Impact of Kidney Disease Outcomes Quality Initiative guidelines on the prevalence of chronic kidney disease after living donor nephrectomy

Quantifying Postdonation Risk of ESRD in Living Kidney Donors

Studies have estimated the average risk of postdonation ESRD for living kidney donors in the United States, but personalized estimation on the basis of donor characteristics remains unavailable. We studied 133,824 living kidney donors from 1987 to 2015, as reported to the Organ Procurement and Transplantation Network, with ESRD ascertainment via Centers for Medicare and Medicaid Services linkage, using Cox regression with late entries. Black race (hazard ratio [HR], 2.96; 95% confidence interval [95% CI], 2.25 to 3.89; P<0.001) and male sex (HR, 1.88; 95% CI, 1.50 to 2.35; P<0.001) was associated with higher risk of ESRD in donors. Among nonblack donors, older age was associated with greater risk (HR per 10 years, 1.40; 95% CI, 1.23 to 1.59; P<0.001). Among black donors, older age was not significantly associated with risk (HR, 0.88; 95% CI, 0.72 to 1.09; P=0.3). Greater body mass index was associated with higher risk (HR per 5 kg/m2, 1.61; 95% CI, 1.29 to 2.00; P<0.001). Donors who had a first-degree biological relationship to the recipient had increased risk (HR, 1.70; 95% CI, 1.24 to 2.34; P<0.01). C-statistic of the model was 0.71. Predicted 20-year risk of ESRD for the median donor was only 34 cases per 10,000 donors, but 1% of donors had predicted risk exceeding 256 cases per 10,000 donors. Risk estimation is critical for appropriate informed consent and varies substantially across living kidney donors. Greater permissiveness may be warranted in older black candidate donors; young black candidates should be evaluated carefully.

Does size matter? Kidney transplant donor size determines kidney function among living donors

BACKGROUND

Kidney donor outcomes are gaining attention, particularly as donor eligibility criteria continue to expand. Kidney size, a useful predictor of recipient kidney function, also likely correlates with donor outcomes. Although donor evaluation includes donor kidney size measurements, the association between kidney size and outcomes are poorly defined.

METHODS

We examined the relationship between kidney size (body surface area-adjusted total volume, cortical volume and length) and renal outcomes (post-operative recovery and longer-term kidney function) among 85 kidney donors using general linear models and time-to-chronic kidney disease data.

RESULTS

Donors with the largest adjusted cortical volume were more likely to achieve an estimated glomerular filtration rate (eGFR) ≥60 mL/min/1.73 m2 over a median 24-month follow-up than those with smaller cortical volumes (P <0.001), had a shorter duration of renal recovery (1.3-2.2 versus 32.5 days) and started with a higher eGFR at pre-donation (107-110 versus 91 mL/min/1.73 m2) and immediately post-nephrectomy (∼63 versus 50-51 mL/min/1.73 m2). Similar findings were seen with adjusted total volume and length.

CONCLUSIONS

Larger kidney donors were more likely to achieve an eGFR ≥60 mL/min/1.73 m2 with renal recovery over a shorter duration due to higher pre-donation and initial post-nephrectomy eGFRs.

Nephrectomy-induced reduced renal function and the health-related quality of life of living kidney donors

OBJECTIVE

To evaluate the health impact of nephrectomy on living kidney donors (LKDs) by comparing the health-related quality of life (HrQOL) scores measured by Short Form-36 (SF36) between those with and without postdonation renal function impairment (PRFI).

METHODS

Eighty-two LKDs (47 females, mean age=50.2±11.2 years) were prospectively recruited to participate in a SF-36 HrQOL survey. Chart review, individual baseline, and postoperative renal function (eGFR) was determined using the Modification of Diet in Renal Disease formula. PRFI was defined as eGFR<60 mL/min/1.73 m² or proteinuria. Mean SF-36 domain scores were compared between those with and without PRFI.

RESULTS

After a median follow-up of 5.7 years, the prevalence of postdonation comorbidities was 29.3% (n=24) PRFI, 25.6% (n=21) hypertension, 6.1% (n=5) diabetes, and 3.7% (n=3) heart disease, and no LKDs developed end-stage renal disease. Mean eGFR before and after donor nephrectomy was 95.5±23.4 and 71.0±17.3 mL/min/1.73 m² (P<.01). Mean SF-36 scores of LKDs were not significantly different between those with and without PRFI in all the domains (all P>.05). Similarly, the proportion of LKDs with PRFI did not differ significantly between the patients with SF-36 domain scores above and below the published reference values.

CONCLUSION

Nephrectomy-induced PRFI may not have a significant impact on the HrQOL of the LKD population with a low proportion of other major comorbidities such as diabetes and ischemic heart disease.

Cross-talk between AMP-activated protein kinase and renin-angiotensin system in uninephrectomised rats

INTRODUCTION

The renal renin-angiotensin system (RAS) and the ultrasensitive energy sensor AMP-activated protein kinase (AMPK) have been implicated in normal and aberrant states of the kidney, but interaction between the RAS and AMPK remains unknown.

