Aldosterone and parathyroid hormone: a precarious couple for cardiovascular disease

Animal and human studies support a clinically relevant interaction between aldosterone and parathyroid hormone (PTH) levels and suggest an impact of the interaction on cardiovascular (CV) health. This review focuses on mechanisms behind the bidirectional interactions between aldosterone and PTH and their potential impact on the CV system. There is evidence that PTH increases the secretion of aldosterone from the adrenals directly as well as indirectly by activating the renin-angiotensin system. Upregulation of aldosterone synthesis might contribute to the higher risk of arterial hypertension and of CV damage in patients with primary hyperparathyroidism. Furthermore, parathyroidectomy is followed by decreased blood pressure levels and reduced CV morbidity as well as lower renin and aldosterone levels. In chronic heart failure, the aldosterone activity is inappropriately elevated, causing salt retention; it has been argued that the resulting calcium wasting causes secondary hyperparathyroidism. The ensuing intracellular calcium overload and oxidative stress, caused by PTH and amplified by the relative aldosterone excess, may increase the risk of CV events. In the setting of primary aldosteronism, renal and faecal calcium loss triggers increased PTH secretion which in turn aggravates aldosterone secretion and CV damage. This sequence explains why adrenalectomy and blockade of the mineralocorticoid receptor tend to decrease PTH levels in patients with primary aldosteronism. In view of the reciprocal interaction between aldosterone and PTH and the potentially ensuing CV damage, studies are urgently needed to evaluate diagnostic and therapeutic strategies addressing the interaction between the two hormones.

Can vitamin D deficiency cause diabetes and cardiovascular diseases? Present evidence and future perspectives

Several studies have shown that vitamin D may play a role in many biochemical mechanisms in addition to bone and calcium metabolism. Recently, vitamin D has sparked widespread interest because of its involvement in the homeostasis of the cardiovascular system. Hypovitaminosis D has been associated with obesity, related to trapping in adipose tissue due to its lipophilic structure. In addition, vitamin D deficiency is associated with increased risk of cardiovascular disease (CVD) and this may be due to the relationship between low vitamin D levels and obesity, diabetes mellitus, dyslipidaemia, endothelial dysfunction and hypertension. However, although vitamin D has been identified as a potentially important marker of CVD, the mechanisms through which it might modulate cardiovascular risk are not fully understood. Given this background, in this work we summarise clinical retrospective and prospective observational studies linking vitamin D levels with cardio-metabolic risk factors and vascular outcome. Moreover, we review various randomised controlled trials (RCTs) investigating the effects of vitamin D supplementation on surrogate markers of cardiovascular risk. Considering the high prevalence of hypovitaminosis D among patients with high cardiovascular risk, vitamin D replacement therapy in this population may be warranted; however, further RCTs are urgently needed to establish when to begin vitamin D therapy, as well as to determine the dose and route and duration of administration.

Homoarginine, heart failure, and sudden cardiac death in haemodialysis patients

AIMS

Sudden cardiac death (SCD) is a major contributor to the excess mortality of patients on maintenance dialysis. Homoarginine deficiency may lead to decreased nitric oxide availability and endothelial dysfunction. Based on this rationale we assessed whether homoarginine deficiency is a risk factor for SCD in dialysis patients.

METHODS AND RESULTS

This study examined the association of homoarginine with cardiovascular outcomes in 1255 diabetic haemodialysis patients from the German diabetes and dialysis study. During a median of 4 years of follow-up, hazard ratios (HR) (95% CI) for reaching the following pre-specified, adjudicated endpoints were determined: SCD, myocardial infarction, stroke, death due to heart failure, and combined cardiovascular events. There was a strong association of low homoarginine concentrations with the presence of congestive heart failure and left ventricular hypertrophy as well as increased levels of brain natriuretic peptide. Per unit decrease in homoarginine, the risk of SCD increased three-fold (HR 3.1, 95% CI 2.0-4.9), attenuating slightly in multivariate models (HR 2.4; 95% CI 1.5-3.9). Patients in the lowest homoarginine quintile experienced a more than two-fold increased risk of SCD, and more than three-fold increased risk of heart failure death than patients in the highest quintile, which accounted for the high incidence of combined cardiovascular events. Low homoarginine showed a trend towards increased risk of stroke, however, myocardial infarction was not meaningfully affected.

CONCLUSION

Low homoarginine is a strong risk factor for SCD and death due to heart failure in haemodialysis patients. Further studies are needed to elucidate the underlying mechanisms, offering the potential to develop new interventional strategies.

Hyperparathyroidism in patients with primary aldosteronism: cross-sectional and interventional data from the GECOH study

CONTEXT

Experimental studies suggest that aldosterone induces hypercalciuria and might contribute to hyperparathyroidism.

OBJECTIVE

We aimed to test for differences in PTH levels and parameters of calcium and vitamin D metabolism in patients with primary aldosteronism (PA) compared with patients with essential hypertension (EH) and to evaluate the impact of PA treatment on these laboratory values.

DESIGN, SETTING, AND PARTICIPANTS

The Graz Endocrine Causes of Hypertension study includes hypertensive patients referred for screening for endocrine hypertension at a tertiary care center in Graz, Austria.

MAIN OUTCOME MEASURES

Differences in PTH levels between patients with PA and EH.

RESULTS

Among 192 patients, we identified 10 patients with PA and 182 with EH. PTH levels (mean ± sd in picograms per milliliter) were significantly higher in PA patients compared with EH (67.8 ± 26.9 vs. 46.5 ± 20.9; P = 0.002). After treatment of PA with either adrenal surgery (n = 5) or mineralocorticoid receptor antagonists (n = 5), PTH concentrations decreased to 43.9 ± 14.9 (P = 0.023). Serum 25-hydroxyvitamin D concentrations were similar in both groups. Compared with EH, serum calcium concentrations were significantly lower (2.35 ± 0.10 vs. 2.26 ± 0.10 mmol/liter; P = 0.013), and there was a nonsignificant trend toward an increased spot urine calcium to creatinine ratio in PA [median (interquartile range) 0.19 (0.11-0.31) vs. 0.33 (0.12-0.53); P = 0.094].

CONCLUSIONS

Our results suggest that PA contributes to secondary hyperparathyroidism. Further studies are warranted to evaluate whether PTH has implications for PA diagnostics and whether mineralocorticoid receptor antagonists have a general impact on PTH and calcium metabolism.

Low serum zinc levels in patients undergoing coronary angiography correlate with immune activation and inflammation

INTRODUCTION

Low serum zinc concentrations are associated with adverse outcomes. To explain this phenomenon we aimed to investigate whether low zinc levels are related to immune activation, renal function and coronary artery disease (CAD).

