The performance of three serum creatinine-based formulas in estimating GFR in former kidney donors

Impact of measured versus estimated glomerular filtration rate-based screening on living kidney donor characteristics: A study of multiple cohorts

Background

Most transplant centers in the Netherlands use estimated glomerular filtration rate (eGFR) for evaluation of potential living kidney donors. Whereas eGFR often underestimates GFR, especially in healthy donors, measured GFR (mGFR) allows more precise kidney function assessment, and therefore holds potential to increase the living donor pool. We hypothesized that mGFR-based donor screening leads to acceptance of donors with lower pre-donation eGFR than eGFR-based screening.

Methods

In this longitudinal cohort study, we compared eGFR (CKD-EPI) before donation in one center using mGFR-based screening (mGFR-cohort, n = 250) with two centers using eGFR-based screening (eGFR-cohort1, n = 466 and eGFR-cohort2, n = 160). We also compared differences in eGFR at five years after donation.

Results

Donor age was similar among the cohorts (mean±standard deviation (SD) mGFR-cohort 53±10 years, eGFR-cohort1 52±13 years, P = 0.16 vs. mGFR-cohort, and eGFR-cohort2 53±9 years, P = 0.61 vs. mGFR-cohort). Estimated GFR underestimated mGFR by 10±12 mL/min/1.73m² (mean±SD), with more underestimation in younger donors. In the overall cohorts, mean±SD pre-donation eGFR was lower in the mGFR-cohort (91±13 mL/min/1.73m²) than in eGFR-cohort1 (93±15 mL/min/1.73m², P<0.05) and eGFR-cohort2 (94±12 mL/min/1.73m², P<0.05). However, these differences disappeared when focusing on more recent years, which can be explained by acceptance of more older donors with lower pre-donation eGFR over time in both eGFR-cohorts. Five years post-donation, mean±SD eGFR was similar among the centers (mGFR-cohort 62±12 mL/min/1.73m², eGFR-cohort1 61±14 mL/min/1.73m², eGFR-cohort2 62±11 mL/min/1.73m², P = 0.76 and 0.95 vs. mGFR-cohort respectively). In the mGFR-cohort, 38 (22%) donors were excluded from donation due to insufficient mGFR with mean±SD mGFR of 71±9 mL/min/1.73m².

Conclusions

Despite the known underestimation of mGFR by eGFR, we did not show that the routine use of mGFR in donor screening leads to inclusion of donors with a lower pre-donation eGFR. Therefore eGFR-based screening will be sufficient for the majority of the donors. Future studies should investigate whether there is a group (e.g. young donors with insufficient eGFR) that might benefit from confirmatory mGFR testing.

Comparison of 6 equations for estimating glomerular filtration rate in a Chinese benign hypertensive nephrosclerosis population

Equations to estimate glomerular filtration rate (eGFR) are useful for monitoring tje renal status of benign hypertensive nephrosclerosis (BHN). This study aimed to compare the applicability of 6 equations (Cockcroft-Gault [CG] adjusted for body surface area, original modification of diet in renal disease [MDRD], American abbreviated MDRD, Chinese modified MDRD, Chinese abbreviated MDRD, and Chronic Kidney Disease Epidemiology [CKD-EPI]) to estimate GFR in a Chinese BHN population. A total of 179 patients diagnosed with BHN were enrolled. The GFR estimated by each equation was compared to the reference GFR (rGFR) measured using the dual plasma sampling technetium-labeled diethylenetriaminepentaacetic acid method. The Chinese modified and Chinese abbreviated MDRD equations overestimated the rGFR, while the CG, CG adjusted for body surface area, original MDRD, American abbreviated MDRD, and CKD-EPI equations underestimated the rGFR. The difference in performance between estimated GFR (eGFR) based on the American abbreviated MDRD equation and the rGFR was not statistically significant (P = .191), while differences in the others were statistically significant (P < .05). Furthermore, the advantages in deviation, absolute deviation, deviation degree, precision, and accuracy were also significantly different from those of the other equations. Our findings suggest that eGFR based on the American abbreviated MDRD equation is suitable for the Chinese BHN population.

Measured Glomerular Filtration Rate After Kidney Donation: No Evidence of Accelerated Decay

BACKGROUND

The rate of measured glomerular filtration rate (GFR) change in kidney donor years after donation has not been adequately addressed. Whether this change is accelerated in the setting of 1 kidney is also understudied.

METHODS

Two hundred fourteen randomly selected donors underwent serial GFR measurements of nonradioactive iohexol. Estimated GFR at each visit was calculated using the Chronic Kidney Disease Epidemiology Collaboration and Modification of Diet in Renal Disease study equations.

RESULTS

Glomerular filtration rate visits were 4.8 ± 1.3 years apart and the second occurring 16.9 ± 9.1 years after donation. Most (97.7%) were white, 60.8% female, and 78.5% were related to their recipient. Most, 84.6%, had a GFR of 60 mL/min per 1.73 m or higher, 14.0% had a GFR between 45 and 60 mL/min per 1.73 m, and 1.4% had a GFR less than 45 mL/min per 1.73 m. Between visits 1 and 2, 56.5% had a GFR decline, 36.0% increase, and in 7.5%, there was no change. Overall, GFR declined at a rate of -0.42 mL/min per 1.73 m per year. Of GFR estimating models, only Chronic Kidney Disease Epidemiology Collaboration-Creatinine equation produced a slope that was steeper than measured GFR.

CONCLUSIONS

Nearly 2 decades postdonation GFR declined at a rate similar to that seen in the general population, and in one third, GFR continues to increase.

MDRD or CKD-EPI for glomerular filtration rate estimation in living kidney donors

INTRODUCTION

The evaluation of the measured Glomerular Filtration Rate (mGFR) or estimated Glomerular Filtration Rate (eGFR) is key in the proper assessment of the renal function of potential kidney donors. We aim to study the correlation between glomerular filtration rate estimation equations and the measured methods for determining renal function.

MATERIAL AND METHODS

We analysed the relationship between baseline GFR values measured by Tc-⁹⁹m-DTPA (diethylene-triamine-pentaacetate) and those estimated by the four-variable Modification of Diet in Renal Disease (MDRD4) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in a series of living donors at our institution.

RESULTS

We included 64 donors (70.6% females; mean age 48.3±11 years). Baseline creatinine was 0.8±0.1 mg/dl and it was 1.1±0.2 mg/dl one year after donation. The equations underestimated GFR when measured by Tc⁹⁹m-DTPA (MDRD4-9.4 ± 25ml/min, P<.05, and CKD-EPI-4.4 ± 21ml/min). The correlation between estimation equations and the measured method was superior for CKD-EPI (r=.41; P<.004) than for MDRD4 (r=.27; P<.05). eGFR decreased to 59.6±11 (MDRD4) and 66.2±14ml/min (CKD-EPI) one year after donation. This means a mean eGFR reduction of 28.2±16.7 ml/min (MDRD4) and 27.31±14.4 ml/min (CKD-EPI) at one year.

