Calciotropic and phosphaturic hormones in heart failure

Determinants of circulating calcitriol in cardiovascular disease

Circulating calcitriol may contribute to the risk of cardiovascular disease (CVD), but its regulation in patients with CVD is poorly characterized. We therefore aimed to assess determinants of circulating calcitriol in these patients. We analyzed 2183 independent samples from a large cohort of patients scheduled for coronary angiography and 1727 independent samples from different other cohorts from patients with a wide range of CVDs, including heart transplant candidates, to quantify the association of different parameters with circulating calcitriol. We performed univariable and multivariable linear regression analyses using the mathematical function that fitted best with circulating calcitriol. In the multivariable analysis of the large single cohort, nine parameters remained significant, explaining 30.0 % (32.4 % after exclusion of 22 potential outliers) of the variation in circulating calcitriol (r=0.548). Log-transformed 25-hydroxyvitamin D [25(OH)D] and log-transformed glomerular filtration rate were the strongest predictors, explaining 17.6 % and 6.6 %, respectively, of the variation in calcitriol. In the analysis of the combined other cohorts, including heart transplant candidates, the multivariable model explained a total of 42.6 % (46.1 % after exclusion of 21 potential outliers) of the variation in calcitriol (r=0.653) with log-transformed fibroblast growth factor-23 and log-transformed 25(OH)D explaining 29.0 % and 6.2 %, respectively. Circulating 25(OH)D was positively and FGF-23 inversely associated with circulating calcitriol. Although significant, PTH was only a weak predictor of calcitriol in both analyses (<2.5 %). In patients with CVD, FGF-23 and 25(OH)D are important independent determinants of circulating calcitriol. The relative importance of these two parameters may vary according to CVD severity. Future studies should focus on the clinical importance of regulating circulating calcitriol by different parameters.

Vitamin D deficiency and driveline infection in patients with a left ventricular assist device implant

Driveline infection is a frequent complication in recipients of durable left ventricular assist devices (LVAD), but its cause is largely unclear. Since vitamin D supplementation can reduce the risk of infections, we aimed at investigating the association of vitamin D deficiency with driveline infection. In 154 patients with continuous flow LVAD implants, we assessed 2-year risk of driveline infection according to vitamin D status (circulating 25-hydroxyvitamin D < 25 nmol/L or ⩾25 nmol/L). Of the study cohort, 34% (n = 53) had 25-hydroxyvitamin D concentrations <25 nmol/L. Kaplan-Meir estimates of 2-year freedom from driveline infection were in the vitamin D deficient and vitamin D non-deficient groups 49.7% and 74.2%, respectively (p = 0.017). Covariate-adjusted hazard ratio of driveline infection for the vitamin D deficient versus non-deficient group was 2.51 [95% CI: 1.11-5.69; p = 0.028). Circulating concentrations of endocrine regulators of calcium and phosphorus metabolism such as parathyroid hormone, 1,25-dihydroxyvitamin D, and fibroblast growth factor-23 were not significantly associated with the risk of driveline infection (p-values > 0.15). In total, our data indicate that in LVAD recipients deficient vitamin D status is a predictor of driveline infection, but future studies are needed to investigate whether these associations are causal.

Narrative review of recent studies on the role of vitamin D in the prevention of cardiac and renal risk and additional considerations for COVID-19 vulnerability

The role of vitamin D in maintaining a healthy cardiovascular (CV) and the renal system has received increasing attention. Low vitamin D levels are associated with the incidence of hypertension, cardiac remodeling, and chronic congestive heart failure. Low vitamin D levels also influence renal disease progression and albuminuria deterioration. Moreover, recent research indicates that vitamin D deficiency can be a potential risk factor for coronavirus disease-19 (COVID-19) infection and poorer outcomes. Data are inconclusive as to whether supplementation with vitamin D agents reduces CV disease risk or COVID-19 severity. Conversely, in patients with kidney disease, vitamin D supplementation is associated with improved kidney function and albuminuria. This narrative review considers recent data on the effects of vitamin D on the CV and renal system, as well as its possible role regarding COVID-19 complications.

Predialysis serum phosphate and intradialytic hypotension

INTRODUCTION

Intradialytic hypotension (IDH) is a common complication of hemodialysis (HD) and is associated with excess morbidity and mortality. Higher serum phosphate is associated with adverse cardiovascular outcomes in maintenance HD patients; however, its association with IDH has not previously been assessed.

METHODS

This is an analysis of a prospective cohort of 969 HD patients (80,968 HD sessions) receiving HD at a large dialysis organization (LDO) and a post-hoc analysis of 1838 HD patients (10,594 HD sessions) in the Hemodialysis study (HEMO), a multicenter randomized controlled trial that examined standard or high-dose HD and low-flux or high-flux membranes. Unadjusted and adjusted mixed effects regression models were fit to determine the association of pre-HD serum phosphate with IDH, defined as a nadir intra-HD systolic blood pressure (SBP) <90 mmHg.

