Early Hypertension and Diabetes After Living Kidney Donation: A National Cohort Study

Chronic Kidney Disease Risk in Living Kidney Transplant Donors: A Long-Term Follow-Up Study

BACKGROUND

Living kidney donors (LKD) may experience some untoward consequences following donation such as development of chronic kidney disease (CKD). In this study, we aimed to investigate the rate of development of CKD and factors affecting the development of CKD in LKDs during long-term follow-up from a center in Turkey.

METHODS

This study was a retrospective analysis of LKDs followed between January 2000 and December 2017. Pre-transplant and post-transplant clinical data of the 338 LKDs were recorded and compared. Factors affecting the development of stage 3 and later stages of CKD were analyzed.

RESULTS

Majority of the donors were females (64.2%), and the median age of all donors was 47 (39-54) years. Stage 3 CKD developed in 50 donors during the median follow-up of 71 months. Older age at the time of transplantation and a low pre-transplant estimated glomerular filtration rate (eGFR) were determined as the factors affecting the development of stage 3 CKD (p < 0.001, p < 0.001). The receiver operating characteristic analysis showed that the cut-off age for the development of stage 3 CKD was 50.5 years. Newly diagnosed hypertension was detected in 57 patients (16.8%) after the transplantation. While hypertension was seen at a rate of 42% in those with an eGFR <60 mL/min/1.73 m2, it was detected at 19.4% in the group with an eGFR >60 mL/min/1.73 m2 (p < 0.001).

CONCLUSION

These results reveal that being a LKD is associated with the development of CKD and hypertension. Age and eGFR values at the time of transplantation were the determinants for the development of CKD.

External Validation of Toulouse-Rangueil eGFR12 Prediction Model After Living Donor Nephrectomy

Decreased postdonation eGFR is associated with a higher risk of ESRD after living kidney donation, even when accounting for predonation characteristics. The Toulouse-Rangueil model (TRM) estimates 12 month postdonation eGFR (eGFR12) to inform counseling of candidates for living donation. The TRM was validated in several single-center European cohorts but has not been validated in US donors. We assessed the TRM in living kidney donors in the US using SRTR data 1/2000-6/2021. We compared the 2021 CKD-EPI equation eGFR12 observed estimates to the TRM eGFR12 predictions. Median (IQR) bias was -3.4 (-9.3, 3.4) mL/min/1.73 m2. Bias was higher for males vs. females (bias [IQR] -4.4 [-9.9, 1.8] vs. -2.9 [-8.8, 4.1]) and younger (31-40) vs. older donors (>50) (bias -4.9 [-10.6, 3.0] vs. -2.1 [-7.5, 4.0]). Bias was also larger for Black vs. White donors (bias (-6.7 [-12.1, -0.3], p < 0.001) vs. (-3.4 [-9.1, 3.1], p < 0.001)). Overall correlation was 0.71. In a sensitivity analysis using the 2009 CKD-EPI equation, results were generally consistent with exception to a higher overall bias (bias -4.2 [-9.8, 2.4]). The TRM overestimates postdonation renal function among US donors. Overestimation was greatest for those at higher risk for postdonation ESRD including male, Black, and younger donors. A new equation is needed to estimate postdonation renal function.

Change in Body Mass Index and Attributable Risk of New-Onset Hypertension Among Obese Living Kidney Donors

OBJECTIVE

To examine whether body mass index (BMI) changes modify the association between kidney donation and incident hypertension.

BACKGROUND

Obesity increases hypertension risk in both general and living kidney donor (LKD) populations. Donation-attributable risk in the context of obesity, and whether weight change modifies that risk, is unknown.

METHODS

Nested case-control study among 1558 adult LKDs (1976-2020) with obesity (median follow-up: 3.6 years; interquartile range: 2.0-9.4) and 3783 adults with obesity in the Coronary Artery Risk Development in Young Adults (CARDIA) and Atherosclerosis Risk in Communities (ARIC) studies (9.2 y; interquartile range: 5.3-15.8). Hypertension incidence was compared by donor status using conditional logistic regression, with BMI change investigated for effect modification.

RESULTS

Overall, LKDs and nondonors had similar hypertension incidence [incidence rate ratio (IRR): 1.16, 95% confidence interval (95% CI): 0.94-1.43, P =0.16], even after adjusting for BMI change (IRR: 1.25, 95% CI: 0.99-1.58, P =0.05). Although LKDs and nondonors who lost >5% BMI had comparable hypertension incidence (IRR: 0.78, 95% CI: 0.46-1.34, P =0.36), there was a significant interaction between donor and >5% BMI gain (multiplicative interaction IRR: 1.62, 95% CI: 1.15-2.29, P =0.006; relative excess risk due to interaction: 0.90, 95% CI: 0.24-1.56, P =0.007), such that LKDs who gained weight had higher hypertension incidence than similar nondonors (IRR: 1.83, 95% CI: 1.32-2.53, P <0.001).

