Renal resistive index as a new independent risk factor for new-onset diabetes mellitus after kidney transplantation.

Pulse pressure and urinary albumin excretion were recently identified as risk factors of new-onset diabetes after renal transplantation (NODAT), suggesting that microvascular injury may be implicated in NODAT. However, the relationship between of microvascular injury and NODAT is unknown. In the present long-term (median follow-up: 5.7years; observation period: 4908 patient-years) retrospective study in 656 renal transplant recipients, the association between baseline renal resistance index (RI, used as a marker of widespread microvascular damage) and the incidence of NODAT was assessed. The incidence of NODAT was 11.2% and 14.6% at 5 and 10years, respectively, after transplantation. RI at 3months was a risk factor for NODAT [hazard ratio (HR) per 0.1: 2.19 (1.55-3.09), P<0.0001]. RI >0.75 (vs. 0≤0.75) was a potent a predictor of NODAT [HR: 3.29 (1.91-5.67), P<0.0001], even after adjustments [HR: 3.29 (1.50-7.24), P=0.0030] on age, weight, glucose, nephropathy, and arterial pressure. Similar results were observed when RI was measured at 1month [HR per 0.1:1.74 (1.33-2.27), P<0.0001] and 12months [HR per 0.1:1.74 (1.33-2.27), P<0.0001] after transplantation. High RI early after renal transplantation is a long-term risk factor for NODAT, and could be used to refine the individual risk of NODAT.

Kidney transplant with multiple renal artery grafts from deceased donors: are long-term graft and patient survival compromised?

BACKGROUND: Kidneys with multiple arteries are often transplanted. However, the long-term outcome of such kidneys recovered exclusively from deceased donors is not clear. OBJECTIVE: To determine whether use of renal grafts with multiple arteries affects long-term graft survival and function. METHODS: The outcomes of 259 consecutive kidney transplants between 1996 and 2000 were retrospectively reviewed. Patients were divided into 2 groups, multiple renal artery graft recipients (n = 70) and single renal artery graft recipients (n = 189). Short-term complications and long-term outcomes (survival rates, blood pressure after transplant, creatinine clearance, and proteinuria levels at 1, 3, 5, and 7 years after transplant) were compared between the 2 groups. RESULTS: Early vascular complications were more common (P = .02) in multiple artery graft recipients (18.6%) than in single artery graft recipients (7.9%), mainly because of occlusion of a polar artery in grafts with multiple renal arteries (7.1%). Urologic complications were no more frequent in one group than in the other (5.7% vs 5.3%; P = .89). The 2 groups did not differ significantly (P = .33) in long-term graft survival, with a median follow-up of 9.05 years (range, 0.1-12.7 years). Mean (SD) for creatinine clearance (59.4 [22.6] vs 55.9 [20.3] mL/min; P = .47), proteinuria (0.77 [2.1] vs 0.4 [0.8] g/24 h; P = .19), and systolic blood pressure (133.6 [14.5] vs 133.7 [17.5] mm Hg; P = .85) did not differ significantly between the 2 groups 7 years after transplant. CONCLUSIONS: Kidney transplant with grafts containing multiple renal arteries rather than grafts with a single renal artery does not significantly influence patient and graft outcomes.

Association between a polymorphism in the human programmed death-1 (PD-1) gene and cytomegalovirus infection after kidney transplantation.

BACKGROUND: Cytomegalovirus (CMV) infection is the most frequent infectious disease following organ transplantation. Strategies to prevent this infection remain a matter for debate, and discovering genetic risk factors might assist in adapting preventive strategies. By inhibiting IFNgamma production, programmed death 1 (PD-1) has a crucial role in anti-CMV immune response. A single nucleotide polymorphism (SNP) within intron 4 of the gene (rs11568821), called PD-1.3, has recently been reported to be clinically relevant in several immune disorders. However, its association with CMV infection has never been reported. METHODS: In this study, the risk of CMV infection according to PD-1.3 genotype was investigated in 469 kidney graft recipients transplanted between 1995 and 2005. RESULTS: It was found that the A allele was associated with the risk of CMV infection in seropositive patients who did not receive CMV prophylaxis (OR=2.60, p=0.006). Multivariate analysis including other risk factors for CMV infection showed that this allele was independently associated with CMV infection (OR=2.54; p=0.010). Interestingly, combined analysis of PD-1.3 with the IL12B 3'UTR SNPs (previously shown to be associated with CMV infection) revealed that patients with the PD-1.3 A allele had a much higher risk of CMV infection compared to those having neither risk allele (OR=3.76; p=0.0003). CONCLUSION: This study identified a new genetic risk factor for CMV infection after kidney transplantation and suggests that an adjustment of CMV prophylaxis based on genetic markers would merit further investigation.

