Amber Reeves-Daniel

Wake Forest School of Medicine, Winston-Salem, NC, United States

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Publications (25)75.9 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: BACKGROUND: Relationships between race/ethnicity, recipient medical insurance, and living donor kidney transplantation (LKT) are incompletely described. METHODS: Associations between medical insurance and LKT were assessed in 447 recipients at a southeastern US transplant center. Primary and secondary payers were included in the analyses. RESULTS: A total of 387 deceased donor transplantations and 60 LKTs were performed in 246 (55%) European American (EA), 175 (39.2%) African American (AA), 15 (3.4%) Asian, and 11 (2.5%) Hispanic recipients. Among recipients, 182 (40.8%) were privately insured, 125 (28%) had Medicaid, and the remainder had Medicare, Medicare supplements, or Medicare replacement policies. A higher proportion of patients with private insurance, relative to those without private insurance, received LKT (22% vs. 7.6%, p < 0.0001). Among ethnic groups, LKT with, vs. without, private insurance was 27.5% vs. 12.4% in EAs (p = 0.0028) and 14.3% vs. 0.9% in AAs (p = 0.0005). Medicaid recipients (n = 125) were less likely to receive LKT than those without Medicaid (4.8% vs. 16.8%, p = 0.0003). Among the 69 AA recipients with Medicaid, none received LKT (0 Medicaid vs. 9.5% without Medicaid, p = 0.0065). CONCLUSIONS: Recipient insurance status is associated with LKT, positively with private insurance and negatively with Medicaid. AAs were impacted to a greater extent, potentially contributing to lower rates of LKT.
    Clinical Transplantation 06/2013; · 1.63 Impact Factor
  • Amudha Palanisamy, Amber M Reeves-Daniel, Barry I Freedman
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    ABSTRACT: Dramatic improvements have been seen in short-term kidney allograft survival over recent decades with introduction of more potent immunosuppressant medications and regimens. Unfortunately, improvements in long-term graft survival have lagged behind. The genomics revolution is providing new insights regarding the potential impact of kidney donor genotypes on long-term graft survival. Variation in the donor apolipoprotein L1 (APOL1), caveolin 1 (CAV1), and multi-drug resistance 1 encoding P-glycoprotein genes (ABCB1) are all associated with graft survival after kidney transplantation. Although the precise mechanisms whereby these donor gene variants confer risk for graft loss have yet to be determined, these findings provide novel opportunities for modifying interactive environmental factors and optimizing kidney allocation with the ultimate goal of improving long-term graft survival rates.
    Pediatric Nephrology 06/2013; · 2.94 Impact Factor
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    ABSTRACT: Familial aggregation of non-diabetic end-stage renal disease (ESRD) is found in African Americans and variants in the apolipoprotein L1 gene (APOL1) contribute to this risk. To detect genetic associations with milder forms of nephropathy in the high-risk families, analyses were performed using generalized estimating equations to assess relationships between kidney disease phenotypes and APOL1 variants in 786 relatives of 470 families. Adjusting for familial correlations, 23.1, 46.7, and 30.2% of genotyped relatives possessed two, one, or no APOL1 risk variants, respectively. Relatives with two compared with one or no risk variants had statistically indistinguishable median systolic blood pressure, urine albumin to creatinine ratio, estimated glomerular filtration rate (GFR; MDRD equation), and serum cystatin C levels. After adjusting for age, gender, age at ESRD in families, and African ancestry, significant associations were detected between APOL1 with overt proteinuria and estimated GFR (CKD-EPI equation), with a trend toward significance for quantitative albuminuria. Thus, relatives of African Americans with non-diabetic ESRD are enriched for APOL1 risk variants. After adjustment, two APOL1 risk variants weakly predict mild forms of kidney disease. Second hits appear necessary for the initiation of APOL1-associated nephropathy.Kidney International advance online publication, 13 June 2012; doi:10.1038/ki.2012.217.
