Hypertension, cardiovascular disease and cause of death in Danish living kidney donors: matched cohort study

Knowledge, attitude, and practice toward postoperative self-management among kidney transplant recipients

BACKGROUND

Patient involvement is crucial to the success of kidney transplants. This study aimed to investigate the knowledge, attitude, and practice (KAP) toward postoperative self-management among kidney transplant recipients.

METHODS

A web-based cross-sectional study was conducted in Ruijin Hospital (Shanghai, China) between March 24, 2023, and April 15, 2023 in kidney transplant recipients. A questionnaire was designed to collect data about the characteristics of the participants and their KAP toward postoperative self-management. KAP scores were calculated based on participants' responses, using predefined scoring criteria tailored to evaluate each dimension of KAP effectively.

RESULTS

A total of 483 valid questionnaires were collected, including 189 (39.13%) participants aged between 46 and 60 years. The mean score of knowledge, attitude and practice were 23.44 ± 4.87 (possible range: 0-28), 43.59 ± 2.65 (possible range: 10-50), 52.52 ± 4.64 (possible range: 0-58), respectively. The multivariate analysis showed knowledge scores (OR = 1.15, 95% CI = 1.10-1.20, p < 0.001), attitude scores (OR = 1.22, 95% CI = 1.12-1.32, p < 0.001) and undergone transplantation within 1 year (OR = 3.92, 95% CI = 1.60-9.63, p = 0.003) were independently associated with good practice. Knowledge scores (OR = 1.06, 95% CI = 1.02-1.10, p = 0.003), attitude scores (OR = 1.16, 95% CI = 1.08-1.25, p < 0.001), aged 16-35 years (OR = 0.38, 95% CI = 0.18-0.78, p = 0.009), underwent a single kidney transplant surgery (OR = 3.97, 95% CI = 1.28-12.38, p = 0.017) were independently associated with medication adherence.

CONCLUSIONS

Kidney transplant recipients had good knowledge, positive attitude and good practice toward postoperative self-management. Implementing personalized education, psychological support, and close monitoring strategies is recommended to optimize postoperative self-management in kidney transplant recipients.

Health Inequity in Likelihood and Time to Renal Recovery after Living Kidney Donation: Implications for Kidney Health in Black Americans

BACKGROUND

Live donor kidney transplantation has been popularized to help mitigate the organ shortage crisis. At the time of living donor nephrectomy, living donors lose 50% of their kidney function or glomerular filtration rate (GFR). Studies have shown that in healthy living donors, the remaining kidney is able to adapt and recover 10% to 25% of postdonation lost GFR. GFR recovery is critical to long-term kidney health, particularly for Black Americans who disproportionately suffer from kidney disease with an incidence 2.5 times White Americans. To date, no study has examined whether health inequities in renal recovery postdonation exist.

STUDY DESIGN

We retrospectively analyzed 100,121 living kidney donors reported to the Scientific Registry of Transplant Recipients between 1999 and 2021. We estimated GFR (eGFR) using the Chronic Kidney Disease Epidemiology Collaboration 2021 equation and predicted the likelihood (logistic regression) and time (Cox regression) to recovery of 60% and 75% predonation eGFR. Models adjusted for age, sex, race, BMI, and predonation eGFR.

RESULTS

Black patients were 47% (adjusted odds ratio 0.53, 95% CI 0.50 to 0.56, p < 0.001) and 43% (adjusted odds ratio 0.57, 95% CI 0.54 to 0.60, p < 0.001) less likely to recover 60% and 75% of predonation eGFR, respectively, compared with their White counterparts. The hazard ratio for time to renal recovery of 60% and 75% of predonation eGFR was 22% (adjusted hazard ratio 0.78, 95% CI 0.76 to 0.80, p < 0.001) and 38% (adjusted hazard ratio 0.62, 95% CI 0.60 to 0.65, p < 0.001) lower, respectively, than White patients.

CONCLUSIONS

Black living kidney donors were less likely to recover predonation eGFR, and time to renal recovery was significantly longer than their White counterparts. These data highlight the need for enhanced living kidney donor follow-up, particularly for Black living kidney donors who are at greatest future risk of end-stage kidney disease.

