Impact of early surgical complications on kidney transplant outcomes.

BACKGROUND: Kidney transplantation (KT) improves clinical outcomes of patients with end stage renal disease. Little has been reported on the impact of early post-operative surgical complications (SC) on long-term clinical outcomes following KT. We sought to determine the impact of vascular complications, urological complications, surgical site complications, and peri-graft collections within 30 days of transplantation on patient survival, graft function, and hospital readmissions. METHODS: We conducted a single-centre, observational cohort study examining adult patients (≥ 18 years) who received a kidney transplant from living and deceased donors between January 1st, 2005 and December 31st, 2015 with follow-up until December 31st, 2016 (n = 1,334). Univariable and multivariable analyses were performed with Cox proportional hazards models to analyze the outcomes of SC in the early post-operative period after KT. RESULTS: The cumulative probability of SC within 30 days of transplant was 25%, the most common SC being peri-graft collections (66.8%). Multivariable analyses showed significant relationships between Clavien Grade 1 SC and death with graft function (HR 1.78 [95% CI: 1.11, 2.86]), and between Clavien Grades 3 to 4 and hospital readmissions (HR 1.95 [95% CI: 1.37, 2.77]). CONCLUSIONS: Early SC following KT are common and have a significant influence on long-term patient outcomes.

Cannabis use is associated with reduced access to kidney transplantation and an increased risk of acute rejection post-transplant.

BACKGROUND: The association between cannabis use and access to waitlisting, transplantation, and post-transplant outcomes remains uncertain. METHODS: Patients referred for kidney transplant (KT) to the University Health Network from January 1, 2003, to June 30, 2020, and followed until December 31, 2020, were included. Predictors of reported cannabis use were examined using a logistic regression model. The association between cannabis use and time to clearance for KT, undergoing KT, and post-transplant outcomes was evaluated using Cox proportional hazards models. RESULTS: Among 3734 patients, the prevalence of reported cannabis use was 11.8%. Cannabis use was associated with a lower likelihood of KT clearance (adjusted hazard ratio [aHR] .82 [95% confidence interval (CI): .72, .94]). Once cleared for KT, cannabis use did not predict the subsequent receipt of KT (aHR .92, [95% CI: .79, 1.08]). Among 2091 KT recipients, cannabis use was associated with a higher likelihood of biopsy-proven acute rejection (aHR 1.55, [95% CI: 1.06, 2.27]). The relative hazard of death-censored graft failure was similarly elevated (aHR 1.60 [95% CI: .95, 2.72]). Cannabis use did not predict total graft failure (aHR 1.33 [95% CI: .90, 1.96]), death with graft function (aHR 1.06 [95% CI: .59, 1.89]), or hospital readmission in the first-year post-transplant (aHR 1.26 [95% CI: .95, 1.68]). CONCLUSIONS: Cannabis users have less access to transplantation and an increased risk of acute rejection, possibly leading to more graft loss. Further studies are warranted to understand possible mechanisms for the increased risk of allograft immune injury among cannabis users.

Renal cell carcinoma in kidney transplant recipients: incidence, trends, clinical management & outcomes.

OBJECTIVE: To describe the incidence, characteristics, clinical management, and outcomes of renal cell carcinoma (RCC) among a large, single-centre cohort of kidney transplant recipients (KTR). METHODS: We conducted an observational cohort study looking at KTR transplanted between January 2000-December 2017 (n = 2443) with ≥ 1 year of follow-up. Simultaneous kidney/pancreas transplants were excluded. The Kaplan-Meier product-limit method was used to determine the incidence of RCC. Characteristics and management of RCC were examined using descriptive statistics. Risk factors and clinical outcomes were analyzed using Cox regression models. RESULTS: The incidence of RCC among our cohort was 0.32 per 100 person-years, 2.1% of all KTRs. Almost half (47.1%) of cases occurred within 4 years post-transplant. The majority of cases were T1a (86.3%), clear-cell (45.1%), and in the native kidney (80.4%). KTR diagnosed with RCC had a twofold higher incidence of other malignancies versus KTR without RCC. Overall mortality, but not cancer-specific mortality, at 2- and 5-years post-transplant was threefold higher among KTR with RCC than those without. CONCLUSIONS: Incidence of RCC among our KTR was slightly higher than the general population; majority of cases occur in the native kidneys and are low stage, low grade. Indolent histologic variants were more common than the general population. KTR with RCC had a higher incidence of other malignancies. Overall, but not cancer-specific, mortality was higher among KTRs diagnosed with RCC.