METHODS

Ninety-six rats were stratified into four groups: sham, uninephrectomised, uninephrectomised rats treated with the angiotensin-converting enzyme inhibitor lisinopril or the angiotensin receptor blocker losartan. Histopathological examination at 9 months post-operation and biochemical measurements at 3, 6 and 9 months were performed for changes in renal structure and function. The expression of AMPK and angiotensin II at 9 months was detected by immunofluorescence microscopy and western blot.

RESULTS

Compared with sham rats, uninephrectomised rats demonstrated progressive glomerulosclerosis, tubular atrophy with cast formation and chronic inflammatory infiltration, in parallel to elevated serum urea, creatinine, urine total protein to creatinine ratio and reduced serum albumin. Overexpression of angiotensin II coexisted with a 85.6% reduction of phosphorylated to total AMPK ratio in the remnant kidney of uninephrectomised rats. RAS blockade by the angiotensin-converting enzyme inhibitor or angiotensin receptor blocker substantially normalised AMPK expression, morphological and functional changes of the remnant kidney.

CONCLUSIONS

Uninephrectomy-induced RAS activation and AMPK inhibition in the remnant kidney could be substantially corrected by RAS blockade, suggesting a cross-talk between AMPK and RAS components in uninephrectomised rats.

Measurement of renal function in a kidney donor: a comparison of creatinine-based and volume-based GFRs

OBJECTIVE

We aimed to evaluate the performance of various GFR estimates compared with direct measurement of GFR (dGFR). We also sought to create a new formula for volume-based GFR (new-vGFR) using kidney volume determined by CT.

MATERIALS AND METHODS

GFR was measured using creatinine-based methods (MDRD, the Cockcroft-Gault equation, CKD-EPI formula, and the Mayo clinic formula) and the Herts method, which is volume-based (vGFR). We compared performance between GFR estimates and created a new vGFR model by multiple linear regression analysis.

RESULTS

Among the creatinine-based GFR estimates, the MDRD and C-G equations were similarly associated with dGFR (correlation and concordance coefficients of 0.359 and 0.369 and 0.354 and 0.318, respectively). We developed the following new kidney volume-based GFR formula: 217.48-0.39XA + 0.25XW-0.46XH-54.01XsCr + 0.02XV-19.89 (if female) (A = age, W = weight, H = height, sCr = serum creatinine level, V = total kidney volume). The MDRD and CKD-EPI had relatively better accuracy than the other creatinine-based methods (30.7% vs. 32.3% within 10% and 78.0% vs. 73.0% within 30%, respectively). However, the new-vGFR formula had the most accurate results among all of the analyzed methods (37.4% within 10% and 84.6% within 30%).

CONCLUSIONS

The new-vGFR can replace dGFR or creatinine-based GFR for assessing kidney function in donors and healthy individuals.

KEY POINTS

• Accurate prediction of GFR is crucial in kidney donors. • DTPA is accurate but costly, invasive, and clinically difficult to apply. • Volume-based GFR estimation performs as well as the Cr-based method. • New volume-based GFR estimation performs better among GFR estimation formulas.

Renal parenchymal histopathology predicts life-threatening chronic kidney disease as a result of radical nephrectomy

The preoperative prediction of post-radical nephrectomy renal insufficiency plays an important role in the decision-making process regarding renal surgery options. Furthermore, the prediction of both postoperative renal insufficiency and postoperative cardiovascular disease occurrence, which is suggested to be an adverse consequence caused by renal insufficiency, contributes to the preoperative policy decision as well as the precise informed consent for a renal cell carcinoma patient. Preoperative nomograms for the prediction of post-radical nephrectomy renal insufficiency, calculated using patient backgrounds, are advocated. The use of these nomograms together with other types of nomograms predicting oncological outcome is beneficial. Post-radical nephrectomy attending physicians can predict renal insufficiency based on the normal renal parenchymal pathology in addition to preoperative patient characteristics. It is suggested that a high level of global glomerulosclerosis in nephrectomized normal renal parenchyma is closely associated with severe renal insufficiency. Some studies showed that post-radical nephrectomy severe renal insufficiency might have an association with increased mortality as a result of cardiovascular disease. Therefore, such pathophysiology should be recognized as life-threatening, surgically-related chronic kidney disease. On the contrary, the investigation of the prediction of mild post-radical nephrectomy renal insufficiency, which is not related to adverse consequences in the postoperative long-term period, is also promising because the prediction of mild renal insufficiency might be the basis for the substitution of radical nephrectomy for nephron-sparing surgery in technically difficult or compromised cases. The deterioration of quality of life caused by post-radical nephrectomy renal insufficiency should be investigated in conjunction with life-threatening matters.