CONCLUSIONS

In our experience, CKD-EPI is the equation that better correlates with mGFR-Tc⁹⁹m-DTPA when assessing renal function for donor screening purposes.

Assessment of long-term cardiovascular effects of unilateral nephrectomy

PURPOSE

There is conflicting evidence regarding long-term effects of unilateral nephrectomy such as cardiovascular diseases. Excessive increase in blood pressure (BP) during exercise called "hypertensive response to exercise" may be a sign of unborn hypertension and increased cardiovascular risk. Decrease in glomerular filtration rate (GFR) in patients with unilateral nephrectomy may be associated with disturbance of circadian BP changes without affecting the absolute levels of BP. We aimed to investigate the circadian BP changes and hypertensive response to exercise in normotensive patients with preserved renal functions who had undergone unilateral nephrectomy for other causes rather than organ donation.

METHODS

This study enrolled 32 patients (mean age 43.4 ± 9.9 years, male 15) with unilateral nephrectomy and 40 healthy controls (mean age 47 ± 6.1 years, male 17). All patients were undergone both office and ambulatory BP measurements and treadmill stress test.

RESULTS

The median time since nephrectomy was 12 (9-22) years in the patient group. The median GFR of the patient group was lower than that of the controls without significance [85.1 (76.0-97.9) vs. 93.2 (84.5-104.9), respectively; p = 0.14]. There was no significant difference between groups in terms of office BP measurements, night time diastolic and systolic BP, mean arterial pressure (MAP), night/day time ratio of MAP in ambulatory BP measurements. The results of treadmill stress tests and hypertensive response to exercise ratios were also similar between the groups.

CONCLUSION

This study revealed that there was no increase in long-term cardiovascular risks one decade after unilateral nephrectomy based on circadian BP changes and hypertensive response to exercise in normotensive patients.

Evaluation of renal function in a specific population of living kidney donors

BACKGROUND

The increase in candidates for kidney transplant has led to growth in the number of living donor transplants. Therefore, studies that adequately evaluate the possible long-term consequences of elective transplant nephrectomy are needed.

OBJECTIVE

To evaluate the possible long-term adverse effects of transplant nephrectomy on the renal function of living kidney donors.

DESIGN

A cross-sectional study.

PARTICIPANTS

Thirty-three living kidney donors registered in the transplant programme of a centre in Alagoas, Brazil.

MEASUREMENTS

Demographic characteristics, anthropometric measures, clinical data and biomarkers (creatinine, eGFR, microalbuminuria, cholesterol and triglycerides) were measured. Creatinine clearance was calculated using the Cockcroft-Gault and Modification of Diet in Renal Disease formulae.

RESULTS

Of the 33 individuals, 63.63% were female, and the median age was 45 years. Additionally, 24.24% of these individuals had altered blood pressure, 39.39% had altered abdominal circumference (AC) and 36.36% were obese, with a body mass index ≥30. Furthermore, 33.33% of these individuals had elevated triglyceride levels. The average eGFR was 97.33 (33.03-175.9) ml/min/1.73 m² (CG) and 84.14 (29.4-131) ml/min/1.73 m² (MDRD). The microalbuminuria level was altered in 12.12% patients.

CONCLUSION

Kidney donation is unquestionably a safe procedure. However, a better understanding of the long-term consequences of living donor kidney transplantation is still needed. This knowledge may have important implications for the follow-up of these patients. Our study has demonstrated a non-negligible presence of an early marker of glomerular injury and a decrease in the GFR of some patients, thereby reinforcing the proposal for long-term follow-up of living kidney donors.

Cystatin-C is associated with partial recovery of kidney function and progression to chronic kidney disease in living kidney donors: Observational study

Donor nephrectomy in living-donor kidney transplantation may result in hyperfiltration injury in remnant kidney; however, its clinical implication in partial recovery of kidney function (PRKF) in remnant kidney and chronic kidney disease (CKD) progression remains unclear. Thus, we investigated the effect of PRKF on CKD development in the residual kidney and the utility of cystatin-C (Cys-C) in evaluating renal function in living-donor kidney transplantation donors.The electronic medical records and laboratory results of 1648 kidney transplant (KT) donors and 13,834 healthy nondonors between January 2006 and November 2014 were reviewed. The predictors of PRKF and CKD diagnosed by Kidney Disease: Improving Global Outcomes (KDIGO) criteria were evaluated by multivariate analysis. CKD risk was compared between KT donors and healthy nondonors using Cox proportional hazard regression analysis following propensity score matching (PSM).The incidence of PRKF for KT donors was 49.3% (813). CKD incidence was 24.8% (408) in KT donors and 2.0% (277) in healthy nondonors. The predictors of PRKF were, male sex (odds ratio [OR], 17.32; 95% confidence interval [CI] 9.16-32.77), age (OR, 1.02; 95% CI, 1.00-1.04; P < 0.001), Cys-C concentration (OR, 1.02; 95% CI, 1.00-1.04; P = 0.02), and preoperative albumin level (OR, 0.49; 95% CI, 0.27-0.89; P = 0.02). The predictors of CKD were age (hazards ratio [HR], 1.04; 95% CI, 1.02-1.05; P < 0.001), Cys-C concentration (HR, 1.024; 95% CI, 1.012-1.037; P < 0.001), and PRKF (HR, 1.41; 95% CI, 1.04-1.92; P = 0.03). After PSM, the risk of progression to CKD was higher in KT donors than in healthy nondonors (HR, 58.4; 95% CI, 34.2-99.8; P < 0.001).Donor nephrectomy is associated with PRKF and progression to CKD. Cys-C is a useful early marker for detecting PRKF and CKD.

