Quantitative EEG findings in patients with chronic renal failure.

OBJECTIVE: Chronic renal failure frequently causes uremic encephalopathy with impairment of various cognitive functions, but the pathophysiology of uremic syndrome is complex and poorly understood. In this study, we wished to establish a reliable tool and monitor system to evaluate the central nervous system dysfunction of patients with uremic encephalopathy. METHODS: A group of 31 patients with chronic renal failure was assessed with online real time brain mapping using the CATEEM technology to detect deviations and abnormal EEG patterns. Quantitative EEG data were compared with those of an age-matched healthy control group and correlated to laboratory markers and various dosages of erythropoietin. RESULTS: Electrical power was most prominent in delta, theta and alpha frequencies in the temporal and central brain areas (electrode positions T5, T6, C3 and C4). Explorative statistical comparison of the two data sets with respect to these brain areas revealed that the increases in electrical power in delta, theta and alpha frequency bands were different from healthy people with p-values of p<0.003 (delta), p<0.0003 (theta), p<0.01 (alpha 1) and p<0.01 (alpha 2). In addition, high levels of hemoglobin were significantly correlated with higher theta activity. CONCLUSION: We detected distinct EEG deviations from normality in patients with chronic renal failure. Online real time brain mapping using the CATEEM technology provides a unique possibility to monitor mental impairment and serves as a control for therapeutical intervention.

Increased reduction of dimethylarginines and lowered interdialytic blood pressure by the use of biocompatible membranes.

Hypertension contributes to cardiac and cerebrovascular complications in HD patients. Endogenous inhibitors of nitric oxide synthase accumulate in renal failure and may interfere with the regulation of vascular tone. We investigated the elimination of asymmetric dimethylarginine (ADMA) by using biocompatible Polyamide Strade mark membranes in low-flux (Polyflux 6L) or high-flux (Polyflux 14S) hemodialysis or hemodiafiltration (HDF) compared with hemodialysis with cellulosic membranes. Removal rates for ADMA, symmetric dimethylarginine (SDMA), and beta2-microglobulin significantly increased in HDF. The plasma total amino acid concentration and the arginine/ADMA ratio increased, and the mean 24-hour blood pressure decreased during the study. In a second study, we investigated whether plasma amino acids and interdialytic blood pressure are influenced by the use of a biocompatible membrane and HDF. Seventeen end-stage renal disease patients were treated for six weeks with hemodialysis using cellulosic membranes, six weeks with low-flux hemodialysis using Polyflux 6L, and six weeks with HDF using Polyflux 14S. Only in the diabetic patients were the hemoglobin concentration (from 10.6 +/- 1.5 to 11.9 +/- 0.6 mg/dL) and hematocrit (from 33.6 +/- 1.9 to 36.2 +/- 1.5%) increased significantly, whereas the mean 24-hour systolic blood pressure decreased (from 154 +/- 22 to 129 +/- 18 mm Hg). No significant changes were observed in nondiabetic patients. We conclude that primarily diabetic patients seem to benefit from the use of biocompatible membranes--most in HDF--after a period of six weeks. The regulation of nitric oxide pathways by ADMA removal and changed ADMA/arginine ratio might be contributing factors. Further prospective studies are required to show whether the long-term application of HDF or other changes of dialysis treatment modalities may help to improve well-being, morbidity, and mortality in hemodialysis patients.

[Risk factors for urothelial carcinoma: drinking measures, smoking and other life style-related risk factors--results of the Berlin Urothelial Study (BUS)]. / Risikofaktoren für das Urothelkarzinom: Trinkmenge, Rauchen und andere lebensstilbezogene Risikofaktoren--Ergebnisse der Berliner Urothelstudie (BUS).

With the exception of smoking and several occupational exposures there is little knowledge about risk factors for urothelial cancer. A case control study in the area of former West Berlin was performed from 1990-1995 to investigate the role of several lifestyle risk factors, such as smoking, drinking behaviour and regular intake of analgesics and laxatives. The study includes 647 hospital-based incident cases with bladder cancer (n = 571), renal pelvis cancer (n = 51), and ureter cancer (n = 25), and 647 population-based controls which were matched individually by sex and age. Data analyses were carried out using standard methods for case control studies (conditional multiple logistic regression analysis). Odds ratios (OR) and 95% confidence intervals (CI) were applied as effect parameter. Statistically significantly increased odds ratios were observed for current smoking (OR: 3.46, 95% CI: 2.50-4.78), previous but now abandoned smoking (OR: 1.51, 95% CI: 1.09-2.81), and for regular intake of laxatives (OR: 2.52, 95% CI: 1.56-4.09). Furthermore, an increased risk for urothelial cancer was observed for daily consumption of three and more litres of cold drinks (OR: 2.65 95% CI: 1.12-6.24). The results underline that lifestyle factors other than smoking may contribute to a higher risk of urothelial cancer.

