Association between pre-donation serum uric acid concentration and change in renal function after living kidney donation in women

Acute kidney injury and the compensation of kidney function after nephrectomy in living donation

Acute kidney injury (AKI) incidence is growing rapidly, and AKI is one of the predictors of inpatient mortality. After nephrectomy, all the patients have decreased kidney function with AKI and recover from AKI. However, the characteristic and behavior of AKI is different from usual AKI and compensatory kidney function has been well known in the postoperative setting, especially in living donors. In this review, we have focused on the compensation of kidney function after nephrectomy in living donors. We discuss factors that have been identified as being associated with kidney recovery in donors including age, sex, body mass index, remnant kidney volume, estimated glomerular filtration rate, and various comorbidities.

[Renal functional compensation after unilateral radical nephrectomy of renal cell carcinoma]

OBJECTIVE

To investigate factors influencing renal functional compensation(RFC) of the preserved kidney after radical nephrectomy (RN).

METHODS

A total of 286 patients treated with RN in Peking University People's Hospital were retrospectively analyzed. Preoperative body mass index (BMI), systolic blood pressure (SBP), history of smoking, history of chronic diseases and other basic information, as well as preoperative blood biochemistry, urine routine, imaging examination results were recorded. All the patients underwent ^99mtechnetium-diethylenetriamine pentaacetic acid (^99mTc-DTPA) renal scans before operation. The surgical method, pathology and blood creatinine values from 1 month to 60 months after RN were recorded. Preoperative and postoperative estimated glomerular filtration rate (eGFR) was calculated by the chronic kidney disease epidemiology collaboration (CKD-EPI) formula. Renal functional compensation was defined as percent change in eGFR of the preserved kidney after RN compared with the preoperative eGFR. Univariate and multivariate regression analyses were used to identify predictive factors of RFC.

RESULTS

Median age was 61 years and 65.4% of the patients were male. Early stage (T1 or T2) tumors were found in 83.6% of the cases. 18.5% of the patients had preoperative diabetes mellitus, 39.5% had hypertension, 19.2% had a history of smoking, and 27.6% were found to have renal cyst on the contralateral side. In the study, 226 cases underwent laparoscopic radical nephrectomy and 60 cases underwent open radical nephrectomy. Renal clear cell carcinoma was the most common pathological type, accounting for 88.5%. The median tumor maximum diameter was 4.5 cm (0.7-13.5 cm). Median renal function compensation was 27% one month after radical nephrectomy. Functional stability was then observed to 5 years. The results of univariate analysis showed that age, gender, preoperative blood uric acid, preoperative urine protein, contralateral renal cyst, and percentage of split renal function of contralateral kidney were correlated with RFC (P < 0.05). Among them, UA level and split renal function of contralateral kidney were strongly negatively correlated with RFC. The results of multivariate linear regression analysis showed age (P < 0.001), blood uric acid (P < 0.001), urine protein (P=0.002), preoperative eGFR (P < 0.001) and the split renal function of contralateral kidney (P < 0.001) were independent predictors of RFC.

CONCLUSION

The basic examinations, such as blood biochemistry, urine routine and renal scan before RN are of great significance in predicting the compen-satory ability of the preserved kidney after RN, which is supposed to be taken into consideration when making clinical decision.

The relationship between serum uric acid levels and development of obesity in living kidney donors after donor nephrectomy

BACKGROUND

Hyperuricaemia plays a role in the pathogenesis of obesity and related metabolic disorders. The aim of this study to investigate the relationship between pre-donation serum uric acid (SUA) level and obesity development after nephrectomy in living kidney donors.

METHODS

Living donors of kidney transplants between 1998 and 2019 were evaluated. Donors with less than 1 year of follow-up were excluded from the study. The participants were divided into two groups according to last control body mass index (BMI) (obese; ≥ 30 kg/m² and nonobese; <30 kg/m² ) and median baseline SUA level (<4.6 mg/dL and ≥4.6 mg/dL).

RESULTS

In the included 240 donors, the mean follow-up was 50 ± 44 (12-216) months. The mean age was 47 ± 11 (19-82) years, and 46.6% of donors were male. At last control, the percentage of obese donors had increased significantly compared to pre-donation time (22.5% vs 33.8%; P < .001) and last control obese donors had both higher baseline SUA (5.1 ± 1.4 vs 4.5 ± 1.2; P < .01) and BMI (30.7 ± 2.6 vs 24.8 ± 3.0; P < .001). Cox regression analysis showed that there is an independent relationship between the baseline SUA level and development of obesity (odds ratio: 1.30 [CI; 1.12-1.50]; P < .001). In Kaplan-Meier analysis, the development of obesity was significantly higher in kidney donors with high SUA level.

CONCLUSION

Living kidney donors (LKD) have a tendency to obesity after nephrectomy. Preoperative serum uric acid level gives important information in LKDs that it could foresee the development of obesity after donation.

