Plasma COOH-terminal proendothelin-1: a marker of fatal cardiovascular events, all-cause mortality, and new-onset albuminuria in type 2 diabetes? (ZODIAC-29)

ET-1 as a Sex-Specific Mechanism Impacting Age-Related Changes in Vascular Function

Aging is a primary risk factor for cardiovascular disease (CVD), which is the leading cause of death in developed countries. Globally, the population of adults over the age of 60 is expected to double by the year 2050. CVD prevalence and mortality rates differ between men and women as they age in part due to sex-specific mechanisms impacting the biological processes of aging. Measures of vascular function offer key insights into cardiovascular health. Changes in vascular function precede changes in CVD prevalence rates in men and women and with aging. A key mechanism underlying these changes in vascular function is the endothelin (ET) system. Studies have demonstrated sex and sex hormone effects on endothelin-1 (ET-1), and its receptors ETA and ETB. However, with aging there is a dysregulation of this system resulting in an imbalance between vasodilation and vasoconstriction. Thus, ET-1 may play a role in the sex differences observed with vascular aging. While most research has been conducted in pre-clinical animal models, we describe more recent translational data in humans showing that the ET system is an important regulator of vascular dysfunction with aging and acts through sex-specific ET receptor mechanisms. In this review, we present translational evidence (cell, tissue, animal, and human) that the ET system is a key mechanism regulating sex-specific changes in vascular function with aging, along with therapeutic interventions to reduce ET-mediated vascular dysfunction associated with aging. More knowledge on the factors responsible for the sex differences with vascular aging allow for optimized therapeutic strategies to attenuate CVD risk in the expanding aging population.

Association Between Serum Carnosinase Concentration and Activity and Renal Function Impairment in a Type-2 Diabetes Cohort

Introduction: Genetic studies have identified associations of carnosinase 1 (CN1) polymorphisms with diabetic kidney disease (DKD). However, CN1 levels and activities have not been assessed as diagnostic or prognostic markers of DKD in cohorts of patients with type 2 diabetes (T2D).

Methods: We established high-throughput, automated CN1 activity and concentration assays using robotic systems. Using these methods, we determined baseline serum CN1 levels and activity in a T2D cohort with 970 patients with no or only mild renal impairment. The patients were followed for a mean of 1.2 years. Baseline serum CN1 concentration and activity were assessed as predictors of renal function impairment and incident albuminuria during follow up.

Results: CN1 concentration was significantly associated with age, gender and estimated glomerular filtration rate (eGFR) at baseline. CN1 activity was significantly associated with glycated hemoglobin A1c (HbA1c) and eGFR. Serum CN1 at baseline was associated with eGFR decline and predicted renal function impairment and incident albuminuria during the follow-up.

Discussion: Baseline serum CN1 levels were associated with presence and progression of renal function decline in a cohort of T2D patients. Confirmation in larger cohorts with longer follow-up observation periods will be required to fully establish CN1 as a biomarker of DKD.

Association of C-Terminal Pro-Endothelin-1 with Mortality in the Population-Based KORA F4 Study

Introduction

Endothelin-1 and its prohormone C-terminal pro-endothelin-1 (CT-proET-1) have been linked to metabolic alterations, inflammatory responses and cardiovascular events in selected study populations. We analyzed the association of CT-proET-1 with cardiovascular events and mortality, carotid intima-media-thickness as surrogate for early atherosclerotic lesions, biomarkers of subclinical inflammation and adipokines in a population-based study.

Methods

The cross-sectional and prospective analyses used data from the KORA F4 study with a median follow-up time of 9.1 (8.8–9.4) years. Data on CT-proET-1 and mortality were available for 1554 participants, data on the other outcomes in subgroups (n = 596–1554). The associations were estimated using multivariable linear regression and Cox proportional hazard models adjusted for sex, age, body mass index, estimated glomerular filtration rate, arterial hypertension, diabetes, low-density and high-density lipoprotein cholesterol, current and former smoking and physical activity. The Bonferroni method was used to correct for multiple testing.

Results

In the fully adjusted model, CT-proET-1 was associated with cardiovascular (hazard ratio (HR) per standard deviation increase: 1.66; 95% confidence interval (CI): 1.10–2.51; p = 0.017) and all-cause mortality (HR: 2.03; 95% CI 1.55–2.67; p < 0.001), but not with cardiovascular events, and was inversely associated with the intima-media thickness (β: −0.09 ± 0.03; p = 0.001). CT-proET-1 was positively associated with five out of ten biomarkers of subclinical inflammation and with two out of five adipokines after correction for multiple testing. After inclusion of biomarkers of subclinical inflammation in the Cox proportional hazard model, the association of CT-proET-1 with all-cause mortality persisted (p < 0.001).

