Metabolic syndrome and cardiovascular risk in renal transplant recipients: effects of statin treatment

Coronary artery disease in lung transplant patients

Coronary artery disease (CAD) is a pathology often found in patients with end-stage lung disease. Although in the past CAD might have been considered an absolute contraindication, modern revascularization techniques have helped increase the number of transplants performed in this population. However, discrepancies in the guidelines for perioperative evaluation and risk mitigation strategies for the ischemic cardiac burden are present in the current literature. This is a review of the available data regarding perioperative evaluation, revascularization tactics, postoperative management, and survival rate that patients with different grades of coronary artery disease present after lung transplantation.

Management of metabolic alterations in adult kidney transplant recipients: A joint position statement of the Italian Society of Nephrology (SIN), the Italian Society for Organ Transplantation (SITO) and the Italian Diabetes Society (SID)

Chronic metabolic alterations such as post-transplant diabetes mellitus (PTDM), dyslipidaemias and overweight/obesity significantly impact on kidney transplant (KT) outcomes. This joint position statement is based on the evidence on the management of metabolic alterations in KT recipients (KTRs) published after the release of the 2009 KDIGO clinical practice guideline for the care of KTRs. Members of the Italian Society of Nephrology (SIN), the Italian Society for Organ Transplantation (SITO) and the Italian Diabetes Society (SID) selected to represent professionals involved in the management of KTRs undertook a systematic review of the published evidence for the management of PTDM, dyslipidaemias and obesity in this setting. The aim of this work is to provide an updated review of the evidence on the prevention, diagnosis and treatment of metabolic alterations in KTRs, in order to support physicians, patients and the Healthcare System in the decision-making process when choosing among the various available options.

Serum Apolipoprotein B and A1 Concentrations Predict Late-Onset Posttransplant Diabetes Mellitus in Prevalent Adult Kidney Transplant Recipients

Background

Glucose metabolism links closely to cholesterol metabolism. Posttransplant diabetes mellitus (PTDM) adversely affects posttransplant outcomes, but its risk factors in relation to cholesterol metabolism have not been fully delineated. The apolipoprotein B/A1 (Apo B/A1) ratio, which is associated with insulin resistance, has not been evaluated in kidney transplant recipients as a risk factor for PTDM.

Objective

The objective of this study was to determine whether serum apolipoprotein profiles predict late PTDM, defined as a new onset diabetes occurring greater than 3 months posttransplant.

Design

Retrospective chart review of a prevalent population of kidney transplant recipients.

Setting

Large transplant center in Ontario, Canada.

Patients

We identified 1104 previously nondiabetic adults who received a kidney transplant between January 1, 1998, and December 1, 2015, and were followed at 1 transplant center.

Measurements

Recipients provided testing for serum apolipoprotein B (Apo B) and apolipoprotein A1 (Apo A1) concentrations from 2010, either at 3 months posttransplant for new transplant recipients or the next clinic visit for prevalent recipients. Late PTDM defined using Canadian Diabetes Association criteria as occurring ≥3 months posttransplant was recorded until May 1, 2016.

Methods

All analyses were conducted with R, version 3.4.0 (The R Foundation for Statistical Computing). Comparisons were made using Student t test, Fisher exact test or chi-square test, Kaplan-Meier methodology with the logrank test, or Cox proportional hazards analysis as appropriate. Covariates for the multivariate Cox proportional hazards models of PTDM as the outcome variable were selected based on significance of the univariate associations and biological plausibility.

Results

There were 53 incident late PTDM cases, or 1.71 cases per 100 patient-years. Incident late PTDM differed between the highest and lowest quartiles for Apo B/A1 ratio, 2.47 per 100 patient-years vs 0.88 per 100 patient-years (P = .005 for difference). In multiple Cox regression analysis, first measured serum Apo B/A1 concentration better predicted subsequent PTDM than low-density lipoprotein cholesterol (LDL-C; hazard ratio [HR] = 7.80 per unit increase, P = .039 vs HR = 1.05 per unit increase, P = .774). Non-high-density lipoprotein cholesterol (HDL-C) concentrations also did not predict PTDM (P = .136). By contrast to Apo B, Apo A1 was protective against PTDM in statin users (HR = 0.17 per unit increase, P = .016).