Development and Validation of a Hypertension Risk Calculator for Living Kidney Donors

BACKGROUND

Ideally, when deciding whether to donate, kidney donor candidates would understand their long-term risks. Using single-center data (N = 4055; median [quartiles] follow-up: 18 [9-28] y), we developed a calculator for postdonation hypertension and validated it using long-term data from an external single-center cohort (N = 1189, median [quartiles] follow-up: 9 [5-17] y).

METHODS

Risk factors considered were routinely obtained at evaluation from donor candidates. Two modeling approaches were evaluated: Cox proportional hazards and random survival forest models. Cross-validation prediction error and Harrell's concordance-index were used to compare accuracy for model development. Top-performing models were assessed in the validation cohort using the concordance-index and net reclassification improvement.

RESULTS

In the development cohort, 34% reported hypertension at a median (quartiles) of 16 (8-24) y postdonation; and in the validation cohort, 29% reported hypertension after 17 (10-22) y postdonation. The most accurate model was a Cox proportional hazards model with age, sex, race, estimated glomerular filtration rate, systolic and diastolic blood pressure, body mass index, glucose, smoking history, family history of hypertension, relationship with recipient, and hyperlipidemia (concordance-index, 0.72 in the development cohort and 0.82 in the validation cohort).

CONCLUSIONS

A postdonation hypertension calculator was developed and validated; it provides kidney donor candidates, their family, and care team a long-term projection of hypertension risk that can be incorporated into the informed consent process.

Long-term Medical Outcomes of Living Kidney Donors

Historically, to minimize risks, living kidney donors have been highly selected and healthy. Operative risks are well-defined, yet concern remains about long-term risks. In the general population, even a mild reduction in glomerular filtration rate (GFR) is associated with cardiovascular disease, chronic kidney disease, and end-stage kidney disease (ESKD). However, reduction in GFR in the general population is due to kidney or systemic disease. Retrospective studies comparing donors with matched general population controls have found no increased donor risk. Prospective studies comparing donors with controls (maximum follow-up, 9 years) have reported that donor GFR is stable or increases slightly, whereas GFR decreases in controls. However, these same studies identified metabolic and vascular donor abnormalities. There are a few retrospective studies comparing donors with controls. Each has limitations in selection of the control group, statistical analyses, and/or length of follow-up. One such study reported increased donor mortality; 2 reported a small increase in absolute risk of ESKD. Risk factors for donor ESKD are similar to those in the general population. Postdonation pregnancies are also associated with increased risk of hypertension and preeclampsia. There is a critical need for long-term follow-up studies comparing donors with controls from the same era, geographic area, and socioeconomic status who are healthy, with normal renal function on the date matching the date of donation, and are matched on demographic characteristics with the donors. These data are needed to optimize donor candidate counseling and informed consent.

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.

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.

Functional adaptation after kidney tissue removal in patients is associated with increased plasma atrial natriuretic peptide concentration

BACKGROUND

Following nephrectomy, the remaining kidney tissue adapts by an increase in GFR. In rats, hyperfiltration can be transferred by plasma. We examined whether natriuretic peptides (ANP, BNP) increase in plasma proportionally with kidney mass reduction and, if so, whether the increase relates to an increase in GFR.

METHODS

Patients (n = 54) undergoing partial or total unilateral nephrectomy at two Danish centers were followed for one year in an observational study. Glomerular filtration rate was measured before, 3, and 12 months after surgery. Natriuretic propeptides (proANP and proBNP) and aldosterone were measured in plasma before and at 24 hours, five days, 21 days, three months, and 12 months. Cyclic GMP was determined in urine.

RESULTS

There was no baseline difference in GFR between total- and partial nephrectomy (90.1 mL/min ±14.6 vs. 82.9±18, p = 0.16). Single-kidney GFR increased after 3 and 12 months (12.0 and 11.9 ml/min/1.73m2, +23.3%). There was no change in measured GFR 3 and 12 months after partial nephrectomy. ProANP and proBNP increased 3-fold 24h after surgery and returned to baseline after five days. The magnitude of acute proANP and proBNP increases did not relate to kidney mass removed. ProANP, not proBNP, increased 12 months after nephrectomy. Plasma aldosterone and urine cGMP did not change. Urine albumin/creatine ratio increased transiently after partial nephrectomy. Blood pressure was similar between groups.

CONCLUSION

ANP and BNP increase acutely in plasma with no relation to degree of kidney tissue ablation. After 1year, only unilateral nephrectomy patients display increased plasma ANP which could support adaptation.