FINDINGS

In the LDO cohort, baseline mean pre-HD serum phosphate was 5.2 ± 1.7 mg/dl. IDH occurred in 15.6% of HD sessions. In the adjusted model, higher pre-HD serum phosphate (per 1 mg/dl) was associated with a 12% increased risk of IDH (aOR 1.12, 95% CI 1.10-1.13, p <0.001). In exploratory models where pre-HD laboratory values were available, the effect estimate was attenuated but remained statistically significant (aOR 1.05; 95% CI 1.02-1.08; p <0.01). Participants in the highest (compared with the lowest) quartile of pre-HD serum phosphate had a 56% greater risk of IDH in the adjusted model (aOR Q4:Q1 1.56; 95% CI 1.44-1.68, p <0.001). The association of higher phosphate with IDH was consistent in the HEMO data.

DISCUSSION

Higher pre-HD serum phosphate is independently associated with an increased risk of IDH. As HD may cause an acute decline in serum phosphate, future studies to investigate the mechanisms of this association are warranted.

Vitamin D and Cardiovascular Disease: An Updated Narrative Review

During the last two decades, the potential impact of vitamin D on the risk of cardiovascular disease (CVD) has been rigorously studied. Data regarding the effect of vitamin D on CVD risk are puzzling: observational data indicate an inverse nonlinear association between vitamin D status and CVD events, with the highest CVD risk at severe vitamin D deficiency; however, preclinical data and randomized controlled trials (RCTs) show several beneficial effects of vitamin D on the surrogate parameters of vascular and cardiac function. By contrast, Mendelian randomization studies and large RCTs in the general population and in patients with chronic kidney disease, a high-risk group for CVD events, largely report no significant beneficial effect of vitamin D treatment on CVD events. In patients with rickets and osteomalacia, cardiovascular complications are infrequently reported, except for an increased risk of heart failure. In conclusion, there is no strong evidence for beneficial vitamin D effects on CVD risk, either in the general population or in high-risk groups. Whether some subgroups such as individuals with severe vitamin D deficiency or a combination of low vitamin D status with specific gene variants and/or certain nutrition/lifestyle factors would benefit from vitamin D (metabolite) administration, remains to be studied.

Endocrine Challenges in Patients with Continuous-Flow Left Ventricular Assist Devices

Heart failure (HF) remains a leading cause of morbidity, hospitalization, and mortality worldwide. Advancement of mechanical circulatory support technology has led to the use of continuous-flow left ventricular assist devices (LVADs), reducing hospitalizations, and improving quality of life and outcomes in advanced HF. Recent studies have highlighted how metabolic and endocrine dysfunction may be a consequence of, or associated with, HF, and may represent a novel (still neglected) therapeutic target in the treatment of HF. On the other hand, it is not clear whether LVAD support, may impact the outcome by also improving organ perfusion as well as improving the neuro-hormonal state of the patients, reducing the endocrine dysfunction. Moreover, endocrine function is likely a major determinant of human homeostasis, and is a key issue in the recovery from critical illness. Care of the endocrine function may contribute to improving cardiac contractility, immune function, as well as infection control, and rehabilitation during and after a LVAD placement. In this review, data on endocrine challenges in patients carrying an LVAD are gathered to highlight pathophysiological states relevant to this setting of patients, and to summarize the current therapeutic suggestions in the treatment of thyroid dysfunction, and vitamin D, erythropoietin and testosterone administration.

Calcium daily intake and the efficacy of a training intervention on optimizing calcium supplementation therapy: A clinical audit

BACKGROUND AND AIMS

Calcium is an essential element for human health, with key roles in the prevention and therapy of multifactorial conditions. Calcium dietary intake is often insufficient in the general population. The aim of this study was to perform a clinical audit for general practitioners (GPs) to understand the efficacy of training intervention on doctors' awareness about dietary calcium and supplements.

METHODS AND RESULTS

General practice outpatients were enrolled (Before Clinical Audit, BCA) from the same sanitary district, and calcium dietary intake was evaluated with a validated questionnaire, also collecting information about the consumption of calcium and vitamin D supplements. Then, a training intervention with a frontal lesson and discussion with GPs involved was performed. After one month of this intervention, a second outpatient enrolment was performed (Post Clinical Audit, PCA) in the same general practices to evaluate differences in nutritional suggestions and supplement prescription by GPs. In BCA, the calcium dietary intake was low, with nobody reaching 1000 mg as suggested by the guidelines. Only 6.6% and 24.5% took calcium and vitamin D supplements, respectively; in the PCA, these percentages increased to 28% and 78% for calcium and vitamin D supplements, respectively (p < 0.01 PCA vs BCA). There were no differences in calcium dietary intake between BCA and PCA.