METHODS

Serum concentrations of zinc and the immune activation markers neopterin and C-reactive protein (CRP) were measured in 2048 patients derived from the LUdwigshafen RIsk and Cardiovascular Health (LURIC) study, a cohort study among patients referred for coronary angiography.

RESULTS

Zinc concentrations did not differ between patients with CAD (mean±SD: 13.3±2.4 μmol/L) and controls (13.3±2.2 μmol/L; Welch's t test: p=n.s.) but CAD patients had higher neopterin (8.6±7.4 nmol/L) and CRP (9.7±19.6 mg/L) concentrations compared to controls (neopterin: 7.5±4.8 nmol/L, p=0.0005; CRP: 5.5±10.0 mg/L, p<0.0001). There was an inverse correlation between serum zinc concentrations and neopterin (Spearman's rank correlation: r(s)=-0.222) and CRP (r(s)=-0.166; both p<0.0001) concentrations.

CONCLUSIONS

Our results indicate increased inflammatory processes in patients with low zinc levels. Further studies should clarify whether inflammation related processes such as renal wasting contribute to zinc deficiency and underlie the adverse health consequences of low serum zinc levels.

Associations of Sun Exposure with 25-Hydroxyvitamin D and Parathyroid Hormone Levels in a Cohort of Hypertensive Patients: The Graz Endocrine Causes of Hypertension (GECOH) Study

Sunlight-induced vitamin D, synthesis in the skin is the major source of vitamin D, but data on the relationship of sun-related behaviour with vitamin D and parathyroid hormone (PTH) levels are relatively sparse. We evaluated whether habitual sun exposure is associated with 25-hydroxyvitamin D (25[OH]D) and PTH levels and whether there exist seasonal variations. We examined 111 hypertensive patients in Austria (latitude 47° N). Frequent sunbathing at home and outdoor sports were associated with higher 25(OH)D levels (P < 0.05 for both). Red or blond scalp hair as a child, memory of sunburns, preferring sunbathing, frequent stays on the beach or in open-air pools, and solarium use were associated with lower PTH levels (P < 0.05 for all). Multiple linear regression analyses including age, sex, and body mass index showed that sun exposure score was significantly associated with 25(OH)D (beta coefficient = 0.27; P = 0.004) and by trend with PTH (beta coefficient = -0.16; P = 0.09). These associations were more prominent in summer in which 25(OH)D levels were significantly higher compared to winter. Translation of these findings into recommendations for the prevention and treatment of vitamin D deficiency remains a challenge for the future.

Vitamin D deficiency and mortality risk in the general population: a meta-analysis of prospective cohort studies

BACKGROUND

Low vitamin D status may increase mortality risk.

OBJECTIVE

We used nonparametric ("highest compared with lowest" categories) and parametric (>2 categories) statistical models to evaluate associations of 25-hydroxyvitamin D [25(OH)D] serum concentrations and mortality in observational studies among general populations.

DESIGN

We searched PubMed, EMBASE, Web of Science, and reference lists for relevant articles. We included studies that contained data on relative risks (RRs) for mortality for different 25(OH)D concentrations, which included a corresponding measure of uncertainty, and this yielded 14 prospective cohort studies that involved 5562 deaths out of 62,548 individuals. We applied log-transformed RRs and CIs, adjusted for the maximal number of confounding variables. In the parametric model, which is based on 11 studies and 59,231 individuals, we used the lowest quantile as the reference category.

RESULTS

For "highest compared with lowest" categories of 25(OH)D, the estimated summary RR of mortality was 0.71 (95% CI: 0.50, 0.91). In the parametric model, the estimated summary RRs (95% CI) of mortality were 0.86 (0.82, 0.91), 0.77 (0.70, 0.84), and 0.69 (0.60, 0.78) for individuals with an increase of 12.5, 25, and 50 nmol 25(OH)D serum values/L, respectively, from a median reference category of ∼27.5 nmol/L. There was, however, no significant decrease in mortality when an increase of ∼87.5 nmol/L above the reference category occurred.

CONCLUSION

Data suggest a nonlinear decrease in mortality risk as circulating 25(OH)D increases, with optimal concentrations ∼75-87.5 nmol/L.

Hyperglycaemia and vitamin D: a systematic overview

Vitamin D plays a role in a range of functions that may impact on glycaemic control. In this study we systematically report on clinical studies evaluating the impact of vitamin D on aspects of hyperglycaemia in non-pregnant adults. A total of 1,294 articles, of which 417 were reviews, were identified. No well-designed randomised, controlled trials were identified that specifically investigated the effects of vitamin D supplementation on glucose and insulin concentrations. The majority of the studies that are available were poorly designed, having limited numbers, short study duration, or were conducted in volunteers with normal baseline, as measured by 25-hydroxyvitamin D (25(OH)D), concentrations or used inadequate doses of the supplements to normalise vitamin D concentrations, or used inappropriate analyses. Most studies did not observe improvements in glycaemia, with few exceptions. The results were more equivocal for aspects of insulin resistance. Most found no benefit on measures of insulin resistance, although some did. However, more studies described improved insulin release, although data from the studies to date are really inadequate to provide any reliable conclusions. Well-conducted randomised, controlled trials with adequate vitamin D doses are required to effectively assess whether this vitamin can reduce the incidence of diabetes.

Relationship between plasma aldosterone concentration and soluble cellular adhesion molecules in patients referred to coronary angiography

OBJECTIVE

Evidence is emerging that aldosterone contributes to the development and progression of atherosclerosis and cardiovascular disease. Little is known, however, regarding an association between circulating aldosterone levels and soluble cellular adhesion molecules in humans.

METHODS

We investigated the relationship between plasma aldosterone concentration (PAC) and soluble cellular adhesion molecules in a large cohort of patients referred to coronary angiography. After exclusion of patients with ongoing mineralocorticoid receptor blocker use, oral contraceptive or hormone replacement therapy, 1,733 patients (mean age: 62.5±10.8 years; 26.4%% women; mean PAC: 101.5±93.5 pg/mL) remained eligible for analyses.

RESULTS

Pearson correlation analysis as well as age and gender adjusted partial correlation analysis revealed a positive association between PAC and soluble (s) E-, L- and P-selectin levels but not with sICAM-1 and sVCAM-1, respectively. In multivariate adjusted analyses of covariance (ANCOVA) sE- (p=0.026), sL- (p=0.049) and sP-selectin (p<0.001) levels increased steadily from the first (reference) to the third gender-specific tertile of PAC. No significant variation across PAC tertiles was found for sICAM-1 (p=0.767) and sVCAM1 (p=0.425) levels, respectively. Finally, multivariate regression analyses revealed circulating aldosterone as an important predictor for soluble selectin levels.

CONCLUSION

Our findings in a large cohort of patients indicate that upregulation of selectins might represent a novel mechanism of aldosterone mediated development and progression of atherosclerosis. In view of aldosterone as a novel cardiovascular risk factor independent of angiotensin II, our findings warrant further interventional studies which should evaluate anti-atherosclerotic effects of aldosterone blocking treatment strategies in humans.

