Hyperlipidemia as a risk factor of renal allograft function impairment

Non-Immunologic Causes of Late Death-Censored Kidney Graft Failure: A Personalized Approach

Despite continuous advances in surgical and immunosuppressive protocols, the long-term survival of transplanted kidneys is still far from being satisfactory. Antibody-mediated rejection, recurrent autoimmune diseases, and death with functioning graft are the most frequent causes of late-kidney allograft failure. However, in addition to these complications, a number of other non-immunologic events may impair the function of transplanted kidneys and directly or indirectly lead to their failure. In this narrative review, we will list and discuss the most important nonimmune causes of late death-censored kidney graft failure, including quality of the donated kidney, adherence to prescriptions, drug toxicities, arterial hypertension, dyslipidemia, new onset diabetes mellitus, hyperuricemia, and lifestyle of the renal transplant recipient. For each of these risk factors, we will report the etiopathogenesis and the potential consequences on graft function, keeping in mind that in many cases, two or more risk factors may negatively interact together.

Risk factors for complications and graft failure in kidney transplant patients with sepsis

Immunosuppressive therapies decrease the incidence of acute kidney rejection after kidney transplantation, but also increase the risk of infections and sepsis. This study aimed to identify the risk factors associated with complications and/or graft failure in kidney transplant patients with sepsis. A total of 14,658 kidney transplant patients with sepsis, identified in the National Inpatient Sample (NIS) database (data from 2005-2014), were included in the study and classified into three groups: patients without complications or graft failure/dialysis (Group 1), patients with complications only (Group 2), and patients with complications and graft failure/dialysis (Group 3). Multinomial logistic regression analyses were conducted to evaluate factors associated with kidney transplant recipients. Multivariate analysis showed that, compared to Group 1, patients from Group 2 or Group 3 were more likely to be Black and to have cytomegalovirus infection, coagulopathy, and glomerulonephritis (p ≤ 0.041). Also, Group 2 was more likely to have herpes simplex virus infection, and Group 3 was more likely to have hepatitis C infection and peripheral vascular disorders, compared to Group 1 (p ≤ 0.002). In addition, patients in Group 3 were more likely to be Black and to have hepatitis C infection, peripheral vascular disorders, coagulopathy, and hypertension compared to Group 2 (p ≤ 0.039). Age and female gender were associated with lower odds of complications after kidney transplantation regardless of graft rejection/dialysis (p ≤ 0.049). Hyperlipidemia and diabetes decreased the chance of complications and graft failure/dialysis after kidney transplant (p < 0.001). In conclusion, the study highlights that black race, male gender, and specific comorbidities can increase the risk of complications and graft failure in kidney transplant patients with sepsis.

Paediatric obesity and renal transplantation: current challenges and solutions

The increased incidence of obesity in the paediatric population poses significant challenges to renal transplantation. Whilst the body mass index appears to be widely used as a measure of obesity in adults, there are no standardised definitions in the paediatric population, making comparative analyses difficult. In the paediatric transplant population, obesity is associated with an increased incidence of surgical complications, diabetes, hyperlipidaemia and cardiovascular morbidity, leading to diminished graft function and impacting patient and graft survival. Management of obesity in renal transplantation requires multiple interventions starting with life-style and behavioural modification combined with medical and possibly surgical therapies, representing a unique challenge in the childhood setting. In this review we discuss the current challenges of obesity and potential solutions in the setting of paediatric transplantation.

Post-transplant dyslipidemia: Mechanisms, diagnosis and management

Post-transplant dyslipidemia is highly prevalent and presents unique management challenges to the clinician. The two major outcomes to consider with post-transplant therapies for dyslipidemia are preserving or improving allograft function, and reducing cardiovascular risk. Although there are other cardiovascular risk factors such as graft dysfunction, hypertension, and diabetes, attention to dyslipidemia is warranted because interventions for dyslipidemia have an impact on reducing cardiac events in clinical trials specific to the transplant population. Dyslipidemia is not synonymous with hyperlipidemia. Numerous mechanisms exist for the occurrence of post-transplant dyslipidemia, including those mediated by immunosuppressive drug therapy. Statin therapy has received the most attention in all solid organ transplant recipient populations, although the effect of proper dietary advice and adjuvant pharmacological and non-pharmacological agents should not be dismissed. At all stages of treatment appropriate monitoring strategies for side effects should be implemented so that the benefits from these therapies can be achieved. Clinicians have a choice when there is a conflict between various transplant society and lipid society guidelines for therapy and targets.

