Comparison of renal function after donor and radical nephrectomy

Predicting new-baseline glomerular filtration rate (NBGFR) after donor nephrectomy: validation of a split renal function (SRF)-based formula

BACKGROUND

Accurate prediction of post-donor nephrectomy (DN) glomerular filtration rate is potentially useful for evaluating and counselling living kidney donors. Currently, there are limited tools to evaluate post-operative new-baseline glomerular filtration rate (NBGFR) in kidney donors. We aim to validate a conceptually simple formula based on split renal function (SRF) previously developed for radical nephrectomy patients.

METHODS

Eighty-three consecutive patients who underwent DN from 2010 to 2016 were included. Pre-operative CT imaging and functional data including pre-DN baseline Global GFR (108.2 ± 13.2 mL/min/1.73m2) were included. Observed NBGFR was defined as the latest eGFR 3-12 months post-DN. SRF, defined as volume of the contralateral non-resected kidney normalised by total volume of kidneys, was determined from pre-operative cross-sectional imaging (49.2 ± 2.36%). The equation derived from Rathi et al. is as detailed: Predicted NBGFR = 1.24 × (Global GFR Pre-DN) x (SRF).

RESULTS

The relationship between predicted NBGFR (66.0 ± 8.29 mL/min/1.73m2) and observed NBGFR (74.9 ± 16.4 mL/min/1.73m2) was assessed by evaluating correlation coefficients, bias, precision, accuracy, and concordance. The new SRF-based formula for NBGFR prediction correlated strongly with observed post-operative NBGFR (Pearson's r = 0.729) demonstrating minimal bias (median difference = 7.190 mL/min/1.73m2) with good accuracy (96.4% within ± 30%, 62.7% within ± 15%) and precision (IQR of bias =  - 0.094 to 16.227).

CONCLUSION

The SRF-based formula was also able to accurately discriminate all but one patient to an NBGFR of > 45 mL/min/1.73m2. We utilised the newly developed SRF-based formula for predicting NBGFR in a living kidney donor population. Counselling of donor post-operative renal outcomes may then be optimised pre-operatively.

Chronic Kidney Disease and Cancer: Inter-Relationships and Mechanisms

Chronic kidney disease (CKD) has been recognized as an increasingly serious public health problem globally over the decades. Accumulating evidence has shown that the incidence rate of cancer was relatively higher in CKD patients than that in general population, which, mechanistically, may be related to chronic inflammation, accumulation of carcinogenic compounds, oxidative stress, impairment of DNA repair, excessive parathyroid hormone and changes in intestinal microbiota, etc. And in patients with cancer, regardless of tumor types or anticancer treatment, it has been indicated that the morbidity and incidence rate of concomitant CKD was also increased, suggesting a complex inter-relationship between CKD and cancer and arousing increasing attention from both nephrologists and oncologists. This narrative review focused on the correlation between CKD and cancer, and underlying molecular mechanisms, which might provide an overview of novel interdisciplinary research interests and the potential challenges related to the screening and treatment of CKD and cancer. A better understanding of this field might be of help for both nephrologists and oncologists in the clinical practice.

Hypertension and obesity in living kidney donors

Over the past few decades, the shortage in the kidney donor pool as compared to the increasing number of candidates on the kidney transplant waitlist led to loosening of kidney donors’ acceptance criteria. Hypertension and obesity represent risk factors for chronic kidney disease, both in native kidneys and those in kidney transplant recipients. While great progress has been made in kidney transplantation from living donors to benefit the recipient survival and quality of life, progress has been slow to fully risk-characterize the donors. This review critically reassesses the current state of understanding regarding the risk of end-stage kidney disease in those donors with obesity, hypertension or both. Accurate risk assessment tools need to be developed urgently to fully understand the risk glomerular filtration rate compensation failure in the remaining kidney of the donors.

Clinical assessment of stabilisation of renal function after nephrectomy

INTRODUCTION AND OBJECTIVE

Nephrectomy leads to derangement of renal function and various adaptive changes by the remaining kidney over a period of time. This study is performed to evaluate the amount of derangement of renal function in donor and radical nephrectomy, how much the remaining kidney adapts over a period of time and the time taken for stabilisation of renal function.