Oncological and functional outcomes after radical nephrectomy for renal cell carcinoma: a comprehensive analysis of prognostic factors

OBJECTIVES

To investigate mortality rates and to comprehensively analyze prognostic indicators after radical nephrectomy for renal cell carcinoma.

METHODS

Data were collected from 147 patients who underwent potentially curative radical nephrectomy for renal cell carcinoma. The following data were analyzed: tumor pathology, patient demographics and clinical parameters, such as pre- and postoperative estimated glomerular filtration rate, as well as the cause of death. Cause-specific survival rates were calculated including deaths caused by renal cell carcinoma and cardiovascular disease. A Cox proportional hazard model was used for statistical analysis.

RESULTS

A univariate analysis showed that age at surgery (≥70 years), postoperative estimated glomerular filtration rate (<45 mL/min/1.73 m(2)), pathological high T stage, grade and venous invasion were significant poor prognostic indicators. The multivariate analysis provided evidence that pathological venous invasion was a significant poor prognostic indicator, whereas age at surgery (≥70 years), pre- (<65 mL/min/1.73 m(2)) or postoperative (<45 mL/min/1.73 m(2)) estimated glomerular filtration rate and pathological high grade were significant poor prognostic indicators in T1 tumor cases.

CONCLUSIONS

Post-radical nephrectomy renal function insufficiency can lead to a poor prognostic outcome, especially in patients with T1 renal cell carcinoma. Physicians should consider a comprehensive follow up focusing on possible causes of death, including those related to both renal cell carcinoma and cardiovascular disease events after radical nephrectomy.

Fas expression in nephrectomized, non-cancerous specimens predicts post-nephrectomy chronic kidney disease progression in patients with renal and upper urinary tract malignancies

OBJECTIVES

Despite the surgical curability of renal cell carcinoma (RCC) and upper urinary tract urothelial carcinoma (UUT-UC), post-nephrectomy chronic kidney disease (CKD) continues to be a cause of concern. We investigated the correlation between the expression of apoptotic regulatory molecules in the nephrectomized, noncancerous cortex, as well as CKD progression and CKD-related mortality.

MATERIALS AND METHODS

Fas and Bcl-2 mRNA and protein expression in surgically resected specimens from 100 patients with RCC and UUT-UC were determined. The estimated glomerular filtration rates (eGFR) were determined sequentially before surgery and up to 5 years after surgery. The relationships between CKD progression, the expression of these molecules in the renal cortex, and the clinical characteristics were analyzed.

RESULTS

The mean 1-year postoperative percent eGFR decrease was 30.2 (Standard deviation [SD]: 15.2). The 1-year postoperative percent eGFR decrease greater than the approximate value of mean ± SD (45) was categorized as severe renal functional deterioration (SRFD). Glomerular Fas protein expression and a Fas/β-actin mRNA ratio >0.3 were independent predictors for SRFD. Significantly increased mortality rates due to cardiovascular events were indicated by glomerular Fas protein expression, Fas mRNA levels >0.3, and SRFD. No significant change in Bcl-2 levels was observed.

CONCLUSIONS

This study is the first report to demonstrate the significance of Fas expression in the nephrectomized normal cortex as a predictor of post-nephrectomy CKD progression. The results from nephrectomized kidney showed that the natural course of renal function in the remaining kidney may be affected not only by Fas-induced glomerular cell apoptosis but also by the total amount of Fas mRNA in cortical cells.

Cardiovascular disease in kidney donors: matched cohort study

OBJECTIVE

To determine whether people who donate a kidney have an increased risk of cardiovascular disease.

DESIGN

Retrospective population based matched cohort study.

PARTICIPANTS

All people who were carefully selected to become a living kidney donor in the province of Ontario, Canada, between 1992 and 2009. The information in donor charts was manually reviewed and linked to provincial healthcare databases. Matched non-donors were selected from the healthiest segment of the general population. A total of 2028 donors and 20,280 matched non-donors were followed for a median of 6.5 years (maximum 17.7 years). Median age was 43 at the time of donation (interquartile range 34-50) and 50 at the time of follow-up (42-58).

MAIN OUTCOME MEASURES

The primary outcome was a composite of time to death or first major cardiovascular event. The secondary outcome was time to first major cardiovascular event censored for death.

RESULTS

The risk of the primary outcome of death and major cardiovascular events was lower in donors than in non-donors (2.8 v 4.1 events per 1000 person years; hazard ratio 0.66, 95% confidence interval 0.48 to 0.90). The risk of major cardiovascular events censored for death was no different in donors than in non-donors (1.7 v 2.0 events per 1000 person years; 0.85, 0.57 to 1.27). Results were similar in all sensitivity analyses. Older age and lower income were associated with a higher risk of death and major cardiovascular events in both donors and non-donors when each group was analysed separately.

CONCLUSIONS

The risk of major cardiovascular events in donors is no higher in the first decade after kidney donation compared with a similarly healthy segment of the general population. While we will continue to follow people in this study, these interim results add to the evidence base supporting the safety of the practice among carefully selected donors.