Clinical assessment of lipid profiles in live kidney donors

BACKGROUND

Abnormal serum lipid profiles are an issue in chronic kidney disease (CKD), but the clinical ramifications of dyslipidemia in live kidney donors are unclear. Thus, we explored the relationship between serum lipids and residual renal function in living donors post-nephrectomy.

METHODS

Charts of living donors who underwent nephrectomy between January 2010 and March 2013 were reviewed, targeting those with 6-month follow-up examinations at minimum. Altogether, 282 donors were studied, examining total cholesterol (TC), triglyceride (TG), low-density lipoprotein (LDL), and high-density lipoprotein (HDL) levels assayed before donation by standard techniques. Median follow-up time was 14 months. The relationship between postoperative renal function and allograft biopsy results was assessed. Recursive partitioning was applied to identify optimal cut-off points for each parameter.

RESULTS

Median (interquartile range) serum TC, TG, LDL, and HDL levels were 183 (161-205) mg/dL, 86 (63-131) mg/dL, 108 (92-128) mg/dL, and 53 (44-62) mg/dL, respectively. The glomerular filtration rate at last follow-up was associated with TC (r = -0.187; P = .002) and LDL (r = -0.172; P = .005) levels, but showed no correlation with TG and HDL. Root nodes of TC and LDL determinations in recursive partitioning were 170.5 mg/dL and 80.5 mg/dL, respectively, serving as thresholds for further evaluation. On logistic regression analysis, the likelihood of CKD (glomerular filtration rate < 60 mL/min/1.73 m(2)) at last follow-up was greater in donors with elevated TC and LDL levels (odds ratio = 1.96 and 3.33; P = .021 and .029, respectively).

CONCLUSION

Kidney donors with serum TC and LDL elevations require close observation, given their demonstrable predisposition to CKD after donation.

Obesity and kidney transplantation

Obesity confers increased risk for graft loss and death among renal transplant recipients. However the relationship of changes in body weight and composition to outcome on the transplant waitlist and post-transplantation is not straightforward. Strategies to manage weight in the waitlisted patient and after kidney transplantation must be performed in the context of a multidisciplinary approach and individualized based on risk factors in particular patients. Although retrospective studies offer considerable insights into the relationship between obesity and kidney transplant outcome, causal inferences must be made with great caution.

The role of obesity in kidney transplantation outcome

BACKGROUND

The number of obese kidney transplant candidates has been growing. However, there are conflicting results regarding to the effect of obesity on kidney transplantation outcome. The aim of this study was to investigate the association between the body mass index (BMI) and graft survival by using continuous versus categoric BMI values as an independent risk factor in renal transplantation.

METHODS

We retrospectively reviewed 376 kidney transplant recipients to evaluate graft and patient survivals between normal-weight, overweight, and obese patients at the time of transplantation, considering BMI as a categoric variable.

RESULTS

Obese patients were more likely to be male and older than normal-weight recipients (P = .021; P = .002; respectively). Graft loss was significantly higher among obese compared with nonobese recipients. Obese patients displayed significantly lower survival compared with nonobese subjects at 1 year (76.9% vs 35.3%; P = .024) and 3 years (46.2% vs 11.8%; P = .035).

CONCLUSIONS

Obesity may represent an independent risk factor for graft loss and patient death. Careful patient selection with pretransplantation weight reduction is mandatory to reduce the rate of early posttransplantation complications and to improve long-term outcomes.