Cardiovascular Effects of Unilateral Nephrectomy in Living Kidney Donors

There is a robust inverse graded association between glomerular filtration rate (GFR) and cardiovascular risk, but proof of causality is lacking. Emerging data suggest living kidney donation may be associated with increased cardiovascular mortality although the mechanisms are unclear. We hypothesized that the reduction in GFR in living kidney donors is associated with increased left ventricular mass, impaired left ventricular function, and increased aortic stiffness. This was a multicenter, parallel group, blinded end point study of living kidney donors and healthy controls (n=124), conducted from March 2011 to August 2014. The primary outcome was a change in left ventricular mass assessed by magnetic resonance imaging (baseline to 12 months). At 12 months, the decrease in isotopic GFR in donors was -30±12 mL/min/1.73m(2). In donors compared with controls, there were significant increases in left ventricular mass (+7±10 versus -3±8 g; P<0.001) and mass:volume ratio (+0.06±0.12 versus -0.01±0.09 g/mL; P<0.01), whereas aortic distensibility (-0.29±1.38 versus +0.28±0.79×10(-3) mm Hg(-1); P=0.03) and global circumferential strain decreased (-1.1±3.8 versus +0.4±2.4%; P=0.04). Donors had greater risks of developing detectable highly sensitive troponin T (odds ratio, 16.2 [95% confidence interval, 2.6-100.1]; P<0.01) and microalbuminuria (odds ratio, 3.8 [95% confidence interval, 1.1-12.8]; P=0.04). Serum uric acid, parathyroid hormone, fibroblast growth factor-23, and high-sensitivity C-reactive protein all increased significantly. There were no changes in ambulatory blood pressure. Change in GFR was independently associated with change in left ventricular mass (R(2)=0.28; P=0.01). These findings suggest that reduced GFR should be regarded as an independent causative cardiovascular risk factor.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01028703.

Investigating kidney donation as a risk factor for hypertension and microalbuminuria: findings from the Swiss prospective follow-up of living kidney donors

OBJECTIVES

To assess the role of nephrectomy as a risk factor for the development of hypertension and microalbuminuria.

DESIGN

Prospective, long-term follow-up study.

SETTING

Swiss Organ Living-Donor Health Registry.

PARTICIPANTS

All living kidney donors in Switzerland between 1993 and 2009.

INTERVENTIONS

Data on health status and renal function before 1 year and biennially after donation were collected.

PRIMARY AND SECONDARY OUTCOME MEASURES

Comparison of 1-year and 5-year occurrences of hypertension among normotensive donors with 1-year and 5-year estimates from the Framingham hypertension risk score. Multivariate random intercept models were used to investigate changes of albumin excretion after donation, correcting for repeated measurements and cofactors such as age, male gender and body mass index.

RESULTS

A total of 1214 donors contributed 3918 data entries with a completed biennial follow-up rate of 74% during a 10-year period. Mean (SD) follow-up of donors was 31.6 months (34.4). Median age at donation was 50.5 years (IQR 42.2-58.8); 806 donors (66.4%) were women. Donation increased the risk of hypertension after 1 year by 3.64 (95% CI 3.52 to 3.76; p<0.001). Those participants remaining normotensive 1 year after donation return to a risk similar to that of the healthy Framingham population. Microalbuminuria before donation was dependent on donor age but not on the presence of hypertension. After nephrectomy, hypertension became the main driver for changes in albumin excretion (OR 1.19; 95% CI 0.13 to 2.25; p=0.03) and donor age had no effect.

CONCLUSIONS

Nephrectomy propagates hypertension and increases susceptibility for the development of hypertension-induced microalbuminuria.

Cardiovascular Effects of Unilateral Nephrectomy in Living Kidney Donors

There is a robust inverse graded association between glomerular filtration rate (GFR) and cardiovascular risk, but proof of causality is lacking. Emerging data suggest living kidney donation may be associated with increased cardiovascular mortality although the mechanisms are unclear. We hypothesized that the reduction in GFR in living kidney donors is associated with increased left ventricular mass, impaired left ventricular function, and increased aortic stiffness. This was a multicenter, parallel group, blinded end point study of living kidney donors and healthy controls (n=124), conducted from March 2011 to August 2014. The primary outcome was a change in left ventricular mass assessed by magnetic resonance imaging (baseline to 12 months). At 12 months, the decrease in isotopic GFR in donors was -30±12 mL/min/1.73m(2). In donors compared with controls, there were significant increases in left ventricular mass (+7±10 versus -3±8 g; P<0.001) and mass:volume ratio (+0.06±0.12 versus -0.01±0.09 g/mL; P<0.01), whereas aortic distensibility (-0.29±1.38 versus +0.28±0.79×10(-3) mm Hg(-1); P=0.03) and global circumferential strain decreased (-1.1±3.8 versus +0.4±2.4%; P=0.04). Donors had greater risks of developing detectable highly sensitive troponin T (odds ratio, 16.2 [95% confidence interval, 2.6-100.1]; P<0.01) and microalbuminuria (odds ratio, 3.8 [95% confidence interval, 1.1-12.8]; P=0.04). Serum uric acid, parathyroid hormone, fibroblast growth factor-23, and high-sensitivity C-reactive protein all increased significantly. There were no changes in ambulatory blood pressure. Change in GFR was independently associated with change in left ventricular mass (R(2)=0.28; P=0.01). These findings suggest that reduced GFR should be regarded as an independent causative cardiovascular risk factor.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01028703.

Comparison of cystatin C and creatinine-based equations for GFR estimation after living kidney donation

BACKGROUND

The performance of glomerular filtration rate (GFR) equations incorporating both cystatin C (CysC) and serum creatinine (Creat) in living kidney donors has not been studied before.

METHODS

From a population of 3,698 living kidney donors, 257 donors were randomly selected to undergo GFR measurement (mGFR) by the plasma disappearance of iohexol. GFR was estimated with the Modification of Diet in Renal Disease (MDRD) equation and the Chronic Kidney Disease Epidemiology Collaboration study eGFR(CKD-EPI-Creat) in 257 donors and the two newly developed equations using CysC with and without Creat, eGFR(CKD-EPI-CysC) and eGFR(CKD-EPI-Creat+CysC), in 215 donors.

RESULTS

Mean mGFR was 71.8±11.8 mL/min/1.73 m. The eGFR(MDRD) exhibited least and only negative bias and the three other models were comparable in terms of bias. The eGFR(CKD-EPI-Creat+CysC) equation was most precise; r=0.64. Both eGFR(MDRD) and eGFR(CKD-EPI-Creat+CysC) had high percentage (94.4% and 92.6%, respectively) of estimates falling within 30% of mGFR versus estimates by eGFR(CKD-EPI-Creat) and eGFR(CKD-EPI-CysC) equations (87.2% and 85.1%, respectively). The eGFR(MDRD) was by far most accurate in identifying those with mGFR less than 60 mL/min/1.73 m whereas the CKD-EPI models were extremely accurate in classifying those with mGFR greater than or equal to 60 mL/min/1.73 m.

CONCLUSIONS

eGFR(CKD-EPI-Creat+CysC) equation provides comparable accuracy to the eGFR(MDRD) in overall estimation of mGFR, but with higher precision. However, eGFR(CKD-EPI-Creat+CysC) clearly misses many of those with a post-donation GFR less than 60 mL/min/1.73 m and therefore eGFR(MDRD) is preferable in detecting donors with GFR less than 60 mL/min/1.73 m.

Do living kidney donors have CKD?

