The Clinical Utility of Genetic Testing in the Diagnosis and Management of Adults with Chronic Kidney Disease.

SIGNIFICANCE STATEMENT: Accurate diagnosis of a patient's underlying cause of CKD can influence management and ultimately overall health. The single-arm, interventional, prospective Renasight Clinical Application, Review, and Evaluation study assessed the utility of genetic testing with a 385 gene kidney disease panel on the diagnosis and management of 1623 patients with CKD. Among 20.8% of patients who had positive genetic findings, half resulted in a new or reclassified diagnosis. In addition, a change in management because of genetic testing was reported for 90.7% of patients with positive findings, including treatment changes in 32.9%. These findings demonstrate that genetic testing has a significant effect on both CKD diagnosis and management. BACKGROUND: Genetic testing in CKD has recently been shown to have diagnostic utility with many predicted implications for clinical management, but its effect on management has not been prospectively evaluated. METHODS: Renasight Clinical Application, Review, and Evaluation RenaCARE (ClinicalTrials.gov NCT05846113 ) is a single-arm, interventional, prospective, multicenter study that evaluated the utility of genetic testing with a broad, 385 gene panel (the Renasight TM test) on the diagnosis and management of adult patients with CKD recruited from 31 US-based community and academic medical centers. Patient medical history and clinical CKD diagnosis were collected at enrollment. Physician responses to questionnaires regarding patient disease categorization and management were collected before genetic testing and 1 month after the return of test results. Changes in CKD diagnosis and management after genetic testing were assessed. RESULTS: Of 1623 patients with CKD in 13 predefined clinical disease categories (ages, 18-96; median, 55 years), 20.8% ( n =338) had positive genetic findings spanning 54 genes. Positive genetic findings provided a new diagnosis or reclassified a prior diagnosis in 48.8% of those patients. Physicians reported that genetic results altered the management of 90.7% of patients with a positive genetic finding, including changes in treatment plan, which were reported in 32.9% of these patients. CONCLUSIONS: Genetic testing with a CKD-focused 385 gene panel substantially refined clinical diagnoses and had widespread implications for clinical management, including appropriate treatment strategies. These data support the utility of broader integration of panels of genetic tests into the clinical care paradigm for patients with CKD. CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: ClinicalTrials.gov, NCT05846113 .

Analysis of Native Kidney Function Recovery With Renal Scintigraphy Following Simultaneous Liver-Kidney Transplantation.

BACKGROUND: Patients undergoing simultaneous liver-kidney transplantation (SLK) have impaired native kidney function. The relative contribution of allograft versus native function after SLK is unknown. We sought to characterize the return of native kidney function following SLK. METHODS: Following SLK, patients underwent technetium-99 m-mercaptoacetyltriglycine renal scintigraphy following serum creatinine nadir. Kidney contributions to estimated glomerular filtration rate (eGFR) were determined. Patients with native kidney function at serum creatinine nadir contributing eGFR ≥30 versus <30 mL/min/1.73 m 2 were compared, and multiple linear regression analysis for native eGFR improvement was performed. RESULTS: Thirty-one patients were included in this analysis. Average native kidney contribution to overall kidney function following SLK was 51.1% corresponding to native kidney eGFR of 44.5 mL/min/1.73 m 2 and native kidney function eGFR improvement of 30.3 mL/min/1.73 m 2 ( P < 0.001). Twenty-six of 31 patients had native kidney contribution of eGFR ≥30 mL/min/1.73 m 2 . Hepatorenal syndrome as the sole primary etiology of kidney dysfunction was 100% specific for native kidney eGFR >30 mL/min/1.73 m 2 and predicted native eGFR improvement ( P = 0.03). CONCLUSIONS: Substantial improvement in native kidney function follows SLK, and hepatorenal syndrome as the sole primary etiology of kidney dysfunction is predictive of improvement. Whether such patients are suitable for liver transplant followed by surveillance with option for subsequent kidney transplants requires investigation.