Conclusion

These results emphasize the complexity of endothelin-1 actions and/or indicator functions of CT-proET-1. CT-proET-1 is a risk marker for all-cause mortality, which is likely independent of vascular endothelin-1 actions, cardiovascular disease and inflammation.

Hyponatremia and activation of vasopressin secretion are both independently associated with 30-day mortality: results of a multicenter, observational study

BACKGROUND

Hyponatremia is a common feature of acute illness and associated with increased mortality. This may be explained by a stress-mediated activation of the vasopressin system with an increase in free-water reabsorption.

OBJECTIVES

To investigate whether the association between hyponatremia and mortality could be explained by activation of the vasopressin system.

METHODS

We prospectively enrolled adult, medical patients seeking emergency care in three centres in Switzerland, France and the United States. We investigated associations between admission plasma sodium and copeptin, a stable portion of the vasopressin-precursor peptide, with 30-day mortality. We performed uni- and multivariate regression analysis.

RESULTS

Of 6962 included patients, 18% had hyponatremia (sodium ≤135 mmol L^-1 ), which doubled their risk for mortality compared to patients with normonatremia (8.3% vs. 3.8%). This association was confirmed in a multivariate-adjusted logistic regression analysis [adjusted odds ratio (OR) 1.47, 95% CI 1.12-1.93, P = 0.005]. Vasopressin levels, mirrored by copeptin, were also increased in nonsurvivors and strongly associated with mortality (adjusted OR 3.42, 95% CI 2.76-4.25, P < 0.001). The association between hyponatremia and mortality remained unchanged when adding copeptin levels to the regression model (fully adjusted OR 1.53, 95% CI 1.16-2.00, P = 0.002).

CONCLUSION

This prospective study including medical patients upon emergency room admission found hyponatremia as well as an activation of the vasopressin system to be independently associated with mortality. This suggests that stress- and vasopressin-independent mechanisms are responsible for the association of low sodium levels with mortality.

Incidence of chronic kidney disease among people with diabetes: a systematic review of observational studies

AIMS

The aim was to systematically review published articles that reported the incidence of chronic kidney disease among people with diabetes.

METHODS

A systematic literature search was performed using MEDLINE, Embase and CINAHL databases. The titles and abstracts of all publications identified by the search were reviewed and 10 047 studies were retrieved.

RESULTS

A total of 71 studies from 30 different countries with sample sizes ranging from 505 to 211 132 met the inclusion criteria. The annual incidence of microalbuminuria and albuminuria ranged from 1.3% to 3.8% for Type 1 diabetes. For Type 2 diabetes and studies combining both diabetes types, the range was from 3.8% to 12.7%, with four of six studies reporting annual rates between 7.4% and 8.6%. In studies reporting the incidence of eGFR < 60 ml/min/1.73 m² using the Modification of Diet on Renal Disease (MDRD) equation, apart from one study which reported an annual incidence of 8.9%, the annual incidence ranged from 1.9% to 4.3%. The annual incidence of end-stage renal disease ranged from 0.04% to 1.8%.

CONCLUSIONS

The annual incidence of microalbuminuria and albuminuria is ~ 2-3% in Type 1 diabetes, and ~ 8% in Type 2 diabetes or mixed diabetes type. The incidence of developing eGFR < 60 ml/min/1.73 m² is ~ 2-4% per year. Despite the wide variation in methods and study design, within a particular category of kidney disease, there was only modest variation in incidence rates. These findings may be useful in clinical settings to help understand the risk of developing kidney disease among those with diabetes.

