Predicting coronary heart disease in renal transplant recipients: A prospective study

Chronic kidney disease management: comparison between renal transplant recipients and nontransplant patients with chronic kidney disease

BACKGROUND/AIM

Renal transplant recipients (RTR) and patients with native chronic kidney disease (CKD) have similar complications. It is not known how the management of CKD in RTR differs from that of patients with native CKD. This study compares the management of complications related to CKD between RTR and patients with native CKD.

METHODS

Cross-sectional study of all RTR with stage 4 or 5 CKD (n = 72). The control group consisted of 72 native CKD patients matched by glomerular filtration rate (within 2 ml/min/1.73 m(2)). Multivariate logistic regression analysis was performed to account for potential confounding variables.

RESULTS

Multivariate analysis revealed RTR to more likely have uncontrolled hypertension (adjusted odds ratio AOR 3.8; 95% confidence interval CI 1.3-10.7), less likely to be on angiotensin-converting enzyme inhibitors (AOR 0.11; 95% CI 0.04-0.32), more likely to be anemic and not be on erythropoietin (AOR 6.4; 95% CI 0.99-41.9), and more likely to have dyslipidemia and not be on statin (AOR 4.3; 95% CI 1.4-13.4).

CONCLUSIONS

This study suggests that the management of non-RTR in a multidisciplinary CKD clinic differs significantly from the CKD management in a traditional transplant clinic. A disease management approach like a multidisciplinary clinic may be an appropriate model for the future.

Metabolic Syndrome and Atherosclerotic Events in Renal Transplant Recipients

BACKGROUND

Metabolic syndrome (MS) is a known cardiovascular risk factor in the general population. We explored the influence of MS on the occurrence of atherosclerotic events (AEs) after renal transplantation.

METHODS

Three hundred thirty-seven renal transplant recipients were included in the study. Various parameters (e.g., anthropometric and biological) were measured 1 year after transplant.

RESULTS

One year after transplant, 32% of the study population met criteria for MS. Older age, male gender, pretransplant high body mass index, and an increase in body mass index>or=5% in the first year after transplant were predictive factors for development of MS at 1 year after transplant. Forty-two patients (12.4%) experienced AEs during the 8 years of follow-up. The cumulated incidence of AEs was greater in patients with MS compared with others without MS (25% vs. 7%; P<0.001). In multivariate analysis, patients with MS at 1 year after transplant had an increased risk of AE (hazard ratio 3.40, 95% confidence interval 1.58-7.32, P=0.002). Older age, low creatinine clearance, high C-reactive protein level, and a past history of cardiovascular disease were other independent risk factors for AE.

CONCLUSIONS

Similar to the general population, MS is an independent risk factor for AE after renal transplantation. Relevant preventive measures targeting different aspects of MS would then have a potential impact on prevalence of AE in this population.

A J-shaped association between high-sensitivity C-reactive protein and mortality in kidney transplant recipients

In kidney transplant recipients (KTR), C-reactive protein (CRP) has been shown to be associated with increased mortality, but data on this association within the high-sensitivity (hs) range of CRP (<5 mg/l) are lacking. We prospectively studied 710 prevalent and stable KTR over >6 years. We thawed frozen plasma and measured baseline hs-CRP using an ultrasensitive assay. Detailed clinical and demographic baseline characteristics were available for study. We stratified patients by quartile of hs-CRP within the hs range (<5 mg/l), and also included KTRs whose hs-CRP was above the hs range (>5-10 and >10 mg/l). We used multivariate proportional hazards models to test for independent associations. After careful multivariate adjustment, we found a J-shaped association between hs-CRP and mortality. Compared with KTR whose hs-CRP was in the second lowest quartile of hs-CRP (0.06-1.26 mg/l), patients in the lowest quartile (<0.06 mg/l) had more than twice their mortality risk (HR = 2.07; 95% CI: 1.05-4.07), as did patients whose hs-CRP was > or =2.44 mg/l (all HRs >2.27). No association was found between hs-CRP and death-censored allograft loss. In contrast to the general population, the association between hs-CRP and mortality in KTRs is not linear, but J-shaped, suggesting that KTRs with very low hs-CRP may also be at increased risk of death.