Limitations

Posttransplant diabetes mellitus cases occurring before apolipoprotein testing was implemented were not included in the analysis.

Conclusions

Apolipoproteins B and A1 better predict late PTDM than conventional markers of cholesterol metabolism.

Metabolic syndrome definitions and components in predicting major adverse cardiovascular events after kidney transplantation

Metabolic syndrome (MetS) associates with cardiovascular risk post-kidney transplantation, but its ambiguity impairs understanding of its diagnostic utility relative to components. We compared five MetS definitions and the predictive value of constituent components of significant definitions for major adverse cardiovascular events (MACE) in a cohort of 1182 kidney transplant recipients. MetS definitions were adjusted for noncomponent traditional Framingham risk factors and relevant transplant-related variables. Kaplan-Meier, logistic regression, and Cox proportional hazards analysis were utilized. There were 143 MACE over 7447 patient-years of follow-up. Only the World Health Organization (WHO) 1998 definition predicted MACE (25.3 vs 15.5 events/1000 patient-years, P = 0.019). Time-to-MACE was 5.5 ± 3.5 years with MetS and 6.8 ± 3.9 years without MetS (P < 0.0001). MetS was independent of pertinent MACE risk factors except age and previous cardiac disease. Among MetS components, dysglycemia provided greatest hazard ratio (HR) for MACE (1.814 [95% confidence interval 1.26-2.60]), increased successively by microalbuminuria (HR 1.946 [1.37-2.75]), dyslipidemia (3.284 [1.72-6.26]), hypertension (4.127 [2.16-7.86]), and central obesity (4.282 [2.09-8.76]). MetS did not affect graft survival. In summary, although the WHO 1998 definition provides greatest predictive value for post-transplant MACE, most of this is conferred by dysglycemia and is overshadowed by age and previous cardiac disease.

HMG CoA reductase inhibitors (statins) for kidney transplant recipients

BACKGROUND

People with chronic kidney disease (CKD) have higher risks of cardiovascular disease compared to the general population. Specifically, cardiovascular deaths account most deaths in kidney transplant recipients. Statins are a potentially beneficial intervention for kidney transplant patients given their established benefits in patients at risk of cardiovascular disease in the general population. This is an update of a review first published in 2009.

OBJECTIVES

We aimed to evaluate the benefits (reductions in all-cause and cardiovascular mortality, major cardiovascular events, myocardial infarction and stroke, and progression of CKD to requiring dialysis) and harms (muscle or liver dysfunction, withdrawal, cancer) of statins compared to placebo, no treatment, standard care, or another statin in adults with CKD who have a functioning kidney transplant.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register to 29 February 2012 through contact with the Trials Search Co-ordinator using search terms relevant to this review.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) and quasi-RCTs that compared the effects of statins with placebo, no treatment, standard care, or statins on mortality, cardiovascular events, kidney function and toxicity in kidney transplant recipients.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed risk of bias. Treatment effects were expressed as mean difference (MD) for continuous outcomes (lipids, glomerular filtration rate (GFR), proteinuria) and relative risk (RR) for dichotomous outcomes (major cardiovascular events, mortality, fatal or non-fatal myocardial infarction, fatal or non-fatal stroke, elevated muscle or liver enzymes, withdrawal due to adverse events, cancer, end-stage kidney disease (ESKD), acute allograft rejection) together with 95% confidence intervals (CI).