c-Src tyrosine kinase mediates high glucose-induced endothelin-1 expression

Endothelin-1 (ET-1) plays an important role in the pathophysiology of diabetes-associated cardiovascular disorders. The molecular mechanisms leading to ET-1 upregulation in diabetes are not entirely defined. c-Src tyrosine kinase regulates important pathophysiological aspects of vascular response to insults. In this study, we aimed to elucidate whether high glucose-activated c-Src signaling plays a role in the regulation of ET-1 expression. Human endothelial cells EAhy926 (ECs) were exposed to normal or high levels of glucose for 24h. Male C57BL/6J mice were rendered diabetic with streptozotocin and then treated with a specific c-Src inhibitor (Src I1) or c-Src siRNA. Real-time PCR, Western blot, and ELISA, were used to investigate ET-1 regulation. The c-Src activity and expression were selectively downregulated by pharmacological inhibition and siRNA-mediated gene silencing, respectively. High glucose dose-dependently up-regulated c-Src phosphorylation and ET-1 gene and protein expression levels in human ECs. Chemical inhibition or silencing of c-Src significantly decreased the high-glucose augmented ET-1 expression in cultured ECs. In vivo studies showed significant elevations in the aortic ET-1 mRNA expression and plasma ET-1 concentration in diabetic mice compared to non-diabetic animals. Treatment with Src I1, as well as in vivo silencing of c-Src, significantly reduced the upregulated ET-1 expression in diabetic mice. These data provide new insights into the regulation of ET-1 expression in endothelial cells in diabetes. Pharmacological targeting of c-Src activity and/or expression may represent a potential therapeutic strategy to reduce ET-1 level and to counteract diabetes-induced deleterious vascular effects.

Determinants of mortality in patients with type 2 diabetes: a review

We aimed to review and summarize the evidence from accomplished trials analyzing factors influencing mortality in patients with T2DM and to provide some recommendations for targets and treatment in the European region. The following databases were searched for relevant trials: PubMed and the Cochrane Library. Of 3.806 citations, 134 trials met our inclusion criteria.

RESULTS

The reduction in lifetime for 65 + -years-old patients having less than 10 years T2DM amounts to 1.8 years. Having T2DM for more than 10 years lifetime will be reduced by 2.7 years. However, the lifetime shortening factor of T2DM will even be stronger for 40 + -years-old patients at onset. Males will lose 11.6 years of life and 18.6 QUALYs. T2DM among females will reduce life by 14 QUALYs by 22 years. From a statistical point of view, the highest mortality rate will occur in an over 55-years-old European smoking and non-compliant diabetic woman with alcohol abuse living in a rural area with a low level of education and a low socio-economic status. Furthermore, other co-morbidities such as cardiovascular diseases, gout, and depression affect mortality. Additionally, mortality will increase with a BMI over 35 and also with a BMI under 20-25. This refers to the obesity paradox indicating a higher mortality rate among normal weight patients with T2DM compared to overweight patients with T2DM. HbA1c-levels between 6.5 % and 7 % are associated with the lowest impact on mortality.

Plasma Adrenomedullin and Allelic Variation in the ADM Gene and Kidney Disease in People With Type 2 Diabetes

Production of adrenomedullin (ADM), a vasodilator peptide, increases in response to ischemia and hypoxia in the vascular wall and the kidney. This may be an adaptive response providing protection against organ damage. We investigated the hypothesis that ADM has a nephroprotective effect in two prospective cohorts of patients with type 2 diabetes recruited in France. The highest tertile of plasma MR-proADM (a surrogate for ADM) concentration at baseline was associated with the risk of renal outcomes (doubling of plasma creatinine concentration and/or progression to end-stage renal disease) during follow-up in both cohorts. Four SNPs in the ADM gene region were associated with plasma MR-proADM concentration at baseline and with eGFR during follow-up in both cohorts. The alleles associated with lower eGFR were also associated with lower plasma MR-proADM level. In conclusion, plasma MR-proADM concentration was associated with renal outcome in patients with type 2 diabetes. Our data suggest that the ADM gene modulates the genetic susceptibility to nephropathy progression. Results are consistent with the hypothesis of a reactive rise of ADM in diabetic nephropathy, blunted in risk alleles carriers, and with a nephroprotective effect of ADM. A possible therapeutic effect of ADM receptor agonists in diabetic renal disease would be worth investigating.

Alanine aminotransferase and mortality in patients with type 2 diabetes (ZODIAC-38)

INTRODUCTION

Combined data suggest a bimodal association of alanine aminotransferase (ALT) with mortality in the general population. Little is known about the association of ALT with mortality in patients with type 2 diabetes. We therefore investigated the association of ALT with all-cause, cardiovascular and noncardiovascular mortality in patients with type 2 diabetes.

DESIGN

A prospective study was performed in patients with type 2 diabetes, treated in primary care, participating in the Zwolle Outpatient Diabetes project Integrating Available Care (ZODIAC) study. Cox regression analyses were performed to determine the associations of log2 -transformed baseline ALT with all-cause, cardiovascular and noncardiovascular mortality.

