Mehmet Emin Yilmaz

Mortality and cardiovascular events in online haemodiafiltration (OL-HDF) compared with high-flux dialysis: results from the Turkish OL-HDF Study

BACKGROUND Online haemodiafiltration (OL-HDF) is considered to confer clinical benefits over haemodialysis (HD) in terms of solute removal in patients undergoing maintenance HD. The aim of this study was to compare postdilution OL-HDF and high-flux HD in terms of morbidity and mortality. METHODS In this prospective, randomized, controlled trial, we enrolled 782 patients undergoing thrice-weekly HD and randomly assigned them in a 1:1 ratio to either postdilution OL-HDF or high-flux HD. The mean age of patients was 56.5 ± 13.9 years, time on HD 57.9 ± 44.6 months with a diabetes incidence of 34.7%. The follow-up period was 2 years, with the mean follow-up of 22.7 ± 10.9 months. The primary outcome was a composite of death from any cause and nonfatal cardiovascular events. The major secondary outcomes were cardiovascular and overall mortality, intradialytic complications, hospitalization rate, changes in several laboratory parameters and medications used. RESULTS The filtration volume in OL-HDF was 17.2 ± 1.3 L. Primary outcome was not different between the groups (event-free survival of 77.6% in OL-HDF versus 74.8% in the high-flux group, P = 0.28), as well as cardiovascular and overall survival, hospitalization rate and number of hypotensive episodes. In a post hoc analysis, the subgroup of OL-HDF patients treated with a median substitution volume >17.4 L per session (high-efficiency OL-HDF, n = 195) had better cardiovascular (P = 0.002) and overall survival (P = 0.03) compared with the high-flux HD group. In adjusted Cox-regression analysis, treatment with high-efficiency OL-HDF was associated with a 46% risk reduction for overall mortality {RR = 0.54 [95% confidence interval (95% CI) 0.31-0.93], P = 0.02} and a 71% risk reduction for cardiovascular mortality [RR = 0.29 (95% CI 0.12-0.65), P = 0.003] compared with high-flux HD. CONCLUSIONS The composite of all-cause mortality and nonfatal cardiovascular event rate was not different in the OL-HDF and in the high-flux HD groups. In a post hoc analysis, OL-HDF treatment with substitution volumes over 17.4 L was associated with better cardiovascular and overall survival.

A population-based survey of Chronic REnal Disease In Turkey—the CREDIT study

Background. Chronic kidney disease (CKD) is a growing health problem worldwide that leads to end-stage kidney failure and cardiovascular complications. We aimed to determine the prevalence of CKD in Turkey, and to evaluate relationships between CKD and cardiovascular risk factors in a population-based survey. Methods. Medical data were collected through home visits and interviews. Serum creatinine, blood glucose, total cholesterol, triglycerides, HDL, LDL and uric acid were determined from 12-h fasting blood samples, and spot urine tests were performed for subjects who gave consent to laboratory evaluation. Results. A total of 10 872 participants were included in the study. The final analysis was performed on 10 748 subjects (mean age 40.5 ± 16.3 years; 55.7% women) and excluded 124 pregnant women. A low glomerular filtration rate (GFR) (< 60 mL/min/1.73 m2) was present in 5.2% of the subjects who were evaluated for GFR, while microalbuminuria and macroalbuminuria were observed in 10.2% and 2% of the subjects, respectively. The presence of CKD was assessed in subjects who gave consent for urinary albumin excretion measurement (n = 8765). The overall prevalence of CKD was 15.7%; it was higher in women than men (18.4% vs. 12.8%, P < 0.001) and increased with increasing age of the subjects. The prevalence of hypertension (32.7% in the general population), diabetes (12.7%), dyslipidaemia (76.3%), obesity (20.1%) and metabolic syndrome (31.3%) was significantly higher in subjects with CKD than subjects without CKD (P < 0.001 for all). Conclusions. The prevalence of CKD in Turkey is 15.7%. Cardiovascular risk factors were significantly more prevalent in CKD patients.

