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Featured researches published by M.E. Uyar.


Transplant International | 2007

Adherence, depression and quality of life in patients on a renal transplantation waiting list

Beril Akman; M.E. Uyar; Baris Afsar; Siren Sezer; Fatma Nurhan Ozdemir; Mehmet Haberal

To study nonadherence, and its relationship with depression and quality of life (QOL) in patients on a cadaveric renal transplantation waiting list (RTWL). In 86 RTWL patients (56 men/30 women), there were 49 nonadherent patients (age, 46.8 ± 21.8 years) and 37 adherent patients (age, 42.8 ± 12.1 years). Clinical nonadherence was defined as skipping or shortening dialysis sessions, interdialytic weight gain (IDWG) of >5.7% body weight, a predialysis potassium level of >6 mEq/l and a predialysis phosphate level of >7.5 mg/dl. For each study subject, marital status, level of education duration of dialysis, prior renal transplantation, IDWG, predialysis blood urea nitrogen (BUN) value and creatinine, potassium, phosphate levels were recorded as were scores from the short form‐36 and Beck depression inventory (BDI). A high IDWG (33.7% of the subjects) was the most common nonadherence pattern noted. Age, sex, marital status, duration of dialysis, prior transplantation, comorbid conditions the predialysis BUN values, the levels of creatinine, potassium, and phosphate were not significantly different between the two groups (P > 0.05). The level of education was higher in adherent group (P = 0.018). QOL and BDI scores were negatively correlated (P = 0.001, r = −0.561). Nonadherent patients had lower QOL (P = 0.04) and higher depression scores (P = 0.01) than did adherent patients. Of the depressed patients, 77.8% had a comorbid condition. Nonadherence was only associated with BDI scores (OR, 2.146; CI, 2.052–2.350; P = 0.002). In dialysis patients, close monitoring of adherence, early diagnosis of depression, and the treatment of disease may further enhance QOL during the waiting period for a cadaveric renal transplant.


Renal Failure | 2007

Prevalence and Predictors of Arrhythmia in End Stage Renal Disease Patients on Hemodialysis

Huseyin Bozbas; Ilyas Atar; Aylin Yildirir; Aliseydi Ozgul; M.E. Uyar; Nurhan Ozdemir; Haldun Muderrisoglu; Bülent Özin

Background. Sudden death is common in end-stage renal disease (ESRD). Cardiac arrhythmia is observed frequently in patients with ESRD and is thought to be responsible for this high rate of sudden death. This study investigated the prevalence and the predictors of arrhythmia in patients on maintenance dialysis. Methods. Ninety-four patients on hemodialysis program were enrolled in the study. Routine laboratory results were noted. Arrhythmia, periods of silent ischemia, and heart-rate variability analyses were obtained from 24-hour Holter monitor recordings. Corrected QT (QTc) dispersion was calculated from 12-lead surface EKG. Echocardiographic and tissue Doppler examinations were performed on interdialytic days as well. Ventricular arrhythmia was classified according to Lown classification; classes 3 and above were accepted as complex ventricular arrhythmia (CVA). Results. The mean age was 52.5±13.2 years; 44 (46.8%) were women. Ventricular premature contractions were detected in 80 (85.1%) patients, of whom 35 (37.2%) were classified as complex ventricular arrhythmia (CVA). Coronary artery disease, hypertension, and QTc dispersion appeared as independent factors predictive of CVA development. Atrial premature contractions (APC) were detected in 53 patients (56.4%) and supraventricular arrhythmia in 15 (16%) patients; all were identified as atrial fibrillation. Duration of dialysis therapy was found as an independent predictor of APC. Conclusion. Arrhythmia is frequently observed in ESRD patients receiving hemodialysis and may be responsible for the high rate of sudden mortality. Hypertension, CAD, and QTc dispersion are independent predictors of CVA, and duration of dialysis therapy is an independent factor affecting APC development in these patients.