MAIN RESULTS

We identified 22 studies (3465 participants); 17 studies (3282 participants) compared statin with placebo or no treatment, and five studies (183 participants) compared two different statin regimens.From data generally derived from a single high-quality study, it was found that statins may reduce major cardiovascular events (1 study, 2102 participants: RR 0.84, CI 0.66 to 1.06), cardiovascular mortality (4 studies, 2322 participants: RR 0.68, CI 0.45 to 1.01), and fatal or non-fatal myocardial infarction (1 study, 2102 participants: RR 0.70, CI 0.48 to 1.01); although effect estimates lack precision and include the possibility of no effect.Statins had uncertain effects on all-cause mortality (6 studies, 2760 participants: RR 1.08, CI 0.63 to 1.83); fatal or non-fatal stroke (1 study, 2102 participants: RR 1.18, CI 0.85 to 1.63); creatine kinase elevation (3 studies, 2233 participants: RR 0.86, CI 0.39 to 1.89); liver enzyme elevation (4 studies, 608 participants: RR 0.62, CI 0.33 to 1.19); withdrawal due to adverse events (9 studies, 2810 participants: RR 0.89, CI 0.74 to 1.06); and cancer (1 study, 2094 participants: RR 0.94, CI 0.82 to 1.07).Statins significantly reduced serum total cholesterol (12 studies, 3070 participants: MD -42.43 mg/dL, CI -51.22 to -33.65); low-density lipoprotein cholesterol (11 studies, 3004 participants: MD -43.19 mg/dL, CI -52.59 to -33.78); serum triglycerides (11 studies, 3012 participants: MD -27.28 mg/dL, CI -34.29 to -20.27); and lowered high-density lipoprotein cholesterol (11 studies, 3005 participants: MD -5.69 mg/dL, CI -10.35 to -1.03).Statins had uncertain effects on kidney function: ESKD (6 studies, 2740 participants: RR 1.14, CI 0.94 to 1.37); proteinuria (2 studies, 136 participants: MD -0.04 g/24 h, CI -0.17 to 0.25); acute allograft rejection (4 studies, 582 participants: RR 0.88, CI 0.61 to 1.28); and GFR (1 study, 62 participants: MD -1.00 mL/min, CI -9.96 to 7.96).Due to heterogeneity in comparisons, data directly comparing differing statin regimens could not be meta-analysed. Evidence for statins in people who have had a kidney transplant were sparse and lower quality due to imprecise effect estimates and provided limited systematic evaluation of treatment harm.

AUTHORS' CONCLUSIONS

Statins may reduce cardiovascular events in kidney transplant recipients, although treatment effects are imprecise. Statin treatment has uncertain effects on overall mortality, stroke, kidney function, and toxicity outcomes in kidney transplant recipients. Additional studies would improve our confidence in the treatment benefits and harms of statins on cardiovascular events in this clinical setting.

Is liver transplantation a risk factor for cardiovascular disease? A meta-analysis of observational studies

Up to two-thirds of patients develop metabolic syndrome within the first 5 years after orthotopic liver transplantation (OLT). However, data on overall cardiovascular (CV) morbidity and mortality among OLT recipients and particularly those who develop metabolic syndrome remain elusive. A literature search using MEDLINE, the Cochrane Central Register of Controlled Trials, the Cochrane Database of Systematic Reviews, and meeting abstracts (along with their bibliographies) was performed to identify studies. Data on ischemic CV events were extracted from each study and were used for pooled analyses. Overall pooled estimates and 95% confidence intervals (CIs) for the incidence of CV events and deaths were obtained with a random effects model. Twelve observational studies reporting CV outcomes for 4792 post-OLT recipients who were followed for 28,783 person-years were included. Pooled estimates showed that the 10-year risk of developing CV events among the post-OLT recipients was 13.6% (95% CI = 9%-8.1%). Pooled estimates from case-control studies showed that the post-OLT group had an approximately 64% greater risk of experiencing CV events than controls (standardized incidence ratio = 1.64, 95% CI = 1.18-2.20). Among OLT recipients, those with metabolic syndrome were approximately 4 times more likely to have a CV event [odds ratio (OR) = 4.01, 95% CI = 1.94-8.32] without any significant increase in all-cause mortality (OR = 1.15, 95% CI = 0.63-2.10). In conclusion, this systematic review suggests that OLT recipients and particularly those with metabolic syndrome have a high risk for CV events. However, the literature is limited and lacks high-quality studies. Future prospective studies are warranted to confirm these findings and determine whether aggressive risk-reduction strategies can attenuate the increased CV risk seen in this population.

