Hypertension and nephrology

[Importance, prevalence and therapy of vitamin D deficiency]

SZABÓ András

FEBRUARY 28, 2011

Hypertension and nephrology - 2011;15(01)

[Annual citations in the PubMed database on vitamin D were approximately 5000, this represents a doubling in the last decade and a 20% increase in the last year. There is renewed interest in vitamin D synthesis, metabolism and action. The two principal reasons for increased interest can be: 1. new knowledge regarding the nonhormonal, autocrine, and paracrine actions of 1,25-dihydroxylated vitamin D metabolites in man, 2. the worsening, worldwide trend to vitamin D insufficiency. Clinical vitamin D research in last years has confirmed the presence of a worldwide problem of vitamin D depletion, a problem that appears to be worsening. Largescale population based studies bear out long-held concerns that low serum 25(OH)D levels are associated with a number of adverse outcomes in the human musculoskeletal, innate immune, and cardiovascular systems. In fact, low vitamin D levels are significantly associated with all-cause mortality in the U.S. population and Hungary respectively. It is hypothesized that the global rise in incidence of obesity contributes to the worsening of the problem of vitamin D deficiency, amplifying adverse impacts on the host skeleton, immunoreactivity to microbes, and metabolic status. Finally, it should be remembered that treatment of vitamin D deficiency has two phases: restoration of 25(OH)D levels up to more than 30 ng/ml; and maintenance of the serum 25(OH)D level in that range. The present upper level (UL) of vitamin D intake that is deemed to be safe (2000 IU/day) must be re-evaluated considering data acquired over the past 15 years.]

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Further articles in this publication

Hypertension and nephrology

[Scylla and Charybdis - the treatment of hypertension]

RADÓ János

Hypertension and nephrology

[The effect of antihypertensive drugs on central blood pressure]

PÁLL Dénes, KOMONYI Éva, LENGYEL Szabolcs, PARAGH György, KATONA Éva

[It is well known, that there is a difference between peripheral and central systolic and pulse pressure. As the pressure wave travels distally from the heart, there is a significant increase, which is called pressure amplification. Central blood pressure can be measured easily and non-invasively, and the result shows a positive correlation with cardiovascular end-points. Several antihypertensive drugs can differently decrease central and peripheral blood pressure. The effect of diuretics on central systolic and pulse pressure is neutral or negative. While traditional β-blockers (e.g. atenolol) have a definitive negative effect, nebivolol shows a positive one. The calcium antagonists tend to have a favorable effect, while the clear beneficial effect of the angiotensin converting enzime inhibitors is well documented. There are only few data on angiotensin receptor blockers, however, the results seem to be promising.]

Hypertension and nephrology

[The clinical significance of peripheral and central blood pressure form the neurologist’s point of view]

BERECZKI Dániel, VASTAGH Ildikó

[Hypertension - affecting both the large and the small cerebral vessels - is the most frequent risk factor for cerebrovascular disorders manifesting in stroke, hypertensive encephalopathy or vascular dementia. The central pressure measured at the proximal part of the aorta has more important role in the development of vascular hypertrophy and carotid atherosclerosis than the pressure measured in the brachial artery. Central aortic pressure more accurately reflects the filling conditions of the left ventricle and thus the pressure conditions affecting the cerebral vascular system, than brachial pressure values, therefore possibly predicts more reliably the risk of cardiovascular events than brachial pressure values. Features of the stiffness of large arteries (like pulse wave velocity) more directly reflect the chronic effect of ageing, hypertension and diabetes than brachial or even central aortic pressure. Therefore in upcoming clinical trials arterial stiffness and central aortic pressure should be considered as possible surrogate endpoints. Antihypertensive treatment is an important part of primary and secondary stroke prevention. Decreasing blood pressure in hypertensive subjects significantly decreases the risk of stroke and other vascular events, and the extent of risk reduction primarily depends on the extent of the decrease in blood pressure. Several factors should be considered when choosing from treatment options. The use of traditional β blockers - partly due to their smaller effects on central blood pressure - decreased recently. Further observations will decide on the role of third generation β blockers in the prevention of cardiovascular mortality and morbidity.]