Renal Failure | 2004

Pulmonary Function in Uremic Patients on Long‐term Hemodialysis

Özgür Karacan; Emre Tutal; M.E. Uyar; Fusun Oner Eyuboglu; Siren Sezer; F. Nurhan Özdemir

Twenty patients with end‐stage renal failure who were on maintenance hemodialysis (HD) underwent pulmonary function testing (PFT) before and shortly after an HD session. On pre‐HD PFT, the mean values of all parameters except residual volume (RV) were in the normal range. Mean RV was high (152.9%), and mean diffusing capacity of the lung for carbon monoxide (DLCO) was high‐normal (110.4%). The pre‐HD static inspiratory (PImax) and expiratory pressures (PEmax) were much lower than normal (67.4% and 36.3%, respectively). After the HD session, repeat PFT revealed a small increase in expiratory flow rates, and a significant drop in PImax. There was a strong correlation between PImax and PEmax (r = 0.567, p < 0.01) at the pre‐ and post‐HD stages, indicating that common mechanism(s) are responsible for impairment of both inspiratory and expiratory muscle strength. The well‐preserved DLCO was thought to be due to the use of biocompatible dialyzer membranes. Chronic vascular congestion might be the other explanation of high DLCO.


Transplantation Proceedings | 2013

Body Composition Analysis of Patients on Waiting List for Cadaveric Renal Transplantation: A Comparison of Hemodialysis and Peritoneal Dialysis Patients

Zeynep Bal; M.E. Uyar; Emre Tutal; O. Guliyev; Siren Sezer; Mehmet Haberal

BACKGROUND Bioelectrical impedance analysis is a simple, noninvasive method of assessing body composition. Dialysis modality and selection of buffer type may have an impact on body composition. The aim of our study was to compare body compositions of patients from the waiting list for cadaveric renal transplantation according to the dialysis modality. METHODS We examined a total of 152 (110 hemodialysis [HD] and 42 continuous ambulatory peritoneal dialysis [CAPD]) patients. Demographic data were collected from patient charts. The last 6 months routine laboratory evaluations including hemoglobin, serum creatinine, intact parathyroid hormone, albumin, C reactive protein, calcium, phosphorus were collected. Body compositions were measured using the Tanita BC-420MA Body Composition Analyzer (Tanita, Tokyo, Japan). We made a subanalysis of the CAPD group according to buffer choices as follows: lactate-buffered (n = 16) and bicarbonate/lactate-buffered (n = 26) solution users. RESULTS The body weight (P = .022), body mass index (BMI; 25.8 ± 4.7 vs 23.4 ± 4.9 kg/m(2), P = .009), muscle mass (P = .01), fat-free mass (P = .013), and visceral fat ratio (9.5 ± 5.4 vs 7.3 ± 4.1 %, P = .022) were significantly higher in the CAPD group. Total body water of CAPD patients were also higher (P = .003), but total body water ratios of HD and CAPD groups were similar. Fat and fat-free mass ratios of patient groups were also similar. Comparing CAPD subgroups we observed that patients using bicarbonate/lactate-buffered solutions had higher body weights (P = .038), BMI (27.1 ± 5 vs 23.7 ± 3.5 kg/m(2), P = .018) values, and visceral fat ratios (8.0 ± 5.2 vs 4.6 ± 2.5 %, P = .023). These patients also tend to have higher fat mass without statistical significance (P = .074). Fat, muscle, and fat-free mass total body water ratios of peritoneal dialysis subgroups were similar. CONCLUSION We believe that body composition analysis should be used as a complementary method for assessing nutritional status of PD and CAPD patients as body weight or BMI measurements do not reflect fat, muscle masses, and visceral fat ratios in these patients. Stable, well nourished CAPD patients should be closely observed and be encouraged to increase daily exercise and/or decrease calorie intake from other sources to decrease risks associated with abdominal obesity.


Transplantation proceedings | 2013

Reliability of bioelectrical impedance analysis in the evaluation of the nutritional status of hemodialysis patients - a comparison with Mini Nutritional Assessment.