A 50% reduction in cyclosporine exposure in stable renal transplant recipients: renal function benefits.

BACKGROUND: Although cyclosporine maintenance therapy reduces the risk of acute rejection and increases short-term graft survival in renal transplant recipients, its associated nephrotoxicity increases the risk of chronic graft dysfunction. The dose that allows an optimal risk-to-benefit ratio has not been established. METHODS: This multicentre study enrolled stable renal allograft recipients receiving cyclosporine and mycophenolate mofetil without corticosteroids in their second year post-transplant. Patients were randomized to a cyclosporine dose targeted to a standard area under the concentration-time curve (AUC)(0-12 h) (usual exposure, n = 104) or 50% of the study standard AUC(0-12 h) (low exposure, n = 108) using a three-point pharmacokinetic sampling. The primary endpoint was the percentage of patients with treatment failure at 24 months (graft loss/acute rejection/nephrotoxicity/>15% serum creatinine level increase). RESULTS: Treatment failure was reported in 37 out of 101 (37%) patients in the usual-exposure and 19 out of 106 (18%) patients in the low-exposure groups (P = 0.003). Mean estimated glomerular filtration rate decreased from baseline to 2 years with usual exposure and increased with low exposure (P < 0.001). Mean systolic and diastolic blood pressures were lower with low exposure (P = 0.03 and P = 0.008, respectively). CONCLUSION: In renal transplant recipients receiving maintenance therapy without corticosteroids, a minimization strategy using three-point pharmacokinetic sampling to reduce and maintain cyclosporine exposure to 50% of the usual levels is safe and reduces the risk of graft dysfunction.

Autosomal dominant polycystic kidney disease: risk factor for nonmelanoma skin cancer following kidney transplantation.

Nonmelanoma skin cancers (NMSC) are the most common malignant tumors following solid organ transplantation. Risk factors for NMSC mainly include immunosuppression, age, sun exposure and patient phototype. Recent findings have suggested that autosomal dominant polycystic kidney disease (ADPKD) may increase the risk of developing NMSC. We performed a monocenter retrospective study including all kidney recipients between 1985 and 2006 (n = 1019). We studied the incidence of NMSC, solid cancers and post-transplantation lymphoproliferative disease (PTLD), and analyzed the following parameters: age, gender, phototype, time on dialysis, graft rank, immunosuppressive regimen, history of cancer and kidney disease (ADPKD versus others). Median follow-up was 5.5 years (range: 0.02-20.6; 79 838 patient-years). The cumulated incidence of NMSC 10 years after transplantation was 12.7% (9.3% for solid cancers and 3.5% for PTLD). Autosomal dominant polycystic kidney disease and age were risk factors for NMSC (HR 2.63; P < 0.0001 and HR 2.21; P < 0.001, respectively) using univariate analysis. The association between ADPKD and NMSC remained significant after adjustments for age, gender and phototype using multivariate analysis (HR 1.71; P = 0.0145) and for immunosuppressive regimens (P < 0.0001). Autosomal dominant polycystic kidney disease was not a risk factor for the occurrence of solid cancers after transplantation (HR 0.96; P = 0.89). Our findings suggest that ADPKD is an independent risk factor for developing NMSC after kidney transplantation.

Association between a polymorphism in the IL-12p40 gene and cytomegalovirus reactivation after kidney transplantation.

