due to post-renal transplant were excluded.

RESULTS

There were 15 (9.14 %) patients who had conceived, out of which 11 (73.33) patients delivered and 4 (26.67 %) patients had spontaneous abortion. Two patients developed gestational hypertension and one had preeclampsia. On follow-up, all babies were normal and none of them had delayed developmental milestones.

CONCLUSION

Preconceptional counseling should be done in these patients regarding risk of developing preeclampsia during pregnancy and preterm delivery. These patients can have good pregnancy outcome with close monitoring during antenatal period.

Longitudinal Assessment of Renal Perfusion and Oxygenation in Transplant Donor-Recipient Pairs Using Arterial Spin Labeling and Blood Oxygen Level-Dependent Magnetic Resonance Imaging

OBJECTIVES

The aims of this study were to assess renal function in kidney transplant recipients and their respective donors over 2 years using arterial spin labeling (ASL) and blood oxygen level-dependent (BOLD) magnetic resonance imaging (MRI) and to prospectively evaluate the effect of losartan on functional MRI measures in recipients.

MATERIALS AND METHODS

The study included 15 matched pairs of renal transplant donors and recipients. Arterial spin labeling and BOLD MRI of the kidneys were performed on donors before transplant surgery (baseline) and on both donors and recipients at 3 months, 1 year, and 2 years after transplant. After 3 months, 7 of the 15 recipients were prescribed 25 to 50 mg/d losartan for the remainder of the study. A linear mixed-effects model was used to evaluate perfusion, R2*, estimated glomerular filtration rate, and fractional excretion of sodium for changes across time or associated with losartan treatment.

RESULTS

In donors, cortical perfusion in the remaining kidney decreased by 50 ± 19 mL/min per 100 g (11.8%) between baseline and 2 years (P < 0.05), while cortical R2* declined modestly by 0.7 ± 0.3 s-1 (5.6%; P < 0.05). In transplanted kidneys, cortical perfusion decreased markedly by 141 ± 21 mL/min per 100 g (34.2%) between baseline and 2 years (P < 0.001), while medullary R2* declined by 1.5 ± 0.8 s-1 (8.3%; P = 0.06). Single-kidney estimated glomerular filtration rate increased between baseline and 2 years by 17.7 ± 2.7 mL/min per 1.73 m (40.3%; P < 0.0001) in donors and to 14.6 ± 4.3 mL/min per 1.73 m (33.3%; P < 0.01) in recipients. Cortical perfusion at 1 and 2 years in recipients receiving 25 to 50 mg/d losartan was 62 ± 24 mL/min per 100 g higher than recipients not receiving the drug (P < 0.05). No significant effects of losartan were observed for any other markers of renal function.

CONCLUSIONS

The results suggest an important role for noninvasive functional monitoring with ASL and BOLD MRI in kidney transplant recipients and donors, and they indicate a potentially beneficial effect of losartan in recipients.

Transplantation of Restored Kidneys From Unrelated Donors After Resection of Renal Cell Carcinoma: Results From 10 Patients

PURPOSE

To relieve the chronic shortage of donor kidneys, we conducted a prospective kidney transplantation trial using kidneys removed from 10 unrelated patients (51 to 79 years of age) who had undergone nephrectomy for small renal cell carcinoma (1.5 to 3.9 cm) of low-to-moderate complexity based on RENAL (radius, exophytic/endophytic properties, nearness of tumor to the collecting system or sinus in millimeters, anterior/posterior location relative to polar lines) nephrometry (objective description helpful for operative indication and planning).

METHODS

Donors were selected from among 15 patients who opted to undergo nephrectomy for small renal cell carcinoma. A total of 76 dialysis patients 34 to 85 years of age who agreed to undergo restored kidney transplantation were recruited as transplant candidates.

RESULTS

In stage 1 (5 cases), high-risk patients were selected without human leukocyte antigen testing, and accelerated acute rejection occurred in 4 of 5 recipients. This trial was subsequently extended with human leukocyte antigen testing, and an additional 5 patients were enrolled in stage 2. Eight recipients, including 4 recipients with a history of renal transplantation, experienced rejection; 1 patient resumed dialysis 35 months after transplantation. The most recent serum creatinine levels ranged from 1.10 to 3.19 mg/dL in the 9 recipients with functioning grafts and from 0.84 to 4.68 mg/dL in the 10 donors. No tumor recurrence was noted at 32 to 58 months after surgery in either the recipients or the donors.