Living kidney donor transplantation is an increasingly used treatment for end-stage renal disease because it both confers excellent outcomes to transplant recipients, and is considered a safe procedure for prospective donors. The short- and long-term safety of prospective donors is paramount to the continued success of living donation. Although the initial experience with living kidney donors mostly included the healthiest donors, increasing need for organs and secular trends in the general population have subtly reshaped prevailing suitability criteria for donation. As the practice of living donation evolved over time, our understanding of kidney disease has also changed as we embraced the framework of the K-DOQI guidelines. It is not uncommon for donors to fit into some of the K-DOQI guidelines paradigms of risk and disease; however, whether there is a true biological consequence or whether it is a merely semantic conundrum remains unclear. Regardless, this is an important issue, and therefore future efforts should aim at addressing this matter.

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.

Impact of estimated glomerular filtration rate after valve and combined valve and coronary surgery

Preoperative renal impairment predicts postoperative mortality in patients undergoing cardiac surgery. We examined the impact of three equations for glomerular filtration rate (GFR) estimation on mortality. This is a retrospective, observational study on patients undergoing valve (n = 594) and combined valve and coronary procedures (n = 412). Glomerular filtration rate was estimated with modification in diet and renal disease (MDRD), Cockcroft-Gault (CG) equation, and Mayo-Clinic (MC) equation. Mean age was 65 ± 11 years and mean logistic EuroSCORE was 9.0 [95% confidence interval (CI): 8.4-9.7]. Preoperative kidney dysfunction (eGFR <60 ml/min/1.73 m²) is associated with increased risk for mortality. Hazard ratios for 30-day mortality differed between eGFR equations [MC 2.6 (95% CI: 1.6-4.1); MDRD 2.9 (95% CI: 1.9-4.4); CG 3.9 (95% CI: 2.2-5.2)]. Discriminatory performance of GFR equations was comparable with logistic EuroSCORE, but CG and MC discriminated significantly better than MDRD. Median intensive care unit stay did not differ, but Bland-Altman plots showed considerable variation between eGFR equations, indicating that they cannot be used interchangeably. Substantial amount of agreement was achieved with CG and MDRD. Only one equation should be used in one institution. The bias between equations varied considerably. Impaired preoperative kidney dysfunction is associated with increased risk for mortality irrespective of the formula used.

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

PURPOSE

We evaluated the prevalence of chronic kidney disease stage 3 or worse based on the National Kidney Foundation Kidney Disease Outcomes Quality Initiative guidelines after living kidney donation at a single institution.

MATERIALS AND METHODS

The collected data of 86 consecutive patients who underwent uneventful donor nephrectomy between 1987 and 2008 were evaluated retrospectively. Estimated glomerular filtration rate was determined using the Modification of Diet in Renal Disease from serum creatinine levels collected before and after surgery in kidney donor followup clinics. Chronic kidney disease was defined as an estimated glomerular filtration rate of less than 60 ml/minute/1.73 m(2) according to the Kidney Disease Outcomes Quality Initiative guidelines. Cox regression analyses were then used to determine the impact of predictors on the development of chronic kidney disease.

RESULTS

All donors (mean age 41.2, SD 9.9 years) had a mean preoperative estimated glomerular filtration rate of 88.7 ml/min/1.73 m(2) (SD 16.3). Median followup was 6.4 years (range 0.9 to 21.0). Progression to stage 3 or worse chronic kidney disease was seen in 24.4% (95% CI 15.2-33.7) of patients. There were 2 patient deaths secondary to cancer and none required dialysis. Multivariable analysis showed that preoperative estimated glomerular filtration rate less than 82 ml/minute/1.73 m(2) was an independent risk factor for post-donation chronic kidney disease. For every 1 ml/minute/1.73 m(2) increase in baseline estimated glomerular filtration rate, the hazard of postoperative chronic kidney disease was reduced by 7% (HR 0.93, 95% CI 0.89-0.97, p = 0.001).

CONCLUSIONS

Kidney Disease Outcomes Quality Initiative stage 3 chronic kidney disease or worse occurs in 24.4% of kidney donors. Long-term prospective studies and closer followup of donors are needed to identify its implications, given the associated risk of cardiovascular diseases with chronic kidney disease in the general population.

Race and renal function early after live kidney donation: an analysis of the United States Organ Procurement and Transplantation Network Database

Among Americans, the risk for kidney disease is higher in individuals of African descent (AA) when compared with Caucasians. We considered whether there are similar racial differences in kidney function soon after donor nephrectomy. Of the 31,928 live kidney donors that donated between the years 2000 and 2005, 16,996 (53%) had post-donation serum creatinine recorded at a mean follow-up of 156 d (range 1-1410 d). A total of 14,525 (85%) were Caucasians and 2471 (15%) were AA. When compared with Caucasians, AA donors were more likely to be younger, heavier, and male, had a higher baseline serum creatinine and a shorter duration of follow-up. After accounting for these differences, the serum creatinine after donation and fractional rise in serum creatinine after donation were similar between the two groups (AA vs. Caucasian donors, 1.3 ± 0.3 vs. 1.2 ± 0.3 mg/dL; 53% vs. 45%) and the post-donation estimated glomerular filtration rate was also similar (57.2 ± 0.6 vs. 56.0 ± 0.2 mL/min per 1.73 m(2)). We observed no major clinical difference in glomerular filtration rate and ability to compensate for loss of renal mass soon after live kidney donation between Caucasian and AA donors.

Renal function equations before and after living kidney donation: a within-individual comparison of performance at different levels of renal function

BACKGROUND AND OBJECTIVES

The Modification of Diet in Renal Disease (MDRD) study equation and the Cockcroft-Gault (CG) equation perform poorly in the (near-) normal range of GFR. Whether this is due to the level of GFR as such or to differences in individual characteristics between healthy individuals and patient with chronic kidney disease (CKD) is unknown.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We evaluated the performance of MDRD, CG per BSA (CG/(BSA)) and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations compared with measured GFR (mGFR; I-iothalamate) at 4 months before and 2 months after donation in 253 consecutive living kidney donors.

RESULTS

mGFR declined from 103 ± 15 to 66 ± 11 ml/min per 1.73 m(2) after donation. All equations underestimated mGFR at both time points. Arithmetic performance analysis showed improved performance after donation of all equations, with significant reduction of bias after donation. Expressed as percentage difference, mGFR-estimated GFR (eGFR) bias was reduced after donation only for CG/(BSA). Finally, in 295 unselected individuals who were screened for donation, mGFR was below the cutoff for donation of 80 ml/min per 1.73 m(2) in 19 individual but in 166, 98, and 74 for MDRD, CDK-EPI, and CG/(BSA), respectively.