Mycophenolate mofetil and C-reactive protein in renal transplant recipients

BACKGROUND

C-reactive protein (CRP) is a strong predictor of cardiovascular disease, all-cause mortality, and renal allograft loss. Little is known about the effects of immunosuppressive and cardiovascular risk-modifying drugs on CRP in renal transplant recipients.

METHODS

We retrospectively identified stable patients with > or =1 highly sensitive CRP measurements between January 1 and August 31, 2005. Variables collected included patient demographics; transplant, dialysis, and cardiovascular disease-related variables; and medication profiles. Univariate correlations with CRP were assessed by unpaired Student t testing, analysis of variance, or chi analysis and followed by multivariate linear regression with stepwise backward elimination until a final stable model was attained.

RESULTS

CRP levels were obtained in 298 recipients. In univariate analysis, body mass index (P<0.0001) and systolic blood pressure (P=0.009) showed a positive correlation, whereas number of immunosuppressive drugs (P=0.05) and use of mycophenolate mofetil (MMF) (P=0.003) were negatively correlated with CRP levels. By multivariate analysis, only body mass index (P<0.0001) and MMF dose (P<0.0001) were independently and opposingly correlated with CRP. Mean CRP level was 5.18+/-5.7 mg/L in patients not taking MMF compared with 3.13+/-3.5 mg/L in those on 2000 mg per day (P=0.002).

CONCLUSIONS

MMF use correlates inversely with CRP levels in renal transplant recipients, suggesting that immunosuppressive regime design may alter allograft and cardiovascular disease risk in these patients. Prospective study of the effects of MMF on novel cardiovascular disease risk factors such as CRP is warranted.

Metabolic and nutritional complications of renal transplantation

Renal transplantation is the gold standard therapy for patients with end-stage renal disease. However, renal transplantation is associated with various metabolic and nutritional complications. This review focuses primarily on factors that have a significant impact on cardiovascular disease, namely, hyperlipidemia, posttransplant diabetes mellitus, and hyperhomocysteinemia. The prevalence of hyperlipidemia in renal transplant patients is estimated at 80% to 90%. Corticosteroids, cyclosporine, and sirolimus are commonly associated with hyperlipidemia. The incidence of posttransplant diabetes mellitus is estimated to be 24% at 36 months post transplant. Glucocorticoids induce metabolic changes that result in hyperglycemia. Calcineurin inhibitors have direct islet cell toxicity and induced alterations in the transcriptional regulation of insulin. Hyperhomocysteinemia is common in renal transplant recipients and is an independent risk factor for cardiovascular disease.

The use of oral glucose tolerance tests to risk stratify for new-onset diabetes after transplantation: An underdiagnosed phenomenon

BACKGROUND

Fasting glucose measurements are insensitive at detecting new-onset diabetes after transplantation (NODAT) and ignore the diagnosis of impaired glucose tolerance (IGT). Both NODAT and IGT confer a higher risk of developing cardiovascular disease. IGT is also a risk factor for NODAT. The aim of this study was to use an oral glucose tolerance test (OGTT) to risk stratify for NODAT and IGT in renal transplant recipients and to relate cardiovascular and phenotypic risk with glycemic dysregulation.

METHODS

In all, 858 renal transplant recipients are under follow up at the University Hospital of Wales, Cardiff, UK. Excluded patients had pretransplant diabetes (78), NODAT (89), or were transplanted less than six months (47), leaving 646 recipients. All remaining recipients with two fasting blood glucoses between 5.6 and 6.9 mmol/L were invited to have an OGTT. A diagnosis of NODAT, IGT, and impaired fasting glucose (IFG) was based on World Health Organization guidelines.