METHOD

A total of 60 patients who underwent nephrectomy (Radical/Donor) were followed up for 12 months with serial estimation of renal function and was compared with preoperative renal function. Data was analysed with statistical analysis.

RESULT

Patients who underwent radical nephrectomy had 37% initial decline in renal function which was later stabilised at 19% lower than baseline value. Patient who underwent donor nephrectomy had initially 39% decline in renal function which was later stabilised at 24% lower than normal.

CONCLUSION

Removal of functional renal tissue led to reduction of renal function. This decline is more evident in the initial post-operative period and then begin to stabilise over months. The greater is the amount of normal tissue removed, the greater is the reduction of renal function and more time it will take to stabilise, increasing overall morbidity of the patient. This study suggests that even patients with normal GFRs should be followed up postoperatively to determine their ultimate renal functional outcomes.

Comparison of long-term kidney functions after radical nephrectomy and simple nephrectomy

Objective

To determine if there is a difference in proceeding to CKD between patients who had undergone radical nephrectomy (RN) and simple nephrectomy (SN) for different indications by comparing the short- and long-term renal function.

Materials and Methods

We retrospectively analyzed the records of all patients who underwent nephrectomy (either for malign or benign indications) in our clinic between January 2007 and September 2017. The patients were divided into 2 groups according the type of surgery: 1) Radical nephrectomy Group, 2) Simple Nephrectomy Group. Renal function was evaluated with Glomerular Filtration Rate (GFR) calculated using the MDRD formula.

Results

A total of 276 patients were included in the study. There were 202 patients in RN Group and 74 patients in SN Group. The mean age of the patients in RN Group and SN Group were age 59,2 ± 11,5 and 49,9 ± 15,1 years, respectively (p = 0.001). GFR levels of patients in RN Group versus SN Group were as follows: Preoperative period: 84.9 vs. 81 mL/min/1.73 m²; postoperative 1st day: 60.5 vs. 84.4 mL/min/1.73 m², postoperative 1st month 58.9 vs. 76 mL/min/1.73 m², postoperative 1st year: 59.5 vs. 74.1 mL/min/1.73 m²; at last control 60.3 and 76.1 mL/min/1.73 m². While preoperative GFR was found to be similar in two groups (p = 0.26), postoperative GFR values were found to be significantly lower in Group RN (p < 0.001). In comparison of the decrease in GFR in two groups at last follow-up, significantly higher decrease was observed in RN Group, 29% vs. 6%, (p < 0.05).

Conclusion

The decrease in GFR exists more common and intensive after RN compared to SN. In long-term, compensation mechanisms that develop after sudden nephron loss like radical nephrectomy deteriorates kidney function more than gradual nephron loss as in benign etiologies which indicates simple nephrectomy.

The Correlates of Kidney Dysfunction – Tumour Nephrectomy Database (CKD-TUNED) Study: Protocol for a Prospective Observational Study

Background:

Tumour nephrectomy conveys a significant risk of adverse renal functional outcomes postoperatively, however there are limited strategies for predicting patients at increased risk of these outcomes. The Correlates of Kidney Dysfunction – Tumour Nephrectomy Database (CKD-TUNED) study is a prospective observational study evaluating the risk of chronic kidney disease and end-stage kidney disease in tumour nephrectomy patients.

Methods:

The CKD-TUNED study involves analysis of clinical data and collection of tissue, urine and blood samples for the purposes of forming a tissue repository resource for future investigation. Recruitment began in 2013 and is expected to continue until 2023, with a projected sample size between 700-1000 subjects.

Results:

All relevant ethics and site-specific approvals have been granted and all relevant infrastructure is in place. Study methods are undergoing validation and refinement. As of June 2017 there are 267 participants enrolled in the study.

Conclusion:

It is anticipated that this study will have the potential to identify risk factors for adverse renal functional outcomes following tumour nephrectomy, which can be used in the development of predictive models with clinical utility, and in turn improve patient outcomes.