CONCLUSIONS

A higher level of GFR as such is associated with larger absolute underestimation of true GFR by eGFR. For donor screening purposes, eGFR should be interpreted with great caution; when in doubt, true GFR should be performed to prevent unjustified decline of prospective kidney donors.

Definition of chronic kidney disease after uninephrectomy in living donors: what are the implications?

BACKGROUND

Living kidney transplant donors generally have a favorable renal functional outcome postuninephrectomy, but concern remains that a reduced glomerular filtration rate (GFR) postuninephrectomy might have harmful effects. This study examines the short-term (3 months) effect of donor nephrectomy on GFR and the occurrence of stage 3 chronic kidney disease (CKD) postuninephrectomy.

METHODS

The prevalence of stage 3 CKD (Kidney Disease Quality Outcome Initiative [GFR<60 mL/min/1.73 m]) was examined in 196 living donors by comparing preuninephrectomy and 3-month postuninephrectomy values of GFR using I-iothalamate GFR (iGFR), modification of diet in renal disease estimated GFR (eGFR), Cockcroft-Gault estimated creatinine clearance, and endogenous 24-hr creatinine clearance. The accuracy of GFR estimations for predicting iGFR was also studied.

RESULTS

The mean GFR before and after donation were iGFR, 105+/-18 and 68+/-13 mL/min/1.73 m; eGFR, 98+/-19 and 63+/-12 mL/min/1.73 m; Cockcroft-Gault estimated creatinine clearance, 125+/-33 and 85+/-22 mL/min/1.73 m, and endogenous 24-hr creatinine clearance, 133+/-38 and 86+/-24 mL/min/1.73 m, respectively. Stage 3 CKD was found postuninephrectomy in 53 donors (27%) by iGFR and in 73 donors (38%) by eGFR. The prevalence of stage 3 CKD was greater with older age. GFR estimation equations did not accurately predict iGFR, particularly postuninephrectomy.

CONCLUSIONS

Stage 3 CKD is commonly observed after living kidney donation, particularly in older donors. The long-term impact of stage 3 CKD postuninephrectomy is poorly understood and may not have the same implications as stage 3 CKD in other conditions. eGFR is a poor predictor of true GFR in kidney donors.

The state of U.S. living kidney donors

BACKGROUND AND OBJECTIVES

Increasing living kidney donation mandates ongoing assessment of living donors for future health risks and revision of national health policy.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Living kidney donors as reported to the Organ Procurement and Transplant Network database from January 1988 through December 2008 were reviewed for minor medical abnormalities, presence of donor health care coverage, and occurrence of surgical complications and death.

RESULTS

At donation in 2008, 19.5% were obese, 2.0% had a history of hypertension, and 3.5% had proteinuria. The median estimated GFR of living donors was 92.2 ml/min. Additionally, 12.2% of donors were reported not to have health insurance at the time of donation. By racial background, 14.9% of black and 17.0% of Hispanic donors did not have insurance at donation. Perioperative complications included blood transfusion (0.4%), reoperation (0.5%), and vascular complications (0.2%). Death occurred within 30 days of donation in 0.03% donating between October 1999 and December 2008. During those same years, overall donor death was 2.8%.

CONCLUSIONS

Almost one quarter of living donors have medical conditions that may be associated with future health risk. Close follow-up and a registry of these donors are necessary. Only then will we be able to inform prospective living donors most accurately of the real risk of donation on their health and survival. Additionally, these data speak to the need for a national discussion on the provision of health insurance for living donors.

Diabetes after kidney donation

Kidney donors, similar to the general population, are at risk for development of type 2 diabetes mellitus (T2DM). The course of donors who develop T2DM has not been studied. We surveyed 3777 kidney donors regarding the development of T2DM. Of the 2954 who responded, 154 developed T2DM 17.7 +/- 9.0 years after donation. The multivariable risk of development of T2DM was associated with type 1 DM in the recipient, male gender and body mass index >30 kg/m(2) at time of donation. Compared to age, gender, duration after donation and body mass index (BMI)-matched non-diabetic donor controls; diabetic donors were more likely to have hypertension (70.8% vs. 36.2%, p = 0.005), proteinuria (18.8% vs. 3.9%, p < 0.0001) but had a similar serum creatinine. eGFR change after T2DM development was -0.80 +/- 0.94 mL/min/year, -0.70 +/- 0.86 in nondiabetic donors with similar duration after donation and -0.61 +/- 0.76 mL/min/year in age, gender, BMI and duration after donation matched nondiabetic donor controls. These preliminary and short-term data demonstrate that factors associated with T2DM in kidney donors are similar to those in the general population and donors screened carefully at the time of donation do not appear to have an acceleration of diabetic kidney disease.

A study of renal outcomes in African American living kidney donors

BACKGROUND

Little is known about the long-term outcomes of African American living kidney donors (AALKDs). We undertook this study to describe renal outcomes of AALKDs several years after donation.

METHODS

We invited 107 AALKDs to come for follow-up health evaluation.

RESULTS

Thirty-nine subjects (36.4%) completed evaluation at a mean of 7.1+/-1.6 (range, 3.9-10.2) years postdonation. The mean estimated glomerular filtration rate using the abbreviated Modification of Diet in Renal Disease equation [eGFR(MDRD)] at follow-up was 72.1+/-16.3 (range, 42-106) mL/min/1.73 m2, and 18% of subjects had an eGFR(MDRD) of 30 to 59. The mean absolute and relative decrease in eGFR(MDRD) from the time of donation to follow-up was 30.5+/-16.4 mL/min/1.73 m2 and 28.8%, respectively. Subjects whose body mass index was more than or equal to 35 kg/m2 (n=8) were found to have a greater decrement in e(MDRD) than those with body mass index less than 35 kg/m2 (40.1+/-7.3 and 28.3+/-17.1 mL/min/1.73 m2, respectively; P=0.009). Sixteen (41%) were hypertensive at follow-up, as defined as treatment with antihypertensive medications (n=8) or average blood pressure of more than or equal to 140 systolic or 90 mm Hg diastolic (n=10, of whom two were on antihypertensive medications). One subject had macroalbuminuria (>300 microg/mg creatinine), and six (15.4%) had microalbuminuria (30-300 microg/mg creatinine).

CONCLUSIONS

AALKDs experience a substantial incidence of hypertension and a modest drop in eGFR(MDRD) postdonation, and obesity may increase the magnitude of renal decline. Further study is urgently needed to determine the long-term risks of AALKDs.

Short-term renal outcomes in African American and Caucasian donors following live kidney donation

INTRODUCTION

Although African Americans (AA) are considered higher risk kidney donors than Caucasians, limited data are available regarding outcomes of AA donors.