The epidemiology of early deep vein thrombosis in kidney transplant recipients.

BACKGROUND: Because kidney transplant recipients may be at increased risk for deep vein thrombosis (DVT) following transplantation, we investigated the incidence, risk factors, treatments and outcomes of early DVT among kidney transplant recipients. METHODS: An observational, single-centre cohort study was conducted among adult kidney transplant recipients from Jan. 1, 2005, to Dec. 31, 2016 with 1-year followup. Time to DVT was assessed using the Kaplan-Meier method. Cox proportional hazards and linear regression models were used to analyze risk factors for and outcomes of DVT. RESULTS: The cumulative incidence of DVT was 4.25% at 3 months after transplant. In multivariable analysis, the use of depleting induction agents (hazard ratio [HR] 2.13, 95% confidence interval [CI] 1.05-4.35]), white recipient race (HR 1.84. 95% CI 1.08-3.12), the use of kidneys from expanded criteria donors (HR 2.13, 95% CI 1.05-4.32) and lower recipient body mass index (HR 0.95, 95% CI 0.91-1.00) increased the risk for early DVT. Peritransplant DVT prophylaxis was not associated with early DVT. Early DVT was not associated with reduced graft function, death, graft failure or first hospital readmission. CONCLUSION: Risk factors for early DVT in our cohort of kidney transplant recipients included white recipient race, use of depleting agents, lower recipient body mass index and use of expanded criteria donors. As practice patterns of donor and recipient selection in kidney transplantation evolve, the results of this study may aid in perioperative risk assessments and decision-making about the use of DVT prophylaxis.

Incidence, risk factors, outcomes, and clinical management of BK viremia in the modern era of kidney transplantation.

BK viremia is endemic among kidney transplant recipients (KTRs). Incidence, risk factors, outcomes, and clinical management of detectable versus high BK viremia have not been considered previously in KTR in the modern era. This observational study examined KTR transplanted between January 1, 2009 and December 31, 2016. Any BK viral load in the serum constituted detectable BK viremia and ≥103 copies/ml constituted high viremia. Among 1193 KTRs, the cumulative probability of developing detectable and high BK viremia within 2 years posttransplant were 27.8% and 19.6%, respectively. Significant risk factors for detectable BK viremia included recipient age (HR 1.02 [95% CI: 1.01, 1.03]) and donor age (HR 1.01 [95% CI: 1.00, 1.02]). Recipient age also predicted high BK viremia (HR 1.02 [95% CI: 1.01, 1.03]), whereas White race (HR 0.70 [95% CI: 0.52, 0.95]), nondepleting induction therapy (HR 0.61 [95% CI: 0.42, 0.89]), and delayed graft function (HR 0.61 [95% CI: 0.42, 0.88]) were protective. Mean estimated glomerular filtration rates were 4.28 ml/min/1.72 m2 (95% CI: 2.71, 5.84) lower with detectable BK viremia. Although low viral load was usually not acted upon at first presentation, antiproliferative dose reductions were the most common initial management. BK viremia remains a common early complication in a modern cohort of KTRs. These findings highlight the benefit of early BKV monitoring in addition to intensive clinical management. Clinical responses beyond first positive BK viremia tests, and their implications for graft outcomes, merit further investigation.

Surgical site complications in kidney transplant recipients: incidence, risk factors and outcomes in the modern era.