CONCLUSIONS

Overall, LKDs and nondonors with obesity had similar hypertension incidence. Weight stability and loss were associated with similar hypertension incidence by donor status. However, LKDs who gained >5% saw increased hypertension incidence versus similar nondonors, providing support for counseling potential LKDs with obesity on weight management postdonation.

Recommendations for living donor kidney transplantation

This Guide for Living Donor Kidney Transplantation (LDKT) has been prepared with the sponsorship of the Spanish Society of Nephrology (SEN), the Spanish Transplant Society (SET), and the Spanish National Transplant Organization (ONT). It updates evidence to offer the best chronic renal failure treatment when a potential living donor is available. The core aim of this Guide is to supply clinicians who evaluate living donors and transplant recipients with the best decision-making tools, to optimise their outcomes. Moreover, the role of living donors in the current KT context should recover the level of importance it had until recently. To this end the new forms of incompatible HLA and/or ABO donation, as well as the paired donation which is possible in several hospitals with experience in LDKT, offer additional ways to treat renal patients with an incompatible donor. Good results in terms of patient and graft survival have expanded the range of circumstances under which living renal donors are accepted. Older donors are now accepted, as are others with factors that affect the decision, such as a borderline clinical history or alterations, which when evaluated may lead to an additional number of transplantations. This Guide does not forget that LDKT may lead to risk for the donor. Pre-donation evaluation has to centre on the problems which may arise over the short or long-term, and these have to be described to the potential donor so that they are able take them into account. Experience over recent years has led to progress in risk analysis, to protect donors' health. This aspect always has to be taken into account by LDKT programmes when evaluating potential donors. Finally, this Guide has been designed to aid decision-making, with recommendations and suggestions when uncertainties arise in pre-donation studies. Its overarching aim is to ensure that informed consent is based on high quality studies and information supplied to donors and recipients, offering the strongest possible guarantees.

The Living Kidney Donor Safety Study: Protocol of a Prospective Cohort Study

Background

Living kidney donation is considered generally safe in healthy individuals; however, there is a need to better understand the long-term effects of donation on blood pressure and kidney function.

Objectives

To determine the risk of hypertension in healthy, normotensive adults who donate a kidney compared with healthy, normotensive non-donors with similar indicators of baseline health. We will also compare the 2 groups on the rate of decline in kidney function, the risk of albuminuria, and changes in health-related quality of life.

Design Participants and Setting

Prospective cohort study of 1042 living kidney donors recruited before surgery from 17 transplant centers (12 in Canada and 5 in Australia) between 2004 and 2014. Non-donor participants (n = 396) included relatives or friends of the donor, or donor candidates who were ineligible to donate due to blood group or cross-match incompatibility. Follow-up will continue until 2021, and the main analysis will be performed in 2022. The anticipated median (25th, 75th percentile, maximum) follow-up time after donation is 7 years (6, 8, 15).

Measurements

Donors and non-donors completed the same schedule of measurements at baseline and follow-up (non-donors were assigned a simulated nephrectomy date). Annual measurements were obtained for blood pressure, estimated glomerular filtration rate (eGFR), albuminuria, patient-reported health-related quality of life, and general health.

Outcomes

Incident hypertension (a systolic/diastolic blood pressure ≥ 140/90 mm Hg or receipt of anti-hypertensive medication) will be adjudicated by a physician blinded to the participant's donation status. We will assess the rate of change in eGFR starting from 12 months after the nephrectomy date and the proportion who develop an albumin-to-creatinine ratio ≥3 mg/mmol (≥30 mg/g) in follow-up. Health-related quality of life will be assessed using the 36-item RAND health survey and the Beck Anxiety and Depression inventories.

Limitations

Donation-attributable hypertension may not manifest until decades after donation.

Conclusion

This prospective cohort study will estimate the attributable risk of hypertension and other health outcomes after living kidney donation.

Examining post-donation outcomes in Hispanic/Latinx living kidney donors in the United States: A systematic review

We conducted a systematic review to assess outcomes in Hispanic donors and explore how Hispanic ethnicity was characterized. We searched PubMed, EMBASE, and Scopus through October 2021. Two reviewers independently screened study titles, abstracts, and full texts; they also qualitatively synthesized results and independently assessed quality of included studies. Eighteen studies met our inclusion criteria. Study sample sizes ranged from 4007 to 143,750 donors and mean age ranged from 37 to 54 years. Maximum follow-up time of studies varied from a perioperative donor nephrectomy period to 30 years post-donation. Hispanic donors ranged between 6% and 21% of the donor populations across studies. Most studies reported Hispanic ethnicity under race or a combined race and ethnicity category. Compared to non-Hispanic White donors, Hispanic donors were not at increased risk for post-donation mortality, end-stage kidney disease, cardiovascular disease, non-pregnancy-related hospitalizations, or overall perioperative surgical complications. Compared to non-Hispanic White donors, most studies showed Hispanic donors were at higher risk for diabetes mellitus following nephrectomy; however, mixed findings were seen regarding the risk for post-donation chronic kidney disease and hypertension. Future studies should evaluate cultural, socioeconomic, and geographic differences within the heterogeneous Hispanic donor population, which may further explain variation in health outcomes.

