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.

Prevalence of familial hypercholesterolemia in patients presenting with premature acute coronary syndrome

Background

Familial hypercholesterolemia (FH) is a common genetic disorder responsible for premature and severe cardiovascular morbidity and mortality. The FH prevalence in patients who experienced a premature acute coronary syndrome (ACS) ranges from 5 to 50% according to previous studies and no comparison with FH prevalence in general population are available in those studies.

Purpose

We aimed to assess the prevalence of clinical FH among patients with premature acute myocardial infarction (MI) (age ≤50 years) and to compare it with FH prevalence in a control population (age ≤50 years), coming from the same population pool.

Methods

Patients with diagnosis of premature MI (age ≤50 years) referred to Ambroise Paré hospital from 2014 to 2018 were included. FH prevalence was estimated via the Dutch Lipid Clinic Network score, based on personal and familial history of premature cardiovascular disease, and LDL-cholesterol levels. FH was “possible” with a score between 3 and 5 points, “probable” with a score between 6 and 8 and “definite” with a score >8 and no FH was defined as a score <3. FH prevalence in patients with MI was compared to FH prevalence in a general population (age ≤50 years), coming from the prospective cohort CARVAR 92.

Results

Among the 457 patients with premature MI, 220 (48%) patients had no FH, 208 (46%) had a “possible” FH and 29 (6%) had a “probable” or “definite” FH. In the control population, 9900 subjects aged ≤50 years were identified: 9343 (94.37%) had no FH, 541 (5.46%) had a “possible” FH and 16 (0.16%) had a “probable” or “definite” FH. Considering subjects with “probable” or “definite” FH, FH prevalence was 37.5 times greater among patients with premature MI than in control population (p<0.0001).

Conclusion

Familial hypercholesterolemia is >30-fold more common in patients referred for premature MI than in general population of the same age, coming from the same population pool. This highlights the need for FH diagnosis after a first episode of MI to enhance lipid-lowering therapy and allow an early identification of family members.

Funding Acknowledgement

Type of funding sources: None.

Impact of sex and glucose-lowering treatments on hypoglycaemic symptoms in people with type 2 diabetes and chronic kidney disease. The French Chronic Kidney Disease - Renal Epidemiology and Information Network (CKD-REIN) Study

AIM

To describe current practices of glucose-lowering treatments in people with diabetes and chronic kidney disease (CKD), the associated glucose control and hypoglycaemic symptoms, with an emphasis on sex differences.

METHODS

Among the 3033 patients with CKD stages 3-5 recruited into the French CKD-REIN study, 645 men and 288 women had type 2 diabetes and were treated by glucose-lowering drugs.

RESULTS

Overall, 31% were treated only with insulin, 28% with combinations of insulin and another drug, 42% with non-insulin glucose-lowering drugs. In CKD stage 3, 40% of patients used metformin, 12% at stages 4&5, similar for men and women; in CKD stage 3, 53% used insulin, similar for men and women, but at stages 4&5, 59% of men and 77% of women used insulin. Patients were reasonably well controlled, with a median HbA1c of 7.1% (54mmol/mol) in men, 7.4% (57mmol/mol) in women (P=0.0003). Hypoglycaemic symptoms were reported by 40% of men and 59% of women; they were not associated with the estimated glomerular filtration rate, nor with albuminuria or with HbA1c in multivariable analyses, but they were more frequent in people treated with insulin, particularly with fast-acting and pre-mixed insulins.

CONCLUSION

Glucose-lowering treatment, HbA1c and hypoglycaemic symptoms were sex dependent. Metformin use was similar in men and women, but unexpectedly low in CKD stage 3; its use could be encouraged rather than resorting to insulin. Hypoglycaemic symptoms were frequent and need to be more closely monitored, with appropriate patient-education, especially in women.

A proposed nomenclature and diagnostic criteria for protein-energy wasting in acute and chronic kidney disease

The recent research findings concerning syndromes of muscle wasting, malnutrition, and inflammation in individuals with chronic kidney disease (CKD) or acute kidney injury (AKI) have led to a need for new terminology. To address this need, the International Society of Renal Nutrition and Metabolism (ISRNM) convened an expert panel to review and develop standard terminologies and definitions related to wasting, cachexia, malnutrition, and inflammation in CKD and AKI. The ISRNM expert panel recommends the term 'protein-energy wasting' for loss of body protein mass and fuel reserves. 'Kidney disease wasting' refers to the occurrence of protein-energy wasting in CKD or AKI regardless of the cause. Cachexia is a severe form of protein-energy wasting that occurs infrequently in kidney disease. Protein-energy wasting is diagnosed if three characteristics are present (low serum levels of albumin, transthyretin, or cholesterol), reduced body mass (low or reduced body or fat mass or weight loss with reduced intake of protein and energy), and reduced muscle mass (muscle wasting or sarcopenia, reduced mid-arm muscle circumference). The kidney disease wasting is divided into two main categories of CKD- and AKI-associated protein-energy wasting. Measures of chronic inflammation or other developing tests can be useful clues for the existence of protein-energy wasting but do not define protein-energy wasting. Clinical staging and potential treatment strategies for protein-energy wasting are to be developed in the future.