The effect of vitamin D supplementation on peripheral regulatory T cells and β cell function in healthy humans: a randomized controlled trial

BACKGROUND

Increasing evidence supports the role of vitamin D (vitD) in modifying the risk to develop type 1 diabetes (T1D) and other autoimmune diseases. VitD3 might stimulate regulatory T cells (Tregs), a central player in the maintenance of self-tolerance. In addition, direct effects of vitD on β-cell function are postulated. The aim of our study was to evaluate the effect of a high dose vitD supplementation on Tregs frequency (%Tregs) and β-cell function assessed by a mixed meal tolerance test (MMTT) in healthy humans.

METHODS

A double-blind, placebo controlled trial was performed in 59 healthy adult subjects (49% females). Subjects received oral vitD3 (140,000 IU monthly) or placebo for 3 months. %Tregs within 20,000 CD4+ T cells of peripheral blood was determined by multi-parametric FACS-analysis. A liquid MMTT was carried out before and after treatment.

RESULTS

%Tregs increased significantly in the vitD group, but remained unchanged in the placebo group. Fasting C-peptide concentrations did not change significantly in either group. Similarly, the mean AUC for C-peptide after 3 months and the change in mean values from baseline to the end of the treatment were comparable in both groups.

CONCLUSIONS

A short time high dose vitD3 supplementation significantly increased the frequency of Tregs, but did not further improve β-cell function in apparently healthy subjects. The immunomodulatory potential of vitD might be an important mechanistic link for the association of vitD and T1D.

Vitamin D, cardiovascular disease and mortality

A poor vitamin D status, i.e. low serum levels of 25-hydroxyvitamin D [25(OH)D], is common in the general population. This finding is of concern not only because of the classic vitamin D effects on musculoskeletal outcomes, but also because expression of the vitamin D receptor (VDR) and vitamin D metabolizing enzymes in the heart and blood vessels suggests a role of vitamin D in the cardiovascular system. VDR-knockout mice suffer from cardiovascular disease (CVD), and various experimental studies suggest cardiovascular protection by vitamin D, including antiatherosclerotic, anti-inflammatory and direct cardio-protective actions, beneficial effects on classic cardiovascular risk factors as well as suppression of parathyroid hormone (PTH) levels. In epidemiological studies, low levels of 25(OH)D are associated with increased risk of CVD and mortality. Data from randomized controlled trials (RCTs) are sparse and have partially, but not consistently, shown some beneficial effects of vitamin D supplementation on cardiovascular risk factors (e.g. arterial hypertension). We have insufficient data on vitamin D effects on cardiovascular events, but meta-analyses of RCTs indicate that vitamin D may modestly reduce all-cause mortality. Despite accumulating data suggesting that a sufficient vitamin D status may protect against CVD, we still must wait for results of large-scale RCTs before raising general recommendations for vitamin D in the prevention and treatment of CVD. In current clinical practice, the overall risks and costs of vitamin D supplementation should be weighed against the potential adverse consequences of untreated vitamin D deficiency.

The lipid accumulation product is associated with increased mortality in normal weight postmenopausal women

Lipid accumulation product (LAP) is an emerging cardiovascular risk factor, which is calculated from waist circumference (WC) and triglyceride (TG) levels. The aim of this study was to elucidate the relationship between LAP and cardiovascular mortality as well as the presence of type 2 diabetes with respect to gender-specific differences. We determined WC and fasting TG levels and the cardiovascular and metabolic phenotypes coronary artery disease (CAD), hypertension, metabolic syndrome, and diabetes mellitus in 2,279 men and 875 postmenopausal women who were routinely referred to coronary angiography. The LAP was calculated as (WC (cm)--65) × (TG (mmol/l)) for men and as (WC (cm)--58) × (TG (mmol/l)) for women. LAP levels were independently associated with congestive heart failure mortality in all postmenopausal women and with all-cause mortality in diabetic postmenopausal women but not in men. Multivariable-adjusted hazard ratios (with 95% confidence intervals) for all-cause, cardiovascular, and congestive heart failure mortality in the third compared to the first LAP tertile were 4.28 (1.94-9.44; P < 0.001), 3.47 (1.28-9.40; P = 0.015), and 10.77 (1.21-95.88; P = 0.033), respectively, in normal weight postmenopausal women, whereas no significant associations were found in men. LAP levels were highly associated with type 2 diabetes in all subjects, postmenopausal women, and men. High LAP values are predictive of mortality independently of other cardiovascular risk factors in normal weight and diabetic postmenopausal women but not in men. Type 2 diabetes (T2DM) was highly associated with LAP in women and men. Our study validates an inexpensive and simple risk profiling that may allow identifying postmenopausal women at high cardiovascular risk.

Wasting and sudden cardiac death in hemodialysis patients: a post hoc analysis of 4D (Die Deutsche Diabetes Dialyse Studie)

BACKGROUND

Wasting is common in hemodialysis patients and often is accompanied by cardiovascular disease and inflammation. The cardiovascular risk profile meaningfully changes with the progression of kidney disease, and little is known about the impact of wasting on specific clinical outcomes. This study examined the effects of wasting on the various components of cardiovascular outcome and deaths caused by infection in hemodialysis patients.

STUDY DESIGN

Prospective cohort study.

SETTING & PARTICIPANTS

1,255 hemodialysis patients from 178 centers participating in Die Deutsche Diabetes Dialyse Studie (4D) in 1998-2004.

PREDICTOR

Moderate wasting was defined as body mass index, albumin, and creatinine values less than the median (26.7 kg/m(2), 3.8 g/dL, and 6.8 mg/dL, respectively) and C-reactive protein level less than the median (5 mg/L) at baseline. Severe wasting was defined as body mass index, albumin, and creatinine levels less than the median and C-reactive protein level greater than the median at baseline.

OUTCOMES & MEASUREMENTS

Risks of sudden cardiac death (SCD), myocardial infarction (MI), stroke, combined cardiovascular events, deaths due to infection, and all-cause mortality were determined using Cox regression analyses during a median of 4 years of follow-up.

RESULTS

196 patients had wasting (severe, n = 109; and moderate, n = 87). Overall, 617 patients died (160 of SCD and 128 of infectious deaths). Furthermore, 469 patients experienced a cardiovascular event, with MI and stroke occurring in 200 and 103 patients, respectively. Compared with patients without wasting (n = 1,059), patients with severe wasting had significantly increased risks of SCD (adjusted HR, 1.8; 95% CI, 1.1-3.1), all-cause mortality (adjusted HR, 1.8; 95% CI, 1.4-2.4), and deaths due to infection (adjusted HR, 2.3; 95% CI, 1.2-4.3). In contrast, MI was not affected. The increased risk of cardiovascular events (adjusted HR, 1.5; 95% CI, 1.0-2.1) was explained mainly by the effect of wasting on SCD.