RESULTS

In 1187 patients with type 2 diabetes (67 ± 12 years, 45% female), ALT levels were 11 (8-16) U/L. During median follow-up for 11.1 (6.1-14.0) years, 553 (47%) patients died, with 238 (20%) attributable to cardiovascular causes. Overall, ALT was inversely associated with all-cause mortality (hazard ratio [HR] 0.81; 95% confidence interval [CI] 0.72-0.92), independently of potential confounders. This was less attributable to cardiovascular mortality (HR 0.87; 95% CI 0.72-1.05), than to noncardiovascular mortality (HR 0.77; 95% CI 0.65-0.90). Despite the overall inverse association of ALT with mortality, it appeared that a bimodal association with all-cause mortality was present with increasing risk for levels of ALT above normal (P = 0.003).

DISCUSSION

In patients with type 2 diabetes, low levels of ALT are associated with an increased risk of all-cause mortality, in particular noncardiovascular mortality, compared to normal levels of ALT, while risk again starts to increase when levels are above normal.

Is the association of serum sodium with mortality in patients with type 2 diabetes explained by copeptin or NT-proBNP? (ZODIAC-46)

BACKGROUND AND AIMS

Hyponatremia has been associated with an increased mortality risk in the general population. Diabetes is a condition predisposing for elevated levels of arginine vasopressin (AVP) and heart failure, both common causes of hyponatremia. These factors, however, are also associated with an increased mortality risk. We aimed to investigate whether serum sodium is associated with cardiovascular and all-cause mortality in type 2 diabetes and whether these associations could be explained by copeptin, a surrogate for AVP, or NT-proBNP, a marker for heart failure.

METHODS

Patients with type 2 diabetes participating in the observational ZODIAC study were included. Cox regression analyses were used to investigate the association of serum sodium with mortality.

RESULTS

We included 1068 patients (age 67 ± 12 years, 45% male, serum sodium 142 ± 3 mmol/L). After 15 years of follow-up, 519 patients (49%) died, with 225 cardiovascular deaths (21%). In univariable analyses, serum sodium, copeptin, and NT-proBNP were all significantly associated with cardiovascular and all-cause mortality. These associations remained significant after combination of these markers in a multivariable model. Serum sodium and NT-proBNP remained significantly associated with mortality after further adjustment for potential confounders, whereas copeptin lost significance after adjustment for SCr and ACR.

CONCLUSION

Low serum sodium was associated with an increased risk of cardiovascular and all-cause mortality in type 2 diabetes. Moreover, these associations were not explained by copeptin and NT-proBNP. Whether low serum sodium itself leads to poor outcome or is a marker for (unidentified) co-morbidity severity or use of specific medications remains to be elucidated.

The relationship between N-terminal prosomatostatin, all-cause and cardiovascular mortality in patients with type 2 diabetes mellitus (ZODIAC-35)

BACKGROUND

The hormone somatostatin inhibits growth hormone release from the pituitary gland and is theoretically linked to diabetes and diabetes related complications. This study aimed to investigate the relationship between levels of the stable somatostatin precursor, N-terminal prosomatostatin (NT-proSST), with mortality in type 2 diabetes (T2DM) patients.

METHODS

In 1,326 T2DM outpatients, participating in this ZODIAC prospective cohort study, Cox proportional hazards models were used to investigate the independent relationship between plasma NT-proSST concentrations with all-cause and cardiovascular mortality.

RESULTS

Median concentration of NT-proSST was 592 [IQR 450-783] pmol/L. During follow-up for 6 [3-10] years, 413 (31%) patients died, of which 176 deaths (43%) were attributable to cardiovascular causes. The age and sex adjusted hazard ratios (HRs) for all-cause and cardiovascular mortality were 1.48 (95%CI 1.14 - 1.93) and 2.21 (95%CI 1.49 - 3.28). However, after further adjustment for cardiovascular risk factors there was no independent association of log NT-proSST with mortality, which was almost entirely attributable to adjustment for serum creatinine. There were no significant differences in Harrell's C statistics to predict mortality for the models with and without NT-proSST: both 0.79 (95%CI 0.77 - 0.82) and 0.81 (95%CI 0.77 - 0.84).

CONCLUSIONS

NT-proSST is unsuitable as a biomarker for cardiovascular and all-cause mortality in stable outpatients with T2DM.

Plasma pro-endothelin-1 peptide concentrations rise in chronic kidney disease and following selective endothelin A receptor antagonism

Background

Endothelin 1 (ET‐1) contributes to chronic kidney disease (CKD) development and progression, and endothelin receptor antagonists are being investigated as a novel therapy for CKD. The proET‐1 peptides, endothelin‐like domain peptide (ELDP) and C‐terminal pro‐ET‐1 (CT‐proET‐1), are both potential biomarkers of CKD and response to therapy with endothelin antagonists.