    Kidney International 06/2012; · 8.52 Impact Factor
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    A M Reeves-Daniel, B I Freedman
    American Journal of Transplantation 02/2012; 12(2):502; author reply 503. · 6.19 Impact Factor
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    A M Reeves-Daniel, J Divers, C D Langefeld, B I Freedman
    American Journal of Transplantation 08/2011; · 6.19 Impact Factor
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    ABSTRACT: Coding variants in the apolipoprotein L1 gene (APOL1) are strongly associated with nephropathy in African Americans (AAs). The effect of transplanting kidneys from AA donors with two APOL1 nephropathy risk variants is unknown. APOL1 risk variants were genotyped in 106 AA deceased organ donors and graft survival assessed in 136 resultant kidney transplants. Cox-proportional hazard models tested for association between time to graft failure and donor APOL1 genotypes. The mean follow-up was 26.4 ± 21.8 months. Twenty-two of 136 transplanted kidneys (16%) were from donors with two APOL1 nephropathy risk variants. Twenty-five grafts failed; eight (32%) had two APOL1 risk variants. A multivariate model accounting for donor APOL1 genotype, overall African ancestry, expanded criteria donation, recipient age and gender, HLA mismatch, CIT and PRA revealed that graft survival was significantly shorter in donor kidneys with two APOL1 risk variants (hazard ratio [HR] 3.84; p = 0.008) and higher HLA mismatch (HR 1.52; p = 0.03), but not for overall African ancestry excluding APOL1. Kidneys from AA deceased donors harboring two APOL1 risk variants failed more rapidly after renal transplantation than those with zero or one risk variants. If replicated, APOL1 genotyping could improve the donor selection process and maximize long-term renal allograft survival.
    American Journal of Transplantation 05/2011; 11(5):1025-30. · 6.19 Impact Factor
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    ABSTRACT: Hypertension may be a either a cause or an effect of kidney disease. Although hypertension is an important component of the expanded criteria donor definition, risks of transplanting deceased donor kidneys from hypertensive standard criteria donors (SCD) are less well understood. Retrospective single-center study in all adult patients who received a deceased donor kidney transplant from a SCD to evaluate the role of donor hypertension as a pre-transplant risk factor for death-censored graft loss (DCGL) and renal function. From October 2001 through May 2008, 297 kidney transplants were performed from donation after brain death SCDs. A total of 47 (15.8%) grafts were lost, including 19 (6.4%) deaths with functioning grafts. Univariate analysis of death-censored cases (n = 278) identified history of donor hypertension, cold ischemia time (CIT) >30 h, and African American (AA) recipients as significant pre-transplant risk factors predictive for DCGL at five yr follow-up (mean 38 months, all p < 0.02). Cox regression analysis showed donor hypertension (relative risk 2.2, p = 0.04) to be a significant risk factor for DCGL, whereas CIT >30 h and AA recipient ethnicity showed only trends toward DCGL. Renal function as determined by serum creatinine levels was significantly higher in recipients of hypertensive compared with non-hypertensive SCD kidneys at all time points out to 48 months follow-up and the disparity in renal function increased over time. Transplanting SCD kidneys from hypertensive donors is associated with worse graft function and an increased risk of graft loss.
    Clinical Transplantation 04/2011; 25(4):E437-46. · 1.63 Impact Factor
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    ABSTRACT: The purpose of the study was to characterize differences in donor and recipient relationships between African American (AA) and Caucasian living kidney donors. Data from all successful living kidney donors at a single institution between 1991 and 2009 were reviewed. Relationships between donor and recipient were categorized and between-group comparisons performed. The study sample consisted of 73 (18%) AA and 324 Caucasian living kidney donors. The distribution of donor-recipient relationships differed significantly between AA and Caucasians. AA donors were more likely to be related to the recipient (88% vs. 74%, p = 0.007) than Caucasians. AA donors were more likely to participate in child to parent donation and were less likely to participate in parent to child donation or to donate to unrelated individuals. Sibling and spousal donations were similar in both groups. Caucasian donors were more likely to be unrelated to the recipient than AA donors. Differences exist in donor-recipient relationships between AA and Caucasian living kidney donors. Future studies exploring cultural differences and family dynamics may provide targeted recruitment strategies for AA and Caucasian living kidney donors. Living unrelated kidney transplantation appears to be a potential growth area for living kidney donation in AA.