Bone mineral density and its correlation with clinical and laboratory factors in chronic peritoneal dialysis patients

The aim of this study was to assess the clinical and laboratory correlations of bone mineral density (BMD) measurements among a large population of patients on chronic peritoneal dialysis (PD). This cross-sectional, multicenter study was carried out in 292 PD patients with a mean age of 56 ± 16 years and mean duration of PD 3.1 ± 2.1 years. Altogether, 129 female and 163 male patients from 24 centers in Canada, Greece, and Turkey were included in the study. BMD findings, obtained by dual-energy X-ray absorptiometry (DEXA) and some other major clinical and laboratory indices of bone mineral deposition as well as uremic osteodystrophy were investigated. In the 292 patients included in the study, the mean lumbar spine T-score was −1.04 ± 1.68, the lumbar spine Z-score was −0.31 ± 1.68, the femoral neck T-score was −1.38 ± 1.39, and the femoral neck Z score was −0.66 ± 1.23. According to the WHO criteria based on lumbar spine T-scores, 19.2% of 292 patients were osteoporotic, 36.3% had osteopenia, and 44.4% had lumbar spine T-scores within the normal range. In the femoral neck area, the prevalence of osteoporosis was slightly higher (26%). The prevalence of osteoporosis was 23.3% in female patients and 16.6% in male patients with no statistically significant difference between the sexes. Agreements of lumbar spine and femoral neck T-scores for the diagnosis of osteoporosis were 66.7% and 27.3% and 83.3% for osteopenia and normal BMD values, respectively. Among the clinical and laboratory parameters we investigated in this study, the body mass index (BMI) (P < 0.001), daily urine output, and urea clearance time × dialysis time/volume (Kt/V) (P < 0.05) were statistically significantly positive and Ca × PO4 had a negative correlation (P < 0.05) with the lumbar spine T scores. Femoral neck T scores were also positively correlated with BMI, daily urine output, and KT/V; and they were negatively correlated with age. Intact parathyroid hormone levels did not correlate with any of the BMD parameters. Femoral neck Z scores were correlated with BMI (P < 0.001), and ionized calcium (P < 0.05) positively and negatively with age, total alkaline phosphatase (P < 0.05), and Ca × P (P < 0.01). The overall prevalence of fractures since the initiation of PD was 10%. Our results indicated that, considering their DEXA-based BMD values, 55% of chronic PD patients have subnormal bone mass—19% within the osteoporotic range and 36% within the osteopenic range. Our findings also indicate that low body weight is the most important risk factor for osteoporosis in chronic PD patients. An insufficient dialysis dose (expressed as KT/V) and older age may also be important risk factors for osteoporosis of PD patients.