RESULTS

We identified 134 patients who fulfilled the inclusion criteria, of whom 122 had an OGTT (91% of cohort). In all, 51% of patients were found to have abnormal glucose metabolism: 10% NODAT, 14% combined IGT/IFG, 9% IGT alone, and 18% IFG alone. Clinical phenotype was not predictive of diabetic risk on multivariate analysis.

CONCLUSIONS

Our results confirm fasting glucose underestimates the prevalence of NODAT and ignores the prevalence of IGT. These findings suggest routine use of an OGTT in renal transplant recipients is a valuable clinical tool to risk stratify each patient for the development of NODAT and cardiovascular disease.

Therapy Insight: management of cardiovascular disease in the renal transplant recipient

Cardiovascular disease causes the deaths of up to 50% of renal transplant recipients who have a functioning graft. As in other states of chronic kidney disease, both overload cardiomyopathy (chronic heart failure and left ventricular hypertrophy) and ischemic heart disease are evident; age and gender are important risk factors for both of these disorders. Potentially treatable risk factors include smoking, hyperlipidemia, diabetes and hypertension for ischemic heart disease, and anemia, hypertension and diabetes for cardiomyopathy. Although definitive evidence on the effectiveness of interventions is lacking, it seems reasonable to treat renal transplant recipients as patients at the highest risk of cardiovascular disease. Aggressive targeting of lifestyle factors, blood pressure, cholesterol and sugar regulation is likely to have a major impact on patient and graft survival and should be initiated well before transplantation. Maintenance of hemoglobin with erythropoietic agents is controversial but might improve quality of life. Although immunosuppressive agents have distinct effects on cardiovascular risk factors, the impact on outcomes is impossible to predict on the basis of current data, and no firm recommendations can be made.

Relative risk of new-onset diabetes during the first year after renal transplantation in patients receiving tacrolimus or cyclosporine immunosuppression

Clinical trials have consistently shown a higher incidence of new-onset diabetes mellitus with tacrolimus than cyclosporine. However, in protocol-driven studies steroid doses are comparable in both treatment arms, while in clinical practice steroid dose used in conjunction with tacrolimus or cyclosporine may differ. This retrospective study analysed renal transplant recipients without pre-existing diabetes receiving tacrolimus (n = 100) or cyclosporine (n = 100) for whom one-year follow-up data were available. Diabetes was defined as use of insulin or oral hypoglycemic agents; fasting glucose >6.9 mmol/L; or non-fasting glucose >11 mmol/L on three consecutive occasions. Tacrolimus-treated patients were significantly older than cyclosporine-treated patients (49 +/- 14 vs. 44 +/- 13 yr, p < 0.05) and received a significantly lower cumulative dose of corticosteroids over the first three months post-transplant (1284 +/- 379 vs. 1714 +/- 486 mg, p < 0.0001). At 3, 6, 9 and 12 months significantly more tacrolimus-treated patients had new-onset diabetes than cyclosporine- treated patients. At 12 months, 18 patients receiving tacrolimus and two receiving cyclosporine had diabetes (p < 0.0001). There was a clear relationship between age and incidence of new-onset diabetes at three months in the tacrolimus cohort. After stratifying patients by age group, the frequency of diabetes was significantly higher with tacrolimus than with cyclosporine in patients aged 40-60 yr [8/46 (17.4%) vs. 2/48 (4.2%), p < 0.05] and >60 yr [9/28 (32.1%) vs. 0/14 (0%), p < 0.05]. The mean tacrolimus trough level during the first three months was similar in patients with diabetes (13.1 +/- 2.3 ng/mL) or without diabetes (13.0 +/- 2.8 ng/mL, n.s.). These results indicate that new-onset diabetes is strongly and significantly associated with tacrolimus vs. cyclosporine in renal transplant recipients, even when steroid dosing is lower with tacrolimus.