Chronic kidney disease as cause of cardiovascular morbidity and mortality

To make an evidence-based evaluation of the relationship between kidney failure and cardiovascular risk, we reviewed the literature obtained from a PubMed search using pre-defined keywords related to both conditions and covering 18 years (1986 until end 2003). Eighty-five publications, covering 552 258 subjects, are summarized. All but three studies support a link between kidney dysfunction and cardiovascular risk. More importantly, the association is observed very early during the evolution of renal failure: an accelerated cardiovascular risk appears at varying glomerular filtration rate (GFR) cut-off values, which were >/=60 ml/min in at least 20 studies. Many studies lacked a clear definition of cardiovascular disease and/or used a single determination of serum creatinine or GFR as an index of kidney function, which is not necessarily corresponding to well-defined chronic kidney disease. In six studies, however, chronic kidney dysfunction and cardiovascular disease were well defined and the results of these confirm the impact of kidney dysfunction. It is concluded that there is an undeniable link between kidney dysfunction and cardiovascular risk and that the presence of even subtle kidney dysfunction should be considered as one of the conditions necessitating intensive prevention of this cardiovascular risk.

[Evaluation of lipoperoxidation in hemodialysis patients with a simple test using the "Free Oxygen Radical Monitor"]

Incidence of cardiovascular events is higher in hemodialysis (HD) patients than in general population. Oxidative stress represents a major specific risk factor of accelerated atheroma particularly in association with inflammation and malnutrition. The aim of our study is to evaluate a simple test of lipid peroxidation measurement using the "Free Oxygen Radical Monitor" (FORM) (Callegari, Italy). The results obtained in HD patients were compared to standard oxidative stress markers, such as thiobarbituric acid reacting substances, carbonyls and vitamin E in plasma, and glutathione, oxidized to reduced form ratio, in erythrocytes. In conclusion, the FORM system presents no sufficient sensibility and specificity to determine oxidative stress in HD patients.

[Cardioprotection: an essential component for predialysis chronic renal failure treatment]

Cardiovascular (CV) disease in uremic patients is a major concern to the nephrologist because it represents the main cause of morbidity and mortality in chronic renal failure patients, both predialysis and while on dialysis therapy. CV mortality is 3 to 20 times higher in dialysis patients than in the general population at similar age. Of note, a high prevalence of CV comorbidity is already present at start of maintenance dialysis, and is predictive of subsequent mortality on dialysis. CV disease progresses over years prior to the onset of ESRD, because risk factors develop from the early stage of chronic renal insufficiency. However, CV disease may be prevented or attenuated in patients who benefit from early, regular care of CV risk factors. Mechanisms of uremic cardiopathy, the major cause of mortality in uremic patients, are multifactorial and their effects are cumulative. Risk factors for left ventricular hypertrophy are hypertension, anemia, fluid overload and arteriosclosis, all of which are amendable by therapy. Risk factors for accelerated atherosclerosis, responsible for ischemic cardiopathy and myocardial infarction, are both common factors (e.g., hypertension, tobacco smoking and diabetes) and factors more specific for the uremic state (e.g., dyslipidemia, hyperhomocysteinemia and oxidative stress), all of which also are amendable by proper therapy. As a result, mixed hypertensive and ischemic cardiomyopathy develops, ultimately leading to cardiac failure, together with accidents resulting from valvular and arterial calcifications (favored by calcium-phosphate disorders), and from occlusion of coronary, cerebral and peripheral arteries. Cardioprotective therapy thus has become a cornerstone in the management of chronic renal failure patients, in conjunction with renoprotective therapy. Cardioprotective strategy involves optimal treatment of hypertension, anemia, fluid overload, dyslipidemia, hyperhomocysteinemia and calcium-phosphate disorders, and smoking cessation. To achieve a maximal efficacy, such treatment has to be initiated as early as possible in the course of renal failure. Because of its complexity, the integrated combined nephrotective and cardioprotective therapy requires early and sustained guidance by a nephrologist throughout the whole predialysis period.