Long-term impact of baseline serum uric acid levels on living kidney donors: a retrospective study

BACKGROUND

Preoperative characteristics of living kidney donors are commonly considered during donor selection and postoperative follow-up. However, the impact of preoperative uric acid (UA) levels is poorly documented. The aim of this study was to evaluate the association between preoperative serum UA levels and post-donation long-term events and renal function.

METHODS

This was a single-center retrospective analysis of 183 living kidney donors. The donors were divided into high (≥5.5 mg/dl) and low (< 5.5 mg/dl) UA groups. We analyzed the relationship between preoperative UA levels and postoperative estimated glomerular filtration rate (eGFR), as well as adverse events (cardiovascular events and additional prescriptions for hypertension, gout, dyslipidemia, and diabetes mellitus), over 5 years after donation.

RESULTS

In total, 44 donors experienced 52 adverse events over 5 years. The incidence of adverse events within 5 years was significantly higher in the high UA group than in the low UA group (50% vs. 24%, p = 0.003); this was true even after the exclusion of hyperuricemia-related events (p = 0.047). UA emerged as an independent risk factor for adverse events (p = 0.012). Donors with higher UA levels had lower eGFRs after donation, whereas body mass index, hemoglobin A1c, blood pressure, and low-density lipoprotein cholesterol did not have any impact on the eGFR.

CONCLUSIONS

The findings suggest that preoperative UA levels should be considered during donor selection and postoperative follow-up.

Predictive Factors of Renal Adaptation After Nephrectomy in Kidney Donors

BACKGROUND

Despite compensatory hyperfiltration in remaining nephrons following donor nephrectomy, some donors show impaired renal adaptation and low estimated glomerular filtration rate (eGFR). We investigated the factors predicting early renal adaptation after nephrectomy and identified kidney donors at risk of inadequate renal adaptation.

METHODS

A total of 265 living kidney donors from 2010 to 2013 were retrospectively analyzed. Renal function was serially followed for 6 months after the operation. Regression analyses were performed to identify the independent predictors of low eGFR (eGFR <60 mL/min/1.73 m²) and impaired renal adaptation (%Modification of Diet in Renal Disease [MDRD] <66% of baseline eGFR).

RESULTS

A total of 148 donors belonged to the low eGFR group, and changes in eGFR (ΔeGFR) at postoperative (PO) 1 day and 1 month were identified as independent predictors of low eGFR. Impaired renal adaptation was related to age, ΔeGFR PO 2-3 days, and ΔeGFR PO 1 month. Early renal adaptation was associated with age, male gender, and residual kidney computerized tomography angiography (CTA) volume. The best sensitivity and specificity were obtained with a cutoff value of ΔeGFR 31 at PO 1 day and 1 month for predicting low eGFR and with a value of ΔeGFR 27 at PO 2-3 days and 1 month for predicting impaired renal adaptation.

CONCLUSIONS

Our study showed that the degree of early renal adaptation determines subsequent renal function in kidney donors. Closer monitoring and management may be required in old or male donors with small residual CTA kidney volume as well as donors with persistent ΔeGFR >27 within 1 month of nephrectomy.

Gout after living kidney donation: correlations with demographic traits and renal complications

BACKGROUND

The demographic and clinical correlates of gout after living kidney donation are not well described.

METHODS

Using a unique database that integrates national registry identifiers of U.S. living kidney donors (1987-2007) with billing claims from a private health insurer (2000-2007), we identified post-donation gout based on medical diagnosis codes or pharmacy fills for gout therapies. The frequencies and demographic correlates of gout after donation were estimated by Cox regression with left- and right-censoring. We also compared the rates of renal diagnoses among donors with and without gout, matched in the ratio 1:3 by age, sex, and race.

RESULTS

The study sample of 4,650 donors included 13.1% African Americans. By seven years, African Americans were almost twice as likely to develop gout as Caucasian donors (4.4 vs. 2.4%; adjusted hazard ratio, aHR, 1.8; 95% confidence interval (CI) 1.0-3.2). Post-donation gout risk also increased with older age at donation (aHR per year 1.05) and was higher in men (aHR 2.80). Gout rates were similar in donors and age- and sex-matched general non-donors (rate ratio 0.86; 95% CI 0.66-1.13). Compared to matched donors without gout, donors with gout had more frequent renal diagnoses, reaching significance for acute kidney failure (rate ratio 12.5; 95% CI 1.5-107.0), chronic kidney disease (rate ratio 5.0; 95% CI 2.1-11.7), and other disorders of the kidney (rate ratio 2.2; 95% CI 1.2-4.2).

CONCLUSION

Donor subgroups at increased risk of gout include African Americans, older donors, and men. Donors with gout have a higher burden of renal complications after demographic adjustment.