LIMITATIONS

Selective patient cohort.

CONCLUSIONS

Wasting was associated strongly with SCD, but not MI, in diabetic hemodialysis patients. Nonatherosclerotic cardiac disease potentially has a major role to account for the increased cardiovascular events in patients with wasting, suggesting the need for novel treatment strategies.

High Estradiol Levels are Associated with Increased Mortality in Older Men Referred to Coronary Angiography

There is evidence showing an important role of estrogens in men’s health. We aimed to evaluate whether estradiol levels are associated with overall mortality and specific fatal events.

We measured estradiol levels in 2 078 men who were routinely referred for coronary angiography (1997–2000).

The main outcome measures were Cox proportional hazard ratios (HRs) for mortality from all causes, from cardiovascular and non-cardiovascular causes including cancer according to estradiol levels.

Multivariable HRs (with 95% confidence intervals) for all-cause, non-cardiovascular, and cancer mortality were 1.43 (1.08–1.91), 2.11 (1.34–3.34), and 2.27 (1.00–5.19), respectively, in the fourth estradiol quartile as compared to the first. There was no significant association of estradiol levels with cardiovascular mortality. In multivariate adjusted analyses, higher estradiol levels in men were significantly associated with prevalent strokes, peripheral vascular disease, and carotid artery stenosis compared to lower estradiol levels.

High levels of estradiol are associated with all-cause and non-cardiovascular mortality in a large cohort of older men referred to coronary angiography. Further studies are warranted to confirm our results and to elucidate the underlying mechanisms.

Low free testosterone levels are associated with all-cause and cardiovascular mortality in postmenopausal diabetic women

OBJECTIVE

Hyperandrogenemia is associated with cardiovascular risk factors in women but evidence about the relationship of testosterone levels with mortality is sparse. We aimed to evaluate whether total testosterone (TT), free testosterone (FT), and sex hormone-binding globulin (SHBG) are associated with all-cause and cardiovascular mortality in a cohort of postmenopausal women.

RESEARCH DESIGN AND METHODS

We measured TT and SHBG levels in 875 postmenopausal women who were referred for coronary angiography (during 1997-2000). FT was calculated according to the Vermeulen method. The main outcome measures were Cox proportional hazard ratios (HRs) for mortality from all causes and from cardiovascular causes.

RESULTS

After a median follow-up time of 7.7 years, 179 women (20.5%) had died. There were 101 deaths due to cardiovascular disease (56.4% of all deaths). We found no association of FT, TT, and SHBG levels with mortality in all postmenopausal women. In postmenopausal diabetic women, multivariable-adjusted HRs (with 95% CIs) in the fourth compared with the first FT quartile for all-cause and cardiovascular mortality were 0.38 (0.08-0.90), P = 0.025, and 0.28 (0.08-0.90), P = 0.032, respectively. We found no association of TT and SHBG with mortality in diabetic postmenopausal women.

CONCLUSIONS

In postmenopausal diabetic women referred for coronary angiography, low FT levels are independently associated with increased all-cause and cardiovascular mortality.

Vitamin D status and mortality risk in CKD: a meta-analysis of prospective studies

BACKGROUND

Vitamin D deficiency, assessed as low 25-hydroxyvitamin D (25[OH]D) level, is highly prevalent in patients with chronic kidney disease (CKD) and is associated with various adverse health outcomes. Whether low 25(OH)D levels in patients with CKD are an independent risk factor for mortality remains to be studied in detail, and this was the objective of our work.

STUDY DESIGN

A systematic review and meta-analysis of prospective observational studies.

SETTING & POPULATION

Patients with CKD. CKD was diagnosed mainly as decreased estimated glomerular filtration rate.

SELECTION CRITERIA FOR STUDIES

We performed a systematic literature search in MEDLINE, ISI, and EMBASE to identify prospective studies reporting on 25(OH)D levels and mortality.

PREDICTOR

25(OH)D serum concentrations.

OUTCOME

All-cause mortality.

RESULTS

10 studies with an overall sample of 6,853 patients with CKD were included. Relative risk of mortality per 10-ng/mL (25-nmol/L) increase in 25(OH)D level was 0.86 (95% CI, 0.82-0.91), with no indication of publication bias or significant heterogeneity (I(2) =15%; P = 0.3). Summary estimates for CKD cohorts with and without dialysis treatment showed homogeneous results (P = 0.9).

LIMITATIONS

Results may be limited by heterogeneity, unconsidered confounders, and the observational design of the studies. Furthermore, publication bias by unpublished null findings on the association of 25(OH)D level and mortality cannot be ruled out and ascertainment of CKD was based largely on estimated glomerular filtration rate.

CONCLUSIONS

Higher 25(OH)D levels are associated with significantly improved survival in patients with CKD. Whether treatment of low 25(OH)D level using natural vitamin D supplementation improves survival in patients with CKD remains to be elucidated in randomized controlled trials.

Associations of plasma renin with 10-year cardiovascular mortality, sudden cardiac death, and death due to heart failure

AIMS

Renin is the key regulator of the renin-angiotensin-aldosterone system. Previous studies have reported conflicting results on the relation of plasma renin with fatal cardiovascular events. This study in a large cohort of patients sought to evaluate the association between plasma renin concentration (PRC) and cardiovascular mortality after long-term follow-up of almost 10 years.

METHODS AND RESULTS

Plasma renin concentration [median: 11.4 (6.0-24.6) pg/mL] was measured in 3303 patients (mean age: 62.7 ± 10.6 years; 30.3% women) referred to coronary angiography. After a median follow-up of 9.9 years, 554 participants (16.8%) with PRC measurement at baseline had died due to fatal cardiovascular events. Multivariable-adjusted Cox analysis revealed that when compared with participants in the lowest PRC quartile, those in the highest quartile were at increased risk of cardiovascular mortality (hazard ratio: 1.79, 95% CI 1.28-2.48). Analyses of specific causes of cardiovascular death showed that for each standard deviation increase in log-PRC there was a 22% (P = 0.006) increase in risk of sudden cardiac death and a 23% (P = 0.033) greater risk of death due to heart failure. The association of PRC with cardiovascular mortality remained stable after adjustment for established cardiovascular risk factors, ongoing antihypertensive medication, immunoreactive angiotensin II, and aldosterone levels. Age, N-terminal pro-B-type natriuretic peptide levels, coronary artery disease, the use of angiotensin-converting enzyme-inhibitors, beta-blockers, diuretics, and kidney function were important effect modifiers.

CONCLUSIONS

Plasma renin concentration is associated with long-term cardiovascular mortality in patients referred to coronary angiography. Further intervention studies should determine whether renin is a potential therapeutic target or only a marker of mortality risk in various cardiovascular risk groups.