BACKGROUND: Surgical site complications (SSCs) are an important source of morbidity after kidney transplantation. We assessed the incidence, risk factors, outcomes and economic impact of SSCs in a large, diverse population of kidney transplant recipients. METHODS: We conducted a single-centre, observational cohort study of adult (age ≥ 18 yr) patients who underwent kidney transplantation between Jan. 1, 2005, and Dec. 31, 2015, with a minimum of 1 year of follow-up. Cases of SSC, including infections and wound dehiscence, were determined from patient records. Inpatient and outpatient hospital costs were determined 6 and 12 months after transplantation. We used the Kaplan-Meier product-limit method to determine the cumulative probability of SSCs and other outcomes. We evaluated risk factors and clinical outcomes using Cox proportional hazard ratios. Linear regression models were used to study the effect of SSCs on graft function. RESULTS: The incidence rate of SSCs within 30 days after transplantation was 4.19 per 100 person-months. The cumulative probability of developing an SSC within 30 days after transplantation was 4.13% (95% confidence interval [CI] 3.23%-5.28%). Increased recipient body mass index (BMI) (hazard ratio [HR] 1.07, 95% CI 1.02-1.11), longer cold ischemic time (HR 1.05, 95% CI 1.01-1.09) and transplantation in 2010-2012 versus 2005-2009 (HR 2.20, 95% CI 1.19-4.04) were risk factors for SSC development. In multivariable stepwise Cox proportional hazard models, SSC was a significant risk factor for death-censored graft failure (HR 3.08, 95% CI 1.60-5.90) and total graft failure (HR 2.09, 95% CI 1.32-3.32). Cumulative median hospital costs were $2238.46 greater for patients with an SSC than for those without. CONCLUSION: Increased BMI, longer cold ischemic time and the 2010-2012 transplantation period predisposed to SSCs. The development of SSCs was associated with a higher risk of graft failure. Strategies to minimize SSCs may improve outcomes after kidney transplantation and reduce costs.

Lymphoceles: impact on kidney transplant recipients, graft, and healthcare system.

INTRODUCTION: Following kidney transplantation, lymphoceles can impact patient and graft outcomes, while resulting in significant hospital resource utilization. We aimed to characterize the incidence, risk factors, outcomes, and clinical management of lymphoceles among kidney transplant recipients and review impact on health system utilization at a high-volume center. MATERIALS AND METHODS: We conducted a single-center, observational cohort study on adults transplanted between January 1, 2005 and December 31, 2017. Incidence, risk factors, and clinical outcomes were assessed using the Kaplan-Meier product-limit method, multivariable logistic regression model, and Cox proportional hazards model, respectively. RESULTS: Lymphoceles developed in 72 of 1881 patients (3.8%). Multivariate analysis demonstrated that a longer time on dialysis before transplant [HR 1.09 (95% CI: 1.02, 1.17)], laparoscopic donor nephrectomy [HR 2.31 (95% CI: 1.04, 5.12)], and depleting induction therapy [HR 0.39 (95% CI: 0.18, 0.87)] were significant risk factors for lymphocele development. Lymphoceles independently increased the likelihood of hospital readmission [HR 3.96 (95% CI: 2.99, 5.25)] but had no significant effect on the likelihood of graft failure or death with graft function. Of 72 cases, 44 received a radiological or surgical intervention. Fifteen of 44 lymphoceles required further intervention due to re-accumulation or complications. CONCLUSION: Patients with longer dialysis times, kidneys from laparoscopic donor nephrectomy, and depleting induction therapy were associated with an increased risk for developing symptomatic lymphoceles. Our center's treatment for symptomatic lymphoceles did not result in significant graft dysfunction, but significantly higher healthcare resource utilization was noted.

Ureteral strictures post-kidney transplantation: Trends, impact on patient outcomes, and clinical management.