Cardiovascular Biomarkers in CKD: Pathophysiology and Implications for Clinical Management of Cardiac Disease

Cardiovascular disease (CVD) is a major cause of morbidity and mortality in patients with all forms of chronic kidney disease (CKD). The underlying pathological state is caused by a complex interplay of traditional and nontraditional risk factors that results in atherosclerosis, arteriosclerosis, and altered cardiac morphological characteristics. This multifactorial disease introduces new challenges in predicting and treating patients with CVD sufficiently early in the course of CKD to positively alter patient outcome. Asymptomatic individuals with progressive CVD are a group of patients that deserve focused attention because early detection and intervention may provide the best opportunity for improved outcome. However, identifying CVD in asymptomatic patients with CKD or end-stage renal disease remains a significant hurdle in the management of these patients. Recently, a number of cardiovascular biomarkers were identified as predictors of patient outcome in individuals with CVD and, with additional research, may be used to guide the early diagnosis of and therapy for CVD in patients with CKD. This review examines the pathophysiological characteristics and potential clinical role of these novel cardiovascular biomarkers in risk stratification, risk monitoring, and selection of preventive therapies for patients with CKD.

Cardiovascular events following renal transplantation: role of traditional and transplant-specific risk factors

Cardiovascular mortality is increased in transplant recipients. However, studies including non-fatal events are critical to assess the burden of disease and to identify novel risk factors. We described the incidence of fatal and non-fatal events, and explored associations and interactions among traditional and transplant-specific risk factors and cardiovascular events (CVE) in a cohort of 922 patients transplanted between 1993 and 1998. One hundred and seventy-six patients experienced 201 CVE (111 cardiac, 48 cerebrovascular, 42 peripheral-vascular). Most CVE were non-fatal. Factors associated with cardiac events were (adjusted hazard ratios) tobacco (3.53; P<0.001), obesity (2.92; P<0.001), diabetes (2.63; P<0.001), multiple rejections (2.19; P=0.008), prior CVE (2.0; P=0.004), dialysis >1 year (1.91; P=0.007), and overweight status (1.68; P=0.04); with cerebrovascular events: diabetes and peritoneal dialysis (11.95; P<0.001), age >45 (6.77; P<0.001), diabetes (4.87; P<0.001), prior CVE (3.73; P<0.001), creatinine >141 micromol/l (3.16; P=0.001), peritoneal dialysis (3.06; P=0.027), and obesity (0.32; P=0.046); with peripheral-vascular events: diabetes (8.48; P<0.001), tobacco and cytomegalovirus (3.88; P<0.001), age >45 (2.31; P=0.019), and prior CVE (2.25; P=0.016); with mortality: tobacco and deceased-donor (3.52; P<0.001), age >45 (1.81; P=0.002), diabetes (1.76; P=0.002), pulse pressure (1.64; P=0.029), prior CVE (1.52; P=0.04), and dialysis >1 year (1.47; P=0.04). The majority of CVE post-transplant were non-fatal. Previous CVE was strongly associated with CVE post-transplant. Interactions among transplant-specific and traditional risks impacted significantly the incidence of CVE. Modifiable factors such as duration of dialysis, deceased-donor transplantation, and acute rejection should be viewed as cardiovascular risks.

Renal transplant dysfunction--importance quantified in comparison with traditional risk factors for cardiovascular disease and mortality

BACKGROUND

Renal transplant recipients (RTR) mainly die of premature cardiovascular disease. Traditional cardiovascular disease risk factors are prevalent in RTR. Additionally, non-traditional risk factors seem to contribute to the high risk. The impact of renal dysfunction was compared with traditional risk factors for cardiovascular morbidity and mortality in 1052 placebo-treated patients of the ALERT trial.

METHODS

All patients were on cyclosporine-based immunosuppressive therapy, follow-up was 5-6 years and captured endpoints included cardiac death, non-cardiovascular death, all-cause mortality, major adverse cardiac event (MACE), non-fatal myocardial infarction (MI) and stroke.