Non-traditional cardiovascular disease risk factors in end-stage renal disease: oxidate stress and hyperhomocysteinemia

Studies in experimental animals have shown that oxidative stress and hyperhomocyst(e)inemia culminate in abnormal vascular and endothelial regulation, functional nitric oxide deficiency, vascular hypertrophy, and atherosclerosis. Oxidative stress is accompanied by increased advanced glycation endproducts and oxidized low density lipoproteins. Studies of patients with end-stage renal disease provide extensive indirect, evidence of increased oxidative stress and more than ninety percent are hyperhomocyt(e)inemic. Presently, only uncontrolled or observational studies are available to assess the effects of anti-oxidant therapy for oxidative stress or folate therapy for hyperhomocyst(e)inemia in these patients. Promising developments include the reports of beneficial effects of a vitamin E coated dialyzer, and the reduction in homocyst(e)ine levels in patients with end-stage renal disease given an intravenous folate metabolite. However, there is presently no therapy available to reverse fully oxidative stress or hyperhomocyst(e)inemia. Therefore, the causative role of these nontraditional risk factors of cardiovascular disease remains untested.

[Incidence of end-stage renal disease in Ile de France: a prospective epidemiological survey]

OBJECTIVES

To evaluate incidence and prevalence of patients with end-stage renal disease (ESRD) treated with maintenance dialysis in the Ile de France district in 1998.

METHODOLOGY

Prospective epidemiologic inquiry with the cooperation of the 91 nephrology departments and dialysis facilities of the Ile de France district (total population: 10,695,300 inhabitants in March 1999), from January 1st to December 31st, 1998. Evaluation of the demographic and clinical characteristics of the 1155 patients accepted on maintenance dialysis in 1998, and recording of the total number of dialyzed patients at the beginning and at the end of the same year.

RESULTS

The total number of ESRD patients was 1155, including 29 (2.5%) children aged < or = 17 years and 86 (7.4%) returns to dialysis following kidney graft failure. Incidence of ESRD in first-dialyzed patients was 100/million/year and overall incidence, including returns from transplantation, was 108/million/year. Mean age of the 1040 adult first-dialysis patients was 59 +/- 16.8 years, with a proportion of those aged > or = 75 years of 21.6%. Patients with vascular renal disease were 22.5% and those with diabetic nephropathy 20.6%. As a whole, 36.5% of patients were referred to the nephrologist < 6 months of starting dialysis. Prevalence of patients on supportive dialysis increased from 417 to 433 per million inhabitants (a 3.8% increase) from the beginning to the end of 1998, with the proportion of patients treated with self-care dialysis or peritoneal dialysis rising by 10%. From January 1995 to January 1999, prevalence of dialysis-treated ESRD patients rose by nearly 4% per year as a mean.

CONCLUSION

Incidence of ESRD patients requiring maintenance dialysis in the Ile de France district reached 100/million in 1998, an increment of 4% per year over the past 4 years. The increase in incidence results from the increasing number of older patients, parallel to the ageing of general population, these patients having a high comorbidity mainly due to diabetes and atherosclerosis. Prevalence of dialysis-treated patients was 433/million population at the end of 1998. It rose at a similar rate as did incidence, although with a growing proportion of out-center dialysis.

Sustained reduction of hyperhomocysteinaemia with folic acid supplementation in predialysis patients

BACKGROUND

Moderate hyperhomocysteinaemia, as occurs in chronic renal failure patients, is an established independent risk factor for atherosclerotic arterial occlusive accidents, the incidence of which is abnormally high in such patients. Folic acid supplementation has been shown to reduce plasma homocysteine level in end-stage renal disease patients treated with haemodialysis or peritoneal dialysis, but its long-term effects in predialysis patients had not been assessed.

METHODS

We prospectively treated a total of 78 predialysis patients with folic acid for at least 1 year (range 12-74 months) together with oral pyridoxine and vitamin B12 supplements. Of the patients, 67 received 5 mg folic acid three times per week, whereas the other 11 patients who were treated with recombinant erythropoietin received 5 mg/day. Plasma fasting total homocysteine concentration was determined at baseline, after 3 months and at the end of follow-up.

RESULTS

Mean (+/-SD) plasma total homocysteine level decreased from 21.2+/-6.4 micromol/l at baseline to 14.2+/-4.6 at 3 months and remained at 12.8+/-3.7 micromol/l at the end of follow-up (average duration 2.8 years), whereas plasma creatinine rose from 268+/-129 to 399+/-234 micromol/l. Mean plasma folate concentration rose from 19+/-12 to 47+/-13 nmol/l and mean plasma vitamin B12 rose from 237+/-119 to 347+/-191 pmol/l from baseline to end of follow-up.

CONCLUSIONS

Moderate folic acid supplementation (2.15 mg/day) allows a substantial (40% as a mean) and sustained (up to 6 years) reduction of plasma total homocysteine level in predialysis uraemic patients without any detectable side effect. Folic acid supplementation may thus contribute to lower the risk of accelerated atherosclerosis in such patients.