CONCLUSIONS

Restored kidney transplantation using kidneys with a small renal tumor seems suitable for carefully selected high-risk recipients and, in particular, elderly kidneys can also function well. Avoiding cancer transmission, fair recipient selection, close follow-up, and a well-organized tracking system warrant further study.

Gestational hypertension and preeclampsia in living kidney donors

BACKGROUND

Young women wishing to become living kidney donors frequently ask whether nephrectomy will affect their future pregnancies.

METHODS

We conducted a retrospective cohort study of living kidney donors involving 85 women (131 pregnancies after cohort entry) who were matched in a 1:6 ratio with 510 healthy nondonors from the general population (788 pregnancies after cohort entry). Kidney donations occurred between 1992 and 2009 in Ontario, Canada, with follow-up through linked health care databases until March 2013. Donors and nondonors were matched with respect to age, year of cohort entry, residency (urban or rural), income, number of pregnancies before cohort entry, and the time to the first pregnancy after cohort entry. The primary outcome was a hospital diagnosis of gestational hypertension or preeclampsia. Secondary outcomes were each component of the primary outcome examined separately and other maternal and fetal outcomes.

RESULTS

Gestational hypertension or preeclampsia was more common among living kidney donors than among nondonors (occurring in 15 of 131 pregnancies [11%] vs. 38 of 788 pregnancies [5%]; odds ratio for donors, 2.4; 95% confidence interval, 1.2 to 5.0; P=0.01). Each component of the primary outcome was also more common among donors (odds ratio, 2.5 for gestational hypertension and 2.4 for preeclampsia). There were no significant differences between donors and nondonors with respect to rates of preterm birth (8% and 7%, respectively) or low birth weight (6% and 4%, respectively). There were no reports of maternal death, stillbirth, or neonatal death among the donors. Most women had uncomplicated pregnancies after donation.

CONCLUSIONS

Gestational hypertension or preeclampsia was more likely to be diagnosed in kidney donors than in matched nondonors with similar indicators of baseline health. (Funded by the Canadian Institutes of Health Research and others.).

Comparison of cystatin C and creatinine-based equations for GFR estimation after living kidney donation

BACKGROUND

The performance of glomerular filtration rate (GFR) equations incorporating both cystatin C (CysC) and serum creatinine (Creat) in living kidney donors has not been studied before.

METHODS

From a population of 3,698 living kidney donors, 257 donors were randomly selected to undergo GFR measurement (mGFR) by the plasma disappearance of iohexol. GFR was estimated with the Modification of Diet in Renal Disease (MDRD) equation and the Chronic Kidney Disease Epidemiology Collaboration study eGFR(CKD-EPI-Creat) in 257 donors and the two newly developed equations using CysC with and without Creat, eGFR(CKD-EPI-CysC) and eGFR(CKD-EPI-Creat+CysC), in 215 donors.

RESULTS

Mean mGFR was 71.8±11.8 mL/min/1.73 m. The eGFR(MDRD) exhibited least and only negative bias and the three other models were comparable in terms of bias. The eGFR(CKD-EPI-Creat+CysC) equation was most precise; r=0.64. Both eGFR(MDRD) and eGFR(CKD-EPI-Creat+CysC) had high percentage (94.4% and 92.6%, respectively) of estimates falling within 30% of mGFR versus estimates by eGFR(CKD-EPI-Creat) and eGFR(CKD-EPI-CysC) equations (87.2% and 85.1%, respectively). The eGFR(MDRD) was by far most accurate in identifying those with mGFR less than 60 mL/min/1.73 m whereas the CKD-EPI models were extremely accurate in classifying those with mGFR greater than or equal to 60 mL/min/1.73 m.

CONCLUSIONS

eGFR(CKD-EPI-Creat+CysC) equation provides comparable accuracy to the eGFR(MDRD) in overall estimation of mGFR, but with higher precision. However, eGFR(CKD-EPI-Creat+CysC) clearly misses many of those with a post-donation GFR less than 60 mL/min/1.73 m and therefore eGFR(MDRD) is preferable in detecting donors with GFR less than 60 mL/min/1.73 m.