RESULTS

A calculated 84 micromol/l increase in serum creatinine was needed to double the risk for cardiac death, an increase of 104 micromol/l to double the risk for non-cardiovascular death and an increase of 92 micromol/l to double the risk for all-cause mortality. MACE risk was doubled if serum creatinine was elevated by 141 micromol/l, age was increased by 23 years, or LDL-cholesterol by 2 mmol/l. Diabetes increased the incidences of cardiac death, all-cause mortality, MACE, stroke and non-fatal MI. A serum creatinine increase of approximately 130 micromol/l, or approximately 20 years increase in age was calculated as similar in risk for cardiac death, all-cause mortality and MACE, and comparable to risk of diabetes in RTR.

CONCLUSION

An increase in serum creatinine of 80-100 micromol/l doubles the risk for cardiac death, non-cardiovascular death and all-cause mortality in RTR. An increase of 130 micromol/l in serum creatinine or approximately 20 years increase in age is comparable to risk of diabetes.

Medical Care of Kidney Transplant Recipients after the First Posttransplant Year

Kidney transplantation is the treatment of choice for patients with ESRD. Despite improvements in short-term patient and graft outcomes, there has been no major improvement in long-term outcomes. The use of kidney allografts from expanded-criteria donors, polyoma virus nephropathy, underimmunosuppression, and incomplete functional recovery after rejection episodes may play a role in the lack of improvement in long-term outcomes. Other factors, including cardiovascular disease, infections, and malignancies, also shorten patient survival and therefore reduce the functional life of an allograft. There is a need for interventions that improve long-term outcomes in kidney transplant recipients. These patients are a unique subset of patients with chronic kidney disease. Therefore, interventions need to address disease progression, comorbid conditions, and patient mortality through a multifaceted approach. The Kidney Disease Outcomes Quality Initiative from the National Kidney Foundation, the European Best Practice Guidelines, and the forthcoming Kidney Disease: Improving Global Outcomes clinical practice guidelines can serve as a cornerstone of this approach. The unique aspects of chronic kidney disease in the transplant recipient require the integration of specific transplant-oriented problems into this care schema and a concrete partnership among transplant centers, community nephrologists, and primary care physicians. This article reviews the contemporary aspects of care for these patients.

Validation of cardiovascular risk scores in a liver transplant population

Increased prevalence of cardiovascular risk factors has been acknowledged in liver transplant recipients, and an increased incidence of cardiovascular events has been suspected. Individual risk determination, however, has not yet been established. Outpatient charts of 438 primary liver transplants have been reviewed, and suspected cardiovascular risk factors were correlated with cardiovascular events observed during a follow-up period of 10 yr. Receiver operation characteristics curve (ROC) analysis was performed to validate established cardiovascular risk scores. For calibration, the Hosmer-Lemeshow test was performed. A total of 303 of 438 patients were available for risk factor analysis at 6 months and demonstrated complete follow-up data (175 male, 128 female). A total of 40 of those 303 patients experienced fatal or nonfatal cardiovascular events (13.2%). In univariate analysis, age (P < 0.001), gender (P = 0.002), body mass index (P = 0.018), cholesterol (P = 0.044), creatinine (P = 0.006), diabetes mellitus (P = 0.017), glucose (0.006), and systolic blood pressure (P = 0.043), but not cyclosporine A (P = 0.743), tacrolimus (P = 0.870), or steroid medication (P = 0.991), were significantly associated with cardiovascular events. Multivariate analysis, however, identified only age, gender, and cholesterol as independent predictors. In ROC analysis, corresponding areas under the curve for Systematic Coronary Risk Evaluation Project (SCORE), Prospective Cardiovascular Münster Study (PROCAM), and Framingham risk scores (FRSs) were calculated with 0.800, 0.778, and 0.707, respectively. Calibration demonstrated an improved goodness of fit for PROCAM compared to SCORE risk calculations. In conclusion, SCORE and PROCAM proved to be valuable in discriminating our liver transplant recipients for their individual risk of cardiovascular events. Furthermore, calibrated PROCAM risk estimates are required to calculate the number of patients needed to treat in the setup of prospective intervention trials.

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.

