Metabolic syndrome is associated with impaired long-term renal allograft function; not all component criteria contribute equally

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 the Metabolic Syndrome on Long-Term Outcomes in Simultaneous Kidney-Pancreas Transplantation

The metabolic syndrome (MS) has been implicated as an important nonimmunologic risk factor for chronic renal transplant dysfunction. The aim of this study was to determine the impact of the MS on outcomes in simultaneous kidney-pancreas transplantation (SKPT). Data were available on 241 patients enrolled in a prospective, multicenter randomized study of daclizumab compared with no antibody induction in SKPT. Presence of MS before and after SKPT was defined using NCEP-ATP III (National Cholesterol Education Program Adult Treatment Panel III) criteria. Body mass index (BMI) was used as a surrogate for waist circumference. MS was present in 59% of patients pretransplantation but only in 19% of patients 1 year after SKPT (P < .0001). Demographic and transplant characteristics were well matched for those with MS (MS+) and without MS (MS-) at 1 year. Presence of MS at 1 year was associated with the following changes at 3 years: increased serum creatinine level (1.65 mg/dL MS- vs 2.05 mg/dL MS+; P = .13); decreased modification of diet in renal disease calculated glomerular filtration rate (GFR; 58 mL/min MS- vs 48 mL/min MS+; P = .02); increased HgbA1C level (5.6% MS- vs 6.6% MS+; P < .001); and lower pancreas graft (PG) survival rate (88% MS- vs 71% MS+; P = .01). Linear regression analysis identified MS+ and the subgroup of MS+ without functioning PG at 1 year as independent risk factors for renal dysfunction, whereas MS+ with functioning PG at 1 year was not a risk factor for renal dysfunction. Presence of MS at 1 year is associated with long-term renal dysfunction after SKPT. Efforts to decrease early PG failure may help mitigate against MS-associated renal dysfunction.

Validation of insulin resistance indexes in a stable renal transplant population

OBJECTIVE

The purpose of this study was to investigate the validity of established insulin resistance indexes, based on fasting blood parameters, in a stable renal transplant population.

RESEARCH DESIGN AND METHODS

Fasting insulin, homeostasis model assessment (HOMA), the quantitative insulin sensitivity check index (QUICKI), and McAuley's index were assessed for correlation and agreement with whole-body glucose uptake (M value) divided by prevailing serum insulin concentrations (I value) assessed during a hyperinsulinemic-euglycemic clamp in 51 stable renal transplant recipients, who were at a median of 7.5 years after transplant. Multivariate linear regression analyses were used to determine independent risk factors for insulin resistance.

RESULTS

The M/I value correlated with fasting insulin concentration (r = -0.56), HOMA (r = -0.53), QUICKI (r = 0.52), and McAuley's index (r = 0.61) (all P < 0.01). Linear regression showed agreement between all indexes and insulin resistance. However, McAuley's index showed the strongest agreement irrespective of age, sex, renal allograft function, and obesity. In multivariate analysis, fasting insulin concentration (beta = -0.59, P = 0.002), fasting triglyceride concentration (beta = -0.33, P = 0.04), and BMI (beta = -1.22, P = 0.05) were independently associated with the M/I value.

CONCLUSIONS

All investigated insulin resistance indexes were valid estimates of insulin resistance in the long-term stable renal transplant population. However, correlation and agreement were strongest for McAuley's index. In addition to fasting insulin and triglyceride concentrations, of which McAuley's index is composed, only BMI seemed to be independently associated with insulin resistance in this population.

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.