CONCLUSION

Training intervention on GPs was successful to sensitize them regarding calcium intake problems; GPs tended to increase the prescription of supplements but not to suggest changes in dietary habits.

The effect of vitamin D on fibroblast growth factor 23: a systematic review and meta-analysis of randomized controlled trials

The phosphaturic hormone fibroblast growth factor 23 (FGF23) is a risk marker of cardiovascular and all-cause mortality. We therefore aimed to synthesize the evidence for the effect of vitamin D administration on circulating FGF23 concentrations. We performed a systematic review and meta-analysis of randomized, placebo-controlled trials (RCTs) in several databases from inception to January 2020. A total of 73 records were identified for full-text review, and 21 articles with 23 studies were included in the final analysis. The selected studies included 1925 participants with 8–156 weeks of follow-up. The weighted mean difference in FGF23 in the vitamin D versus placebo group was +21 pg/ml (95% CI: 13–28 pg/ml; P < 0.001) with considerable heterogeneity among studies (I² = 99%). The FGF23 increment was higher in patients with end-stage kidney/heart failure than in other individuals (+300 pg/ml [95% CI: 41–558 pg/ml] vs. +20 pg/ml [95% CI: 12–28 pg/ml], P_interaction = 0.03), and if baseline 25-hydroxyvitamin D concentrations were <50 nmol/l instead of ≥50 nmol/l (+34 pg/ml [95% CI: 18–51 pg/ml] vs. +9 pg/ml [95% CI: 3–14 pg/ml]; P_interaction = 0.002). Moreover, the FGF23 increment was influenced by vitamin D dose/type (vitamin D dose equivalent ≤ 2000 IU/day: +2 pg/ml [95% CI: 0–3 pg/ml]; vitamin D dose equivalent > 2000 IU/day: +18 pg/ml [95% CI: 6–30 pg/ml]; administration of activated vitamin D: +67 pg/ml [95% CI: 16–117 pg/ml]; P_interaction = 0.001). Results were not significantly influenced by study duration (P_interaction = 0.14), age class (P_interaction = 0.09), or assay provider (P_interaction = 0.11). In conclusion, this meta-analysis of RCTs demonstrates that vitamin D administration of >2000 IU/d vitamin D or activated vitamin D significantly increased concentrations of the cardiovascular risk marker FGF23, especially in patients with end-stage kidney/heart failure.

Are soluble ST2 levels influenced by vitamin D and/or the seasons?

OBJECTIVE

Cardiovascular disease manifestation and several associated surrogate markers, such as vitamin D, have shown substantial seasonal variation. A promising cardiovascular biomarker, soluble ST2 (sST2), has not been investigated in this regard – we therefore determined if systemic levels of sST2 are affected by seasonality and/or vitamin D in order to investigate their clinical interrelation and usability.

DESIGN

sST2 levels were measured in two cohorts involving hypertensive patients at cardiovascular risk, the Styrian Vitamin D Hypertension Trial (study A; RCT design, 8 weeks 2800 IU cholecalciferol daily) and the Ludwigshafen Risk and Cardiovascular Health Study (LURIC; study B; cross-sectional design).

Effects of Vitamin D Supplementation on Renin and Aldosterone Concentrations in Patients with Advanced Heart Failure: The EVITA Trial

OBJECTIVE

1,25-Dihydroxyvitamin D (1,25([OH]₂D) is considered to be a negative endogenous regulator of the renin-angiotensin-aldosterone system (RAAS), but the effect of vitamin D supplementation on the RAAS is inconclusive.

DESIGN

In this prespecified secondary analysis of a randomized controlled trial, we assessed in 165 patients with heart failure (vitamin D group: n = 83; placebo group: n = 82) the effect of three years of vitamin D supplementation with 4000 IU daily on parameters of the RAAS (renin and aldosterone) and on circulating 1,25(OH)₂D, plasma phosphate, and fibroblast growth factor (FGF)-23. We assessed age- and baseline-adjusted between-group differences at study termination.

RESULTS

Almost all patients were under treatment with beta-blockers, inhibitors of the RAAS, and diuretics. Initially, the frequency of concentrations above the laboratory-specific reference range (renin: >23.9 mIU/L; aldosterone: >232 ng/L) in the vitamin D and placebo group was 87.7% and 92.7%, respectively (renin), and 24.1% and 32.5%, respectively (aldosterone). Vitamin D increased adjusted 1,25(OH)₂D concentrations significantly (mean treatment effect and 95% CI: 18.3 pmol/L,7.3 to 29.3 pmol/L; P < 0.001) but had no significant effects on phosphate (0.18 mmol/L, -0.00 to 0.35 mmol/L; P = 0.051), FGF-23 (685 RU/mL, -213 to 1585 RU/mL; P = 0.134), renin (312 mIU/L, -279 to 902 ng/L; P = 0.298), or aldosterone (-0.19 ng/L, -5.09 to 4.70 ng/L; P = 0.938). Vitamin D supplementation was, however, associated with an increase in renin concentrations in the subgroup with baseline 25-hydroxyvitamin D below 30 nmol/L (n = 67; 1365 mIU/, 343 to 2386 mIU/L; P = 0.010).