Methods and Results

We assessed plasma and urine ELDP and plasma CT‐proET‐1 in CKD patients with minimal comorbidity. Next, in a randomized double‐blind crossover study of 27 subjects with proteinuric CKD, we examined the effects of 6 weeks of treatment with placebo, sitaxentan (endothelin A antagonist), and nifedipine on these peptides alongside the primary end points of proteinuria, blood pressure, and arterial stiffness. Plasma ELDP and CT‐proET‐1 increased with CKD stage (both P<0.0001), correlating inversely with estimated glomerular filtration rate (both P<0.0001). Following intervention, placebo and nifedipine did not affect plasma and urine ELDP or plasma CT‐proET‐1. Sitaxentan increased both plasma ELDP and CT‐proET‐1 (baseline versus week 6±SEM: ELDP, 11.8±0.5 versus 13.4±0.6 fmol/mL; CT‐proET‐1, 20.5±1.2 versus 23.3±1.5 fmol/mL; both P<0.0001). Plasma ET‐1 was unaffected by any treatment. Following sitaxentan, plasma ELDP and CT‐proET‐1 correlated negatively with 24‐hour urinary sodium excretion.

Conclusions

ELDP and CT‐proET‐1 increase in CKD and thus are potentially useful biomarkers of renal injury. Increases in response to endothelin A antagonism may reflect EDN1 upregulation, which may partly explain fluid retention with these agents.

Clinical Trial Registration

URL: www.clinicalTrials.gov Unique identifier: NCT00810732

Clinical Risk Stratification Optimizes Value of Biomarkers to Predict New-Onset Heart Failure in a Community-Based Cohort

Background—

We aim to identify and quantify the value of biomarkers for incident new-onset heart failure (HF) in a community-based cohort and subgroups based on cardiovascular risk and evaluate the prognostic value of 13 biomarkers for HF with reduced and preserved ejection fraction.

Methods and Results—

Thirteen biomarkers reflecting diverse pathophysiologic domains were examined in 8569 HF-free participants in Prevention of Vascular and Renal Endstage Disease (mean age, 49 years; 50% men). Subjects were categorized in 2 risk groups based on cardiovascular history. Incremental value per biomarker was assessed using Harrell C-indices. One hundred sixty-eight subjects (2.4%) were diagnosed with new-onset HF in the low-risk group (n=6915; Framingham Risk Score, 5.9%) and 206 (12.2%) subjects in the high-risk group (n=1654; Framingham Risk Score, 18.6%). The association of natriuretic peptides, adrenomedullin, endothelin, and galectin-3 with new-onset HF was stronger in the high-risk group (all P <0.05). Troponin-T, high-sensitive C-reactive protein, urinary albumin excretion, and cystatin-C had similar risk for new-onset HF between both risk groups. The best model for new-onset HF included the combination of N-terminal pro-B-type natriuretic peptide, troponin-T, and urinary albumin excretion, increasing model accuracy to 0.81 (9.5%, P <0.001) in the high-risk group. Except for a modest effect of cystatin-C, no biomarker was associated with increased risk for HF with preserved ejection fraction.

Conclusions—

Risk stratification increases the incremental value per biomarker to predict new-onset HF, especially HF with reduced ejection fraction. We suggest that routine biomarker testing should be limited to the use of natriuretic peptides and troponin-T in patients with increased cardiovascular risk.

Design of the e-Vita diabetes mellitus study: effects and use of an interactive online care platform in patients with type 2 diabetes (e-VitaDM-1/ZODIAC-40)

Trial registration: NCT01570140.

BACKGROUND

Due to ongoing rise in need for care for people with chronic diseases and lagging increase in number of care providers, alternative forms of care provision and self-management support are needed. Empowering patients through an online care platform could help to improve patients' self-management and reduce the burden on the healthcare system.

METHODS

Access to laboratory results and educational modules on diabetes will be offered through a platform for subjects with type 2 diabetes mellitus treated in primary care. Differences in socio-demographic and clinical characteristics between subjects expressing interest vs. disinterest to use the platform will be explored. Platform usage will be tracked and compared. Patient satisfaction and quality of life will be measured by validated questionnaires and economic analyses will be performed.