Hyperlipidemia after allogeneic stem cell transplantation: prevalence, risk factors, and impact on prognosis

Hyperlipidemia is one of the late complications after allogeneic stem cell transplantation (SCT). Although intrahepatic cholestasis caused by chronic graft-versus-host disease (GVHD) or calcineurin inhibitors has been considered as possible etiologies, its prevalence, risk factors, and impact on prognosis have not been investigated well. We performed a retrospective analysis of 194 patients who underwent allogeneic SCT between 1995 and 2008 in our institute and survived more than 100 d after SCT. Overall, 83 (42.8%) and 99 (50.8%) patients developed hypercholesterolemia (≥240 mg/dL) and hypertriglyceridemia (≥200 mg/dL), respectively. In multivariate analysis, the development of chronic GVHD (hazard ratio [HR] 2.04, p < 0.05) and steroid use (HR 2.24, p < 0.01) were independently associated with hypercholesterolemia, while administration of calcineurin inhibitors was not. As for the prognostic impact, multivariate analysis showed that the patients with hypercholesterolemia had a tendency of lower rate of relapse (HR: 0.44, p = 0.07). There was no difference in non-relapse mortality or overall survival between the groups. In conclusion, the development of hypercholesterolemia is regarded as one of the symptoms accompanied with chronic GVHD and might indicate a better control of the primary disease.

Clinical diagnosis of metabolic syndrome: predicting new-onset diabetes, coronary heart disease, and allograft failure late after kidney transplant

Metabolic syndrome is associated with coronary heart disease (CHD) and new-onset diabetes after kidney transplant (NODAT). Using data collected from transplant centers worldwide for the Patient Outcomes in Renal Transplantation study, we examined associations of metabolic syndrome (n = 2253 excluding recipients with diabetes pretransplant), CHD (n = 2253), and NODAT (n = 1840 further excluding recipients with diabetes in the first year post-transplant), with the primary outcome of allograft failure. We assessed risk factors associated with secondary outcomes of metabolic syndrome, NODAT, and CHD after adjusting for type of baseline immunosuppression and transplant center effects. Metabolic syndrome prevalence was 39.8% at 12-24 months post-transplant and 35.4% at 36-48 months. Metabolic syndrome was independently associated with NODAT (hazard ratio 3.46, 95% confidence interval 2.40-4.98, P < 0.0001), CHD (2.03, 1.16-3.52, P = 0.013), and allograft failure (1.36, 1.03-1.79, P = 0.028). Allograft failure occurred in 218 patients (14.6%). After adjustment for metabolic syndrome, NODAT (1.63, 1.18-2.24, P = 0.003) and CHD (5.48, 3.27-9.20, P < 0.0001) remained strongly associated with increased risk of allograft failure. Metabolic syndrome, NODAT, and CHD are risk factors for allograft failure. NODAT and CHD are risk factors for allograft failure, independent of metabolic syndrome.

Smoking is a risk factor for graft failure and mortality after renal transplantation

BACKGROUND

Smoking in renal transplant recipients (RTR) is an acknowledged cardiovascular risk factor. It is, however, unclear whether smoking also increases the risk of graft failure (GF).

METHOD

In this study, we prospectively assessed the association of current smoking versus past and never smoking with GF and mortality in 604 RTR (age 51.5 ± 12.1 years, 55% male).

RESULTS

At inclusion, 133 (22%) were current smokers, 255 (42%) were past smokers and 216 (36%) never smoked. During follow-up of 5.3 (4.7-5.7) years, 41 (7%) RTR experienced GF and 95 RTR (16%) died. Current smoking RTR had higher risk for GF compared to never smoking RTR (hazard ratio, HR = 3.3, 95% CI 1.5-7.1, p = 0.002). Past smoking RTR had similar risk of GF as never smoking RTR (HR = 1.1, 95% CI 0.5-2.6, p = 0.7). Current smoking RTR and past smoking RTR were at higher risk for death than never smoking RTR (HR = 2.1, 95% CI 1.1-3.8, p = 0.016, and HR = 2.4, 95% CI 1.4-4.0, p = 0.001, respectively).