Phosphorus control in peritoneal dialysis patients

Hyperphosphatemia is independently associated with an increased risk of death among dialysis patients. In this study, we have assessed the status of phosphate control and its clinical and laboratory associations in a large international group of patients on chronic peritoneal dialysis (PD) treatment. This cross-sectional multicenter study was carried out in 24 centers in three different countries (Canada, Greece, and Turkey) among 530 PD patients (235 women, 295 men) with a mean+/-s.d. age of 55+/-16 years and mean duration of PD of 33+/-25 months. Serum calcium (Ca(2+)), ionized Ca(2+), phosphate, intact parathyroid hormone (iPTH), 25-hydroxy vitamin D(3), 1,25-dihydroxy vitamin D(3), total alkaline phosphatase, and bone alkaline phosphatase concentrations were investigated, along with adequacy parameters such as Kt/V, weekly creatinine clearance, and daily urine output. Mean Kt/V was 2.3+/-0.65, weekly creatinine clearance 78.5+/-76.6 l, and daily urine output 550+/-603 ml day(-1). Fifty-five percent of patients had a urine volume of <400 ml day(-1). Mean serum phosphorus level was 4.9+/-1.3 mg per 100 ml, serum Ca(2+) 9.4+/-1.07 mg per 100 ml, iPTH 267+/-356 pg ml(-1), ionized Ca(2+) 1.08+/-0.32 mg per 100 ml, calcium phosphorus (Ca x P) product 39+/-19 mg(2)dl(-2), 25(OH)D(3) 8.3+/-9.3 ng ml(-1), 1,25(OH)(2)D(3) 9.7+/-6.7 pg ml(-1), total alkaline phosphatase 170+/-178 U l(-1), and bone alkaline phosphatase 71+/-108 U l(-1). While 14% of patients were hypophosphatemic, with a serum phosphorus level lower than 3.5 mg per 100 ml, most patients (307 patients, 58%) had a serum phosphate level between 3.5 and 5.5 mg per 100 ml. Serum phosphorus level was 5.5 mg per 100 ml or greater in 28% (149) of patients. Serum Ca(2+) level was > or =9.5 mg per 100 ml in 250 patients (49%), between 8.5 and 9.5 mg per 100 ml in 214 patients (40%), and lower than 8.5 mg per 100 ml in 66 patients (12%). Ca x P product was >55 mg(2)dl(-2) in 136 patients (26%) and lower than 55 mg(2)dl(-2) in 394 patients (74%). Serum phosphorus levels were positively correlated with serum albumin (P<0.027) and iPTH (P=0.001), and negatively correlated with age (P<0.033). Serum phosphorus was also statistically different (P = 0.013) in the older age group (>65 years) compared to younger patients; mean levels were 5.1+/-1.4 and 4.5+/-1.1 mg per 100 ml, respectively, in the two groups. In our study, among 530 PD patients, accepted uremic-normal limits of serum phosphorus control was achieved in 58%, Ca x P in 73%, serum Ca(2+) in 53%, and iPTH levels in 24% of subjects. Our results show that chronic PD, when combined with dietary measures and use of phosphate binders, is associated with satisfactory serum phosphorus control in the majority of patients.

The Prevalence and the Characteristics of Tuberculosis Patients Undergoing Chronic Dialysis Treatment: Experience of a Dialysis Center in Southeast Turkey

Tuberculosis remains a significant health problem for patients receiving chronic dialysis. The purpose of this study was to evaluate the prevalence, clinical characteristics, and outcomes of tuberculosis among patients with end-stage renal failure (ESRF) undergoing chronic hemodialysis and continuous ambulatory peritoneal dialysis. Between 1999 and 2006, we diagnosed 21 active tuberculosis patients among a total of 674-dialysis patient in our dialysis center (582 patients on hemodialysis and 92 patients on continuous ambulatory peritoneal dialysis program). Fourteen patients developed extrapulmonary tuberculosis (generally tuberculous lymphadenitis, n = 8) and seven patients developed pulmonary tuberculosis. All patients who developed tuberculosis after starting dialysis had low creatinine clearances and, in general, anemia and hypoalbuminemia. Three of patients greater than 40 years died. In conclusion, tuberculous lymphadenitis was the most frequent form of extrapulmonary tuberculosis in our dialysis population. If no cause is found despite extensive investigations in an end stage renal failure case with fever, loss of weight, and/or atypical lymphadenopathy, the physician should consider the possibility of tuberculosis. Finally, it was considered that ESRF is associated with depressed immune system and elevated risk of tuberculosis; thus, in this population, clinicians must evaluate patients carefully.

The Evaluation of Postdialysis L-Carnitine Administration and Its Effect on Weekly Requiring Doses of rHuEPO in Hemodialysis Patients