BACKGROUND: Cytomegalovirus (CMV) infection is associated with a significant rate of morbidity after organ transplantation. The genetic factors influencing its occurrence have been little investigated. IL-12 plays a crucial role in anti-infectious immune responses, especially by stimulating IFNgamma production. An A-to-C single nucleotide polymorphism (SNP) within the 3'-untranslated region of the IL-12p40 gene has been characterized and was reported to be both functionally and clinically relevant. However, the impact of this single nucleotide polymorphism on events after organ transplantation has never been reported. METHODS: In this study, we investigated the impact of the 3'-untranslated region polymorphism on the occurrence of CMV infection in 469 kidney recipients transplanted at the University Hospital of Tours between 1995 and 2005. The polymorphism was genotyped using the restriction fragment length polymorphism method and CMV infection was determined by pp65 antigenemia. RESULTS: Multifactorial Cox regression analysis demonstrated that the presence of the C allele was an independent risk factor for CMV infection (OR=1.52, P=0.043), the risk being even higher when study was restricted to patients with positive CMV serological status before the graft and who did not receive any CMV prophylaxis (OR=1.88, P=0.028). CONCLUSIONS: This study identified a new genetic risk factor for CMV reactivation after kidney transplantation. The results of our study suggest that C carriers might especially benefit from CMV prophylaxis.

Recipient age and mycophenolate mofetil as the main determinants of outcome after steroid withdrawal: analysis of long-term follow-up in renal transplantation.

The long-term benefit of steroid withdrawal on patient and graft survival is unproven. Steroids were stopped within the first year after kidney transplantation in 223 consecutive low-risk patients initially treated with thymoglobulin and triple-drug therapy. The 15-year actuarial graft survival rate was 83.9%. Risk factors for graft loss were: proteinuria (hazard ratio [HR]: 6.96, P = 0.0003), creatinine >130 micromol/L (HR: 3.37, P = 0.01), recipient age <35 years (HR: 5.31, P = 0.001), and no mycophenolate mofetil (MMF) treatment (HR: 8.83, P = 0.04). Interestingly, recipient age and no MMF treatment were not risk factors in higher-risk patients in whom steroids were continued. The 2-year incidence of acute rejection following steroid withdrawal was 12.1%; the graft survival rate was lower in this group (71.1%). Our findings indicate that late steroid withdrawal results in excellent long-term outcome in most low-risk patients, but it should be attempted with caution in younger patients and when MMF is not used.

Doubling of serum creatinine in clinical trials, cost-effectiveness studies, and individual patients: adequate use in renal transplantation.

BACKGROUND: The predictive value of doubling of serum creatinine (DSC) has never been assessed in renal transplantation. We evaluated it in terms of its use for clinical trials, cost-effectiveness studies, and individual patients. METHODS: Retrospective longitudinal study in 896 renal transplant recipients. RESULTS: Death-censored graft loss occurred in 133 patients, during follow-up (up to 21 years). DSC was a risk factor for graft loss; however, the relative risk was different in patients with glomerular filtration rate less than 40 vs. more than or equal to 40 mL/min (hazard ratio: 14.5 [95% confidence interval: 7.4-28.4] vs. 47.8 [28.4-80.6], P=0.0051). Parameters influencing creatinine value (weight, age, sex) did not modify DSC's predictive value. The use of the composite endpoint DSC or death-censored graft loss instead of death-censored graft loss alone in clinical trials would reduce sample size by 7.1% to 9.0%. The annual probability of DSC to graft loss transition decreased from 76% (follow-up <1 year) to 5% (follow-up ≥10 years). Median graft half-life after DSC was 10 months [95% confidence interval: 6-18] but varied with increasing time to DSC (<1 year: 1 month [0.5-6]; 3-4.9 years: 15 months 5/67) and reference creatinine (<130 µmol/L: 3 months 2/6); ≥130 µmol/L: 25 months 15/37). CONCLUSIONS: DSC may be adequately used to refine the risk of death-censored graft loss for individual patients. However, the use of DSC as an endpoint in clinical trials marginally affects sample size, and the probability of DSC to graft loss transition is not constant, which limits the use of DSC in cost-effectiveness analyses of renal transplantation.

Immunosuppressive medications, clinical and metabolic parameters in new-onset diabetes mellitus after kidney transplantation.