Effects of single-nucleotide polymorphisms in MTHFR and MTRR on mortality and allograft loss in kidney transplant recipients

BACKGROUND

Plasma total homocysteine (tHcy) is associated with cardiovascular outcomes in kidney transplant recipients (KTR). The methylenetetrahydrofolate-reductase (MTHFR) 677C>T polymorphism, an important determinant of plasma tHcy concentrations, could therefore constitute an important prognostic marker.

METHODS

We prospectively followed 710 KTR over >6 years. The MTHFR677C>T, MTHFR1298A>C, MTHFR1793G>A, and MTRR66A>G polymorphisms were analyzed. Demographic, clinical, and transplant-related information was obtained, and patients were followed-up using the Austrian Dialysis and Transplant Registry. Using Cox regression, we established the independent relations of each genotype to the risk of death from any cause, and/or kidney allograft loss.

RESULTS

During a median follow-up of 6.1 years, 154 participants died and 260 kidney allografts were lost. Compared to patients with the MTHFR677CC genotype, patients with MTHFR677CT had an adjusted relative mortality risk of 1.02 (95%CI 0.70-1.47), and those with MTHFR677TT of 0.98 (95%CI 0.52-1.85). Compared to MTHFR677CC, the relative risks of kidney allograft loss were 0.93 (95%CI 0.70-1.23; MTHFR677CT) and 0.78 (95%CI 0.47-1.30; MTHFR677TT), respectively. None of the other genotypes were associated with the risks studied, either. These findings did not depend on whether we controlled for tHcy levels.

CONCLUSION

This study does not support the routine use of MTHFR or MTRR genotyping for prognostic evaluation or risk-stratification in kidney transplant recipients.

The clinical epidemiology of cardiovascular disease in chronic kidney disease

PURPOSE OF REVIEW

To review recent publications concerning the epidemiology and management of cardiovascular disease in the stages of chronic kidney disease.

RECENT FINDINGS

Chronic kidney disease is a state of increased risk for atherosclerotic and cardiomyopathic disease. The mechanisms of cardiovascular disease probably change with the different stages of chronic kidney disease. Both proteinuria and decreased glomerular filtration rate are probably independent cardiovascular disease risk factors, although the impact of the latter is modest. Traditional risk factors are important predictors of cardiovascular disease in chronic kidney disease. Recent randomized controlled trials and cohort studies have supported interventions for smoking cessation, blood pressure control, renin-angiotensin system blockade, the correction of lipid abnormalities, and utilizing antiplatelet agents. Some uraemia-related risk factors predict the development of cardiovascular disease, particularly hypoalbuminaemia, inflammation, anaemia, and homocysteinaemia. However, randomized controlled trials of anaemia correction and of an increased quantity of dialysis were negative.

SUMMARY

The role of oxidant stress, divalent ion abnormalities, various lipid abnormalities and other potential factors require further investigation. To determine whether these uraemia-related factors are markers of cardiovascular disease risk or are actually cardiotoxic requires additional randomized controlled trials.

Abdominal obesity and smoking are important determinants of C-reactive protein in renal transplant recipients

BACKGROUND

C-reactive protein (CRP) is a predictor of coronary heart disease, total mortality and chronic allograft nephropathy in renal transplant recipients. The determinants of CRP have been investigated in the general population, but not in renal transplant recipients. CRP might reflect metabolic aberrations in association with central obesity and systemic atherosclerosis. However, it may also reflect a low-grade immune-mediated response to the graft. In this study we investigated the factors associated with CRP in a renal transplant population.

METHODS

Between August 2001 and July 2003, renal transplant recipients with a functioning graft for more than 1 year (n = 847) were eligible for investigation at their next visit to the outpatient clinic. A total of 606 patients (55% male, aged 51+/-12 years) participated at a median (interquartile range) time of 6.0 (2.6-11.4) years post-transplant.

RESULTS

Median CRP concentration was 2.0 (0.80-4.8) mg/l and mean 24 h creatinine clearance was 62+/-22 ml/min. CRP was significantly associated with body mass index, waist circumference and waist-to-hip ratio (P-value < 0.0001). None of the transplant characteristics except creatinine clearance was associated with CRP. In multiple regression analysis, waist circumference, log sICAM-1 concentration, gender, creatinine clearance and current smoking were independently associated with CRP.