Outcome of patients with ventricular assist devices and acute renal failure requiring renal replacement therapy.

The significance of acute renal failure (ARF) for patients treated with a ventricular assist device (VAD) is uncertain. There is little information on the outcome of patients who require renal replacement therapy during treatment with a VAD. A retrospective review was undertaken to evaluate the impact of renal failure requiring renal replacement therapy on such patients. Studied were 227 patients who were supplied with a VAD at the German Heart Institute Berlin. Fifty-five patients required renal replacement therapy during treatment with a VAD. These were compared with patients not needing renal replacement therapy (ARF and non-ARF groups). Significant differences for the end points of survival, heart transplantation, and discharge from hospital were observed in patients with ARF (p < 0.01). Survival was then analyzed according to indications for treatment with a VAD (bridge to transplantation or cardiac recovery after cardiotomy, transplantation, myocardial infarction, myocarditis, and endocarditis). Survival for bridge-to-transplantation patients was clearly influenced in a negative way by ARF (p < 0.01). For cardiac recovery patients, only a small difference in survival was observed (p = 0.05). We conclude that ARF is a negative predictor for bridge-to-transplantation patients. For cardiac recovery patients the impact of ARF on survival is marginally significant.

[The quality of the treatment of diabetics in kidney failure in Germany]. / Behandlungsqualität niereninsuffizienter Diabetiker in Deutschland.

BACKGROUND AND OBJECTIVE: In recent years there has been a rapid increase in the number of dialysis-dependent diabetics in Germany. Survival on dialysis is not satisfactory and damage acquired in the preterminal stage of renal failure is thought to play an important role. Late referral to a nephrologist and insufficient quality of medical management are thought to contribute importantly to poor outcome. This hypothesis was evaluated in the present study. PATIENTS AND METHOD: The data of all 173 diabetic patients (16 with type 1, 157 with type 2 diabetes, 90 men, 83 women, mean age 63.3 [31-95] years), who had been referred in 1996 for the first time to five renal units, were retrospectively assessed using a structured protocol. RESULTS: Patients were usually referred in advanced renal failure (median creatinine clearance 29 ml/min, range 1-216) with insufficient control of systolic (170 [120-260] mmHg) and diastolic blood pressure (90 [60-180] mmHg), insufficient antihypertensive therapy (without treatment 32 of 173 patients; median number of classes of antihypertensive agents used 2 [range 1-6]; ACE inhibitors 79 of 173 patients), high HbA1c (7.9 [4.9-15.7]%) and LDL cholesterol (176 [67-307] mg/dl). Immediate dialysis was required in 45 patients. CONCLUSION: The data document insufficient quality of treatment and late incorporation of a nephrologist into the medical team involved in the care of diabetic patients. Changes in the structure of diabetes care are necessary to improve treatment quality.

Urothelial cancer at different tumour sites: role of smoking and habitual intake of analgesics and laxatives. Results of the Berlin Urothelial Cancer Study.