Background. In this study, our aim was to evaluate the effect of postdialysis administration of parenteral l-carnitine supplementations on hematological parameters and also on weekly requiring dose of the recombinant human erythropoietine (rHuEPO) in hemodialysis (HD) patients. Material and Methods. The stable 34 patients (17 male, 17 female) were enrolled in the study who were on rHuEPO therapy and a regular maintenance HD program at 5 h, three times a week with bicarbonate dialysate and with biocompatible membranes in HD Center of Medical Faculty Hospital in University of Dicle. rHuEPO was administered subcutanously at 80–120 U/kg/week. The patients were divided into two groups: Group 1, rHuEPO therapy (n = 17) and Group 2, rHuEPO therapy +l-carnitine (n = 17). l-carnitine (l-carnitine ampul, Santa Farma) 1 g was injected postdialysis intravenously via venous route of the dialytic set, three times a week. The patients hemoglobin (Hgb), hematocrit (Hct), serum iron (Fe+ 2), total iron-binding capacity (TIBC), transferrin saturation index (TSI), and serum ferritin (Fer) levels were followed during the 16-week period. The weekly requiring doses of rHuEPO and hematological parameters of patients were recorded at the beginning of the study, at 8 weeks, and at 16 weeks of the study period. Results. In group 1 (n = 17, 13 female, four male), the mean age was 38.8 ± 12.1 years, mean period time on HD therapy was 18.1 ± 14.9 months, and mean Kt/V value was 1.48 ± 0.28. In group 2 (n = 17, 13 male, four female), the mean age was 48.1 ± 15.4 years, mean period time on HD therapy was 34.4 ± 23.0 months, and mean Kt/V value was 1.29 ± 0.20. The hematological parameters of the groups were found as follows: in group 1, Hgb: 7.9–10.8 g/dl, Hct: 25.3–32.5%; in group 2, Hgb: 10.2–11.8 g/dl, Hct: 30.6–35.4%, respectively (p< 0.05). The target Hgb/Hct values were achieved at the end of the study in both groups. Both groups were the same according to their serum Fe+ 2 markers (p > 0.05). But unlike serum Fe+ 2 markers, there were significant differences on weekly requiring doses of rHuEPO therapy between groups. While in group 1, the mean weekly requiring dose of rHuEPO was 6529 U/week (120 U/kg/week) at the beginning of the study, and maintenance weekly requiring dose of rHuEPO was 3588 U/week (66 U/kg/week) at the end of the study, in group 2, they were 4882 U/week (80 U/kg/week), and 1705 U/week (28 U/kg/week), respectively. According to these values, the total reduction in weekly requiring dose of rHuEPO was 45% in group 1, and 65% in group 2; the net gain was 20% in group 2 (p< 0.05). Conclusions. If other factors related to anemia are excluded, the postdialysis parenteral l-carnitine therapy can be considered in selected stable patients, which may improve anemia and may reduce the weekly requiring dose of the rHuEPO and also be cost-effective.

Evaluation of volume overload by bioelectrical impedance analysis, NT-proBNP and inferior vena cava diameter in patients with stage 3&4 and 5 chronic kidney disease

Abstract Background: Determination of fluid overload is important in chronic kidney disease. Early diagnosis and treatment of volume overload may decrease morbidity and mortality. We aimed to determine body composition by using bioelectrical impedance analysis, and studying other clinical characteristics, inferior vena cava diameter, and N-terminal pro-B natriuretic peptide associated with hydration status in chronic kidney disease Stages 3&4 and 5 in patients not undergoing dialysis. Method: We examined 62 patients with Stages 3&4 and 68 patients with Stage 5 chronic kidney disease. Plasma NT-proBNP was measured and analyzed after log transformation. Inferior vena cave diameter was measured with echocardiography and indexed for body surface area. Hydration status was assessed using multi-frequency bioelectrical impedance analysis. Overhydration was defined as overhydration/extracellular water >0.15. Results: Overhydration was more frequent in Stage 5 than in Stages 3&4 patients. Systolic and diastolic blood pressure, inferior vena cava index, and log NT-proBNP were higher in overhydrated compared to non-overhydrated patients. A significant positive correlation existed between overhydration/extracellular water and log NT-proBNP, systolic and diastolic blood pressures, and inferior vena cava index. In multiple linear regression analysis, the variables associated with hydration status were male sex, extracellular water/total body water, and extracellular water/intracellular water (greater overhydration), while serum albumin levels had a negative association with overhydration. Conclusion: Overhydration is more prevalent in Stage 5 chronic kidney disease patients than in Stages 3&4 patients. Bioelectrical impedance analysis, inferior vena cava diameter, and NT-proBNP analysis in chronic kidney disease are useful methods to determine the volume overload.