CONCLUSIONS

In renal transplant recipients waist circumference and smoking are the two most important modifiable independent determinants of CRP. Furthermore, CRP is independently associated with the endothelial function parameter sICAM-1 and, in univariate analyses, associated with multiple cardiovascular risk factors. CRP is not associated with any of the transplant-related factors, except for renal transplant function.

Markers of Inflammation Before and After Renal Transplantation

BACKGROUND

This study aims to compare serum C-reactive protein (CRP), interleukin (IL-6), and tumor necrosis factor (TNF)-alpha in end-stage renal disease (ESRD) patients before versus after receiving renal transplantation (RT) and versus donors.

METHODS

Serum samples from 37 ESRD patients (24 male, age 34+/-13 years) were collected before and after RT; in addition, samples from 31 donors were obtained at transplantation. CRP concentrations were measured using nephelometry, and TNF-alpha and IL-6 were measured by enzyme-linked immunoadsorbent assay.

RESULTS

Ninety-two percent of recipients had a living donor, 73% received cyclosporine A, 27% tacrolimus, and 70% induction with daclizumab. Thirteen percent had acute rejection and 16% chronic allograft nephropathy. All inflammation markers decreased 6 months after RT, but only CRP was below baseline values (baseline: 5.0+/-3.5; 6 months: 3.0+/-0; 12 months: 3.2+/-0.7; 18 months: 3.2+/-0.6; donors: 3.6+/-1.5 mg/L; P<0.05), whereas median TNF-alpha (baseline: 0.1 [0.03-0.2]; 6 months: 0 [0-0.1]; 12 months: 0.3 [0.1-2.6]; 18 months: 0.6 [0.1-1.9]; donors: 0 [0-0.1] pg/mL; P<0.05) and IL-6 (baseline: 1.9 [1.2-7.1]; 6 months: 1.2 [0.6-28.3]; 12 months: 2.6 [1.3-3.4]; 18 months: 2.7 [1.7-4.2]; donors: 1.1 [0.6-1.9] pg/mL; P<0.05) significantly increased up to the end of follow-up. Before RT, CRP correlated with age (r 0.45, P=0.006) and albumin (r -0.36, P=0.04). TNF-alpha and IL-6 were correlated before (r 0.34, P=0.04) and after (r 0.55, P=0.02) RT. Inflammation markers were not different in patients who had acute rejection episodes or chronic nephropathy.

CONCLUSIONS

Compared with controls, patients displayed an inflammatory phenomenon before receiving RT. Serum CRP decreased significantly after RT, whereas TNFalpha and IL-6 increased.

Relevance of Toll-like receptor-4 polymorphisms in renal transplantation

BACKGROUND

Polymorphisms in Toll-like receptor-4 (TLR4) have been reported to be associated with a blunted immune response to microbial pathogens, as well as a decreased risk of atherosclerosis in the general population. We assessed the impact of the two TLR4 variants on the risk of severe infection, the incidence of acute rejection, and the occurrence of atherosclerotic complications in renal transplant recipients (RTR).

METHODS

TLR-4 polymorphisms were assessed in a cohort of 238 RTR. Post-transplant atherosclerotic events, acute rejection, severe bacterial infection, cytomegalovirus (CMV) disease, and opportunistic infections were evaluated as outcomes.

RESULTS

The patients were followed for a mean duration of 95 +/- 29 months after transplant. TLR4 polymorphism was observed in 27 (11.3%) RTR. Subjects with TLR4 polymorphisms were less likely to experience post-transplant atherosclerotic events (RR 0.44; 95% CI 0.21 to 0.93; P= 0.02) and acute rejection (RR 0.41; 95% CI 0.30 to 0.83; P= 0.01), but presented severe bacterial infections (RR 1.33; 95% CI 1.12 to 1.67; P= 0.01) and opportunistic infections (RR 3.03; 95% CI 1.72 to 8.29; P= 0.008) more frequently. TLR4 polymorphism was marginally associated with CMV disease (RR 1.47; 95% CI 0.95 to 2.64; P= 0.08).