Prostaglandin E2 inhibits advanced glycation end product-induced adhesion molecule expression on monocytes, cytokine production, and lymphocyte proliferation during human mixed lymphocyte reaction

Posttransplant diabetes mellitus is a frequent complication among transplant recipients. Ligation of advanced glycation end products (AGEs) with their receptor on monocytes/macrophages plays a role in diabetes complications. The enhancement of adhesion molecule expression on monocytes/macrophages activates T cells, reducing allograft survival. In previous work, we found that toxic AGEs, AGE-2 and AGE-3, induced the expression of intracellular adhesion molecule-1, B7.1, B7.2, and CD40 on monocytes, production of interferon-gamma and tumor necrosis factor alpha, and lymphocyte proliferation during human mixed lymphocyte reaction. AGE-induced up-regulation of adhesion molecule expression was involved in cytokine production and lymphocyte proliferation. Prostaglandin E2 (PGE2) concentration-dependently inhibited the actions of AGE-2 and AGE-3. The effects of PGE2 were mimicked by an EP2 receptor agonist, ONO-AE1-259-01 (11,15-O-dimethyl PGE2), and an EP4 receptor agonist, ONO-AE1-329 [16-(3-methoxymethyl)phenyl-omega-tetranor-3,7dithia PGE1]. An EP2 receptor antagonist, AH6809 (6-isopropoxy-9-oxaxanthene-2-carboxylic acid), and an EP4 receptor antagonist, AH23848 [(4Z)-7-[(rel-1S,2S,5R)-5-((1,1'-biphenyl-4-yl)methoxy)-2-(4-morpholinyl)-3-oxocyclopentyl]-4-heptenoic acid], inhibited the actions of PGE2. The stimulation of EP2 and EP4 receptors is reported to increase cAMP levels. The effects of PGE2 were reversed by protein kinase A (PKA) inhibitors and mimicked by dibutyryl cAMP and an adenylate cyclase activator, forskolin. These results as a whole indicate that PGE2 inhibited the actions of AGE-2 and AGE-3 via EP2/EP4 receptors and the cAMP/PKA pathway.

Advanced glycation end products enhance monocyte activation during human mixed lymphocyte reaction

Posttransplant diabetes mellitus (PTDM) is a frequent complication among transplant recipients. Ligation of advanced glycation end products (AGEs) with their receptor (RAGE) on monocytes/macrophages plays roles in the diabetes complications. The enhancement of adhesion molecule expression on monocytes/macrophages activates T-cells, leading to reduced allograft survival. We investigated the effect of four distinct AGE subtypes (AGE-2/AGE-3/AGE-4/AGE-5) on the expressions of intracellular adhesion molecule (ICAM)-1, B7.1, B7.2 and CD40 on monocytes, the production of interferon (IFN)-gamma and tumor necrosis factor (TNF)-alpha and the proliferation of T-cells during human mixed lymphocyte reaction (MLR). AGE-2 and AGE-3 selectively induced the adhesion molecule expression, cytokine production and T-cell proliferation. The AGE-induced up-regulation of adhesion molecule expression was involved in the cytokine production and T-cell proliferation. AGE-2 and AGE-3 up-regulated the expression of RAGE on monocytes; therefore, the AGEs may activate monocytes, leading to the up-regulation of adhesion molecule expression, cytokine production and T-cell proliferation.

Ezetimibe in Renal Transplant Patients with Hyperlipidemia Resistant to HMG-CoA Reductase Inhibitors

Hyperlipidemia affects the majority of renal transplant patients. Multiple risk factors contribute to elevated serum cholesterol including the use of certain immunosuppressant agents. HMG-Co A reductase inhibitors have become the preferred class of cholesterol-lowering medication with an increasing body of evidence to support their safety, efficacy, and outcomes in both the normal and renal transplant populations. New guidelines recommend lowering previous LDL-c goals as outcomes appears to continually improve. As a result, ezetimibe has been added to patients with persistently elevated triglycerides and/or LDL-c in individuals who possessed a renal transplant and were deemed to be on a maximum safe dose of statin agent. After the addition of ezetimibe, total cholesterol, LDL-c, and triglycerides fell by 21%, 31%, and 13%, respectively. Creatinine phosphokinase, liver enzyme serum levels, and renal function were not affected to any level of clinical significance with the addition of ezetimibe. Large interpatient variability of measurable immunosuppressant levels was seen but no serious adverse events were attributed to a change in levels.