E. Erdoğan; Emre Tutal; M.E. Uyar; Zeynep Bal; Bahar Gurlek Demirci; Burak Sayin; Siren Sezer

INTRODUCTION Protein-energy wasting (PEW) is a strong predictive factor for morbidity and mortality in patients who have end-stage renal disease (ESRD). Mini Nutritional Assessment (MNA) is an important and confirmed tool to evaluate PEW that has been recommended by many guidelines. Bioelectrical impedance analysis (BIA) is a noninvasive technique for assessing body composition. The aim of the present study was to analyze the reliability of BIA in malnutrition diagnosis by comparing it with standard MNA in a group of 100 ESRD patients. METHODS One hundred ESRD patients who were medically stable and under dialysis treatment for at least 6 months were enrolled to the study. Monthly assessed serum creatinine, albumin, C-reactive protein (CRP), and lipid profiles from the last 6 months prior to the study were retrospectively collected. A standard Full-MNA and body composition analyses were applied to all patients. Body compositions were analyzed with the BIA technique using the Body Composition Analyzer (Tanita BC-420 MA; Tanita, Tokyo, Japan). Patients were classified into three groups according to MNA scores as PEW (n = 15, score <17), moderate PEW or risk group (n = 49, score 17-23.5), and well-nourished (n = 36, score ≥ 24) patients. RESULTS Mean duration of maintenance hemodialysis treatment was significantly shorter in the PEW group compared to both of the other groups described (P = .015). Well-nourished and risk groups had lower CRP and higher albumin levels compared to PEW patients; however, these values were statistically similar in these two groups (P = .018, .01, respectively). According to BIA findings, well-nourished patients had the highest fat ratio, fat mass, muscle mass, visceral fat mass, and fat-free mass compared to both moderate the PEW/risk and the PEW groups (P < .05). Risk group patients also had higher muscle mass, visceral fat mass, and fat-free mass values compared to the PEW group (P < .05). A correlation analysis revealed that MNA scores were positively correlated with albumin (P = .005), creatinine (P = .049), fat mass (P = .045), muscle mass (P = .001), visceral fat ratio (P = .007), and BMI (P = .047) and in negative correlation with CRP (r = -0.357, P = .0001) levels. CONCLUSIONS We recommend BIA as a complementary diagnostic tool to evaluate nutritional status of ESRD along with MNA, anthropometric measures, and classical biochemical markers.


Transplantation Proceedings | 2015

Post-transplantation Anemia Predicts Cardiovascular Morbidity and Poor Graft Function in Kidney Transplant Recipients

B. Gurlek Demirci; Siren Sezer; C.B. Sayin; Emre Tutal; M.E. Uyar; F.N. Ozdemir Acar; Mehmet Haberal

OBJECTIVE We aimed to investigate whether low post-transplantation-period hemoglobin levels are predictive of cardiovascular morbidity in terms of left ventricular (LV) hypertrophy and vascular stiffness and to determine the contributing factors of post-transplantation anemia in kidney transplant (KT) recipients. METHODS One hundred fifty (mean age, 38.9 ± 10.8 y; 113 male) KT recipients with functioning grafts were enrolled in the study. All subjects underwent clinical and laboratory evaluations (24-hour urinary protein loss, complete blood count) and transthoracic echocardiography to assess LV systolic function. Arterial stiffness was measured by means of carotid-femoral pulse-wave velocity (PWV). Mean hemoglobin levels were analyzed at the 1st, 6th, 12th, and 24th months after transplantation. Patients were divided into 2 groups according to presence of anemia: patients with anemia (group 1; n = 120) and normal (group 2; n = 30). RESULTS PWV values (6.8 ± 1.9 m/s vs 6.4 ± 1.1 m/s in groups 1 and 2, respectively; P = .002) and LV mass index (LVMI; 252.1 ± 93.7 g/m(2) vs 161.2 ± 38.5 g/m(2) groups 1 and 2, respectively; P = .001) were significantly higher in group 1. Estimated glomerular filtration rate and (64 ± 28.5 m/min vs 77.8 ± 30 m/min in groups 1 and 2, respectively; P = .001) LV systolic function (57.2 ± 5.8% vs 77.8 ± 30% in groups 1 and 2, respectively; P < .005) were significantly lower in group 1. In regression analysis, LV systolic function and LVMI were predictors of post-transplantation hemoglobin levels. CONCLUSIONS Post-transplantation anemia contributes to cardiovascular morbidity by deteriorating LV function and increasing PWV and is therefore associated with poor prognosis for graft survival. Early correction of post-transplantation anemia, especially with the use of erythropoietin, may be beneficial for both graft and recipient survivals.


