Publications by authors named "Ercan Ok"

The relationship between sodium, blood pressure and extracellular volume could not be more pronounced or complex than in a dialysis patient. We review the patients' sources of sodium exposure in the form of dietary salt intake, medication administration, and the dialysis treatment itself. In addition, the roles dialysis modalities, hemodialysis types, and dialysis fluid sodium concentration have on blood pressure, intradialytic symptoms, and interdialytic weight gain affect patient outcomes are discussed.

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Introduction: More frequent and/or longer hemodialysis (HD) has been associated with improvements in numerous clinical outcomes in patients on dialysis. Home HD (HHD), which allows more frequent and/or longer dialysis with lower cost and flexibility in treatment planning, is not widely used worldwide. Although, retrospective studies have indicated better survival with HHD, this issue remains controversial.

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Background The association between common carotid artery intima-media thickness (CCA-IMT) and incident carotid plaque has not been characterized fully. We therefore aimed to precisely quantify the relationship between CCA-IMT and carotid plaque development. Methods and Results We undertook an individual participant data meta-analysis of 20 prospective studies from the Proof-ATHERO (Prospective Studies of Atherosclerosis) consortium that recorded baseline CCA-IMT and incident carotid plaque involving 21 494 individuals without a history of cardiovascular disease and without preexisting carotid plaque at baseline.

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Online hemodiafilration (HDF) treatment may be associated with better quality of life due to improved clearance of middle-molecular-weight uremic toxins and hemodynamic stability in dialysis patients, in addition to better overall survival.

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Background: Due to a critical shortage of available kidney grafts, most patients with Stage 5 Chronic Kidney Disease (CKD5) require bridging dialysis support. It remains unclear whether treatment by different dialysis modalities changes the selection and/or preparation of a potential transplant candidate. Therefore, we assessed whether the likelihood of receiving kidney transplant (both living or deceased kidney donors) differs between haemodialysis (HD) and online haemodiafiltration (HDF) in patients with CKD5D.

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Background: To quantify the association between effects of interventions on carotid intima-media thickness (cIMT) progression and their effects on cardiovascular disease (CVD) risk.

Methods: We systematically collated data from randomized, controlled trials. cIMT was assessed as the mean value at the common-carotid-artery; if unavailable, the maximum value at the common-carotid-artery or other cIMT measures were used.

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Introduction: Numerous studies showed that higher body mass index (BMI) is associated with better survival in hemodialysis (HD) patients. Most of them evaluated short-term mortality. It has been suggested that presence of inflammation may be a key modifier of relationship between BMI and mortality in incident HD patients.

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Extracellular fluid volume overload and its inevitable consequence, hypertension, increases cardiovascular mortality in the long term by leading to left ventricular hypertrophy, heart failure, and ischemic heart disease in dialysis patients. Unlike antihypertensive medications, a strict volume control strategy provides optimal blood pressure control without need for antihypertensive drugs. However, utilization of this strategy has remained limited because of several factors, including the absence of a gold standard method to assess volume status, difficulties in reducing extracellular fluid volume, and safety concerns associated with reduction of extracellular volume.

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Background: During the follow-up in a randomized controlled trial (RCT), participants may receive additional (non-randomly allocated) treatment that affects the outcome. Typically such additional treatment is not taken into account in evaluation of the results. Two pivotal trials of the effects of hemodiafiltration (HDF) versus hemodialysis (HD) on mortality in patients with end-stage renal disease reported differing results.

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Background: From an individual participant data (IPD) meta-analysis from four randomized controlled trials comparing haemodialysis (HD) with post-dilution online-haemodiafiltration (ol-HDF), previously it appeared that HDF decreases all-cause mortality by 14% (95% confidence interval 25; 1) and fatal cardiovascular disease (CVD) by 23% (39; 3). Significant differences were not found for fatal infections and sudden death. So far, it is unclear, however, whether the reduced mortality risk of HDF is only due to a decrease in CVD events and if so, which CVD in particular is prevented, if compared with HD.

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Purpose: Persistent hypercalcemia after kidney transplantation (KTx) may cause nephrocalcinosis and graft dysfunction. The aim of this study was to evaluate patients with hypercalcemia and assess its effect on tubulointerstitial calcification.

Methods: A total of 247 recipients were enrolled.

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Background: Application and consequences of hemodialysis treatment may differ between genders; focusing on these differences may be useful to optimize outcomes.