Posttransplant Diabetes Mellitus: Impact of Good Blood Glucose Regulation on Renal Transplant Recipient Outcome

Posttransplant diabetes mellitus (PTDM) is a frequent complication among renal transplant recipients. This study sought to compare clinical outcomes of patients with PTDM who had strict glucose control with nondiabetic patients and to identify risk factors for atherosclerotic disease in both groups. We retrospectively examined 204 renal allograft recipients transplanted at our center between 1996 and 2002. Demographic features, dialysis and posttransplantation duration, smoking, body mass index, medications, comorbid diseases, number of HLA mismatches, and laboratory parameters including serum levels of creatinine, albumin, calcium, phosphorus, C-reactive protein, lipid parameters, and parathyroid hormone were analyzed as possible risk factors for atherosclerotic disease. Patients were followed for a mean of 59.7 +/- 23.6 months. PTDM was diagnosed according to the American Diabetic Association criteria or the need for an insulin/oral hypoglycemic agent. Twenty-six patients developed PTDM, and these patients had very good diabetes control. One patient with poorly regulated PTDM was excluded. Adverse events which were documented in 24 patients were more frequent among patients with PTDM. Mean age was found to be an independent risk factor for atherosclerotic disease, whereas PTDM was not. There were no differences regarding other atherosclerosis-related or other risk factors (including serum C-reactive protein levels and lipid profiles) between the groups. Nondiabetic subjects tended to have longer graft survival than patients with PTDM, but this finding was not statistically significant. PTDM is an important risk factor for developing atherosclerotic disease. Good control of blood glucose levels can decrease the high morbidity rates and negative influence of PTDM on patient and graft survival rates in this population.

What we CAN do about chronic allograft nephropathy: role of immunosuppressive modulations

Given the potency of modern immunosuppressive agents, kidney transplantation across alloantingen barriers is a routine phenomenon with excellent 1-year graft survival in most centers. However, the improvement in 1-year graft survival has not been matched by improvements in long-term graft function and chronic allograft nephropathy (CAN) remains the second commonest cause of graft attrition over time. Calcineurin inhibitors, namely cyclosporine A (CyA) and tacrolimus, have been implicated as causal agents in the development of the fibrotic processes that are the hallmarks of CAN. Many studies have, therefore, concentrated on the improvement of long term graft function through the modulation of immunosuppressive therapy. It is the purpose of this review to describe and appraise the available evidence for the prevention and management of CAN through modulation of immunosuppressive agents.

Obesity is associated with worsening cardiovascular risk factor profiles and proteinuria progression in renal transplant recipients

Obesity is associated with adverse cardiovascular (CV) parameters and may be involved in the pathogenesis of allograft dysfunction in renal transplant recipients (RTR). We sought the spectrum of body mass index (BMI) and the relationships between BMI, CV parameters and allograft function in prevalent RTR. Data were collected at baseline and 2 years on 90 RTR (mean age 51 years, 53% male, median transplant duration 7 years), categorized by BMI (normal, BMI < or = 24.9 kg/m2; pre-obese, BMI 25-29.9 kg/m2; obese, BMI > or = 30 kg/m2). Proteinuria and glomerular filtration rate (eGFR(MDRD)) were determined. Nine percent RTR were obese pre-transplantation compared to 30% at baseline (p < 0.001) and follow-up (25 +/- 2 months). As BMI increased, prevalence of metabolic syndrome and central obesity increased (12 vs 48 vs 85%, p < 0.001 and 3 vs 42 vs 96%, p < 0.001, respectively). Systolic blood pressure, fasting blood glucose and lipid parameters changed significantly with BMI category and over time. Proteinuria progression occurred in 65% obese RTR (23 (13-59 g/mol creatinine) to 59 (25-120 g/mol creatinine)). BMI was independently associated with proteinuria progression (beta 0.01, p = 0.008) but not with changing eGFR(MDRD.) In conclusion, obesity is common in RTR and is associated with worsening CV parameters and proteinuria progression.