CONCLUSION

RTR with TLR4 polymorphism present a lower risk of post-transplant atherosclerotic events and acute allograft rejection, but experience severe infectious episodes more frequently. This subset of RTR may benefit from a less potent immunosuppression regimen, along with increased preventive measures against infectious agents.

Posttransplant Diabetes Mellitus and Atherosclerotic Events in Renal Transplant Recipients: A Prospective Study

BACKGROUND

Posttransplant diabetes mellitus (PTDM) is a frequent complication in renal-transplant recipients (RTRs). We conducted a prospective study to assess the potential role of PTDM in the development of atherosclerotic events (AE) in RTRs.

METHODS

Three hundred fifty-seven consecutive RTRs were enrolled in this study. The incidence of various AE were assessed with respect to the presence of PTDM and a number of cardiovascular (CV) risk factors.

RESULTS

The patients were followed for a mean duration of 60+/-14 months. Thirty-nine (11%) patients had PTDM. Fifty AE occurred in 48 (13.4%) patients. Although AE were more frequent in RTRs with PTDM compared with nondiabetic patients (33% vs. 8.8%; P=0.007), PTDM was only modestly associated with AE in the multivariate Cox regression analysis (relative risk [RR] 1.34; 95% confidence interval [CI], 1.04-2.18), mostly caused by significant interactions between PTDM and three confounding variables that were independently associated with AE: age, serum C-reactive protein (CRP) level, and serum high-density lipoprotein cholesterol concentration. Patients with high levels of homocysteine showed a significantly increased risk of AE (RR 4.67; 95% CI 1.82-15.87), as did those with high serum levels of CRP (RR 2.57; 95% CI 1.57-6.23).

CONCLUSIONS

Our study shows a significant association between PTDM and AE. Nevertheless, a large amount of the excess risk of posttransplant diabetic RTR is explained by the coexistence of other CV risk factors. Moreover, high serum levels of CRP and hyperhomocystinemia were found to be among the nontraditional factors contributing to AE in our patients.

Incidence and predictors of myocardial infarction after kidney transplantation

The risk and predictors of post-kidney transplantation myocardial infarction (PTMI) are not well described. Registry data collected by the United States Renal Data System were used to investigate retrospectively PTMI among adult first renal allograft recipients who received a transplant in 1995 to 2000 and had Medicare as the primary payer. PTMI events were ascertained from billing and death records, and participants were followed for up to 3 yr after transplant or until the end of observation (December 31, 2000). Extended Cox's hazards analysis was used to identify independent clinical correlates of PTMI (hazard ratio [HR]) and to examine PTMI as an outcomes predictor. Among 35,847 eligible participants, the cumulative incidence of PTMI was 4.3% (95% confidence interval [CI], 4.1 to 4.5%), 5.6% (95% CI, 5.3 to 5.8%), and 11.1% (95% CI, 10.7 to 11.5%) at 6, 12, and 36 mo, respectively. Risk factors for PTMI included older recipient age, pretransplantation comorbidities (diabetes, angina, peripheral vascular disease, and MI), transplantation from older donors and deceased donors, and delayed graft function. Women, blacks, Hispanics, and employed recipients experienced reduced risk. The hazard of PTMI rose after a diagnosis of posttransplantation diabetes (HR, 1.60; 95% CI, 1.35 to 1.88) and markedly increased after graft failure (HR, 2.78; 95% CI, 2.41 to 3.19). In separate analyses, PTMI predicted death-censored graft failure (HR, 1.89; 95% CI, 1.63 to 2.20) and strongly predicted death in a manner that declined with time after PTMI. Risk factors for PTMI include potentially modifiable posttransplantation complications. Because PTMI in turn predicts graft failure and death, reducing the risk for PTMI may improve outcomes after kidney transplantation.