METHODS

We performed a single-center retrospective review of all kidney donors from 1993 to 2007 and evaluated race/ethnic differences in post-donation changes in renal function, incident proteinuria, and systolic blood pressure (SBP) using linear mixed models.

RESULTS

A total of 336 kidney donors (63 AA, 263 Caucasian, 10 other) were evaluated. Before donation, AA had higher serum creatinine concentrations, estimated glomerular filtration rate (GFR) values, and SBP levels than Caucasians. No significant changes in SBP or renal function were observed between the two groups within the first year after donation, although results were limited by incomplete follow-up.

CONCLUSION

AA had higher pre-donation serum creatinine, GFR, and SBP values compared to Caucasians; however, the degree of change in renal function and blood pressure did not differ between groups following kidney donation. Although long-term studies are needed, our study suggests that AA and Caucasians experience similar short-term consequences after donation. The incomplete data available on donor outcomes in our center and in prior publications also indicates a global need to implement systems for structured follow-up of live kidney donors.

The science of Stewardship: due diligence for kidney donors and kidney function in living kidney donation--evaluation, determinants, and implications for outcomes

Living kidney donor transplantation is now a common treatment for ESRD because it provides excellent outcomes to transplant recipients and is considered a safe procedure for prospective donors. The short- and long-term safety of prospective donors is paramount to the continued success of this procedure. Whereas the initial experiences with living kidney donors mostly included the healthiest, the increase in the need for organs and the changing demographic characteristics of the general population have subtly reshaped the suitability for donation. Kidney function assessment is a critical component of the evaluation of prospective donors; therefore, special emphasis is usually placed on this aspect of the evaluation. At the same time, consideration of kidney function after donation is important because it assists with the determination of renal health in donors. This review summarizes the process of predonation kidney function assessment, determinants of pre- and postdonation renal function, and, importantly, the potential implications of kidney function to the long-term outcomes of kidney donors.

Living kidney donors: current state of affairs

Living kidney donation continues as the cornerstone of transplantation. In order to determine with ever-renewing assurance that living donation is safe for the donor, we need to periodically review the literature, review the United Network for Organ Sharing database for donor characteristics that may put them in danger, and scour databases for donors starting dialysis and/or listed for transplant. Additionally, we must encourage financing studies that follow large diverse cohorts of donors over their entire lifetimes in order to detect key characteristics that influence outcomes. Currently, it can be stated that living donation is, on the whole, safe, with few perioperative deaths, complications, or long-term medical issues. Additionally, the living donor reflects the demographics of the general population including increased rates of obesity with some donors having hypertension and low-grade proteinuria. In the long run, death rates (for the white donor) are no different than for the general population, whereas end-stage renal disease rates are slightly increased over the general population, ranging from 0.1% to 1.1%. The higher risk is especially notable in the black donor. Preeclampsia in female donors may also be marginally greater than in those with 2 kidneys. Thus, the new health age brings a rejuvenated responsibility of the medical community and those in governance to design systems that allow more complete and continued follow-up of the living kidney donor, especially those of color.

Appraisal of GFR-estimating equations following kidney donation

BACKGROUND

It is not clear which serum creatinine-based glomerular filtration rate (GFR)-estimating model performs best in kidney donors.

STUDY DESIGN

Study of diagnostic accuracy.

SETTING & PARTICIPANTS

From a population of 3,698 kidney donors, 255 donors underwent iohexol GFR measurement (mGFR). INDEX TEST (INTERVENTION): mGFR by means of plasma disappearance of iohexol.

REFERENCE TEST OR OUTCOME

GFR was estimated (eGFR) by using the Cockcroft-Gault equation (eGFR(CG)), Mayo Clinic equation (eGFR(MC)), and Modification of Diet in Renal Disease (MDRD) Study equation (eGFR(MDRD)).

RESULTS

Mean mGFR was 71.8 +/- 11.8 mL/min/1.73 m(2), and 85.5% had mGFR greater than 60 mL/min/1.73 m(2). eGFR(CG) underestimated mGFR by 3.96 +/- 13.3 mL/min/1.73 m(2) and was within 30% of mGFR 89.4% of the time. eGFR(MC) overestimated mGFR by 8.44 +/- 11.9 mL/min/1.73 m(2) and was within 30% of mGFR in 83.1% of cases. eGFR(MDRD) underestimated mGFR by only 0.43 +/- 11.7 mL/min/1.73 m(2), and the proportion within 30% of mGFR was greatest in the tested model; 94.1% of the time. However, eGFR(MC) was most accurate in classifying donors according to having eGFR less than 60 mL/min/1.73 m(2).

LIMITATIONS

Lack of ethnic diversity and response bias.

CONCLUSIONS

The MDRD Study equation is least biased, and because it is routinely reported by most laboratories, it is the best readily available model for estimating GFR in kidney donors.

Pregnancy outcomes after kidney donation

The outcome of pregnancy in kidney donors has generally been viewed to be favorable. We determined fetal and maternal outcomes in a large cohort of kidney donors. A total of 2102 women have donated a kidney at our institution; 1589 donors responded to our pregnancy surveys; 1085 reported 3213 pregnancies and 504 reported none. Fetal and maternal outcomes in postdonation pregnancies were comparable to published rates in the general population. Postdonation (vs. predonation) pregnancies were associated with a lower likelihood of full-term deliveries (73.7% vs. 84.6%, p = 0.0004) and a higher likelihood of fetal loss (19.2% vs. 11.3%, p < 0.0001). Postdonation pregnancies were also associated with a higher risk of gestational diabetes (2.7% vs. 0.7%, p = 0.0001), gestational hypertension (5.7% vs. 0.6%, p < 0.0001), proteinuria (4.3% vs. 1.1%, p < 0.0001) and preeclampsia (5.5% vs. 0.8%, p < 0.0001). Women who had both pre- and post-donation pregnancies were also more likely to have these adverse maternal outcomes in their postdonation pregnancies. In this large survey of previous living donors in a single center, fetal and maternal outcomes and pregnancy outcomes after kidney donation were similar to those reported in the general population, but inferior to predonation pregnancy outcomes.

Temporal stability of the urinary proteome after kidney transplant: more sensitive than protein composition?