    Clinical Transplantation 04/2011; 25(5):E487-90. · 1.63 Impact Factor
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    ABSTRACT: This article reviews the outcome of pancreas transplantations in diabetic recipients according to risk factors, surgical techniques, and immunosuppression management that evolved over the course of a decade at Wake Forest Baptist Medical Center. A randomized trial of alemtuzumab versus rabbit anti-thymocyte globulin (rATG) induction in simultaneous kidney-pancreas transplantation (SKPT) at our institution demonstrated lower rates of acute rejection and infection in the alemtuzumab group. Consequently, alemtuzumab induction has been used exclusively in all pancreas transplantations since February 2009. Early steroid elimination has been feasible in the majority of patients. Extensive experience with surveillance pancreas biopsies in solitary pancreas transplantation (SPT) is described. Surveillance pancreas biopsy-directed immunosuppression has contributed to equivalent long-term pancreas graft survival rates in SKPT and SPT recipients at our center, in contrast to recent registry reports of persistently higher rates of immunologic pancreas graft loss in SPT. Furthermore, the impact of donor and recipient selection on outcomes is explored. Excellent results have been achieved with older (extended) donors and recipients, in recipients of organs from donation after cardiac death donors managed with extracorporeal support, and in African-American patients. Type 2 diabetics with detectable C-peptide levels have been transplanted successfully with outcomes comparable to those of insulinopenic diabetics. Our experiences are discussed in the light of findings reported in the literature.
    The Review of Diabetic Studies 01/2011; 8(1):17-27.
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    Dwayne A Pierce, Amber M Reeves-Daniel
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    ABSTRACT: To report the case of a kidney allograft recipient on a stable regimen of tacrolimus who exhibited increased tacrolimus concentrations within 24 hours of initiating ranolazine. A 64-year-old kidney allograft recipient on a stable dose of tacrolimus (10 mg twice daily) was admitted for recent worsening of her chronic anginal pain. The patient was initiated on ranolazine 500 mg twice daily on hospital day 2. Tacrolimus concentrations rose from 7.0-10.1 ng/mL preadmission to 17.8 ng/mL within 24 hours of ranolazine initiation. Ranolazine therapy was continued due to the patient's beneficial response; therefore, the tacrolimus dose was eventually decreased by 70% to 3 mg twice daily to maintain steady-state trough concentrations between 6.6 and 7.9 ng/mL with ranolazine therapy. Ranolazine dechallenge on a subsequent admission produced subtherapeutic tacrolimus concentrations requiring dosage increases. Ranolazine, an antianginal agent, is both a substrate and a weak inhibitor of CYP3A as well as a substrate and moderate inhibitor of the P-glycoprotein (P-GP) efflux transport system. Tacrolimus, an immunosuppressant, is also a substrate of CYP3A and P-GP. Through possible inhibition of both P-GP- and CYP3A-mediated first-pass metabolism and CYP3A systemic metabolism, ranolazine may have significantly increased serum concentrations of tacrolimus necessitating an eventual 70% decrease in the tacrolimus dose. Based on the Horn Drug Interaction Probability Scale, this interaction is possible. We suggest that the eventual 70% decrease in tacrolimus dose after ranolazine initiation may indicate that ranolazine decreases the metabolism and clearance of tacrolimus, causing an elevation in tacrolimus concentrations and the potential for tacrolimus toxicity. Clinicians should be aware of this possible interaction when initiating ranolazine in patients on tacrolimus.
    Annals of Pharmacotherapy 09/2010; 44(11):1844-9. · 2.92 Impact Factor
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    ABSTRACT: C1q nephropathy is a rare kidney disease that can present with nephrotic syndrome and typically has the histologic phenotype of either minimal change disease or focal segmental glomerulosclerosis (FSGS). Disagreement exists about whether it is a distinct immune complex-mediated glomerulopathy or it resides in the spectrum of FSGS-minimal change disease. Two African American patients with C1q nephropathy histologically presenting as the collapsing variant of FSGS (collapsing C1q nephropathy) and rapid loss of kidney function were genotyped for polymorphisms in the non-muscle myosin heavy chain 9 gene (MYH9). Both cases were homozygous for the MYH9 E1 risk haplotype, the variant strongly associated with idiopathic FSGS, collapsing FSGS in human immunodeficiency virus-associated nephropathy, and focal global glomerulosclerosis (historically attributed to hypertensive nephrosclerosis). Collapsing C1q nephropathy with rapid progression to end-stage renal disease appears to reside in the MYH9-associated disease spectrum.