Evaluation of fluid status related parameters in hemodialysis and peritoneal dialysis patients: Clinical usefulness of bioimpedance analysis

BACKGROUND AND OBJECTIVE Fluid overload is a common and serious problem that leads to severe complications in dialysis patients. We aimed to compare hydration status as measured with bioimpedance analysis (BIA) method in hemodialysis (HD) and peritoneal dialysis (PD) patients, as well as investigating the association between blood pressure, left ventricular mass index (LVMI) and hydration status. MATERIALS AND METHODS We examined 43 HD and 33 PD patients. Blood pressure was recorded. In each group, echocardiographic examinations were performed on all patients. Hydration status was assessed using multifrequency bioelectrical impedance analysis. Overhydration was defined as an overhydration (OH)/extracellular water (ECW) ratio of >0.15. RESULTS The OH/ECW ratio was significantly higher in PD patients compared to post-HD patients. Overhydration was statistically more frequent in PD than in post-HD patients (30.3% vs. 11.6%, P=0.043). Systolic blood pressure (SBP) in both post-HD and PD groups, and LVMI in the PD group were found to be significantly higher in overhydrated patients than non-overhydrated patients. In multiple linear regression analyses, increased OH/ECW ratio was independently associated with higher SBP and LVMI. CONCLUSIONS Fluid overload may be an even more prevalent and serious problem in PD patients. Overhydration is closely associated with increased blood pressure and LVMI. OH/ECW ratio, a derived parameter of fluid load measured by BIA, was a significant and independent determinant of SBP and LVMI.

The Prevalence and Clinical Features of Tuberculous Peritonitis in CAPD Patients in Turkey, Report of Ten Cases from Multi-centers

Objective. To determine the rate, risk factors and outcome of Tuberculous Peritonitis (TBP) in patients treated with continuous ambulatory peritoneal dialysis (CAPD) in our units. Design. Retrospectively, we reviewed the medical data of all CAPD patients from 12 centers for TBP, covering the period between 1986 and 12 2002. Setting. All patients were from 12 renal clinics at tertiary-care university hospitals. Results. Ten cases of TBP were identified among the CAPD patients in our centers. There were five male and five female patients with a mean age of 37.2 years. None of the patients had tuberculosis history, 6 patients had predominance of PNL. One patient had coincidental bacterial peritonitis. Two patients were successfully treated without the removal of the Tenckhoff catheter. Conclusion. TBP in CAPD patients is a very rare complication. In contrast to predominance of lymphocytes in nonuremic patients with tuberculous peritonitis, CAPD patients with tuberculous peritonitis may have predominance of PNL on examination of the peritoneal fluid. Since TBP has high morbidity and mortality, early diagnosis and treatment of disease are extremely important for improving outcome.

Pulmonary Function in Patients with End-Stage Renal Disease: Effects of Hemodialysis and Fluid Overload.

Background Respiratory system disorders are one of the most prevalent complications in end-stage renal disease patients on hemodialysis. However, the pathogenesis of impaired pulmonary functions has not been completely elucidated in these patients. We designed a study to investigate acute effects of hemodialysis treatment on spirometry parameters, focusing on the relationship between pulmonary function and fluid status in hemodialysis patients. Material/Methods We enrolled 54 hemodialysis patients in this study. Multifrequency bioimpedance analysis (BIA) was used to assess fluid status before and 30 min after the midweek of hemodialysis (HD). Overhydration (OH)/extracellular water (ECW)% ratio was used as an indicator of fluid status. Fluid overload was defined as OH/ECW ≥7%. Spirometry was performed before and after hemodialysis. Results Forced vital capacity (FVC), FVC%, and forced expiratory volume in the first second (FEV1) levels were significantly increased after hemodialysis. FVC, FVC%, FEV1, FEV1%, mean forced expiratory flow between 25% and 75% of the FVC (FEF25–75), FEF25–75%, peak expiratory flow rate (PEFR), and PEFR% were significantly lower in patients with fluid overload than in those without. OH/ECW ratio was negatively correlated with FVC, FVC%, FEV1, FEV1%, FEF25–75, FEF25–75%, PEFR, and PEFR%. Stepwise multiple regression analysis revealed that male sex and increased ultrafiltration volume were independently associated with higher FVC, whereas increased age and OH/ECW ratio were independently associated with lower FVC. Conclusions Fluid overload is closely associated with restrictive and obstructive respiratory abnormalities in HD patients. In addition, hemodialysis has a beneficial effect on pulmonary function tests, which may be due to reduction of volume overload.