The temporal urinary proteome was examined in 4 groups of individuals in order to determine the temporal stability of diverse individuals with apparently good kidney health. The groups consisted of (1) healthy volunteers at zero time, 1 and 6 months, (2) kidney donors before and after surgery, (3) recipients immediately after surgery, and (4) successful kidney transplant recipients from 1 month to 4 years after transplant. Proteins were detected by reverse phase extraction of urine followed by MALDI-TOF profile and by iTRAQ analysis. Unusual components of the MALDI-TOF profiles found only in transplant subjects occurred at m/ z = 3370, 3441 and 3385 (human neutrophil defensins), 4303, 10350, and 11732 (beta-2 microglobulin, B2M). The peaks at m/ z = 4303 and 11732 were also quite intense among kidney donors following surgery. The peaks at m/ z = 4303 and 10350 in transplant recipients were associated with higher serum creatinine. Several additional proteins detected by iTRAQ were up-regulated in a manner that correlated closely with B2M. Overall, despite large differences between protein composition in different transplant recipients, there was remarkable stability for each individual as detected by either MALDI-TOF or iTRAQ analyses. These results suggested that, within limits, stability of profile components may be as important as protein content for definition of kidney health. Longitudinal study of urinary proteins from kidney recipients may demonstrate instability as a sensitive biomarker of adverse kidney health.

Long-term consequences of kidney donation

BACKGROUND

The long-term renal consequences of kidney donation by a living donor are attracting increased appropriate interest. The overall evidence suggests that living kidney donors have survival similar to that of nondonors and that their risk of end-stage renal disease (ESRD) is not increased. Previous studies have included relatively small numbers of donors and a brief follow-up period.

METHODS

We ascertained the vital status and lifetime risk of ESRD in 3698 kidney donors who donated kidneys during the period from 1963 through 2007; from 2003 through 2007, we also measured the glomerular filtration rate (GFR) and urinary albumin excretion and assessed the prevalence of hypertension, general health status, and quality of life in 255 donors.

RESULTS

The survival of kidney donors was similar to that of controls who were matched for age, sex, and race or ethnic group. ESRD developed in 11 donors, a rate of 180 cases per million persons per year, as compared with a rate of 268 per million per year in the general population. At a mean (+/-SD) of 12.2+/-9.2 years after donation, 85.5% of the subgroup of 255 donors had a GFR of 60 ml per minute per 1.73 m(2) of body-surface area or higher, 32.1% had hypertension, and 12.7% had albuminuria. Older age and higher body-mass index, but not a longer time since donation, were associated with both a GFR that was lower than 60 ml per minute per 1.73 m(2) and hypertension. A longer time since donation, however, was independently associated with albuminuria. Most donors had quality-of-life scores that were better than population norms, and the prevalence of coexisting conditions was similar to that among controls from the National Health and Nutrition Examination Survey (NHANES) who were matched for age, sex, race or ethnic group, and body-mass index.

CONCLUSIONS

Survival and the risk of ESRD in carefully screened kidney donors appear to be similar to those in the general population. Most donors who were studied had a preserved GFR, normal albumin excretion, and an excellent quality of life.

Cardiovascular disease and hypertension risk in living kidney donors: an analysis of health administrative data in Ontario, Canada

BACKGROUND

Knowledge of any harm associated with living kidney donation guides informed consent and living donor follow-up. Risk estimates in the literature are variable, and most studies did not use a healthy control group to assess outcomes attributable to donation.

METHODS

We observed a retrospective cohort using health administrative data for donations which occurred in Ontario, Canada between the years 1993 and 2005. There were a total of 1278 living donors and 6359 healthy adults who acted as a control group. Individuals were followed for a mean of 6.2 years (range, 1-13 years) after donation. The primary outcome was a composite of time to death or first cardiovascular event (myocardial infarction, stroke, angioplasty, and bypass surgery). The secondary outcome was time to a diagnosis of hypertension.

RESULTS

There was no significant difference in death or cardiovascular events between donors and controls (1.3% vs. 1.7%; hazard ratio 0.7, 95% confidence interval 0.4-1.2). Donors were more frequently diagnosed with hypertension than controls (16.3% vs. 11.9%, hazard ratio 1.4, 95% confidence interval 1.2-1.7) but were also seen more often by their primary care physicians (median [interquartile range] 3.6 [1.9-6.1] vs. 2.6 [1.4-4.3] visits per person year, P<0.001).

CONCLUSIONS

Based on administrative data, the risk of cardiovascular disease was unchanged in the first decade after kidney donation. The observed increase in diagnosed hypertension may be due to nephrectomy or more blood pressure measurements received by donors in follow-up and requires prospective study.

Reliability of GFR formulas based on serum creatinine, with special reference to the MDRD Study equation

Estimation of glomerular filtration rate (GFR) is central to the diagnosis, evaluation and management of chronic kidney disease (CKD). This review summarizes data on the performance of equations using serum creatinine to estimate GFR, particularly the Modification of Diet in Renal Disease (MDRD) Study equation. The size of studies evaluating GFR estimation equations and their level of sophistication in estimating bias, precision, validity and sensitivity to the source population have improved over the past decade. We update our review from 2006, which included 7 studies with over 500 individuals and 12 studies with 50-499 individuals with measured GFR evaluating the MDRD Study and Cockcroft-Gault equations. More recent studies include an individual level pooling analysis of 5504 participants in 10 studies which showed that creatinine calibration to reference methods improved the performance of the MDRD Study equation but increased bias for the Cockcroft-Gault equation. The MDRD Study equation had a bias of 3.0 %, interquartile range of 29.0 % and percentage of estimates within 30 % of the measured GFR value (P(30)) of 82 % for estimates below 60 mL/(min x 1.73 m(2)). Above this value, the bias was greater (8.7 %) and estimates are less useful since 30 % error is a large absolute error in GFR. Results vary across studies but are generally similar with disappointing performance in the high GFR range, which is of particular interest in early diabetic nephropathy. New equations using serum creatinine can reduce the bias present in the high GFR range but are unlikely to dramatically improve precision, suggesting a need for additional markers. Finally, algorithms are needed to tailor clinical practice based on data from GFR estimates and other participant characteristics, including the source population and level of proteinuria.

Age, gender, race, and associations with kidney failure following living kidney donation

INTRODUCTION

Our previous reports suggested that African Americans (AA) are more likely to develop end-stage renal disease (ESRD) following kidney donation when compared with white counterparts. We sought information on age, gender, and race of kidney donors to determine which groups were over-represented on the kidney transplant waiting list.

METHODS

We queried the United Network for Organ Sharing United Network for Organ Sharing (UNOS) Organ Procurement Transplantation Network (OPTN) database for former donors who were subsequently placed on the kidney transplant waiting list. Information was retrieved on race, gender, age at donation, years between donation and listing, and diagnosis leading to ESRD. Comparisons were made to all kidney donors between 1988 and 2006 using chi-square testing.

RESULTS

In this study, 126 individual kidney donors entered the kidney transplant waiting list. Fifty of the 126 (40%) were AA (P < .0001 compared with all donors, 13% AA). For both AA and whites, male donors and those who donated before age 35 made up a larger proportion of donors on the waiting list than would be expected by their proportion of overall donors.