    American Journal of Kidney Diseases 05/2010; 55(5):e21-4. · 5.29 Impact Factor
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    ABSTRACT: Delayed graft function (DGF) is more common in recipients of kidney transplants from donation after cardiac death (DCD) donors compared to donation after brain death (DBD) donors. Single-center retrospective study to evaluate the impact of DGF on controlled (Maastricht category III) DCD donor kidney transplant outcomes. From 10/01 to 6/08, 578 adult deceased donor kidney transplants were performed including 70 (12%) from DCD and 508 (88%) from DBD donors. Mean follow-up was 36 months. DCD donor kidney transplants had significantly greater rates of DGF (57% DCD vs. 21% DBD, p < 0.0001)) and acute rejection (29% DCD vs. 16% DBD, p = 0.018) compared to DBD donor kidney transplants, but patient and graft survival rates were similar. DBD donor kidney transplants with DGF (n = 109) had significantly greater rates of death-censored graft loss (12.5% DCD vs. 31% DBD), primary non-function (0 DCD vs. 10% DBD) and higher 2 year mean serum creatinine levels (1.4 DCD vs. 2.7 mg/dL DBD) compared to DCD donor kidney transplants with DGF (n = 40, all p < 0.04). On univariate analysis, the presence of acute rejection and older donor age were the only significant risk factors for death-censored graft loss in DCD donor kidney transplants, whereas DGF was not a risk factor. Despite higher rates of DGF and acute rejection in DCD donor kidney transplants, subsequent outcomes in DCD donor kidney transplants with DGF are better than in DBD donor kidney transplants experiencing DGF, and similar to outcomes in DCD donor kidney transplants without DGF.
    Clinical Transplantation 03/2010; 25(2):255-64. · 1.63 Impact Factor
  • Transplantation 01/2010; 90. · 3.78 Impact Factor
  • Transplantation 01/2010; 90. · 3.78 Impact Factor
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    ABSTRACT: Although African Americans (AA) are considered higher risk kidney donors than Caucasians, limited data are available regarding outcomes of AA donors. 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. 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. 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.
    Clinical Transplantation 12/2009; 24(5):717-22. · 1.63 Impact Factor
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    ABSTRACT: Recurrence of focal segmental glomerulosclerosis (FSGS) with nephrotic syndrome is relatively common after kidney transplantation in young recipients whose predialysis course consists of heavy proteinuria, hypertension and subacute loss of kidney function. The gene(s) mediating this effect remain unknown. We report an unusual circumstance where kidneys recovered from a deceased African American male donor with MYH9-related occult FSGS (risk variants in seven of eight MYH9 E1 haplotype single nucleotide polymorphisms) were transplanted into an African American male child with risk variants in four MYH9 E1 risk variants and a European American female teenager with two MYH9 E1 risk variants. Fulminant nephrotic syndrome rapidly developed in the African American recipient, whereas the European American had an uneventful posttransplant course. The kidney donor lacked significant proteinuria at the time of organ procurement. This scenario suggests that donor-recipient interactions in MYH9, as well as other gene-gene and gene-environment interactions, may lead to recurrent nephrotic syndrome after renal transplantation. The impact of transplanting kidneys from donors with multiple MYH9 risk alleles into recipients with similar genetic background at high risk for recurrent kidney disease needs to be determined.
    American Journal of Transplantation 10/2009; 9(10):2435-40. · 6.19 Impact Factor
  • Human Immunology - HUM IMMUNOL. 01/2009; 70.
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    ABSTRACT: African Americans (AA) and women are less likely to receive a live kidney donor (LKD) transplant than Caucasians or men. Reasons for non-donation are poorly understood. A retrospective review of 541 unsuccessful LKD was performed to explore reasons for non-donation and to assess for racial and/or gender differences. We identified 138 AA and 385 Caucasian subjects who volunteered but did not successfully donate. Females (58.2%) were more likely to be excluded than males due to reduced renal function (glomerular filtration rate < 85 mL/min, 7.9% vs. 0.9%, p < 0.0001) or failure to complete the evaluation (6.4% vs. 1.8%, p = 0.01). AA were more commonly excluded due to obesity (body mass index >or= 32 kg/m(2); 30.4% AA vs. 16.6% Caucasian, p = 0.0005) or failure to complete the evaluation (12.3% AA vs. 1.8% Caucasian, p < 0.0001) whereas Caucasians were more often excluded due to kidney stones (1.5% AA vs. 7.3% Caucasian, p = 0.01). Significantly different reasons for exclusion of LKD exist between potential Caucasian and AA LKD, particularly among women. Among the differences that we observed are potentially modifiable barriers to donation including obesity and failure to complete the donor evaluation. A further understanding of these barriers may help point to strategies for more effective recruitment and successful LKD.