INTRODUCTION: Ureteral strictures post-kidney transplantation (KT) can be a significant morbidity to the patient, often requiring surgical intervention and impacting graft function. We sought to investigate the incidence, clinical management, and outcomes of ureteral strictures among kidney transplant recipients (KTRs) at a large, multiorgan transplant center. METHODS: We conducted a single-center cohort study looking at KTRs who had transplant surgery from January 1, 2005 to March 31, 2017 with at least one-year followup (n=1742). Any KTRs done outside of our center or simultaneous multiorgan transplants were excluded. The Kaplan-Meier product-limit method was used to determine the incidence of ureteral strictures. Risk factors for ureteric strictures and clinical outcomes among patients with vs. without ureteric strictures were analyzed using Cox proportional hazards models. RESULTS: The incidence of ureteral strictures was 1.31 (95% confidence interval [CI] 0.85, 2.01) per 100 person-years or a cumulative incidence of 1.2%. We did not find any donor or recipient demographic variables that were independently associated with an increased risk of ureteral stricture development. A large proportion was managed successfully with radiological intervention alone (47.6%). Ureteral strictures were associated with death-censored graft failure (hazard ratio [HR] 7.17, 95% CI 2.81, 18.30), total graft failure (HR 3.04, 95% CI 1.41, 6.59), and hospital re-admission (HR 2.52, 95% CI 1.58, 4.00). CONCLUSIONS: Although uncommon, ureteral strictures can significantly impact patient outcomes after KT. A better understanding of risk factors and clinical management will be important to ensure optimal graft outcomes.

Extracellular Matrix Injury of Kidney Allografts in Antibody-Mediated Rejection: A Proteomics Study.

BACKGROUND: Antibody-mediated rejection (AMR) accounts for >50% of kidney allograft loss. Donor-specific antibodies (DSA) against HLA and non-HLA antigens in the glomeruli and the tubulointerstitium cause AMR while inflammatory cytokines such as TNFα trigger graft injury. The mechanisms governing cell-specific injury in AMR remain unclear. METHODS: Unbiased proteomic analysis of laser-captured and microdissected glomeruli and tubulointerstitium was performed on 30 for-cause kidney biopsy specimens with early AMR, acute cellular rejection (ACR), or acute tubular necrosis (ATN). RESULTS: A total of 107 of 2026 glomerular and 112 of 2399 tubulointerstitial proteins was significantly differentially expressed in AMR versus ACR; 112 of 2026 glomerular and 181 of 2399 tubulointerstitial proteins were significantly dysregulated in AMR versus ATN (P<0.05). Basement membrane and extracellular matrix (ECM) proteins were significantly decreased in both AMR compartments. Glomerular and tubulointerstitial laminin subunit γ-1 (LAMC1) expression decreased in AMR, as did glomerular nephrin (NPHS1) and receptor-type tyrosine-phosphatase O (PTPRO). The proteomic analysis revealed upregulated galectin-1, which is an immunomodulatory protein linked to the ECM, in AMR glomeruli. Anti-HLA class I antibodies significantly increased cathepsin-V (CTSV) expression and galectin-1 expression and secretion in human glomerular endothelial cells. CTSV had been predicted to cleave ECM proteins in the AMR glomeruli. Glutathione S-transferase ω-1, an ECM-modifying enzyme, was significantly increased in the AMR tubulointerstitium and in TNFα-treated proximal tubular epithelial cells. CONCLUSIONS: Basement membranes are often remodeled in chronic AMR. Proteomic analysis performed on laser-captured and microdissected glomeruli and tubulointerstitium identified early ECM remodeling, which may represent a new therapeutic opportunity.

Substance use in kidney transplant candidates and its impact on access to kidney transplantation.

