NT-proBNP and stem cell factor plasma concentrations are independently associated with cardiovascular outcomes in end-stage renal disease hemodialysis patients

Aims

End-stage renal disease (ESRD) treated by chronic hemodialysis (HD) is associated with poor cardiovascular (CV) outcomes, with no available evidence-based therapeutics. A multiplexed proteomic approach may identify new pathophysiological pathways associated with CV outcomes, potentially actionable for precision medicine.

Methods and results

The AURORA trial was an international, multicentre, randomized, double-blind trial involving 2776 patients undergoing maintenance HD. Rosuvastatin vs. placebo had no significant effect on the composite primary endpoint of death from CV causes, nonfatal myocardial infarction or nonfatal stroke. We first compared CV risk-matched cases and controls (n = 410) to identify novel biomarkers using a multiplex proximity extension immunoassay (276 proteomic biomarkers assessed with Olink^TM). We replicated our findings in 200 unmatched cases and 200 controls. External validation was conducted from a multicentre real-life Danish cohort [Aarhus-Aalborg (AA), n = 331 patients] in which 92 Olink^TM biomarkers were assessed. In AURORA, only N-terminal pro-brain natriuretic peptide (NT-proBNP, positive association) and stem cell factor (SCF) (negative association) were found consistently associated with the trial's primary outcome across exploration and replication phases, independently from the baseline characteristics. Stem cell factor displayed a lower added predictive ability compared with NT-ProBNP. In the AA cohort, in multivariable analyses, BNP was found significantly associated with major CV events, while higher SCF was associated with less frequent CV deaths.

Conclusions

Our findings suggest that NT-proBNP and SCF may help identify ESRD patients with respectively high and low CV risk, beyond classical clinical predictors and also point at novel pathways for prevention and treatment.

Kidney function and discrimination of cardiovascular risk in middle-aged men

OBJECTIVE

To define the optimal glomerular filtration rate (GFR) cut off for discriminating the risk of myocardial infarction or cardiovascular death.

DESIGN

Prospective longitudinal observational study.

SETTING

A community-based cohort.

PARTICIPANTS

A total of 2176 nondiabetic 50-year-old men without cardiovascular disease.

METHODS

The men were followed until age 70. GFR was estimated at baseline using the Cockcroft-Gault formula. The optimal GFR cut-off points for discriminating risk of a fatal or nonfatal myocardial infarction and cardiovascular death were defined as the GFR levels maximizing integrated discrimination improvement (IDI).

MAIN OUTCOME MEASURES

Fatal or nonfatal myocardial infarction, cardiovascular death.

RESULTS

During follow-up, 264 men experienced a fatal or nonfatal myocardial infarction, and 218 died of cardiovascular disease. The IDI-defined optimal GFR cut offs in this study were 98 mL min(-1) for discriminating myocardial infarction risk and 92 mL min(-1) for discriminating risk of cardiovascular death. In Cox proportional hazard models adjusting for established risk factors, the myocardial infarction risk was substantially higher in men with GFR below versus above 98 mL min(-1) [hazard ratio (HR) 1.7, 95% confidence interval (CI) 1.3-2.3, P < 0.001], and the risk of cardiovascular death was doubled in men with GFR below versus above 92 mL min(-1) (HR 2.1, 95% CI 1.5-3.0, P < 0.001).

CONCLUSION

The GFR cut-off point for optimal discrimination of cardiovascular risk in the general population may be higher than previously suggested.

Telomere attrition is associated with inflammation, low fetuin-A levels and high mortality in prevalent haemodialysis patients

INTRODUCTION

Chronic kidney disease (CKD) predisposes to a 10- to 20-fold increased cardiovascular risk. Patients undergo accelerated atherogenesis and vascular ageing. We investigated whether telomere attrition, a marker of cell senescence, contributes to this increased mortality risk.

METHODS

This is a cross-sectional study in prevalent haemodialysis patients [n = 175; 98 Males; median (range) age: 66 (23-86) years]. Biochemical markers of oxidative stress and inflammatory status were measured in relation to the patient's leucocyte telomere length. Overall mortality was assessed after a median of 31 (range 2-42) months.

RESULTS

Telomere length was shorter in CKD men, despite women being older (average +/- SD 6.41 +/- 1.23 vs. 6.96 +/- 1.48 kb, P = 0.002). Telomere length was associated with age (rho = -0.18, P = 0.01), fetuin-A (rho = 0.26, P = 0.0004), high-sensitivity C-reactive protein (rho = -0.21, P = 0.005) and IL-6 (rho = -0.17, P = 0.02). In a multivariate logistic regression (pseudo r(2) = 0.14), telomere length was associated with age >65 years (odds ratio: 2.11; 95% CI: 1.10, 4.06), sex (2.01; 1.05, 3.86), fetuin-A (1.85; 0.97, 3.50) and white blood cell count (2.04; 1.02, 4.09). Receiver operating characteristic curves identified a telomere length < 6.28 kb as a fair predictor of mortality. Finally, reduced telomere length was associated with increased mortality, independently of age, gender and inflammation (likelihood ratio 41.6, P < 0.0001), but dependently on fetuin-A levels.

CONCLUSION

Age and male gender seem to be important contributors to reduced telomere length in CKD patients, possibly via persistent inflammation. Reduced telomere length also contributes to the mortality risk of these patients through pathways that could involve circulating levels of fetuin-A.

Renal dysfunction is a strong and independent risk factor for mortality and cardiovascular complications in renal transplantation

Renal transplant recipients (RTR) have shortened life expectancy, primarily due to premature cardiovascular disease (CVD). Traditional CVD risk factors are highly prevalent. In addition, several non-traditional risk factors may contribute to the high risk. The aim of the study was to evaluate the effects of renal dysfunction on mortality and cardiovascular complications in 1052 placebo-treated patients of the Assessment of LEscol in Renal Transplantation (ALERT) trial. Follow-up was 5-6 years and endpoints included cardiac death, non-cardiovascular death, all-cause mortality, major adverse cardiac event (MACE), non-fatal myocardial infarction (MI) and stroke. The effects of serum creatinine at baseline on these endpoints were evaluated. Elevated serum creatinine in RTR was a strong and independent risk factor for MACE, cardiac, non-cardiovascular, and all-cause mortality, but not for stroke or non-fatal MI alone. Serum creatinine was associated with increased mortality and MACE, independent of established CVD risk factors. Graft loss resulted in increased incidences of non-cardiovascular death, all-cause mortality, MACE and non-fatal MI. In conclusion, elevated serum creatinine is a strong risk factor for all-cause, non-cardiovascular and cardiac mortality, and MACE, independent of traditional risk factors, but not for stroke or non-fatal MI alone.