    Clinical Transplantation 10/2008; 23(1):39-46. · 1.63 Impact Factor
  • Dwayne A Pierce, Shea R Holt, Amber Reeves-Daniel
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    ABSTRACT: BACKGROUND: As described in the literature, gabapentin toxicity in patients with impaired renal function can manifest as coma, myoclonus, tremulousness, or altered mental status. Gabapentin is an antiepileptic agent indicated for use as an adjunct therapy in partial seizures and postherpetic neuralgia but is also prescribed for the treatment of diabetic peripheral neuropathy. CASE SUMMARY: A 46-year-old white woman (height, 167 cm; weight, 177 kg; body mass index, 62.8 kg/m2) with a 6-year history of diabetes mellitus and previously normal renal function, presented to the emergency department of Wake Forest University Baptist Medical Center with anuria (a serum creatinine level of 7.4 mg/dL), hearing loss, myoclonus, and confusion with hallucinations lasting for 3 days. Her blood pressure was 110/74 mm Hg. The patient's preadmit medication list included: lisinopril (40 mg QD), hydrochlorothiazide (25 mg QD), and furosemide (80 mg QD) for hypertension; atorvastatin (10 mg QD) for hyperlipidemia; omeprazole (20 mg QD) for gastroesophageal reflux disease; salmeterol/fluticasone inhaler (100/50 microg; 1 puff BID) and albuterol metered-dose inhaler (90 microg as needed) for asthma; metformin (500 mg BID) and insulin lispro per sliding scale for type 2 diabetes mellitus; oxycodone controlled release (60 mg TID) for chronic osteoarthritis and low back pain; alprazolam (0.5 mg every 8 hours as needed) for generalized anxiety disorder; venlafaxine (150 mg BID) for depression; and gabapentin (300 mg TID) for diabetic peripheral neuropathy. The patient's symptoms (hearing loss, myoclonus, and confusion) improved after 1 session of hemodialysis (approximately 10 hours following admission) and had resolved at the time of discharge (4 days later). On admission, the gabapentin concentration was 17.6 microg/mL, and following hemodialysis, the gabapentin concentration was undetectable (by discharge/day 4). The timing of the patient's last dose of gabapentin is unknown. Normal doses for the treatment of diabetic peripheral neuropathy range from 900 to 3600 mg/d divided 3 times daily. Conclusions: We report a patient with acute renal failure who developed hearing loss, myoclonus, and confusion with hallucinations in the presence of elevated gabapentin concentrations. Due to rapid improvement after hemodialysis and discontinuation of gabapentin, we believe that these symptoms were probably due to gabapentin toxicity.
    Clinical Therapeutics 10/2008; 30(9):1681-4. · 2.23 Impact Factor
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    ABSTRACT: Most reports of donation after cardiac death (DCD) donors are exclusive to kidney transplantation and report high rates of delayed graft function (DGF). From April 1, 2003, to October 3, 2007, we performed 53 kidney transplantations and 4 simultaneous kidney-pancreas transplantations from DCD donors. All DCD donor kidneys were managed with pulsatile perfusion preservation, and all simultaneous kidney-pancreas transplantation donors were managed with extracorporeal support. Of 53 DCD kidney transplantations, 44 (83%) were from standard criteria donors (SCD) and 9 (17%) from expanded criteria donors (ECD). With a mean followup of 12 months, actual patient and kidney graft survival rates were 94% and 87%, respectively. Patient and graft survival rates were 100% in the 4 simultaneous kidney-pancreas transplantations. Incidence of DGF was 57% (60% without versus 20% with extracorporeal support, p = 0.036). Comparison of the 53 DCD donor kidney transplantations with 316 concurrent donation after brain death (DBD) donor adult kidney transplantations (178 SCD, 138 ECD) revealed no differences in demographics or outcomes, except that the DCD donor group had fewer ECDs (17% DCD versus 44% DBD; p = 0.0002), fewer 0-antigen mismatch kidney transplantations (7.5% DCD versus 19% DBD; p = 0.05), and more kidneys preserved with pulsatile perfusion (100% DCD versus 52% DBD; p < 0.0001). Incidences of DGF (57% DCD versus 19% DBD; p < 0.0001) and acute rejection (19% DCD versus 10% DBD; p = 0.10) were higher in the DCD donor group, which resulted in a longer initial length of stay (mean 11 days DCD versus 8.0 days DBD; p = 0.006). Despite a high incidence of DGF in the absence of extracorporeal support and greater initial resource use, comparable short-term results can be achieved with DCD and DBD donor kidney transplantations.
    Journal of the American College of Surgeons 06/2008; 206(5):1028-37; discussion 1037. · 4.50 Impact Factor