Self-reported marijuana use and its effects on overall approval in potential living kidney donors.

BACKGROUND: Past and present substance use is an important part of the psychosocial evaluation of potential living kidney donors (LKDs). Increasing state legalizations and social acceptance of marijuana (MJ) use can create challenges for transplant centers. METHODS: We investigated the frequency of reporting MJ use, and its effect on the LKD evaluation. A retrospective chart review was performed on all living donor candidates from December 2016 to December 2019 for reports of MJ use, both on an electronic intake form and during clinical evaluation with a licensed social worker (SW). Active MJ use was defined as current use or use within 1 year of evaluation. Baseline characteristics between MJ users and non-users were compared at each step of donor evaluation. We explored variables associated with MJ use including additional consults and testing during the donor evaluation. Overall approval and donation rates for living donors with active MJ use were compared to non-users. Additionally, 1-year donor follow-up was compared between the two groups. Results of 1818 living donor candidates who completed the intake form, 132 admitted to active MJ use. Compared to non-users, MJ users were more likely to be younger, male, single, renting a home, and with a lower level of education. Thirty three out of 338 candidates who completed a social work evaluation reported MJ use. Compared to non-users, MJ users were more frequently classified as moderate or high risk on SW evaluation, and often required a toxicology screen or psychiatry visit for clearance to donate. Altogether 24.2% of MJ users versus 9.5% of non-users discontinued their evaluation (p < .01). Altogether 42.4% of MJ users versus 56.1% of non-users donated their kidney (p = .13). For those who donated, MJ users were less likely than non-users to follow up at 1 year (57.1% vs. 83.0, p-value .02). CONCLUSION: MJ users were often asked to complete additional steps in their evaluation before an approval decision was made, which may have led to the higher rate of donor drop out observed in this group. Further research is needed to assess the effects of MJ use on living donor candidacy, as well as any effects of MJ use on long-term donor outcomes.

Telemedicine as an ethics teaching tool for medical students within the nephrology curriculum.

A novel patient-centered approach was used to deliver ethics curriculum to medical students. Two medical school clinicians designed a telemedicine session linking their facilities (across 2 continents). The session, Exploring the Patient Experience Through Telemedicine: Dialysis and End-Stage Renal Disease, allowed second-year medical students to explore various parameters of quality of life experienced by dialysis patients. A panel of 4 medical students interviewed a dialysis patient via Skype video connection between the medical school and the hospital's dialysis unit. Interview questions were adapted from the Kidney Disease Quality of Life instrument. During the live video-streamed interview, the remaining 23 second-year medical students observed the session. Afterward, the 23 were offered a voluntary anonymous online feedback survey (15 responded). The 4 panelists submitted narrative responses to 2 open-ended questions about their experience. All 15 responding students "Strongly agreed" or "Agreed" that the session was an aid to their professionalism skills and behaviors; 14 of 15 "Strongly agreed" or "Agreed" that telemedicine technology contributed to their understanding of the topic; 12 of 15 "Strongly agreed" that the session improved their understanding of the psychosocial burdens of dialysis, quality of life, and human suffering, and increased their empathy toward patients; and 12 of 15 "Strongly agreed" or "Agreed" that the session encouraged reflective thinking and was an aid to improving their communication skills. Telemedicine can be an effective and feasible method to deliver an ethics curriculum with a patient-centered approach. Additionally, the cross-cultural experience exposes students to additional contextual features of medicine.

Hospitalizations following living donor nephrectomy in the United States.