JCV viruria associates with suboptimal recovery of kidney function three years after living kidney donation

ABSTRACT Introduction: Few studies have investigated pre-donation factors that could affect renal recovery after living kidney donation (LKD). We retrospectively investigated the role of John Cunningham virus (JCV) infection and other pre-donation factors on the magnitude of kidney function decline after LKD. Methods: Urine JCV viral loads, glomerular filtration rate, and blood pressure were evaluated in 60 consecutive LK donors before donation. Suboptimal compensatory hypertrophy was defined as an eGFR <60% of the pre-donation eGFR. Results: LKD (40% JCV infected) were followed for 3.2±1.6 years. No association was found between age, gender, and baseline hypertension with 1st, 2nd, 3rd, and 4th years post-donation eGFR <60% of the pre-donation eGFR. Mean eGFR recovery at the 3rd year after donation was lower in JCV infected donors vs non-infected donors (61.8% vs 71.0%, p=0.006). Conclusion: We hypothesized that JCV could shift glomeruli into a hyperfiltration state before nephrectomy, modulating the magnitude of compensatory hypertrophy after donation. Conversely, JCV might curtail the ability of the remaining kidney to promote hyperfiltration. Longer follow up is needed to determine whether JCV viruria ultimately leads to lower eGFR over time or if it is a protective factor for the remaining kidney.

Practice Patterns in the Acceptance of Medically Complex Living Kidney Donors with Obesity, Hypertension, Family History of Kidney Disease, or Donor-Recipient Age Discrepancy

Background  To assess the practice patterns of the acceptance of medically complex living kidney donors (MCLKDs).

Methods  We distributed a survey to nephrologists and transplant surgeons (TS) across the world through major international transplant societies. The survey contained questions regarding obesity, abnormal blood glucose profile, mild hypertension, donor-recipient age discrepancy, or family history of kidney disease of unknown etiology.

Results  In total, 239 respondents from 29 countries (42% were nephrologists and 58% were TS).

Most respondents would allow donations from obese donors, especially if they intended to lose weight but would be cautious if these donors had abnormal blood glucose or family history of diabetes mellitus. In hypertensive donors, future pregnancy plans mattered in decisions regarding the acceptance of female donors. Most respondents would allow young donors but would be more cautious if they had a future risk of hypertension or a family history of kidney disease of unknown etiology. They would also allow donations from an older person if prolonged waiting time was anticipated. We found multiple areas of consensus of practice among the diverse members of international transplant societies, with some interesting variations among nephrologists and TS.

Conclusions  This survey highlights the practice patterns of the acceptance of MCLKDs among the international community. In the absence of clear guidelines, this survey provides additional information to counsel kidney donors with these conditions.

Living donation - any news on the donor?

PURPOSE OF REVIEW

Living kidney donation has been an established practice for many years. Although studies from the past decade have uncovered risks to the donor, living kidney donation is still promoted. In this review, the most recent studies are summarized.

RECENT FINDINGS

Retrospective studies with long follow-up have detected an increased risk of hypertension among donors. Donors with hypertension at the time of donation may be at increased risk of adverse outcomes, but results differ. Recent studies have not found increased long-term mortality, but follow-up is short and control groups are of different quality.

SUMMARY

In all, the most recent findings more or less corroborate previous knowledge in the field of living donation. There is still a need for new studies on mortality with appropriate control groups and long enough follow-up.

Prevalence, Mechanisms, Treatment, and Complications of Hypertension Postliving Kidney Donation

Living kidney donors represent a unique population of patients. Potential donors are selected based on the belief that their preoperative fitness is likely to mitigate the risks of long- and short-term harm following uninephrectomy. Studies performed on postdonation outcomes have largely focused on mortality and the risk of end-stage renal failure, but have also investigated secondary outcomes such as cardiovascular morbidity and hypertension. It has been postulated that hypertension is a possible outcome of living kidney donation. A variety of studies have been conducted to investigate the prevalence, epidemiology, mechanisms, treatment strategies, and long-term ramifications of hypertension postdonation. These studies are heterogeneous in their population, design, methodology, and outcome measures and have presented contradicting outcomes. Additionally, the absence of a well-matched control group has made it challenging to interpret and generalise the reported findings. As such, it is not possible to definitively conclude that hypertension occurs at a higher rate among donors than the general population. This article will review the evidence of postdonation hypertension prevalence, mechanisms, treatment, and complications.