BACKGROUND: Due to the increasing public acceptance of substance use, it is important to understand the association between substance use and access to kidney transplant and its outcomes. Here, we assess the sociodemographic predictors of substance use and the association between substance use and KT access. METHODS: Predictors of substance use were examined using a multivariable-adjusted multinomial logistic regression. The association between current substance use (tobacco and drug) and time from referral to listing or receipt of a KT was examined using Cox proportional hazards models. RESULTS: Of 2346 patients, the prevalence of current substance use was 17%. Predictors of current tobacco use were younger age, male sex, Caucasian ethnicity, being unemployed, and unmarried. Predictors of current drug use were younger age, male sex, Caucasian ethnicity, a history of non-adherence, and a history of mental health disorder. Patients with tobacco use had a decreased likelihood of being cleared for KT (hazard ratio [HR]:0.83[0.70, 0.99]) and receiving a KT (HR:0.80 [0.66, 0.96]). No association was seen in this sample for patients with drug use (HR:0.88 [0.69, 1.11] for being cleared for KT and 0.88 [0.69, 1.14] for KT, respectively). CONCLUSIONS: Tobacco use was associated with a decreased likelihood of access to KT whereas there was no statistically significant difference in access to KT between patients with or without drug use.

Incidence, Risk Factors, Clinical Management, and Outcomes of Posttransplant Lymphoproliferative Disorder in Kidney Transplant Recipients.

BACKGROUND: Posttransplant lymphoproliferative disorder (PTLD) is a severe complication after kidney transplantation. This study examined the incidence, risk factors, clinical management, and outcomes of PTLD in a cohort of kidney transplant recipients. DESIGN: This single-center cohort study included 1642 patients transplanted from January 1, 2000, to December 31, 2012, with follow-up until December 31, 2013. The incidence and risk factors for PTLD were examined using a Cox proportional hazards model. A Cox model was also used to assess the association of PTLD and graft outcomes. RESULTS: Sixteen recipients developed PTLD over follow-up. The incidence rate was 0.18 (95% confidence interval [CI]: 0.11-0.29) cases per 100 person-years. Four were from Epstein-Barr virus (EBV) mismatched (D+/R-) transplants and 12 from EBV-positive recipients (R+). Recipients with D+/R- matches were at a significantly higher risk of developing PTLD than R+ (hazard ratio [HR]: 7.52 [95% CI: 2.42-23.32]). Fifteen cases had immunosuppression reduced, 11 cases were supplemented with rituximab or ganciclovir, 6 cases required chemotherapy or radiation, and 6 cases had tumors excised. By the end of follow-up, 6 patients went into remission, 5 returned to chronic dialysis, and 5 patients died. Patients with PTLD were significantly more likely to have total graft failure (return to chronic dialysis, preemptive retransplant, or death with graft function) than patients without PTLD (HR: 3.41 [95% CI: 1.72-6.78). DISCUSSION: Epstein-Barr virus mismatch continues to be a strong risk factor for developing PTLD after kidney transplantation. Recipients with PTLD have a poor prognosis, as the optimal management remains to be elucidated.

Donor kidney volume measured by computed tomography is a strong predictor of recipient eGFR in living donor kidney transplantation.

PURPOSE: The effect of living donor kidney allograft size on recipient outcomes is not well understood. In this study, we sought to investigate the relationship between preoperatively measured donor kidney volume and recipient estimated glomerular filtration rate (eGFR) in living donor kidney transplantation (LDKT). METHODS: We studied computed tomography (CT) donor kidney volumes and recipient outcomes for 438 LDKTs at the Toronto General Hospital between 2007 and 2016. Estimated glomerular filtration rate (eGFR) was calculated at 1, 3, and 6 months and a multivariable linear regression model was fitted to study the effect of donor kidney volume on recipient eGFR. RESULTS: The mean volume and weight of the donated kidneys were 157.3 (± 32.3) cc and 186.7 (± 48.7) g, respectively. Kidney volume was significantly associated with eGFR on multivariable analysis (P < 0.001). Specifically, for every 10 cc increase in kidney volume, there was a 1.68 mL/min, 1.25 mL/min and 0.97 mL/min rise in recipient eGFR at 1, 3, and 6 months, respectively. CONCLUSIONS: Donor kidney volume is a strong independent predictor of recipient eGFR in LDKT, and therefore, may be a valuable addition to predictive models of eGFR after transplant. Further research may determine if the inclusion of donor kidney volume in matching algorithms can improve recipient outcomes.

Incidence, Risk Factors, and Outcomes of Clostridium difficile Infections in Kidney Transplant Recipients.