CONCLUSION

Smoking after renal transplantation is associated with risk for GF and mortality. Since past smoking is a risk factor for mortality but not for GF, smoking cessation may be beneficial to RTR in delaying GF in long term.

Evidence-based statin prescription for cardiovascular protection in renal impairment

Dyslipidemia is a well-known risk factor for cardiovascular disease in the general population, and the cardioprotective role of statins is well established. However, although cardiovascular disease is the major cause of morbidity and mortality in chronic kidney disease (CKD), the role of statin therapy is still under investigation. In CKD the atherosclerotic burden is high and pathophysiology of dyslipidemia is complex; however, the majority of large-scale statin trials excluded patients with CKD. Statins could have different effects in the different stages of CKD. Two large trials involving haemodialysis patients showed unfavourable results, whereas in renal transplant subjects as well as in early CKD subjects, statins reduced cardiovascular risk. The studies involving early CKD patients are post-hoc analyses of large trials and they showed that statins are more effective in secondary than in primary prevention. The aim of this study was to evaluate the effectiveness of statins for prevention of cardiovascular events by calculating the number of patients needed to be treated in different interventional trials. We conclude that dyslipidemia is a modifiable cardiovascular risk and statins appear to be an effective treatment especially in the early stages of CKD. Patients on renal replacement therapy could obtain an advantage from this treatment; however, the patient's clinical prognosis should be taken into account when evaluating treatment.

Risk factors for metabolic syndrome in stable Italian renal transplant patients

BACKGROUND

The prevalence of metabolic syndrome (MS) in renal transplant recipients (RTR) is still under investigation.

METHODS

We performed a cross-sectional study of 107 stable RTR who were diagnosed as having MS defined by the Adult Treatment Panel III of the National Cholesterol Education Program (NCEP-ATP III) criteria. Anthropometric, clinical and biochemical data were collected.

RESULTS

Mean age of the patients studied was 55 ± 11 years (72 male, 35 female), dialysis duration before transplantation 30 ± 31 months, time since transplantation 42 ± 13 months. Mean serum creatinine was 1.68 ± 0.64 mg/dl; creatinine clearance by Cockcroft-Gault formula 53 ± 20 ml/min, glomerular filtration rate by 4-variable MDRD formula 48 ± 18 ml/min/1.73 m(2). Thirty-seven patients (34.5%) had MS. The MS patients had higher weight (76 ± 13 vs. 68 ± 12 kg, p = 0.0033), body mass index (BMI) (26 ± 4 vs. 24 ± 3 kg/m(2), p = 0.0025), waist circumference (101 ± 11 vs. 90 ± 11 cm, p < 0.0001), prevalence of BMI >25 k/m(2) (57 vs. 34%, p = 0.0254), prevalence of diabetes mellitus before transplantation (8 vs. 0%, p = 0.0157), glycaemia (104 ± 31 vs. 87 ± 11 mg/dl, p = 0.0002), and triglyceridaemia (225 ± 105 vs. 112 ± 35 mg/dl, p < 0.0001). They also showed lower levels of high-density lipoprotein cholesterol (48 ± 15 vs. 68 ± 17 mg/dl, p < 0.0001). Multiple logistic regression analysis showed that only BMI was independently associated with MS (OR 1.21, 95% CI 1.06-1.37, p = 0.0037).

CONCLUSIONS

MS according to NCEP-ATP III criteria appears to be present in about one-third of RTR, and even small increases in BMI above 25 kg/m(2) may determine the presence of MS in these patients. Therefore the preventive value of lifestyle modifications is very important for such patients, in order to strictly maintain body fat accumulation within the normal range.