Impact of obesity on renal transplant outcomes

Obesity is a frequent and important consideration to be taken into account when assessing patient suitability for renal transplantation. In addition, posttransplant obesity continues to represent a significant challenge to health care professionals caring for renal transplant recipients. Despite the vast amount of evidence that exists on the effect of pretransplant obesity on renal transplant outcomes, there are still conflicting views regarding whether obese renal transplant recipients have a worse outcome, in terms of short- and long-term graft survival and patient survival, compared with their non-obese counterparts. It is well established that any association of obesity with reduced patient survival in renal transplant recipients is mediated in part by its clustering with traditional cardiovascular risk factors such as hypertension, dyslipidaemia, insulin resistance and posttransplant diabetes mellitus, but what is not understood is what mediates the association of obesity with graft failure. Whether it is the higher incidence of cardiovascular comorbidities jeopardising the graft or factors specific to obesity, such as hyperfiltration and glomerulopathy, that might be implicated, currently remains unknown. It can be concluded, however, that pre- and posttransplant obesity should be targeted as aggressively as the more well-established cardiovascular risk factors in order to optimize long-term renal transplant outcomes.

Open prospective multicenter study of conversion to tacrolimus therapy in renal transplant patients experiencing ciclosporin-related side-effects

The hyperlipidemic and hypertensive effects of ciclosporin constitute a cardiovascular risk. Cosmetic side-effects are known to reduce patients' quality of life. This was a 6-month, open, prospective, multicentre study in 296 adult kidney transplant patients to evaluate the conversion from ciclosporin to a tacrolimus-based regimen. Primary indications for conversion were hyperlipidemia (n =77), hypertension (n = 72), hypertrichosis (n = 32) and gingival hyperplasia (n = 115). At month 6, hyperlipidemia and hypertension were at least moderately improved in 59.1% and 63.5% of patients, and strongly or completely resolved in 29% and 25%. Gingival hyperplasia and hypertrichosis were strongly or completely resolved in 73% and 72% of patients. Mean total cholesterol was reduced from 255 to 218 mg/dl. Mean systolic blood pressure (SBP) was reduced from 152.9 to 137.5 mmHg and mean diastolic blood pressure (DBP) from 90.7 to 85.8 mmHg. Ciclosporin-related side-effects resolved or improved after conversion to tacrolimus.

Factors Predicting Long-term Graft Survival after Kidney Transplantation: Multicenter Study in Japan

A multicenter retrospective study was conducted in 936 living donor kidney transplant recipients treated with cyclosporine (CsA) or tacrolimus (FK) from April 1982. The influences of acute rejection, hyperlipidemia, and hypertension were estimated by Kaplan-Meier's analysis and Wilcoxon's analysis. Of 916 recipients, 532 (58.1%) had acute rejections. The 5- and 10-year graft survival rates in the recipients with acute rejection were 75.2% and 55.2%, respectively. The corresponding rates of the recipients without acute rejection were 80.2% and 70.6%, respectively. The graft survival rate was worse in recipients with late-phase rejection and multiple rejection episodes (p < 0.00006). Of 451 recipients, 176 (39.0%) had hypercholesterolemia 3 years after kidney transplantation. The 5- and 10-year graft survival rates in the recipients with hypercholesterolemia were 88.7% and 68.7%, respectively. Those of the recipients without hypercholesterolemia were 95.2% and 83.9%, respectively. The graft survival rate in the recipients with hypercholesterolemia was lower than that in the recipients without hypercholesterolemia (p = 0.003). Of 323 recipients, 123 (38.1%) had hypertriglyceridemia 3 years after kidney transplantation. The 5- and 10-year graft survival rates in the recipients with hypertriglyceridemia were 93.7% and 80.5%, respectively. Those in the recipients without hypertriglyceridemia were 95.1% and 86.5%, respectively. The graft survival rate in the recipients with hypertriglyceridemia was lower than that in the recipients without hypertriglyceridemia (p = 0.371). Of 367 recipients, 151 (41.1%) had systolic hypertension 3 years after kidney transplantation. The 5- and 10-year graft survival rates in the recipients with hypertension were 85.6% and 64.7%, respectively. Those of the recipients without hypertension were 95.6% and 83.8%, respectively. The graft survival rate in the recipients with hypertension was lower than that in the recipients without hypertension (p < 0.001). Acute rejection, hyperlipidemia (hypercholesterolemia and hypertriglyceridemia), and hypertension are predictive factors for long-term graft survival. Especially the onset time, number of rejections, and efficacy of treatment for acute rejection would have a significant influence on long-term graft survival.