BACKGROUND: Kidney transplant recipients (KTR) may be at increased risk for Clostridium difficile infections (CDI) but risk factors and outcomes in this population have not been well studied. METHODS: An observational cohort study was conducted to determine the incidence, risk factors, and outcomes of CDI in KTR. A total of 1816 KTR transplanted between 2000 and 2013 at the Toronto General Hospital were included. Sixty-eight patients developed CDI. Controls were selected at a 4:1 ratio using risk-set sampling, and risk factors were explored using conditional logistic regression models. The impact of CDI on graft outcomes was evaluated using Cox proportional hazards models. RESULTS: The incidence rate of CDI was 0.64 cases/100 person-years. Independent predictors of CDI included antibiotic use (odds ratio [OR], 2.88; 95% confidence interval [CI], 1.35-6.15), increased duration of hospitalization posttransplant (OR, 1.04; 95% CI, 1.02-1.06]), receiving a deceased donor kidney (OR, 2.98; 95% CI, 1.47-6.05), and a history of biopsy-proven acute rejection (OR, 5.82; 95% CI, 2.22-15.26). In the Cox proportional hazards model, CDI was found to be an independent risk factor for the subsequent development of biopsy-proven acute rejection (hazard ratio, 2.18; 95% CI, 1.34-3.55). CONCLUSIONS: Our results confirm that transplant-specific factors place KTR at a higher risk for CDI. Clostridium difficile infections may increase the risk of adverse outcomes, such as biopsy-proven acute rejection. These findings emphasize the importance of preventive strategies to reduce the morbidity associated with CDI in KTR.

Pre-transplant history of mental health concerns, non-adherence, and post-transplant outcomes in kidney transplant recipients.

OBJECTIVE: The association between pre-transplant mental health concerns and non-adherence and post-transplant outcomes after kidney transplantation is not fully established. We examined the relationship between a pre-transplant history of mental health concerns and non-adherence and post-transplant outcomes among kidney transplant recipients. METHODS: In this retrospective single center cohort study of adult kidney transplant recipients (n=955) the associations between the history of mental health concerns or non-adherence and the time from kidney transplant to biopsy proven acute rejection; death-censored graft failure and total graft failure were examined using Cox proportional hazards models. RESULTS: Mean (SD) age was 51 (13) years, 61% were male and 27% had a history of diabetes. Twenty-two and 11% of patients had mental health concerns and non-adherence, respectively. Fifteen percent of the patients had acute rejection, 5.6% had death-censored graft failure and 13.0% had total graft failure. The history of mental health concerns was not associated with acute rejection, death-censored graft failure or total graft failure. Patients with versus without a history of non-adherence tended to have higher cumulative incidence of acute rejection (23.3% [95% CI: 16.1, 33.2] vs. 13.6% [95% CI: 11.4, 16.2]) and death-censored graft failure (15.0% [95% CI: 6.9, 30.8] vs. 6.4% [95% CI: 4.7, 8.7]) (log rank p=0.052 and p=0.086, respectively). These trends were not significant after multivariable adjustment. CONCLUSION: In summary, a history of pre-transplant mental health concerns or non-adherence is not associated with adverse outcomes in patients who completed transplant workup and received a kidney transplant.

Delayed graft function and the risk of acute rejection in the modern era of kidney transplantation.

Delayed graft function (DGF) is commonly considered a risk factor for acute rejection, although this finding has not been uniformly observed across all studies. The link between DGF and acute rejection may have changed over time due to advances in immunosuppression and medical management. Here we conducted a cohort study of 645 patients over 12 years to evaluate the association of DGF and biopsy-proven acute rejection (BPAR) in a modern cohort of kidney transplant recipients. DGF was defined as the need for at least one dialysis session in the first week after kidney transplantation. The 1-, 3-, and 5-year cumulative probabilities of BPAR were 16.0, 21.8, and 22.6% in the DGF group, significantly different from the 10.1, 12.4, and 15.7% in the non-DGF group. In multivariable Cox proportional hazards model, the adjusted relative hazard for BPAR in DGF (vs. no DGF) was 1.55 (95% confidence interval (CI): 1.03, 2.32). This association was generally robust to different definitions of DGF. The relative hazard was also similarly elevated for T-cell- or antibody-mediated BPAR (1.52 (0.92, 2.51) and 1.54 (0.85, 2.77), respectively). Finally, the association was consistent across clinically relevant subgroups. Thus DGF remains an important risk factor for BPAR in a contemporary cohort of kidney transplant recipients. Interventions to reduce the risk of DGF and/or its aftereffects remain of paramount importance to improve kidney transplant outcomes.