Hypertension and nephrology

[Direct renin inhibitors]

FARSANG Csaba

[The mechanisms of action of direct renin inhibitors and the important clinical findings gained by the first, clinically approved drug, aliskiren are discussed. The relative lack of side effects and the very long-lasting antihypertensive action of aliskiren is emphasized. Investigations showing efficacy and protective effects of aliskiren and its combinations with other antihypertensive drugs (diuretics, calcium antagonists, angiotensin converting enzyme inhibitors, angiotensin receptor blockers) against hypertension-induced subclinical organ damage as well as still ongoing clinical trials are also described.]

Hypertension and nephrology

[The importance of epithelial-mesenchymal transition in kidney fibrosis]

NAGY SZAKÁL Dorottya, SZEBENI Beáta, SZIKSZ Erna, HIMER Leonóra, REUSZ György, VÁSÁRHELYI Barna, TULASSAY Tivadar, VANNAY Ádám

[Epithelial-mesenchymal transition (EMT) plays a central role in physiological and pathological processes of embryogenesis, carcinogenesis and tissue fibrosis. During EMT epithelial cells may transform to myofibroblasts, which are the effector cells of fibrosis. In our summary the process of EMT and its medical importance will be reviewed in relation to renal fibrosis. Regardless of the initiating cause the final common mechanism of organ fibrosis is similar in the different chronic renal diseases. It always involves major inflammatory responses, however the molecular mechanisms involved are still elusive. The EMT now takes centre stage as the point of convergence between inflammation and the progression of degenerative fibrotic diseases. Understanding the pathomechanism of EMT and the significance of signalling pathways involved in this process may lead to a new therapeutic approach in the treatment of chronic renal diseases.]

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Clinical Neuroscience

Risk factors for ischemic stroke and stroke subtypes in patients with chronic kidney disease

GÜLER Siber, NAKUS Engin, UTKU Ufuk

Background - The aim of this study was to compare ischemic stroke subtypes with the effects of risk factors, the relationship between grades of kidney disease and the severity of stroke subtypes. Methods - The current study was designed retrospectively and performed with data of patients who were hospitalised due to ischemic stroke. We included 198 subjects who were diagnosed with ischemic stroke of Grade 3 and above with chronic kidney disease. Results - In our study were reported advanced age, coronary artery disease, moderate kidney disease as the most frequent risk factors for cardioembolic etiology. Hypertension, hyperlipidemia, smoking and alcohol consumption were the most frequent risk factors for large-artery disease. Female sex and anaemia were the most frequent risk factors for small-vessel disease. Dialysis and severe kidney disease were the most frequent risk factors in unknown etiologies, while male sex, diabetes mellitus, prior stroke and mild kidney disease were the most frequent risk factors for other etiologies. National Institute of Health Stroke Scale (NIHSS) scores were lower for small-vessel disease compared with other etiologies. This relation was statistically significant (p=0.002). Conclusion - In order to improve the prognosis in ischemic stroke with chronic kidney disease, the risk factors have to be recognised and the treatment options must be modified according to those risk factors.

Lege Artis Medicinae

[Notes on the management of hypertension in chronic kidney disease ]

AMBRUS Csaba

[The prevalence of hypertension among pa­tients with chronic kidney disease is high, reaching more than 80%. Hypertension is both one of the main causes and also the most common consequence of chronic kidney disease. It is also a main factor responsible for the high cardiovascular morbidity and mortality in this patient population. Blood pressure control can improve patient outcomes, lower cardiovascular risk and slow down the progression of kidney dis­ease, irrespective of the underlying cause. The optimal therapy should therefore focus not only on blood pressure reduction but also on renoprotection. Basic understanding of the renal pathophysiology in hypertension and renal effects of various medications is of paramount importance. In this review, we summarized cornerstones of the antihypertensive therapy in patients with chronic kidney disease. The management of patients receiving kidney replacement therapies, such as hemodialysis, peritoneal dialysis or transplanta­tion requires special knowledge and expe­rience, therefore it is not discussed here. The aim of this review was to allow non-nephrologist physicians to take care of their kidney patients with more confidence and effectiveness.]