The Outcomes of Living Kidney Donation from Medically Complex Donors: Implications for the Donor and the Recipient

Living kidney donation is an important option for patients with end-stage renal disease (ESRD), and has improved life expectancy and quality for patients otherwise requiring maintenance dialysis or deceased-donor transplantation. Given the favorable outcomes of live donation and the shortage of organs to transplant, individuals with potentially unfavorable demographic and clinical characteristics are increasingly being permitted to donate kidneys. While this trend has successfully expanded the live donor pool, it has raised concerns as to which acceptance criteria are safe. This review aims to summarize the existing literature on the outcomes of transplantation from medically complex, living kidney donors, including both donor and recipient outcomes when available.

Risk of end-stage renal disease following live kidney donation

IMPORTANCE

Risk of end-stage renal disease (ESRD) in kidney donors has been compared with risk faced by the general population, but the general population represents an unscreened, high-risk comparator. A comparison to similarly screened healthy nondonors would more properly estimate the sequelae of kidney donation.

OBJECTIVES

To compare the risk of ESRD in kidney donors with that of a healthy cohort of nondonors who are at equally low risk of renal disease and free of contraindications to live donation and to stratify these comparisons by patient demographics.

DESIGN, SETTINGS, AND PARTICIPANTS

A cohort of 96,217 kidney donors in the United States between April 1994 and November 2011 and a cohort of 20,024 participants of the Third National Health and Nutrition Examination Survey (NHANES III) were linked to Centers for Medicare & Medicaid Services data to ascertain development of ESRD, which was defined as the initiation of maintenance dialysis, placement on the waiting list, or receipt of a living or deceased donor kidney transplant, whichever was identified first. Maximum follow-up was 15.0 years; median follow-up was 7.6 years (interquartile range [IQR], 3.9-11.5 years) for kidney donors and 15.0 years (IQR, 13.7-15.0 years) for matched healthy nondonors.

MAIN OUTCOMES AND MEASURES

Cumulative incidence and lifetime risk of ESRD.

RESULTS

Among live donors, with median follow-up of 7.6 years (maximum, 15.0), ESRD developed in 99 individuals in a mean (SD) of 8.6 (3.6) years after donation. Among matched healthy nondonors, with median follow-up of 15.0 years (maximum, 15.0), ESRD developed in 36 nondonors in 10.7 (3.2) years, drawn from 17 ESRD events in the unmatched healthy nondonor pool of 9364. Estimated risk of ESRD at 15 years after donation was 30.8 per 10,000 (95% CI, 24.3-38.5) in kidney donors and 3.9 per 10,000 (95% CI, 0.8-8.9) in their matched healthy nondonor counterparts (P < .001). This difference was observed in both black and white individuals, with an estimated risk of 74.7 per 10,000 black donors (95% CI, 47.8-105.8) vs 23.9 per 10,000 black nondonors (95% CI, 1.6-62.4; P < .001) and an estimated risk of 22.7 per 10,000 white donors (95% CI, 15.6-30.1) vs 0.0 white nondonors (P < .001). Estimated lifetime risk of ESRD was 90 per 10,000 donors, 326 per 10,000 unscreened nondonors (general population), and 14 per 10,000 healthy nondonors.

CONCLUSIONS AND RELEVANCE

Compared with matched healthy nondonors, kidney donors had an increased risk of ESRD over a median of 7.6 years; however, the magnitude of the absolute risk increase was small. These findings may help inform discussions with persons considering live kidney donation.

Renal transplantation from elderly living donors

Acceptance of elderly living kidney donors remains controversial due to the higher incidence of comorbidity and greater risk of postoperative complications. This is a review of publications in the English language between 2000 and 2013 about renal transplantation from elderly living donors to determine trends and effects of donation, and the outcomes of such transplantation. The last decade witnessed a 50% increase in living kidney donor transplants, with a disproportionate increase in donors >60 years. There is no accelerated loss of kidney function following donation, and the incidence of established renal failure (ERF) and hypertension among donors is similar to that of the general population. The overall incidence of ERF in living donors is about 0.134 per 1000 years. Elderly donors require rigorous assessment and should have a predicted glomerular filtration rate of at least 37.5 mL/min/1.73 m(2) at the age of 80. Though elderly donors had lower glomerular filtration rate before donation, proportionate decline after donation was similar in both young and elderly groups. The risks of delayed graft function, acute rejection, and graft failure in transplants from living donors >65 years are significantly higher than transplants from younger donors. A multicentred, long-term, and prospective database addressing the outcomes of kidneys from elderly living donors is recommended.