BACKGROUND AND OBJECTIVES: Living donors represented 43% of United States kidney donors in 2012. Although research suggests minimal long-term consequences of donation, few comprehensive longitudinal studies for this population have been performed. The primary aims of this study were to examine the incidence, risk factors, and causes of rehospitalization following donation. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: State Inpatient Databases (SID) compiled by the Agency for Healthcare Research and Quality were used to identify living donors in four different states between 2005 and 2010 (n=4524). Multivariable survival models were used to examine risks for rehospitalization, and patient characteristics were compared with data from the Scientific Registry of Transplant Recipients (SRTR). Outcomes among patients undergoing appendectomy (n=200,274), cholecystectomy (n=255,231), and nephrectomy for nonmetastatic carcinoma (n=1314) were contrasted. RESULTS: The study population was similar to United States donors (for SRTR and SID, respectively: mean age, 41 and 41 years; African Americans, 12% and 10%; women, 60% and 61%). The 3-year incidence of rehospitalization following donation was 11% for all causes and 9% excluding pregnancy-related hospitalizations. After censoring of models for pregnancy-related rehospitalizations, older age (adjusted hazard ratio [AHR], 1.02 per year; 95% confidence interval [95% CI], 1.01 to 1.03), African American race (AHR, 2.16; 95% CI, 1.54 to 3.03), depression (AHR, 1.88; 95% CI, 1.12 to 3.14), hypothyroidism (AHR, 1.63; 95% CI, 1.06 to 2.49), and longer initial length of stay were related to higher rehospitalization rates among donors. Compared with living donors, adjusted risks for rehospitalizations were greater among patients undergoing appendectomy (AHR, 1.58; 95% CI, 1.42 to 1.75), cholecystectomy (AHR, 2.25; 95% CI, 2.03 to 2.50), and nephrectomy for nonmetastatic carcinoma (AHR, 2.95; 95% CI, 2.58 to 3.37). Risks for rehospitalizations were higher among African Americans than whites in each of the surgical groups. CONCLUSIONS: The SID is a valuable source for evaluating characteristics and outcomes of living kidney donors that are not available in traditional transplant databases. Rehospitalizations following donor nephrectomy are less than seen with other comparable surgical procedures but are relatively higher among donors who are older, are African American, and have select comorbid conditions. The increased risks for rehospitalizations among African Americans are not unique to living donation.

Comorbidity burden and perioperative complications for living kidney donors in the United States.

BACKGROUND AND OBJECTIVES: Since 1998, 35% of kidney transplants in the United States have been derived from living donors. Research suggests minimal long-term health consequences after donation, but comprehensive studies are limited. The primary objective was to evaluate trends in comorbidity burden and complications among living donors. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: The National Inpatient Sample (NIS) was used to identify donors from 1998 to 2010 (n=69,117). Comorbid conditions, complications, and length of stay during hospitalization were evaluated. Outcomes among cohorts undergoing appendectomies, cholecystectomies and nephrectomy for nonmetastatic carcinoma were compared, and sample characteristics were validated with the Scientific Registry of Transplant Recipients (SRTR). Survey regression models were used to identify risk factors for outcomes. RESULTS: The NIS captured 89% (69,117 of 77,702) of living donors in the United States. Donor characteristics were relatively concordant with those noted in SRTR (mean age, 40.1 versus 40.3 years [P=0.18]; female donors, 59.0% versus 59.1% [P=0.13]; white donors, 68.4% versus 69.8% [P<0.001] for NIS versus SRTR). Incidence of perioperative complications was 7.9% and decreased from 1998 to 2010 (from 10.1% to 7.6%). Men (adjusted odds ratio [AOR], 1.37; 95% confidence interval [CI], 1.20 to 1.56) and donors with hypertension (AOR, 3.35; 95% CI, 2.24 to 5.01) were more likely to have perioperative complications. Median length of stay declined over time (from 3.7 days to 2.5 days), with longer length of stay associated with obesity, depression, hypertension, and pulmonary disorders. Presence of depression (AOR, 1.08; 95% CI, 1.04 to 1.12), hypothyroidism (AOR, 1.07; 95% CI, 1.04 to 1.11), hypertension (AOR, 1.38; 95% CI, 1.27 to 1.49), and obesity (AOR, 1.07; 95% CI, 1.03 to 1.11) increased over time. Complication rates and length of stay were similar for patients undergoing appendectomies and cholecystectomies but were less than those with nephrectomies for carcinoma. CONCLUSIONS: The NIS is a representative sample of living donors. Complications and length of stay after donation have declined over time, while presence of documented comorbid conditions has increased. Patients undergoing appendectomy and cholecystectomy have similar outcomes during hospitalization. Monitoring the health of living donors remains critically important.