New-onset diabetes after transplantation (NODAT) is a growing concern in transplantation. All modifiable risk factors are not yet identified. We assessed the relationship between baseline clinical and biochemical parameters and NODAT. Eight-hundred and fifty-seven in-Caucasian renal transplant recipients were included. Charts were individually reviewed. The follow-up was 5.3 years (ranges: 0.25-20.8; 5613 patient-years). The incidence of NODAT was 15.0%, 18.4% and 22.0% at 10, 15 and 20 years following transplantation. Age, body mass index (BMI), glucose (all P < 0.0001) and triglycerides [hazard ratio (HR) per 1 mmol/l: 1.44 [1.17-1.77], P = 0.0006] were potent risk factors whereas steroid withdrawal (HR: 0.69 [0.47-1.01], P = 0.0601) reduced the risk. As compared to cyclosporine, sirolimus (HR: 3.26 [1.63-6.49], P = 0.0008) and tacrolimus (HR: 3.04 [2.02-4.59], P < 0.0001) were risk factors for NODAT. The risk of NODAT was comparable for sirolimus (HR: 2.35 [1.06-5.19], P = 0.0350) and tacrolimus (HR: 2.34 [1.46-3.75], P = 0.0004) after adjustments on age, BMI, glucose and steroid withdrawal; however, unlike sirolimus, tacrolimus remained significant after adjustment on triglycerides. The risk of NODAT appeared similar, but its pathophysiology seemed different in sirolimus- and tacrolimus-treated patients; this observation needs confirmation. However, main independent risk factors were age, BMI, initial glucose and triglycerides.

Enalapril/amlodipine combination in cyclosporine-treated renal transplant recipients: a prospective randomized trial.

BACKGROUND: Most hypertensive renal transplant recipients require two or more antihypertensive medications to achieve blood pressure control. However, which medications must be combined is still a matter of debate. METHODS: A prospective randomized open-label blinded evaluation trial comparing the six-month effects of the amlodipine-enalapril combination (n = 32) vs. enalapril alone (n = 33) and vs. amlodipine alone (n = 34) on arterial pressure, renal function, albuminuria and tolerability. RESULTS: At six months, diastolic arterial pressure was more adequately controlled (i.e., <90 mmHg) in the combination group than in the amlodipine and enalapril groups (100% vs. 82.4% and 84.8%, respectively, p = 0.038). The same trend was observed for systolic arterial pressure (65.6% vs. 58.8% and 51.5%, NS). The six-month change in albuminuria was similar in the combination group and in the enalapril group (-64.7% vs. -59.5%); however, patients in the combination group exhibited a greater reduction in albuminuria than in the amlodipine group (-64.7% vs. -29.0%, p = 0.002). As compared with baseline values, serum creatinine and potassium remained unchanged in the combination group, whereas they increased by 9 +/- 12 micromol/L (p = 0.01) and by 0.2 +/- 0.4 mmol/L (p < 0.01), respectively, in the enalapril group. The cyclosporine trough levels remained unchanged in the combination group, but increased in the amlodipine group. CONCLUSION: Angiotensin-converting enzyme inhibitor (ACEI)-calcium-channel blocker (CCB) combination controls arterial pressure more adequately than ACEI alone or CCB alone, reduces albuminuria and may prevent the ACEI-induced initial rise in serum creatinine.

Respective predictive role of urinary albumin excretion and nonalbumin proteinuria on graft loss and death in renal transplant recipients.

Proteinuria is constituted by urinary albumin (UAE) and nonalbumin proteins (NAP). UAE was shown to predict ESRD and death. Whether NAP predicts graft or patient outcome is unknown in renal transplantation. We retrospectively analyzed the impact of UAE and NAP respectively on end-stage renal disease (ESRD) and death in 616 renal transplant recipients. In subjects with proteinuria <0.25 g/day, 76% of urine proteins were NAP; in those with >1 g/day, 44% of the urine proteins were NAP. Determinants of UAE and NAP were partly different: fasting glucose, body weight, donor cause of death and cyclosporine were significantly associated with NAP (but not UAE); panel reactive antibodies (PRA) and rapamycine were significantly associated with UAE (but not with NAP). NAP expressed as a continuous (HR: per g/day: 4.00 [2.85-5.63], p < 0.0001) or a categorical (presence vs. absence, HR = 29.09[8.80-96.20], p < 0.0001) parameter and UAE (per g/day, HR = 1.86 [1.24-2.78], p < 0.0001) were risk factors for graft loss in univariate analyses. NAP remained significant even after adjustment on UAE. The presence of NAP (HR: 5.37 [2.55-11.34], p < 0.0001) and macroalbuminuria (HR: 4.12 [1.65-10.29], p = 0.0024) were risk factors for death. Proteinuria is made of various proportions of UAE and NAP in renal transplantation; these two parameters provide different information on graft/patient survival.