Cardiovascular complications of immunosuppressive agents in renal transplant recipients

Fatal and nonfatal cardiovascular events are the most important cause of graft loss in patients with a functioning graft following transplantation. The available data indicate that transplant patients have a high prevalence of hypertension, hyperlipidaemia and new onset diabetes mellitus after transplantation. The aetiology and pathogenesis of post-transplant hypertension, hyperlipidaemia and diabetes are multifactorial. In addition, disease of the native kidney and recurrence of renal disease can contribute to the development of cardiovascular disease in transplant recipients. Most transplant patients are at risk of clinically important drug-drug interactions involving immunosuppressive agents. Adverse reactions and drug-drug interactions should not be neglected when selecting an agent for treatment of cardiovascular risk factors in transplant recipients.

Aortic pulse wave velocity in renal transplant patients

BACKGROUND

In subjects with end-stage renal disease (ESRD) undergoing hemodialysis, aortic pulse wave velocity (PWV) is increased independently of blood pressure level and mostly is a strong predictor of cardiovascular risk. Few studies on this subject have been performed in renal transplant patients.

METHODS

Aortic PWV was determined noninvasively in 106 patients with kidney transplantation and treated using a standard immunosuppression protocol. Mean age was 43 +/- 14 years. During the follow-up period (mean duration 54.3 +/- 28.9 months), the following parameters were studied: characteristics of the renal graft, degree of renal insufficiency, number of acute rejections, cardiovascular risk factors, drug medications, and cardiovascular complications.

RESULTS

Aortic PWV was increased in subjects with renal transplants independently of age and mean blood pressure. Acute renal rejection and smoking habits were the principal factors modulating together: the increase of aortic PWV and the reduction of the glomerular filtration rate (GFR). The latter renal parameter was also influenced by the donor age. Two main parameters were predictors of cardiovascular events: a past history of cardiovascular disease and the pulse pressure x heart rate product, the major mechanical consequence of increased PWV.

CONCLUSION

In renal transplant subjects, tobacco consumption and mostly acute renal rejection modulate both aortic stiffness and chronic renal failure independent of blood pressure level and donor characteristics. Pulsatile stress mediates cardiovascular complications and predicts cardiovascular risk, particularly in the presence of increased heart rate.

Conversion from cyclosporine to tacrolimus improves quality-of-life indices, renal graft function and cardiovascular risk profile

Long-term use of cyclosporine after renal transplantation results in nephrotoxicity and an increased cardiovascular risk profile. Tacrolimus may be more favorable in this respect. In this randomized controlled study in 124 renal transplant patients, the effects of conversion from cyclosporine to tacrolimus on renal function, cardiovascular risk factors, and perceived side-effects were investigated after a follow-up of 2 years. After conversion from cyclosporine to tacrolimus renal function remained stable, whereas continuation of cyclosporine was accompanied by a rise in serum creatinine from 142 +/- 48 micromol/L to 157 +/- 62 micromol/L (p < 0.05 comparing both groups). Conversion to tacrolimus resulted in a sustained reduction in systolic and diastolic blood pressure, and a sustained improvement in the serum lipid profile, leading to a reduction in the Framingham risk score from 5.7 +/- 4.3 to 4.8 +/- 5.3 (p < 0.05). Finally, conversion to tacrolimus resulted in decreased scores for occurrence of and distress due to side-effects. In conclusion, conversion from cyclosporine to tacrolimus in stable renal transplant patients is beneficial with respect to renal function, cardiovascular risk profile, and side-effects. Therefore, for most renal transplant patients tacrolimus will be the drug of choice when long-term treatment with a calcineurin inhibitor is indicated.