Bone alkaline phosphatase and mortality in dialysis patients

BACKGROUND AND OBJECTIVES

Serum alkaline phosphatase (AP) is associated with vascular calcification and mortality in hemodialysis patients, but AP derives from various tissues of origin. The aim of this study was to assess the effect of bone-specific AP (BAP) on morbidity and mortality in dialysis patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

From a prospective cohort study of incident dialysis patients in The Netherlands, all patients with measured BAP at 12 months after the start of dialysis (baseline) were included in the analysis (n = 800; mean age, 59 ± 15 years; mean BAP = 18 ± 13 U/L). By Cox regression analyses, we assessed the impact of BAP levels on short-term mortality (6 months) and longer-term mortality (4-year follow-up).

RESULTS

High levels of BAP strongly affected short-term mortality. After adjustment for confounders, patients in the highest BAP tertile had a 5.7-fold increased risk of death within 6 months compared with patients in the lowest tertile. The effect applied to both cardiovascular and noncardiovascular mortality. Furthermore, high levels of BAP were associated with increased cardiovascular mortality in the longer term. In comparison with total AP, the effect sizes related to clinical outcomes were much higher for BAP.

CONCLUSIONS

High levels of BAP were strongly associated with short-term mortality in dialysis patients, pointing out the important impact of bone turnover. Longitudinal assessments of BAP may be useful for the treatment monitoring in clinical practice in dialysis patients.

Arginine bioavailability ratios are associated with cardiovascular mortality in patients referred to coronary angiography

OBJECTIVES

Arginine is the only source for nitric oxide (NO) synthesis. The bioavailability of NO plays a pivotal role in endothelial function and consequently in cardiovascular disease. The aim of the current study is to investigate the association of arginine bioavailability ratios with markers of endothelial function and cardiovascular mortality in patients referred to coronary angiography.

METHODS

We investigated 2236 patients recruited within the LUdwigshafen RIsk and Cardiovascular Health (LURIC) study that were followed up for a median of 7.7 years. Arginine, ornithine and citrulline were chromatographically determined after precolumn-derivatisation followed by postcolumn continuous reaction with ninhydrin. Global arginine bioavailability (GABR) was calculated by arginine divided by the sum of ornithine plus citrulline.

RESULTS

We observed a significant rise in cardiovascular mortality with decreasing GABR and arginine to ornithine ratio quartiles. The adjusted Cox proportional HRs for GABR were 1.27 (0.88-1.83), 1.27 (0.89-1.80) and 1.75 (1.24-2.45) for the 3rd, the 2nd and the 1st quartile respectively in comparison to the 4th quartile. The HRs for the quartiles of the arginine to ornithine ratio were 1.83 (1.25-2.67), 2.17 (1.50-3.20) and 2.02 (1.39-2.92) respectively. Patients with type 2 diabetes mellitus had a significantly lower GABR than persons without diabetes (0.88 ± 0.23 vs. 0.94 ± 0.24, p<0.001). GABR was found to be inversely correlated with endothelial markers as VCAM-1 (r=-0.301, p<0.001) or ICAM-1 (r=-0.136, p<0.001).

CONCLUSIONS

GABR and the arginine to ornithine ratio are associated with markers of endothelial dysfunction and increased risk of cardiovascular mortality. Further studies are warranted to elucidate the pathobiology and clinical relevance of the arginine bioavailability ratios in cardio-metabolic diseases.

Role of vitamin D in arterial hypertension

Vitamin D deficiency is highly prevalent and may contribute to arterial hypertension. The antihypertensive effects of vitamin D include suppression of renin and parathyroid hormone levels and renoprotective, anti-inflammatory and vasculoprotective properties. Low 25-hydroxyvitamin D levels, which are used to classify the vitamin D status, are an independent risk factor for incident arterial hypertension. Meta-analyses of randomized controlled trials showed that vitamin D supplementation reduces systolic blood pressure by 2-6 mmHg. However, further studies are needed before drawing a final conclusion on the effect of vitamin D therapy on blood pressure and cardiovascular risk. In our current clinical practice we should take into account the high prevalence of vitamin D deficiency, the easy, cheap and safe way by which it can be supplemented and the promising clinical data suggesting that vitamin D might be useful for the treatment of arterial hypertension as well as other chronic diseases. Therefore, we recommend that testing for and treating vitamin D deficiency in patients with arterial hypertension should be seriously considered.

Vitamin D status and mortality in chronic kidney disease

BACKGROUND

Vitamin D deficiency is found in the majority of patients with chronic kidney disease (CKD) and may contribute to various chronic diseases. Current guidelines suggest correcting reduced 25-hydroxyvitamin D [25(OH)D] concentrations in CKD patients with an estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m(2). Whether low 25(OH)D levels in these patients are associated with higher mortality is unclear. This issue was addressed in the present work.

METHODS

We examined 444 patients with eGFR <60 mL/min/1.73 m(2) from the Ludwigshafen Risk and Cardiovascular Health Study. This prospective cohort study includes Caucasian patients without primary kidney disease who were routinely referred to coronary angiography at baseline (1997-2000).

RESULTS

During a median follow-up time of 9.4 years, 227 patients died including 159 deaths from cardiovascular causes. Multivariate adjusted hazard ratios (HRs) (with 95% confidence intervals) in severely vitamin D-deficient [25(OH)D <10 ng/mL] compared to vitamin D-sufficient patients [25(OH)D ≥ 30 ng/mL] were 3.79 (1.71-8.43) for all-cause and 5.61 (1.89-16.6) for cardiovascular mortality. Adjusted HRs per 10 ng/mL increase in 25(OH)D levels were 0.63 (0.50-0.79) for all-cause and 0.59 (0.45-0.79) for cardiovascular mortality. There was no significant interaction with parathyroid hormone concentrations.

CONCLUSIONS

Low 25(OH)D levels are associated with increased all-cause and cardiovascular mortality in CKD patients. These findings support suggestions to correct vitamin D deficiency, but whether vitamin D supplementation improves survival remains to be proven in randomized controlled trials.