One size does not fit all: understanding individual living kidney donor risk

Living donor kidney transplantation is the optimal treatment for end-stage kidney disease (ESKD) but confers a risk upon the donor, both in the short term and many years after donation. While perioperative mortality is low and longevity does not appear to be adversely affected, there are small increases in the risk of other important morbidities. The overall risk of ESKD among donors is low but appears to be three- to five-fold higher than among healthy non-donors, and this relative risk is even higher among donors of African ancestry. For these individuals, apolipoprotein L1 genotyping may be helpful. Kidney donors also have an increased risk of developing hypertension post-donation and a modestly increased risk of developing gout. Living kidney donation also increases the risk of gestational hypertension and preeclampsia while not affecting other important pregnancy outcomes. As our understanding of donor risk grows, it is important to counsel prospective donors according to their individual risk and so obtain better informed donor consent. As knowledge advances, it is also important that all clinicians who manage kidney transplant candidates have an up to date understanding of donor risk to inform shared decision making.

Postdonation eGFR and New-Onset Antihypertensive Medication Use After Living Kidney Donation

Background.

Limited data are available regarding clinical implications of lower renal function after living kidney donation. We examined a novel integrated database to study associations between postdonation estimated glomerular filtration rate (eGFR) and use of antihypertensive medication (AHM) treatment after living kidney donation.

Methods.

Study data were assembled by linking national U.S. transplant registry identifiers, serum creatinine (SCr) values from electronic medical records, and pharmacy fill records for 3222 living donors (1989–2016) without predonation hypertension. Estimated GFR (mL/min per 1.73 m²) was computed from SCr values by the CKD-EPI equation. Repeated measures multivariable mixed effects modeling examined the associations (adjusted odds ratio, _95%LCLaOR_{95% UCL}) between AHM use and postdonation eGFR levels (random effect) with fixed effects for baseline donor factors.

Results.

The linked database identified an average of 3 postdonation SCr values per donor (range: 1–38). Lower postdonation eGFR (vs ≥75) bore graded associations with higher odds of AHM use (eGFR 30–44: aOR _0.951.47_2.26; <30: aOR _1.082.52_5.90). Other independent correlates of postdonation AHM use included older age at donation (aOR per decade: _1.081.23_1.40), black race (aOR _1.031.51_2.21), body mass index > 30 kg/m² (aOR _1.011.45_2.09), first-degree donor–recipient relationship (aOR _1.071.38_1.79), “prehypertension” at donation (systolic blood pressure 120–139: aOR _1.101.46_1.94; diastolic blood pressure 80–89: aOR _1.061.45_1.99).

Conclusions.

This novel linkage illustrates the ability to identify postdonation kidney function and associate it with clinically meaningful outcomes; lower eGFR after living kidney donation is a correlate of AHM treatment requirements. Further work should define relationships of postdonation renal function, hypertension, and other morbidity measures.

Surgical Stress Hyperglycemia Associated With New-Onset Diabetes in Living Kidney Donors

BACKGROUND

The aim of this study is to investigate the frequency and risk factors of new-onset diabetes after donation in kidney donors without diabetes.

METHODS

Living donors of kidney transplants between 1998 and 2016 were evaluated. To detect the blood glucose profile of the donors, preoperative fasting glucose (pro-G), nephrectomy evening glucose (nG), and postoperative day 1 fasting glucose (post-G) values were measured.

RESULTS

A total of 195 cases were included in the study. The mean follow-up time in months ± SD (range) was 56 ± 45 (12-215). Of these, 28 (14.3%) donors developed diabetes. The pro-G (103 ± 7.6 vs 93 ± 9.0), nG (208 ± 122 vs 163 ± 67) and post-G (121 ± 25 vs 111 ± 21) values of the donors with new-onset diabetes were higher. Nineteen donors (9.7%) had normal pro-G, nG, and post-G values (group A). However, there were 153 (78.5%) cases with at least 1 abnormal value (group B) and 25 (12.8%) cases that had abnormal values in all (pro-G, nG, and post-G) measurements (group C). The incidence of new-onset diabetes was 0 (0%) in group A, 11% in group B, and 48% in group C (P < .001). In multiple regression analysis, pro-G (Exp[B], 1.08; 95% CI, 1.04-1.13; P < .001) and basal glomerular filtration rate (Exp[B], 0.96; 95% CI, 0.94-0.99; P < .01) independently associated with new-onset diabetes.

CONCLUSIONS

In kidney donors without a history of diabetes, the development of diabetes after donor nephrectomy is an important problem. Pre- and postoperative blood glucose levels provide important information to predict these cases.