Hypertension and nephrology

[Recommendation for the treatment of hyperlipidemia in chronic renal disease]

MÁTYUS János, PARAGH György

[The incidence of chronic kidney disease continuously increases worldwide. Studies suggest that kidney disease is an as powerful cardiovascular risk factor as diabetes mellitus. Because of the high prevalence of lipid disorders, it is likely that dyslipidaemia plays a major role in the high cardiovascular risk of these patients. Evidence supports treating dyslipidaemia in patients with mild or moderate kidney disease, but the results of statin trials in dialysed patients are inconclusive. A practical treatment algorithm is proposed considering the special aspects, the effectiveness and safety of the drugs in the whole spectrum of kidney disease.]

Hypertension and nephrology

[Sevelamer: an old-new phosphate binder in chronic kidney disease]

BERECZKI Csaba, TÚRI Sándor

[Sevelamer HCl is a non-metal and non-calcium based phosphate binder, ion exchange resin, which not selectively binds the phosphate ions in the gastrointestinal tract. In Hungary since 2005, on the basis of strict professional guidelines, sevelamer is available therapy for chronic kidney disease patients with severe hyperphosphatemia on dialysis. On the basis of 17 prospective and retrospective studies, sevelamer HCl is an at least as effective phosphate binder as other calcium based binders, in reducing the serum phosphate level. The advantage of sevelamer compared to the other widely used calcium based phosphate binders is the significantly lower serum calcium level and less hypercalcemic episodes. Sevelamer therapy in chronic kidney disease patients reduces the progression of cardiovascular calcification and it has also a positive effect on cholesterol and LDL-cholesterol levels. The side effects of sevelamer therapy may be acidosis, and gastrointestinal complaints. This year the improved form, sevelamer carbonate, becomes available in Hungary. Sevelamer carbonate has similar phosphate and cholesterol binding capacity as that of sevelamer HCl, but it has several advantages: it has a positive effect on acid-base parameters, and may be administered in powder form, which is beneficial for children and for patients with swallowing disorders. The primary analysis of the DCOR study has not revealed any significant difference in the survival and cardiovascular mortality between patient groups treated with calcium based binder or sevelamer. The RIND trial data showed improved survival of new dialysis patients, who were initially treated with sevelamer. Further clinical studies are needed to kaverify the benefits of sevelamer therapy (mortality, cardiovascular calcification) in chronic kidney disease patients. The management of hyperphosphatemia in chronic renal failure is a major challenge even in the first decade of the 21th century. This is the fact, despite that recently three different groups of phosphate binders are available in the clinical practice: the calcium based binders (calcium carbonate, calcium acetate), sevelamer and lanthanum. Which is the best binder? A calcium based or a non-calcium based one? Over the past decade, these issues are in the mainstream of clinical research of nephrology.]

LAM Extra for General Practicioners

[VITAMIN D TREATMENT: HORMONE THERAPY FOR PATIENTS WHO NEED IT OR SIMPLY A SUPPLEMENTATION FOR EVERYONE?]

SPEER Gábor

[Various medical associations issue different recommendations for the prevention and treatment of vitamin D deficiency. These significant differences are partly explained by the different definition of normal vitamin D level and the use of completely different mathematical models to predict the increase in vitamin D level as a response to therapy. According to the Institute of Medicine (IOM), the target vitamin D level is 20 ng/ml, whereas the Endocrine Society (ES) recommends 30 ng/m as the miminum target value. According to the ES, a 1 ng/ml increase of vitamin D level can be reached by a daily intake of 100 NE, while the IOM recommends 3.6 ng/ml. Moreover, the IOM states that the effect of therapy on serum level is nonlinear. These differences show that the ES and IOM have different views on the risk of adverse effects. The IOM recommends 400 IU vitamin D daily for children younger than 1 year, 800 IU for those above 70 years and 600 IU/per day for everyone else. The ES recommend 400-1000 IU daily for all infants and 1500- 2000 IU for adults. Screening, however, is not recommended by either society. To decrease uncertainty concerning the side effects of higher-dose vitamin D treatment, it is important to understand, use and support the function of the pharmacovigilance system of the pharmaceutical industry that manufactures and markets various (prescription, over-the-counter) preparations. This is what the author aims to highlight in the second part of this article. Using this system, both the doctor and the patient can help support and accept the justification of higher-dose vitamin D therapy.]