Effect of vitamin D supplementation on testosterone levels in men

The male reproductive tract has been identified as a target tissue for vitamin D, and previous data suggest an association of 25-hydroxyvitamin D [25(OH)D] with testosterone levels in men. We therefore aimed to evaluate whether vitamin D supplementation influences testosterone levels in men. Healthy overweight men undergoing a weight reduction program who participated in a randomized controlled trial were analyzed for testosterone levels. The entire study included 200 nondiabetic subjects, of whom 165 participants (54 men) completed the trial. Participants received either 83 μg (3,332 IU) vitamin D daily for 1 year (n = 31) or placebo (n =2 3). Initial 25(OH)D concentrations were in the deficiency range (< 50 nmol/l) and testosterone values were at the lower end of the reference range (9.09-55.28 nmol/l for males aged 20-49 years) in both groups. Mean circulating 25(OH)D concentrations increased significantly by 53.5 nmol/l in the vitamin D group, but remained almost constant in the placebo group. Compared to baseline values, a significant increase in total testosterone levels (from 10.7 ± 3.9 nmol/l to 13.4 ± 4.7 nmol/l; p < 0.001), bioactive testosterone (from 5.21 ± 1.87 nmol/l to 6.25 ± 2.01 nmol/l; p = 0.001), and free testosterone levels (from 0.222 ± 0.080 nmol/l to 0.267 ± 0.087 nmol/l; p = 0.001) were observed in the vitamin D supplemented group. By contrast, there was no significant change in any testosterone measure in the placebo group. Our results suggest that vitamin D supplementation might increase testosterone levels. Further randomized controlled trials are warranted to confirm this hypothesis.

Low free testosterone is associated with heart failure mortality in older men referred for coronary angiography

AIMS

Accumulating evidence suggests that androgen deficiency is associated with cardiovascular disease. We aimed at evaluating whether total testosterone (TT) and free testosterone (FT) are associated with specific cardiovascular events.

METHODS AND RESULTS

We measured TT and sex-hormone-binding globulin levels in 2078 men who were routinely referred for coronary angiography between 1997 and 2000. Free testosterone was calculated according to Vermeulen. Main outcome measures were Cox proportional hazard ratios (HRs) for sudden cardiac death, fatal myocardial infarction, death from congestive heart failure (CHF), as well as other cardiac deaths according to quartiles of TT and FT. The median follow-up time was 7.7 years. Multivariable adjusted HRs (with 95% confidence intervals) in the fourth compared with the first FT quartile and per 1 SD increase in FT for CHF mortality were 0.38 (0.17-0.87) and 0.37 (0.15-0.89), respectively. We observed no independent significant association of FT with sudden cardiac death, fatal myocardial infarction, or other cardiac death. There was no independent association of TT levels with cardiovascular events or cardiac disease.

CONCLUSION

Low levels of FT are independently associated with increased CHF mortality.

Vitamin D deficiency and myocardial diseases

Vitamin D deficiency is common among patients with myocardial diseases because sun-induced vitamin D production in the skin and dietary intake of vitamin D is often insufficient. Knockout mice for the vitamin D receptor develop myocardial hypertrophy and dysfunction. It has also been shown that children with rickets who suffered from severe heart failure could be successfully treated with supplementation of vitamin D plus calcium. In adults, almost all patients with heart failure exhibit reduced 25-hydroxyvitamin D levels, which are used to classify the vitamin D status. In prospective studies, vitamin D deficiency was an independent risk factor for mortality, deaths due to heart failure and sudden cardiac death. Several vitamin D effects on the electrophysiology, contractility, and structure of the heart suggest that vitamin D deficiency might be a causal factor for myocardial diseases. Data from interventional trials, however, are rare and urgently needed to elucidate whether vitamin D supplementation is useful for the treatment of myocardial diseases. In our opinion, the current knowledge of the beneficial effects of vitamin D on myocardial and overall health strongly argue for vitamin D supplementation in all vitamin D-deficient patients with or at high risk for myocardial diseases.

Sex steroids and mortality in men referred for coronary angiography

OBJECTIVE

Accumulating evidence suggests that sex steroids are associated with various chronic diseases. We aimed at evaluating whether total testosterone (TT), free testosterone (FT) and sex hormone-binding globulin (SHBG) are associated with all-cause mortality and specific fatal events.

DESIGN, SETTING AND PARTICIPANTS

We measured TT and SHBG levels in 2078 men who were routinely referred for coronary angiography (1997-2000). FT was calculated according to Vermeulen.

MEASUREMENTS

The main outcome measures were Cox proportional hazard ratios (HRs) for mortality from all causes, from cardiovascular and non-cardiovascular causes and from cancer according to SHBG, FT and TT.

RESULTS

Multivariable-adjusted HRs (with 95% confidence intervals) in the fourth compared to the first SHBG quartile for all-cause, non-cardiovascular and cancer mortality were 1·61 (1·16-2·23), 2·44 (1·39-4·28), and 2·86 (1·03-7·32), respectively. There was no significant association of SHBG levels with cardiovascular mortality. All-cause mortality was significantly reduced per 1 SD increase in FT in the multivariate-adjusted analyses [0·49 (0·30-0·81)]. We observed no significant associations of FT with cardiovascular and cancer mortality, and TT levels were not independently related to any fatal events.

CONCLUSION

High levels of SHBG are associated with adverse health outcomes in a large cohort of older men referred for coronary angiography. Further studies are warranted to confirm our results and to elucidate the underlying mechanisms for our findings.

Symmetrical and asymmetrical dimethylarginine as predictors for mortality in patients referred for coronary angiography: the Ludwigshafen Risk and Cardiovascular Health study

BACKGROUND

Asymmetrical dimethylarginine (ADMA), an endogenous nitric oxide synthase inhibitor, has been linked to cardiovascular risk. The clinical role of its structural isomer symmetrical dimethylarginine (SDMA) remains largely unclear.

METHODS

We measured SDMA and ADMA in 3229 patients undergoing coronary angiography at baseline (1997-2000) and recorded total and cardiovascular mortality during a median follow-up time of 7.7 years. We investigated associations of SDMA with cardiovascular risk factors and mortality and compared its role as a cardiovascular risk factor with ADMA, which predicted mortality in previous analyses of our study.

RESULTS

In linear regression analyses including common cardiovascular risk factors as covariates, SDMA and ADMA were significantly associated with cystatin C, N-terminal pro-B-type natriuretic peptide, New York Heart Association classification, and homocysteine. The regression coefficients were higher for SDMA than for ADMA. In Cox proportional-hazards models adjusted for cardiovascular risk factors, the hazard ratios (HRs) (with 95% CI) in the second, third, and fourth SDMA quartile compared to the lowest quartile were 0.77 (0.60-0.99), 0.99 (0.78-1.25), and 1.51 (1.20-1.91) for total mortality and 0.92 (0.68-1.25), 0.93 (0.68-1.26), and 1.54 (1.14-2.01) for cardiovascular mortality. The same calculations for ADMA quartiles revealed HRs of 1.05 (0.83-1.32), 1.19 (0.95-1.50), and 1.61 (1.30-1.99) for total mortality and HR of 1.00 (0.74-1.34), 1.26 (0.95-1.68), and 1.54 (1.18-2.02) for cardiovascular mortality.

CONCLUSIONS

Serum concentrations of SDMA are independently associated with increased cardiovascular and all-cause mortality in patients undergoing coronary angiography. The pattern of risk linked to SDMA is different from that linked to ADMA, suggesting different pathophysiological roles of these 2 methylarginine metabolites.