Timing of rabbit antithymocyte globulin induction therapy in kidney transplantation: an observational cohort study.

BACKGROUND: Literature on the timing of rabbit antithymocyte globulin (rATG) induction and its effects on kidney transplant outcomes is limited. The manufacturer recommends that the first dose be given intra-operatively, however this may present clinical practice risks and challenges. Our objective was to assess the impact of the timing of the first dose of rATG on kidney transplant outcomes. METHODS: Incident kidney transplant recipients (KTR) from January 2002 to December 2009 receiving the first dose of rATG post-operatively (Post, n = 353) or before reperfusion (Pre, n = 124) were evaluated. Outcomes assessed included eGFR at 1-year, delta eGFR (12 versus 1 month), and incidence of biopsy-proven acute rejection, graft loss, death, and a composite of the time-to-event outcomes. The impact of timing on outcomes was adjusted for potential confounders and assessed using linear and Cox regression models. RESULTS: Among 435 KTR surviving with function to 12 months post-transplant, there was no significant difference in mean estimated glomerular filtration rate or eGFR (55.0 versus 56.7 mL/min, P = 0.46) and delta eGFR (1.8 versus 0.3 mL/min, P = 0.40) in Post versus Pre groups, respectively. At a median follow-up of 3 years, the composite endpoint (time to first biopsy-proven acute rejection, graft loss, or death) was similar by timing group (adjusted HR = 0.94; 95% CI: 0.58, 1.53, P = 0.81) in the total study population. CONCLUSIONS: Timing of rATG had no appreciable impact on clinically relevant endpoints in this study cohort. These results support consideration of more flexible timing of the first dose of rATG induction in KTR.

Increased recipient body mass index is associated with acute rejection and other adverse outcomes after kidney transplantation.

BACKGROUND: Outcomes of kidney transplant recipients with increased body mass index (BMI) remain controversial. We studied the relationship between BMI and clinically relevant outcomes among kidney transplant recipients at a large center. METHODS: We performed an observational cohort study of all recipients of kidney transplants at our center from January 1, 2000 to December 31, 2010 to determine if increased BMI at transplantation is associated with adverse outcomes, including delayed graft function and biopsy-proven acute rejection (BPAR). Recipient BMI was categorized as <20, 20 to 24.9 (reference), 25 to 29.9, 30 to 34.9, and ≥35 kg/m. Potential confounders were included in logistic and Cox proportional hazards models. RESULTS: A total of 1151 patients were studied. Recipient BMI of 30 to 34.9 and ≥35 kg/m were associated with an increased risk of delayed graft function (odds ratio [95% confidence interval [CI], 1.92 [1.16-3.19] and 4.49 [2.24-9.00], respectively). BMI≥35 kg/m was also associated with an increased risk of BPAR (hazard ratio [HR; 95% CI], 2.43 [1.48-3.99]), all-cause graft failure (HR [95% CI], 1.97 [1.09-3.56]), and death-censored graft failure (HR [95% CI], 2.43 [1.07-5.51]). Adjustment for acute rejection as a time-varying covariate significantly attenuated the association with graft failure endpoints. There was no significant relation between BMI and death with graft function. CONCLUSIONS: Increased BMI at kidney transplantation is a predictor of adverse outcomes, including BPAR. The role of pretransplantation weight reduction in improving graft and patient outcomes requires further study.