Long-term outcome of kidney transplant using non-heart-beating donor: multicenter analysis of factors affecting graft survival

This multicenter study was retrospectively evaluated for the predictive factors affecting the long-term graft survival of a kidney transplant from a non-heart-beating donor (NHBD).

PATIENTS AND METHOD

A total of 706 patients received transplants from NHBD in 11 centers between 1986 and 2000 and the results were entered into the analysis. The patients were treated with cyclosporine- or tacrolimus-based immunosuppressive therapy. Graft survival was calculated by the Kaplan-Meier method. Factors selected for univariate analysis were donor age, and acute early and acute late rejection. Hypertension (HT), hyperlipidemia (HL), and diabetes mellitus were also analyzed in 638 recipients whose graft survived for more than 1 yr.

RESULTS

In the cases using NHBD, graft survival for 1, 5, and 10 yr was 87, 69, and 53%, respectively. Donor age of over 55 yr, acute early and late rejection, post-transplant HT and diabetes at the first post-operative year were shown to be significantly harmful on long-term graft survival. For longer graft survival in NHBD kidney transplantations, reducing acute rejection, and controlling blood pressure and sugar are crucial.

New developments in immunosuppressive therapy in renal transplantation

The introduction of new immunosuppressive agents and protocols has improved outcomes for renal transplant recipients by decreasing the risk of rejection and by increasing the function and lifespan of the allograft. This article reviews the major changes in the combinations of therapies used: calcineurin inhibitors, target of rapamycin inhibitors, mycophenolate mofetil, non-depleting monoclonal versus depleting monoclonal and polyclonal antibodies for induction and increasing emphasis on protocols for reduction or avoidance of steroids and calcineurin inhibitors. The new agents with novel immunological targets such as anti-CD40 ligand, LEA29Y, FTY720, anti-CD20 (rituximab, Rituxan, Mabthera) and anti-CH52 (alemtuzumab, Campath), which are under development but have yet to survive the rigors of clinical trials are also discussed. In the presence of low early rejection rates, immunosuppressive therapy is setting new goals such as better graft function (glomerular filtration rates), reduction in adverse effects such as hypertension, hyperlipidaemia and drug toxicity and, above all, the prevention of late graft deterioration.

The impact of body mass index on renal transplant outcomes: a significant independent risk factor for graft failure and patient death

INTRODUCTION

Renal transplant recipients with elevated body mass index (BMI) have been shown to have inferior patient survival as compared to patients with lower BMI. However, previous studies could not establish a link between increased BMI and decreased death censored graft survival. Obesity in nontransplant patients has been associated with hypertension, hyperlipidemia, type II diabetes, proteinuria and glomerulopathy. Given this evidence it is possible that renal transplant recipients with an elevated BMI may have worse long term graft survival. To investigate this hypothesis we retrospectively analyzed 51,927 primary, adult renal transplants registered in the USRDS.

METHODS

BMI at date of transplant was calculated for all patients using BMI=body weight (in kg)=.stature (height, in meters) squared. BMI values were further categorized into 11 categories: below 18, from 18 to 36 at 2 unit increments, and above 36 kg/m2. Primary study end points were graft and patient survival. Secondary study end points were death censored graft survival, chronic allograft failure, delayed graft function, and acute rejection (AR). Cox proportional hazard and logistic regression models investigated the link between categorized BMI and the study end points correcting for potential confounding variables.

RESULTS

BMI showed a very strong association with outcomes after renal transplantation. The extremes of very high and very low BMI were associated with significantly worse patient and graft survival. The same was true for death censored graft survival and chronic allograft failure. Elevated BMI was also associated with an increased risk for delayed graft function while lower BMI was significantly protective. Acute rejection did not show any significant association with BMI.

CONCLUSIONS

BMI has a very strong association with outcomes after renal transplantation independent of most of the known risk factors for patient and graft survival. The extremes of very high and very low BMI before renal transplantation are important risk factors for patient and graft survival. It is important to note that elevated BMI was significantly associated with worse graft survival independent of patient survival. Whether prospective weight adjustment before renal transplantation can favorably affect posttransplant risk needs to be assessed by further studies.