Diabetes mellitus after kidney transplantation: a French multicentre observational study.

BACKGROUND: New-onset diabetes mellitus (NODM)-a common complication of kidney transplantation-is associated with increases in graft loss, morbidity and mortality. METHODS: This is a purely observational study of 527 patients taking a calcineurin inhibitor (CNI), based on data collected at a single routine visit 6-24 months after kidney transplantation. Diabetes was defined according to ADA/WHO guidelines. RESULTS: The mean age of the patients was 47.2 years and 61.1% were men; 49.5% were receiving cyclosporine microemulsion (CsA-ME) and 50.5% tacrolimus (Tac). NODM developed in 7.0% after a median interval of 1.6 months. In CsA-ME-treated patients, the unadjusted cumulative risks of NODM were 5.5% and 8.4% at 1- and 2-year post-transplantation, while in Tac-treated patients, the risks were respectively 17.4% and 21%. Four independent risk factors (RFs) were identified by multivariate analysis: maximum lifetime body mass index>25 [odds ratio (OR)=5.1], pre-transplantation impaired fasting glucose (OR=4.7), hepatitis C status (OR=4.7) and Tac vs CsA-ME treatment (OR=3.0). CONCLUSIONS: NODM is associated with certain RFs present prior to kidney transplantation, and with treatment with Tac as opposed to CsA-ME.

Early low-grade proteinuria: causes, short-term evolution and long-term consequences in renal transplantation.

Proteinuria 1 year after transplantation is associated with poor renal outcome. It is unclear whether low-grade (<1 g/24 h) proteinuria earlier after transplantation and its short-term change affect long-term graft survival. The effects of proteinuria and its change on long-term graft survival were retrospectively assessed in 484 renal transplant recipients. One- and 3-month proteinuria correlated with donor age, donor cardiovascular death, prolonged cold and warm ischemia times and acute rejection. One- and 3-month proteinuria (per 0.1 g/24 h, hazard ratio (HR): 1.07 and 1.15, p<0.0001)-especially low-grade proteinuria (HR: 1.20 and 1.26, p<0.0001)-were powerful, independent predictors of graft loss. Its short-term reduction correlated with arterial pressure (AP) (the lower the 3-month diastolic and 12-month systolic AP, the lower the risk of increasing proteinuria during 1-3 months and 3-12 months periods, respectively: Odds ratio (OR) per 10 MmHg: 0.78, p=0.01 and 0.85, respectively, p=0.02), and was associated with decreased long-term graft loss (per 0.1 g/24 h: HR: 0.88 and 0.98, respectively, p<0.0001), independently of initial proteinuria. Early low-grade proteinuria due to pre-transplant renal lesions, ischemia-reperfusion and immunologic injuries is a potent predictor of graft loss. Short-term reduction in proteinuria is associated with improved long-term graft survival.

Association of donor TNFRSF6 (FAS) gene polymorphism with acute rejection in renal transplant patients: a case-control study.

BACKGROUND: Genetic factors other than HLA have been reported to be associated with the outcome of organ transplantations. Because binding of FasL to its receptor Fas could play an important role in tubulitis and in the death of graft tubular epithelial cells during kidney allograft rejection, a gene polymorphism recently identified in position -671 in the promoter of the TNFRSF6 gene coding for Fas was investigated in donors. METHODS: A case-control study was performed within a cohort of non-hyperimmunized adult patients who had received cadaveric kidney transplants based on the occurrence or absence of acute cellular rejection in the first 6 months after renal transplantation. Each recipient from the acute rejection group (n = 35) was matched for age (+/- 5 years) and number of HLA-DR mismatches with two recipients within the non-acute rejection group (n = 70). RESULTS: The TNFRSF6-GG genotype was more frequent in donors in the group without rejection episodes. In contrast, patients who received a kidney from a TNFRSF6-A carrier were more likely to experience acute rejection episodes (relative risk nearly 2.1). CONCLUSION: This study suggests that donor TNFRSF6 polymorphism directly or indirectly influences acute kidney rejection episodes.