Rates and correlates of health maintenance behaviors after living kidney donation

CONTEXT AND OBJECTIVE

Donating a kidney may provide an opportunity for donors to reevaluate their health maintenance behaviors (eg, regular exercise, smoking cessation, medical checkups). Although the effect of donation on donors' health, quality of life, and financial outcomes has received growing attention, no studies have examined whether donation is related to changes in health maintenance behaviors. The study aims were to (1) describe and compare kidney donors' health maintenance behaviors before and after donation, and (2) determine the correlates of health maintenance behaviors after donation. DESIGN, SETTING, PARTICIPANTS AND MEASURES: We conducted a telephone-interview study with 85 randomly selected laparoscopic kidney donors in a major US transplant center to assess health behaviors before and after donation, postdonation characteristics (eg, quality of life, postsurgical pain), and demographics.

RESULTS

Sample demographics included a median age of 48 years; 55% were female, 82% were white, 71% were married, and 52% were college graduates. Few health behaviors changed significantly from before to after donation. Only the rate of medical checkups increased after donation (P< .001). Logistic regression was used to examine the association of demographics and postdonation characteristics with postdonation health maintenance behaviors, after adjusting for predonation behavior. Older age, higher income, less postsurgical pain, and better physical functioning were associated with more exercise after donation. Longer time since donation was associated with a higher prevalence of obesity.

CONCLUSIONS

These results may help identify donors who are at greater risk for poor health maintenance behaviors after donation and suggest areas of health behavior that should be the focus of education sessions before donation.

Do living kidney donors have CKD?

Living kidney donor transplantation is an increasingly used treatment for end-stage renal disease because it both confers excellent outcomes to transplant recipients, and is considered a safe procedure for prospective donors. The short- and long-term safety of prospective donors is paramount to the continued success of living donation. Although the initial experience with living kidney donors mostly included the healthiest donors, increasing need for organs and secular trends in the general population have subtly reshaped prevailing suitability criteria for donation. As the practice of living donation evolved over time, our understanding of kidney disease has also changed as we embraced the framework of the K-DOQI guidelines. It is not uncommon for donors to fit into some of the K-DOQI guidelines paradigms of risk and disease; however, whether there is a true biological consequence or whether it is a merely semantic conundrum remains unclear. Regardless, this is an important issue, and therefore future efforts should aim at addressing this matter.

Age, gender, and body mass index are associated with renal function after kidney donation

Renal function is thoroughly evaluated before live kidney donation. However, some donors experience impaired recovery of renal function after donation. Our aim was to assess estimated glomerular filtration rate (eGFR) and mean relative (%) increase in creatinine one yr after donor nephrectomy. The study was based on retrospective data from kidney donors during the period 1997-2009. Pre-operative and one-yr follow-up data were available for 721 of 1067 donors. Mean relative increase in creatinine and eGFR were stratified by gender, body mass index (BMI), and age at donation. At one yr post-donation, overweight (BMI > 5 kg/m(2) ) women 50 yr or older experienced the lowest eGFR of 49.6 ± 8.8 mL/min/1.73 m(2) . Men younger than 50 yr with normal weight (BMI < 25 kg/m(2) ) had the highest eGFR of 66.6 ± 10.4 mL/min/1.73 m(2) . Overweight men 50 yr or older had the highest relative increase in creatinine of 49.4% compared to pre-donation. Men under 50 yr with normal weight had the smallest increase in creatinine of 35.2%. In multivariate analysis, older age (p < 0.001), male gender (p < 0.001), and overweight (p = 0.01) were associated with relative increase in creatinine after donation. Potential donors should be offered counseling regarding overweight, as this is a modifiable risk factor.