DISCUSSION

This study is designed to assess the feasibility of use of an online platform in routine primary healthcare for subjects with type 2 diabetes mellitus in the Netherlands, and to study effects of use of the platform on treatment satisfaction, quality of life and clinical parameters. Although providing access to a online platform is not a novel intervention, usage and effects have not yet been studied in this patient population.

Copeptin, a surrogate marker for arginine vasopressin, is associated with cardiovascular and all-cause mortality in patients with type 2 diabetes (ZODIAC-31)

OBJECTIVE

Copeptin, a surrogate marker for arginine vasopressin, has been associated with cardiovascular (CV) events and mortality in patients with type 2 diabetes complicated by end-stage renal disease or acute myocardial infarction. For stable outpatients, these associations are unknown. Our aim was to investigate whether copeptin is associated with CV and all-cause mortality in patients with type 2 diabetes treated in primary care.

RESEARCH DESIGN AND METHODS

Patients with type 2 diabetes participating in the observational Zwolle Outpatient Diabetes Project Integrating Available Care (ZODIAC) study were included. Cox regression analyses with age as time scale were used to assess the relationship of baseline copeptin with CV and all-cause mortality.

RESULTS

We included 1,195 patients (age 67±12 years, 44% male). Median baseline copeptin concentration was 5.4 (interquartile range [IQR] 3.1-9.6) pmol/L. After a median follow-up of 5.9 (IQR 3.2-10.1) years, 345 patients died (29%), with 148 CV deaths (12%). Log2 copeptin was associated with CV (hazard ratio 1.17 [95% CI 0.99-1.39]; P=0.068) and all-cause mortality (1.22 [1.09-1.36]; P=0.001) after adjustment for age, sex, BMI, smoking, systolic blood pressure, total cholesterol to HDL ratio, duration of diabetes, HbA1c, treatment with ACE inhibitors and angiotensin receptor blockers, history of CV diseases, log serum creatinine, and log albumin to creatinine ratio; however, copeptin did not substantially improve risk prediction for CV (integrated discrimination improvement 0.14% [IQR -0.27 to 0.55%]) and all-cause mortality (0.77% [0.17-1.37%]) beyond currently used clinical markers.

CONCLUSIONS

We found copeptin to be associated with CV and all-cause mortality in patients with type 2 diabetes treated in primary care. Intervention studies should show whether the high CV risk in type 2 diabetes can be reduced by suppression of vasopressin, for example by reducing salt intake.

Comparison and evaluation of cardiac biomarkers in patients with intermittent claudication: results from the CAVASIC study

BACKGROUND

Plasma concentrations of the peptides midregional proadrenomedullin (MR-proADM), midregional proatrial natriuretic peptide (MR-proANP), and C-terminal endothelin-1 precursor fragment (CT-proET-1) are increased in various cardiovascular conditions. However, there is limited information about the association and comparative performance of these peptides in peripheral arterial disease (PAD).

METHODS

The associations of MR-proADM, MR-proANP, and CT-proET-1 plasma concentrations with symptomatic PAD were investigated in the CAVASIC (Cardiovascular Disease in Intermittent Claudication) Study. Study participants were a male cohort of 238 patients with a diagnosis of intermittent claudication (IC) and 245 age- and diabetes-matched controls. Results were compared to those for N-terminal pro-B-type natriuretic peptide (NT-proBNP).

RESULTS

Each increase of MR-proADM, MR-proANP, and CT-proET-1 by 1 SD was significantly associated with symptomatic PAD: odds ratio (OR) = 1.78 (95% CI, 1.41-2.25, P < 0.001), OR = 1.32 (95% CI, 1.06-1.66, P = 0.014), and OR = 1.80 (95% CI, 1.43-2.28, P < 0.001), respectively. The association remained significant for all 3 markers after additional adjustment for log C-reactive protein, serum creatinine, HDL cholesterol, and current smoking. When one adjusts for log NT-proBNP and excluding individuals with prevalent cardiovascular disease, MR-proADM and CT-proET-1 still predicted symptomatic PAD. Extended adjustment models including MR-proADM or CT-proET-1 showed significantly improved model fits compared to models including classical cardiac risk factors or NT-proBNP and led to significant reclassification (P < 0.05).

CONCLUSIONS

This study in a male cohort of patients with IC and age- and diabetes-matched controls indicates a significant association of high MR-proADM, MR-proANP, and CT-proET-1 concentrations with PAD. MR-proADM and CT-proET-1 provide additive information in comparison to NT-proBNP. Moreover, MR-proADM and CT-proET-1 significantly predict PAD in those patients and controls free from prevalent CVD.