Transplantation Proceedings | 2013

Evaluation of Nutritional Status in Renal Transplant Recipients in Accordance with Changes in Graft Function

Emre Tutal; Siren Sezer; M.E. Uyar; Zeynep Bal; Bahar Gurlek Demirci; Fatma NurhanOzdemir Acar

INTRODUCTION AND AIMS Renal transplantation (RT) is the ultimate treatment modality for end-stage renal disease (ESRD) patients. Malnutrition is a strong predictor of cardiovascular disease among ESRD patients. Body composition analysis using bioimpedance devices (BIA) is a useful noninvasive tool to detect malnutrition in this population. We investigated the impact of graft function on nutritional status and reliability of BIA to detect malnutrition in RT recipients. METHODS We evaluated retrospectively 189 RT recipients including 59 females, and of overall mean age of 38.3 ± 10.6 years who had a minimum posttransplant follow-up of 12 months. Body Composition Analyzer (Tanita BC-420MA) determinations were complemented with monthly assessments of biochemical parameters. Patients were divided into 3 groups according to glomerular filtration rate (GFR) levels: normal graft function/high GFR group (group 1, normal creatinine levels, no proteinuria and GFR ≥ 90 mL/min; n = 59); low renal function/low GFR group (normal or high creatinine levels with low GFR levels; group 2; GFR 89-60 mL/min; n = 87) and group 3, (GFR < 60 mL/min; n = 43). RESULTS Group 3 patients displayed significantly lower as well as hemoglobin albumin and calcium concentrations, with higher phosphorus and parathyroid hormone levels (P = .0001). They also showed significantly lower body weight (P = .0001), body mass index (P = .002), fat (P = .002) and muscle (P = .0001) contents as well as fat-free mass (P = .0001). Group 2 patients had significantly lower values compared with group 1 and higher values than group 3. GFR values positively correlated with albumin, fat, muscle, and fat-free mass (r = 0.337, 0.299, 0.281, 0.278, respectively; P = .0001). GFR values positively correlated with visceral fat ratio (r = 0.170; P = 0.02), body mass index (r = 0.253; P = .0001), and waist-hip ratio (r = 0.218; P = .006). CONCLUSION Loss of muscle and fat mass is an early sign of malnutrition among RT recipients. It is closely associated with loss of GFR. BIA is a noninvasive and reliable diagnostic tool that should be included in the follow-up of these patients for an early diagnosis of malnutrition-related complications.


Transplantation Proceedings | 2013

Left Ventricular Mass Index and Its Relationship to Ambulatory Blood Pressure and Renal Resistivity Index in Renal Transplant Recipients

Siren Sezer; M.E. Uyar; T. Colak; Zeynep Bal; Emre Tutal; G. Kalaci; Fatma NurhanOzdemir Acar

INTRODUCTION AND AIMS Left ventricular hypertrophy (LVH) is frequently observed in patients with end-stage renal disease and renal allograft recipients. It is an independent, strong predictor of morbidity and mortality. Renal resistive index (RRI) is an important determinant of graft function in transplant recipients. In essential hypertension, increased RRI is associated with reduced renal function and tubulointerstitial damage. In this present study, we investigated the association of ambulatory blood pressure monitoring parameters and RRI on left ventricular mass index among renal transplant recipients. METHODS Charts of 98 renal transplant recipients with echocardiography, ambulatory blood pressure monitoring, and renal Doppler ultrasonography as well as laboratory tests including serum creatinine, glomerular filtration rate, and C-reactive protein (CRP) level at the end of post-transplantation year 1 were analyzed in this study. LVMI was calculated using the Devereux formula with echocardiographic findings. RESULTS Left ventricular mass index (LVMI) positively correlated with mean systolic blood pressure (SBP) (r = 0.512; P = .0001), mean nighttime SBP (r = 0.312; P = .007), mean nighttime diastolic blood pressure (DBP) (r = 0.427; P = .005), renal resistive index (RRI; r = 0.290; P = .004), and age (r = 0.371; P = .001). Multiple logistic regression analysis revealed that mean and maximum nighttime SBP and RRI were independent risk factors for LVMI (P = .001, .035, and .05, respectively). CONCLUSION High RRI is one of the main indicators of cardiovascular disease in renal transplant recipients. Additionally, older age, high blood pressure, and nondipper pattern are important risk factors of LVH.