Demographic and clinical characteristics associated with glomerular filtration rates in living kidney donors.

Due to the shortage of organs, living donor acceptance criteria are becoming less stringent. An accurate determination of the glomerular filtration rate (GFR) is critical in the evaluation of living kidney donors and a value exceeding 80 ml/min per 1.73 m(2) is usually considered suitable. To improve strategies for kidney donor screening, an understanding of factors that affect GFR is needed. Here we studied the relationships between donor GFR measured by (125)I-iothalamate clearances (mGFR) and age, gender, race, and decade of care in living kidney donors evaluated at the Cleveland Clinic from 1972 to 2005. We report the normal reference ranges for 1057 prospective donors (56% female, 11% African American). Females had slightly higher mGFR than males after adjustment for body surface area, but there were no differences due to race. The lower limit of normal for donors (5th percentile) was less than 80 ml/min per 1.73 m(2) for females over age 45 and for males over age 40. We found a significant doubling in the rate of GFR decline in donors over age 45 as compared to younger donors. The age of the donors and body mass index increased over time, but their mGFR, adjusted for body surface area, significantly declined by 1.49+/-0.61 ml/min per 1.73 m(2) per decade of testing. Our study shows that age and gender are important factors determining normal GFR in living kidney donors.

Evaluation of creatinine-based estimates of glomerular filtration rate in a large cohort of living kidney donors.

BACKGROUND: Accurate determination of kidney function is critical in the evaluation of living kidney donors and higher donor glomerular filtration rate (GFR) is associated with better allograft outcomes. However, among transplant centers donor kidney function evaluation varies widely. METHODS: The performance of creatinine clearance (CrCl), Modification of Diet in Renal Disease (MDRD), the re-expressed MDRD equations with standardized creatinine, and the Cockcroft-Gault (CG) formula as compared with (125)I-iothalamate GFR (iGFR) was analyzed in 423 donors. All methods of GFR measurement were then evaluated for their association with graft function at 1 year. RESULTS: The MDRD and re-expressed MDRD equations underestimated iGFR whereas CG showed minimal bias (median difference=-11.0, -16.3, and -0.5 mL/min/1.73 m(2), respectively). CrCl overestimated iGFR (10 mL/min/1.73 m(2)). The MDRD, re-expressed MDRD, and CG formulas were more accurate (88%, 86%, and 88% of estimates within 30% of iGFR, respectively) than CrCl (80% within 30% of iGFR). Interestingly, low bias and high accuracy were achieved by averaging the MDRD estimation with the CrCl result; both methods available to the clinician in most transplant centers. We also showed that predonation GFR as measured by isotopic renal clearance or any of the creatinine-based estimation formulas may be associated with allograft function at 1 year, whereas the widely used CrCl was not. CONCLUSIONS: Variable performance was seen among different GFR estimations, with CrCl being the poorest. Recent recommendations to use the MDRD equation with standardized serum creatinine did not improve its performance. However, recognizing the limited availability of GFR laboratories, these methods are still clinically useful if used with caution and understanding their limitations.

Nephrogenic systemic fibrosis and its association with gadolinium exposure during MRI.

Nephrogenic systemic fibrosis (NSF) is a newly recognized systemic disorder characterized by widespread tissue fibrosis in patients with impaired renal function. Recent reports suggest that NSF is associated with exposure to gadolinium-based contrast agents used in magnetic resonance imaging. NSF can be very debilitating and can lead to serious complications and death. Health care providers should exercise caution when considering the use of gadolinium-based imaging studies in patients with renal dysfunction.