CONCLUSIONS

In patients with advanced heart failure treated according to evidence-based guidelines, vitamin D supplementation did not significantly influence parameters of the RAAS in the entire study cohort but was associated with an increase in plasma renin concentrations in the subgroup with low baseline 25-hydroxyvitamin D concentrations.

Vitamin D deficiency and clinical outcome in patients with chronic heart failure: A review

AIM

The aim of this review was to summarize evidence on the role of Vitamin D deficiency in heart failure (HF), from pathophysiological mechanisms to clinical effects of Vitamin D supplementation.

DATA SYNTHESIS

Chronic HF secondary to left ventricular (LV) systolic dysfunction is a growing health problem, still associated with poor clinical outcome. In recent years, experimental and epidemiological evidence focused on the role of Vitamin D in HF. Cross sectional studies demonstrated that prevalence of HF is increased in patients with Vitamin D deficiency or parathyroid hormone (PTH) plasma level increase, whereas longitudinal studies showed enhanced risk of developing new HF in patients with Vitamin D deficiency. In addition, in patients with established HF, low plasma levels of Vitamin D are associated with worsening clinical outcome. Yet, clinical studies did not definitively demonstrate a benefit of Vitamin D supplementation for preventing HF or ameliorating clinical outcome in patients with established HF.

CONCLUSIONS

Despite convincing experimental and epidemiological data, treatment with Vitamin D supplementation did not show clear evidence of benefit for preventing HF or influencing its clinical course. Ongoing clinical studies will hopefully shed lights on the effects of Vitamin D supplementation on clinical endpoints along the spectrum of HF.

Vitamin-D concentrations, cardiovascular risk and events - a review of epidemiological evidence

Vitamin D has long been established as an elemental factor of bone physiology. Beyond mineral metabolism, the expression of the vitamin D receptor has been identified throughout the cardiovascular (CV) system. Experimental studies showed beneficial effects of vitamin D on heart and vessels, but vitamin D intoxication in animals also led to hypercalcemia and vascular calcification. Our knowledge has been extended by epidemiological studies that showed that 25-hydroxyvitamin D (25(OH)D) levels are inversely associated with an increased CV risk itself, but also with established CV risk factors, such as arterial hypertension, endothelial dysfunction and atherosclerosis. Conversely, randomized controlled trials could not document significant and consistent effects of vitamin D supplementation on CV risk or events. Potential explanations may lie in differences in reference ranges or the possibility that low vitamin D in CV disease is only an epiphenomenon. In the latter case, the key question is why low 25(OH)D levels are such a strong predictor of health. While we wait for new data, the current conclusion is that vitamin D is a strong risk marker for CV risk factors and for CV diseases itself.

Association of serum calcium and heart failure with preserved ejection fraction in patients with type 2 diabetes

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a recognized trigger factor for heart failure with preserved ejection fraction (HFpEF). Recent studies show that higher serum calcium level is associated with greater risk of both T2DM and heart failure. We speculate that increased serum calcium is related to HFpEF prevalence in patients with T2DM.

METHODS

In this cross-sectional echocardiographic study, 807 normocalcemia and normophosphatemia patients with T2DM participated, of whom 106 had HFpEF. Multinomial logistic regression was carried out to determine the variables associated with HFpEF. The associations between serum calcium and metabolic parameters, as well as the rate of HFpEF were examined using bivariate linear correlation and binary logistic regression, respectively. The predictive performance of serum calcium for HFpEF was evaluated using the area under the receiver operating characteristic curve (AUC).

RESULTS

Patients with HFpEF have significantly higher serum calcium than those without HFpEF. Serum calcium was positively associated with total cholesterol, triglycerides, low-density lipoprotein cholesterol, serum uric acid, HOMA-IR and fasting plasma glucose. Compared with patients in the lowest serum calcium quartile, the odds ratio (OR) for HFpEF in patients in the highest quartile was 2.331 (95 % CI 1.088-4.994, p = 0.029). When calcium was analyzed as a continuous variable, per 1 mg/dL increase, the OR (95 % CI) for HFpEF was [2.712 (1.471-5.002), p = 0.001]. Serum calcium can predict HFpEF [AUC = 0.673, 95 % CI (0.620-0.726), p < 0.001].

CONCLUSIONS

An increase in serum calcium level is associated with an increased risk of HFpEF in patients with T2DM.