Vitamin D status and clinical outcomes in incident dialysis patients: results from the NECOSAD study

BACKGROUND

The majority of dialysis patients suffer from vitamin D deficiency, which might contribute to an adverse health outcome. We aimed to elucidate whether European dialysis patients with low 25-hydroxyvitamin D (25(OH)D) levels are at increased risk of mortality and specific fatal events.

METHODS

This was a prospective cohort study of incident dialysis patients in the Netherlands (the NECOSAD). We selected all patients with measured 25(OH)D at 12 months after the start of dialysis, the baseline for our study. By Cox regression analyses, we assessed the impact of 25(OH)D levels on short-term (6 months of follow-up) as well as longer-term mortality (3 years of follow-up). Associations of 25(OH)D levels with cardiovascular and non-cardiovascular mortality were also determined.

RESULTS

The data from 762 patients (39% females, age 59 ± 15 years, 25(OH)D = 18 ± 11 ng/mL) were available. Fifty-one and 213 patients died during a follow-up of 6 months and 3 years, respectively. After adjustments for possible confounders, the hazard ratio (HR) (with 95% CI) for mortality was 2.0 (1.0-3.8) for short-term and 1.5 (1.0-2.1) for longer-term mortality when comparing patients with 25(OH)D levels ≤ 10 ng/mL with those presenting with 25(OH)D levels > 10 ng/mL. Adjusted HRs for cardiovascular mortality were 2.7 (1.1-6.5) and 1.7 (1.1-2.7) for short- and longer-term mortality, respectively. For non-cardiovascular mortality, we observed no relevant association overall. The impact of 25(OH)D levels on clinical events was modified by parathyroid hormone (PTH) status, with low 25(OH)D levels meaningfully affecting outcomes only in patients with PTH levels above the median of 123 pmol/L.

CONCLUSIONS

Vitamin D deficiency in dialysis patients is associated with an adverse health outcome, in particular with short-term cardiovascular mortality. Intervention studies are urgently needed to evaluate whether vitamin D supplementation improves health outcomes of dialysis patients.

Vitamin D deficiency and myocardial structure and function in older men and women: the Hoorn study

BACKGROUND

Vitamin D deficiency is frequently observed in heart failure patients and it has been shown that vitamin D exerts various effects on the heart that may be relevant for the pathogenesis of myocardial diseases.

AIMS

We aimed to elucidate the largely unknown association of 25-hydroxyvitamin D [25(OH)D] serum levels with echocardiographic measures of left ventricular (LV) structure and function.

MATERIAL/SUBJECTS AND METHODS

We measured 25(OH)D serum levels and performed standardized LV echocardiograms in 614 persons from a population-based cohort of older men and women. Echocardiographic data were used to calculate LV mass and geometry and for classification of systolic and diastolic dysfunction. To consider the seasonal variations of 25(OH)D levels we categorized our study participants according to season-specific 25(OH)D quartiles.

RESULTS

LV systolic function, mass and geometry were not significantly associated with 25(OH)D serum levels. In binary logistic regression analyses, the prevalence of LV diastolic dysfunction was significantly higher in the first season-specific 25(OH)D quartile when compared to the fourth quartile [odds ratio 2.32 (95% CI: 1.42-3.80); p=0.001] but significance was lost after adjustments for age [odds ratio 1.51 (0.89-2.57); p=0.123] and established risk factors for heart failure [odds ratio 1.47 (0.84-2.59); p=0.178].

CONCLUSIONS

Serum levels of 25(OH)D are not significantly associated with LV structure and function but a non-significant trend towards increased risk of diastolic dysfunction in persons with vitamin D deficiency warrants further studies.

Homoarginine, Cardiovascular Risk, and Mortality

Background— Homoarginine is an amino acid derivative that may increase nitric oxide availability and enhance endothelial function. The effect of the level of homoarginine on cardiovascular outcome and mortality is unknown.

Methods and Results— We assessed cardiovascular and all-cause mortality according to homoarginine levels in a cohort of 3305 subjects referred for coronary angiography from the LUdwigshafen RIsk and Cardiovascular Health (LURIC) Study. After investigating the relation of homoarginine with kidney function and markers of endothelial dysfunction, we explored its effects on adverse outcomes in a second high-risk cohort of 1244 patients with type 2 diabetes mellitus receiving maintenance hemodialysis (4D study [Die Deutsche Diabetes Dialyse Studie]). In the LURIC study, mean serum homoarginine levels were 2.6±1.1 μmol/L. During a median follow-up of 7.7 years, 766 patients died. After adjustments for age and sex, patients in the lowest quartile (<1.85 μmol/L) had a >4-fold higher rate of dying of cardiovascular disease (hazard ratio 4.1, 95% confidence interval 3.0 to 5.7) than patients in the highest quartile (>3.1 μmol/L). Lower homoarginine levels were associated with lower estimated glomerular filtration rate and higher levels of intercellular adhesion molecule-1 and vascular cell adhesion molecule-1. Hemodialysed patients had lower mean homoarginine levels of 1.2±0.5 μmol/L and experienced a 5-fold increased mortality rate compared with LURIC patients (608 deaths during a median follow-up of 4 years). Homoarginine consistently affected mortality, which was 2-fold higher in 4D study patients in the lowest quartile (<0.87 μmol/L) than in patients in the highest quartile (>1.4 μmol/L).

Conclusions— Homoarginine levels are independently associated with cardiovascular and all-cause mortality in patients referred for coronary angiography and in patients undergoing hemodialysis. Future studies are needed to elucidate the underlying pathomechanisms.

Vitamin D deficiency is associated with sudden cardiac death, combined cardiovascular events, and mortality in haemodialysis patients

Aims

Dialysis patients experience an excess mortality, predominantly of sudden cardiac death (SCD). Accumulating evidence suggests a role of vitamin D for myocardial and overall health. This study investigated the impact of vitamin D status on cardiovascular outcomes and fatal infections in haemodialysis patients.

Methods and results

25-hydroxyvitamin D [25(OH)D] was measured in 1108 diabetic haemodialysis patients who participated in the German Diabetes and Dialysis Study and were followed up for a median of 4 years. By Cox regression analyses, we determined hazard ratios (HR) for pre-specified, adjudicated endpoints according to baseline 25(OH)D levels: SCD (n = 146), myocardial infarction (MI, n = 174), stroke (n = 89), cardiovascular events (CVE, n = 414), death due to heart failure (n = 37), fatal infection (n = 111), and all-cause mortality (n = 545). Patients had a mean age of 66 ± 8 years (54% male) and median 25(OH)D of 39 nmol/L (interquartile range: 28–55). Patients with severe vitamin D deficiency [25(OH)D of≤ 25 nmol/L] had a 3-fold higher risk of SCD compared with those with sufficient 25(OH)D levels >75 nmol/L [HR: 2.99, 95% confidence interval (CI): 1.39–6.40]. Furthermore, CVE and all-cause mortality were strongly increased (HR: 1.78, 95% CI: 1.18–2.69, and HR: 1.74, 95% CI: 1.22–2.47, respectively), all persisting in multivariate models. There were borderline non-significant associations with stroke and fatal infection while MI and deaths due to heart failure were not meaningfully affected.