Transplantation Proceedings | 2013

Low Graft Function and Ongoing Hyperparathyroidism Are Closely Related to Post-Transplantation Osteoporosis

Emre Tutal; M.E. Uyar; T. Colak; Zeynep Bal; Bahar Gurlek Demirci; T. Bozkurt; Siren Sezer; Fatma NurhanOzdemir Acar

INTRODUCTION Renal transplantation (RT) is the gold standard therapy for chronic renal failure. Immunosuppressive drug choice, malnutrition, adynamic bone disease and hyperparathyroidism are important factors impacting the development of posttransplant osteoporosis. Body composition analysis with bioimpedance devices (BIA) is a useful noninvasive tool to detect malnutrition among the RT population. We investigated the effects of graft function, immunosuppressive drug regimens and biochemical characteristics on bone mineral density of RT patients as well as the reliability of BIA measurements to diagnose osteoporosis. METHODS One hundred three recipients with a minimum of 12 months post-RT follow-up underwent body composition analysis using the Tanita Analyzer. The last 6 months of monthly biochemical parameters and glomerular filtration rates (GFR) as well as drug regimens were collected retrospectively from patient charts. Patients were divided into 2 groups, according to their femoral neck and lumbal T scores, as osteoporosis (n = 42) and control groups (n = 61). RESULTS The mean GFR of osteoporotic patients was significantly lower (P = .04) and parathyroid hormone (PTH) levels significantly higher (P = .002). According to BIA, osteoporotic patients showed lower bone mass, fat mass, visceral fat ratio, muscle mass, waist-hip ratios, and body mass index values (P < .05). Correlation analysis revealed GFR to negatively correlate with PTH (r = -0.231, P = .010) and positively with femur t scores (r = 0.389, P = .0001) as well as with BIA findings (P = .0001). In contrast, PTH levels in negatively correlated with lumbar and femoral neck t scores (r = -0.22, -0.4 and P = .026, .0001, respectively) but not with BIA findings including bone mass. CONCLUSION Changes in bone density after RT were affected by graft function. The rapid loss of bone mineral density emphasizes the need for prevention started in the early posttransplant period. BMD measurements provided a guide for treatment and for subsequent evaluation.


Transplantation proceedings | 2015

High-Grade Proteinuria as a Cardiovascular Risk Factor in Renal Transplant Recipients

O. Guliyev; Burak Sayin; M.E. Uyar; Gultekin Genctoy; Siren Sezer; Zeynep Bal; Bahar Gurlek Demirci; Mehmet Haberal

BACKGROUND Proteinuria is a marker of graft damage and is closely associated with a higher risk of morbidity, mortality, and cardiovascular disease in kidney transplant recipients (KTRs). Arterial stiffness is a well-known predictor of vascular calcification and systemic arteriosclerosis. In our study, we aimed to investigate the association between proteinuria and graft/patient survival and to determine whether proteinuria may be a predictor for cardiovascular disease in our KTR population. METHODS Ninety KTRs (31 women; age, 38.7 ± 11 years, with 45.9 ± 9.6 months post-transplantation period) with normal graft functions in the 3 to 5 years of the post-transplantation period were enrolled. All patients were evaluated for their standard clinical (age, sex, and duration of hemodialysis) parameters. High-grade proteinuria was defined as proteinuria >500 mg/day in the 24-hour urine collection. All patients were evaluated by means of pulse-wave velocity (PWV) measurement at the initiation of the study. RESULTS Patients were divided into 2 groups: group 1 (high-grade proteinuria) patients with ≥500 mg/24 hours (n = 30) and group 2 (low-grade proteinuria) patients with <500 mg/24 hours (n = 60). High-grade proteinuria was correlated with higher PWV measurements and lower estimated glomerular filtration levels. Proteinuria appears to precede the elevation of serum creatinine and thus may be a useful marker of renal injury and may also be a contributing factor on deterioration of the graft. CONCLUSIONS High-grade (>500 mg/day) proteinuria in KTRs is strongly associated with poor graft survival and increased risk of cardiovascular events. In our study, we proved the significant difference between high-grade and low-grade proteinuric patients, and we suggest 500 mg/day as the threshold of proteinuria in KTR population.

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