Methods: Data from 1 999 648 hemodialysis sessions performed in 10 984 (3316 incident and 7668 prevalent) patients, treated in 55 centers of the European Clinical Database (EuCliD)-Turkey, were analyzed, and various demographic, clinical, biochemical, therapeutic and prognostic parameters were compared.

Results: There were 1905 male and 1411 female incident and 4339 male and 3329 female prevalent patients.

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Extracellular volume overload and hypertension are important contributors to the high risk of cardiovascular mortality in patients undergoing haemodialysis. Hypertension is present in more than 90% of patients at the initiation of haemodialysis and persists in more than two-thirds, despite use of several antihypertensive medications. High blood pressure is a risk factor for the development of left ventricular hypertrophy, heart failure, and mortality, although there are controversies with some study findings showing poor survival with low-but not high-blood pressure.

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Introduction Not only anemia, but also erythropoiesis stimulating agent (ESA)s for treating anemia may adversely affect prognosis of chronic hemodialysis patients. Various features of naturally (with no ESA usage) nonanemic patients may be useful for defining several factors in the pathogenesis of anemia. Methods Data, retrieved from the European Clinical Database (EuCliD)-Turkey on naturally nonanemic prevalent chronic hemodialysis patients (n: 201) were compared with their anemic (those who required ESA treatment) counterparts (n: 3948).

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Objective: Primary Sjögren's syndrome (pSS) is a common chronic autoimmune disease that primarily affects the salivary and lacrimal glands. Arterial stiffness is one of the earliest detectable manifestations of adverse structural and functional changes within the vessel wall. The aim of this study was to evaluate the relationship between arterial stiffness and pSS.

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Purpose: High fibroblast growth factor-23 (FGF-23) levels are associated with mortality and cardiovascular events in patients with chronic kidney disease. The aim of this cross-sectional study was to investigate the relationship between plasma FGF-23 levels and coronary artery calcification and carotid artery intima-media thickness (CA-IMT) in hemodialysis (HD) patients.

Methods: In this cross-sectional study, plasma intact FGF-23 levels were measured in 229 patients who underwent coronary artery calcification scores (CACs) determined by multi-slice computerized tomography and CA-IMT assessed by using high-resolution color Doppler ultrasonography.

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Exposure to high Ca concentrations may influence the development of low-turnover bone disease and coronary artery calcification (CAC) in patients on hemodialysis (HD). In this randomized, controlled study, we investigated the effects of lowering dialysate Ca level on progression of CAC and histologic bone abnormalities in patients on HD. Patients on HD with intact parathyroid hormone levels ≤300 pg/ml receiving dialysate containing 1.

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Background: Mortality rates remain high for haemodialysis (HD) patients and simply increasing the HD dose to remove more small solutes does not improve survival. Online haemodiafiltration (HDF) provides additional clearance of larger toxins compared with standard HD. Randomized controlled trials (RCTs) comparing HDF with conventional HD on all-cause and cause-specific mortality in end-stage kidney disease (ESKD) patients reported inconsistent results and were at high risk of bias.

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Mortality remains high for hemodialysis patients. Online hemodiafiltration (OL-HDF) removes more middle-sized uremic toxins but outcomes of individual trials comparing OL-HDF with hemodialysis have been discrepant. Secondary analyses reported higher convective volumes, easier to achieve in larger patients, and improved survival.

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Background: Haemodiafiltration (HDF) is the preferred dialysis modality in many countries. The aim of the study was to compare the survival of incident patients on high-volume HDF (HV-HDF) with high-flux haemodialysis (HD) in a large-scale European dialysis population.

Methods: The study population was extracted from 47,979 patients in 369 NephroCare centres throughout 12 countries.

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Aims: Besides diabetic patients, glycated hemoglobin (HbA1c) levels have been reported to predict mortality in non-diabetics patients. However, the importance of HbA1c levels in non-diabetic hemodialysis patients still remains unknown. Thus, we aimed to prospectively investigate the impact of HbA1c on all-cause and cardiovascular mortality in a large group of prevalent non-diabetic hemodialysis patients.

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Aim: Both oxidized LDL and carbamylated LDL are considered important for initiating atherosclerosis in patients with end-stage kidney disease through vascular endothelial cell dysfunction or injury. However their effects on each other and their relationship related to pro-atherosclerotic effects on endothelial cells and macrophages have not been investigated. In this study, we analyzed the competition between LDL carbamylation and oxidation, tested biological effects of carbamylated-oxidized LDL (coxLDL) toward the endothelial cells, assessed its ability to cause foam cell development, and determined the roles of scavenger receptors in this process.

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