Influence of vascular access type on outcome measures in patients on maintenance hemodialysis.

BACKGROUND: Previous studies postulate that end-stage renal disease (ESRD) patients dialyzed with central venous catheters (CVC) have poorer outcomes compared to patients using arteriovenous fistulae (AVF) or arteriovenous grafts (AVG). Clinical practice guidelines should obviate these differences if access was not important. This study compared clinical measures of adequacy, anemia, and nutrition/inflammation in prevalent hemodialysis patients in 2003 by access type. METHODS: Data from The Renal Network Data System were analyzed by univariate analysis of variance to compare Kt/V, URR, albumin, hemoglobin (Hb) and recombinant human erythropoietin (EPO) dose by access type, while adjusting for pertinent factors. RESULTS: 12,501 patients were included. The access type distribution was AVF 36%, AVG 41%, and CVC 23%. CVC patients had lower mean URR, Kt/V, albumin concentration (p < 0.001) than other accesses. Serum Hbs were similar (p = 0.416), however EPO dose (U/kg/week) was higher in those dialyzed with CVC compared to AVF/AVG (p < 0.001). CONCLUSIONS: Despite practice guidelines, patients dialyzed via CVC have poorer outcome measures compared to other accesses. This suggests that AVF should be used and/or appropriate adjustments need to be made for those dialyzed with CVC to achieve equal outcomes. Further studies defining barriers need to be conducted.

Renal failure secondary to acute tubular necrosis: epidemiology, diagnosis, and management.

Acute tubular necrosis (ATN) is a form of acute renal failure (ARF) that is common in hospitalized patients. In critical care units, it accounts for about 76% of cases of ARF. Despite the introduction of hemodialysis > 30 years ago, the mortality rates from ATN in hospitalized and ICU patients are about 37.1% and 78.6%, respectively. The purpose of this review is to discuss briefly the cause, diagnosis, and epidemiology of ARF, and to review in depth the clinical trials performed to date that have examined the influence of growth factors, hormones, antioxidants, diuretics, and dialysis. In particular, the role of the dialysis modality, dialyzer characteristics, and dosing strategies are discussed.

Tolerability of mycophenolate mofetil in patients with systemic lupus erythematosus.

OBJECTIVE: To quantify the adverse events (AE) associated with mycophenolate mofetil (MMF) in patients with systemic lupus erythematosus (SLE), to examine the relationship between AE and dosage of MMF, and to assess the overall tolerability of MMF in SLE patients. METHODS: A consecutive cohort of adults with SLE who received MMF between October 1996 and June 1999 was identified. Charts were reviewed for baseline data, AE, MMF dosing characteristics, and clinical response at baseline, 3 months, and at final followup or drug discontinuation. RESULTS: The 54 SLE patients were followed for a mean of 12.4 +/- 7.0 person-months. Baseline characteristics: 92.6% female, 72.2% white, mean age 38.3 years, and a mean of 9.6 years since diagnosis. Twenty-one of 54 patients (38.9%) had a total of 28 gastrointestinal AE. Twenty-four of 54 (44.4%) patients had a total of 37 infections, only one of which required hospitalization. Leukopenia occurred 3 times but never required dose adjustment. AE occurred at a similar rate at all MMF doses. Kaplan-Meier estimates show most drug discontinuation occurred in the first 2.5 months and 73% of patients were still on the drug at 12 months. Sixteen of 54 patients discontinued MMF because of AE (n = 9), lack of efficacy (n = 3), pregnancy (n = 2), and administrative reasons (n = 2). Clinical improvement in patients was noted with significant decreases in disease activity measured by the SLEDAI and prednisone dose at 3 months and at final followup. CONCLUSION: The majority of patients tolerated MMF. A range of doses was tolerated and associated with clinical improvement, suggesting that a flexible dosing schedule should be considered when using MMF in patients with SLE.