CONCLUSION

AA, males, and young donors may be at higher risk for kidney failure in the years following kidney donation. Mechanisms of increased risk are unclear but deserve further scrutiny. Our data are limited by the small number of patients developing kidney failure, the lack of complete follow-up on all living kidney donors, and the possibility that older donors with kidney failure were not listed because of death or other medical conditions. We believe that discussion of long-term risks may be different for various subgroups, especially for young AA kidney donors.

Functional immunoassay technology (FIT), a new approach for measuring physiological functions: application of FIT to measure glomerular filtration rate (GFR)

This is the first description of functional immunoassay technology (FIT), which as a diagnostic tool has broad application across the whole spectrum of physiological measurements. In this paper, FIT is used to measure the renal clearance of an ultra low-dose administration of a clinically available contrast reagent for the purpose of obtaining an accurate glomerular filtration rate (GFR) measurement. Biomarker-based GFR estimates offer convenience, but are not accurate and are often misleading. FIT overcomes previous analytic barriers associated with obtaining an accurate GFR measurement. We present the performance characteristics of this diagnostic test and demonstrate the method by directly comparing GFR values obtained by FIT to those obtained by an FDA approved nuclear test in 20 adults. Two subjects were healthy volunteers and the remaining 18 subjects had diagnosed chronic kidney disease, with 12 being kidney transplant recipients. Measured GFR values were calculated by the classic UV/P method and by the blood clearance method. GFR obtained by FIT and the nuclear test correlated closely over a wide range of GFR values (10.9-102.1 ml.min(-1).1.73 m(-2)). The study demonstrates that FIT-GFR provides an accurate and reproducible measurement. This nonradioactive, immunoassay-based approach offers many advantages, chiefly that most laboratories already have the equipment and trained personnel necessary to run an ELISA, and therefore this important diagnostic measurement can more readily be obtained. The FIT-GFR test can be used throughout the pharmaceutical development pipeline: preclinical and clinical trials.

Renal function impacts outcomes after intestinal transplantation

BACKGROUND

Although renal dysfunction (RD) has been commonly associated with poor outcome after other solid organ transplants, it has not been studied in detail after intestinal transplantation (ITx). Here we provide a detailed analysis of renal function after ITx, and identify predictors of post-ITx RD.

METHODS

A retrospective analysis of patients undergoing ITx from 1991 to 2006 was performed. For each patient, the estimated glomerular filtration rate (eGFR) was compared with the normal GFR for age and gender to obtain the percent of normal eGFR. Chi-square analysis and log-rank tests were used to identify categorical variables associated with RD (eGFR <75% of normal) and to determine if RD was predictive of post-ITx survival.

RESULTS

Sixty-eight transplantations were performed in 62 patients. Overall patient survival at 1 and 5 years was 78% and 56%, respectively. Renal dysfunction was observed in 16% of patients post-ITx. The most frequent predictors of post-ITx RD were preoperative eGFR less than 75% of normal, pre-ITx location in the intensive care unit, and high-dose tacrolimus immunotherapy. An eGFR less than 75% of normal at days 7, 28, and 365 was predictive of poor patient survival (P<0.05).

CONCLUSIONS

This study provides the first detailed analysis of renal function after ITx. We identified specific risk factors for the development of RD in the first year post-ITx and found a significant association of RD with decreased long-term survival. Given the strong correlation of RD with poor outcome, preserving renal function may be key to improving long-term outcomes in ITx recipients.

Randomized trial of single-dose versus divided-dose rabbit anti-thymocyte globulin induction in renal transplantation: an interim report

BACKGROUND

The optimal dosing protocol for rabbit anti-thymocyte globulin (rATG) induction in renal transplantation has not been determined, but evidence exists that rATG infusion before renal allograft reperfusion improves early graft function. Infusing a large rATG dose over a short interval has not previously been evaluated for its effect on renal function and allograft nephropathy in a prospective, randomized comparison against conventional rATG induction.

METHODS

Between April 20, 2004 and December 26, 2007 we enrolled renal transplant patients into a prospective, randomized, nonblinded trial of two rATG dosing protocols (single dose, 6 mg/kg vs. divided doses, 1.5 mg/kg every other day x 4; target enrollment=160) followed after 6 months by calcineurin-inhibitor withdrawal. Primary endpoints are renal function by calculated glomerular filtration rate (GFR) and chronic allograft nephropathy at protocol biopsy. We now present the early GFR data of all 160 patients and safety and efficacy data of the first 142 patients with 6 months follow up and before calcineurin inhibitor withdrawal (average follow up=23.3+/-11.6 months).

RESULTS

There were no differences between groups in rATG-related adverse events, patient and graft survival, acute rejection, or chronic allograft nephropathy rate at 6 months. Calculated DeltaGFR (POD 1-4) was significantly better in the single-dose group (P=0.02), with a trend toward improved renal function from months 2 to 6 in recipients of deceased donor kidneys (P=0.08).

CONCLUSIONS

This study demonstrates that administering 6 mg/kg of rATG over 24 hr is safe and is associated with improved early renal function compared with administering rATG in alternate-day doses.

Health status and renal function evaluation of kidney vendors: a report from Pakistan

Unrelated kidney transplants have lead to commerce and kidney vending in Pakistan. This study on 104 vendors reports demographics, history, physical and systemic examination, ultrasound findings, renal and liver function and GFR by Cockcroft-Gault. Results were compared with 184 age, sex and nephrectomy duration matched living-related donors controls. Comparison of vendors versus controls showed mean age of 30.55 +/- 8.1 versus 30.65 +/- 7.85 (p = 0.91) years, M:F of 4.5:1 versus 4.2:1 and nephrectomy period of 33.89 +/- 30 versus 32.01 +/- 29.71 (p = 0.60) months respectively. Of the vendors 67% were bonded laborers earning <50 $/month as compared to controls where 68% were skilled laborers and self-employed earning >100 $/month. History of vendors revealed jaundice in 8%, stone disease in 2% and urinary tract symptoms in 4.8%. Postnephrectomy findings between vendors versus donors showed BMI of 21.02 +/- 2.8 versus 23.02 +/- 4.2 (p = 0.0001), hypertension in 17% versus 9.2% (p = 0.04), serum creatinine (mg/dL) of 1.17+/-0.21 versus 1.02 +/- 0.27 (p = 0.0001), GFR (mL/min) of 70.94 +/- 14.2 versus 95.4 +/- 20.44 (p = 0.0001), urine protein/creatinine of 0.150 +/- 0.109 versus 0.10 +/- 0.10 (p = 0.0001), hepatitis C positivity in 27% versus 1.0% (p = 0.0001) and hepatitis B positive 5.7% versus 0.5% (p = 0.04), respectively. In conclusion, vendors had compromised renal function suggesting inferior selection and high risk for developing chronic kidney disease in long term.