Conclusion

Severe vitamin D deficiency was strongly associated with SCD, CVE, and mortality, and there were borderline associations with stroke and fatal infection. Whether vitamin D supplementation decreases adverse outcomes requires further evaluation.

Association of vitamin D status with serum androgen levels in men

OBJECTIVE

Studies in rodents indicate a role of vitamin D in male reproduction, but the relationship between vitamin D and androgen levels in men is largely unexplored. We aimed to investigate the association of 25-hydroxyvitamin D [25(OH)D] levels with testosterone, free androgen index (FAI) and SHBG. Moreover, we examined whether androgen levels show a similar seasonal variation to 25(OH)D.

DESIGN

In this cross-sectional study, 25(OH)D, testosterone and SHBG levels were assessed by immunoassay in 2299 men who were routinely referred for coronary angiography (1997-2000).

MEASUREMENTS

Main outcome measures were associations of 25(OH)D levels with testosterone, SHBG and FAI. FAI was calculated as testosterone (nmol/l)/SHBG (nmol/l) x 100.

RESULTS

Men with sufficient 25(OH)D levels (> or =30 microg/l) had significantly higher levels of testosterone and FAI and significantly lower levels of SHBG when compared to 25(OH)D insufficient (20-29.9 microg/l) and 25(OH)D-deficient (<20 microg/l) men (P < 0.05 for all). In linear regression analyses adjusted for possible confounders, we found significant associations of 25(OH)D levels with testosterone, FAI and SHBG levels (P < 0.05 for all). 25(OH)D, testosterone and FAI levels followed a similar seasonal pattern with a nadir in March (12.2 microg/l, 15.9 nmol/l and 40.8, respectively) and peak levels in August (23.4 microg/l, 18.7 nmol/l and 49.7, respectively) (P < 0.05 for all).

CONCLUSION

Androgen levels and 25(OH)D levels are associated in men and reveal a concordant seasonal variation. Randomized controlled trials are warranted to evaluate the effect of vitamin D supplementation on androgen levels.

Vitamin D and musculoskeletal health, cardiovascular disease, autoimmunity and cancer: Recommendations for clinical practice

BACKGROUND

There is increasing evidence that, in addition to the well-known effects on musculoskeletal health, vitamin D status may be related to a number of non-skeletal diseases. An international expert panel formulated recommendations on vitamin D for clinical practice, taking into consideration the best evidence available based on published literature today. In addition, where data were limited to smaller clinical trials or epidemiologic studies, the panel made expert-opinion based recommendations.

METHODS

Twenty-five experts from various disciplines (classical clinical applications, cardiology, autoimmunity, and cancer) established draft recommendations during a 2-day meeting. Thereafter, representatives of all disciplines refined the recommendations and related texts, subsequently reviewed by all panelists. For all recommendations, panelists expressed the extent of agreement using a 5-point scale.

RESULTS AND CONCLUSION

Recommendations were restricted to clinical practice and concern adult patients with or at risk for fractures, falls, cardiovascular or autoimmune diseases, and cancer. The panel reached substantial agreement about the need for vitamin D supplementation in specific groups of patients in these clinical areas and the need for assessing their 25-hydroxyvitamin D (25(OH)D) serum levels for optimal clinical care. A target range of at least 30 to 40 ng/mL was recommended. As response to treatment varies by environmental factors and starting levels of 25(OH)D, testing may be warranted after at least 3 months of supplementation. An assay measuring both 25(OH)D(2) and 25(OH)D(3) is recommended. Dark-skinned or veiled individuals not exposed much to the sun, elderly and institutionalized individuals may be supplemented (800 IU/day) without baseline testing.

Aldosterone to renin ratio--a reliable screening tool for primary aldosteronism?

Primary aldosteronism (PA) is defined as inappropriately high and (relatively or absolutely) autonomous aldosterone secretion, which is not adequately suppressible by sodium loading. Recent evidence shows that the PA prevalence ranges from 3 to 32%. This high prevalence of PA is suggested to be the result of both more intense screening for PA and improvement of laboratory procedures. Inappropriate high aldosterone secretion is paralleled by severe target organ damage, underlining the importance for the identification of PA at an early stage. The aldosterone to renin ratio (ARR), which reflects aldosterone hypersecretion in regard to its principal trophin renin, is currently considered the most reliable tool for PA screening. Accumulating evidence, however, points to a considerable intra-individual variation of this ratio, emphasizing the importance of standardized screening procedures. In particular, laboratory methods, posture, antihypertensive medication, and dietary salt intake are significant effectors of ARR variation. Furthermore, differentiation between low-renin essential hypertension and PA is difficult and probably arbitrary. It is the purpose of the present review to issue the reliability of the ARR as a screening tool for PA. This review also provides an overview about the physiology of the renin-angiotensin-aldosterone system, highlights current laboratory methods for aldosterone and renin determination, and addresses potential influence factors on the ARR.

Parathyroid hormone level is associated with mortality and cardiovascular events in patients undergoing coronary angiography

AIMS

Elevated parathyroid hormone (PTH) levels have been associated with increased cardiovascular risk in the general population. We aimed to elucidate whether PTH levels are associated with mortality and fatal cardiovascular events in patients referred for coronary angiography.

METHODS AND RESULTS

Intact PTH was measured in 3232 Caucasian patients from the LUdwigshafen RIsk and Cardiovascular Health (LURIC) study, who underwent coronary angiography at baseline (1997-2000). During a median follow-up time of 7.7 years, 742 patients died including 467 deaths due to cardiovascular causes. Unadjusted Cox proportional hazard ratios (HRs) (with 95% confidence intervals) in the fourth when compared to the first PTH quartile were 2.13 (1.75-2.60) for all-cause and 2.47 (1.92-3.17) for cardiovascular mortality. After adjustments for common cardiovascular risk factors, these HRs remained significant with 1.71 (1.39-2.10) for all-cause and 2.02 (1.55-2.63) for cardiovascular mortality. Among specific cardiovascular events we observed a particularly strong association of PTH with sudden cardiac death (SCD). The adjusted HR for SCD in the first vs. the fourth PTH quartile was 2.68 (1.71-4.22).

CONCLUSION

Our results among patients undergoing coronary angiography show that PTH levels are an independent risk factor for mortality and cardiovascular events warranting further studies to evaluate whether PTH modifying treatments reduce cardiovascular risk.