BACKGROUND: In Germany about 20000 new cases of urothelial cancer (UC) and about 7500 deaths from bladder cancer alone occur each year. Among the manifold risk factors, little research has been done on the role of smoking and the habitual intake of analgesics and laxatives-practices that are common in parts of the German population. The aim of this study is to define the proportion of risk derived from these preventable habits for the development of UC at its different sites. Subjects and methods. A case-control study in the area of the former West Berlin was performed from 1990 to 1995 including all newly diagnosed incident cases of UC from the eight hospitals of the study area. Study subjects and population-based controls individually matched by age (+/-2 years) and sex were evaluated by a standardized face-to-face interview about the lifelong exposure to cigarette smoking, analgesics, and laxatives. Adjusted risk analysis was carried out for the main exposure variables in relation to the different sites of UC in the bladder, ureter, and renal pelvis. RESULTS: Six hundred and forty-seven cases of UC (571 bladder, 25 ureter, and 51 renal pelvis) and an identical number of controls were included in the analysis (response rate in cases, 84.6%; in controls, 70.2%). Smoking increased the risk of bladder cancer (BC) by an odds ratio (OR) of 3.22 (95% confidence interval (CI) 2.29-4.52), that of ureter (URC) or renal pelvis cancer (RPC) together by OR 6.20 (95% CI 2.04-18.81), and that of RPC alone by OR 5.91 (95% CI 1.47-23.66). Ex-smoking was associated with an increased risk for BC (OR 1.55, 95% CI 1.10-2.19). Intake of more than 1 kg of phenacetin in analgesic mixtures was associated with an OR of 5.28 for RPC (intake of > or = 1 kg paracetamol, OR 3.27; > or = 1 kg pyrazolones, 1.12) and 0.75 for BC (not significant). Laxatives significantly increased the risk of BC (OR 2.14, 95% CI 1.26-3.63) and RPC/URC (OR 9.62, 95% CI 1. 01-91.24) in both sexes. CONCLUSION: Habitual risks from smoking and intake of laxatives significantly contribute to the development of UC, especially of the renal pelvis and ureter cancer. Intake of at least 1 kg of analgesic substances (anilides, pyrazolones) as calculated from this study base is associated with increased but not significant risks for RPC. These data underline that restrictive and educational measurements focusing on common habits would have a strong impact on preventing UC in Germany.

[Analgesics and laxatives as risk factors for cancer in the efferent urinary tract--results of the Berlin Urothelial Carcinoma Study]. / Analgetika und Laxantien als Risikofaktoren für Krebs der ableitenden Harnwege--Ergebnisse der Berliner Urothelkarzinom-Studie (BUS).

A retrospective case-control study (1990-1995), the Berlin Urothelial Cancer Study (BUS), examined analgesics and laxatives as risks for the induction of urothelial cancer in renal pelvis, ureter and bladder. Especially for renal pelvis cancer could observe substance and dose specific risk of compound analgesics. The analgesic substances Phenacetin, Paracetamol, Acetylsalicylic acid (ASA) and Pyrazolones were assessed. Besides a risk of contact laxatives (chemical or anthranoide ingredients) for urothelial cancer was found, not yet described. The highest risk shows the anthranoide plant Senna. Thus this study confirms the risk of specific analgesic ingredients and found an evidence for a new risk of contact laxatives. As both, analgesics and contact laxatives, are typical OTC--("Over the counter") products, a severe controlling is demanded and for laxatives further studies are needed.

Effect of a silver device in preventing catheter-related infections in peritoneal dialysis patients: silver ring prophylaxis at the catheter exit study.

Catheter-related infections remain a significant cause of method failure in chronic peritoneal dialysis (PD) therapy. Given the increasing antibiotic resistance, such nonpharmacological strategies as local silver devices attract more interest. To establish whether a silver ring device (designed by Grosse-Siestrup in 1992) mounted onto the PD catheter and placed at the exit site at skin level is effective in preventing exit-site and other catheter-related infections, a prospective 12-month, multicenter, controlled study stratified by diabetes status was conducted. The study subjects were assessed by an extensive structured inventory, including a broad spectrum of control variables, such as age, body mass index (BMI), Staphylococcus aureus carrier status, catheter features, mode and quality of PD therapy, comorbidity, and psychosocial rehabilitation. Ten experienced German outpatient dialysis centers (seven adult, three pediatric) participated in the trial. All eligible patients (n=195) from the study area without catheter-related infections during the ascertainment period were included (incidental subjects undergoing PD therapy for at least 3 months). The main outcome measures were the occurrence of first exit-site infections (primary study end point), sinus tract/tunnel infection, and peritonitis. Ninety-seven patients were assigned to the silver ring and 98 patients to the control group. Baseline characteristics of age, sex, proportion of pediatric and incidental patients, S aureus carrier status, and other variables were similar in both groups. The incidence of infections in the silver ring group versus the control group was as follows: 23 of 97 versus 16 of 98 patients had exit-site infections, 12 of 97 versus 12 of 98 patients had sinus tract/tunnel infections, 16 of 97 versus 18 of 98 patients had peritonitis, respectively. Kaplan-Meier analysis for the probability of an infection-free interval showed no statistical difference (log-rank test) between the two groups. Displacement of the silver ring contributed to study termination in 6% of the study group patients, including two patients with catheter loss. Univariate analysis and multiple logistic regression identified younger age (<50 years), low serum albumin level (<35 g/L), number of previously placed PD catheters, short cuff-exit distance (<2 cm), and S aureus nasal carriage as risk factors for the development of exit-site infections. In conclusion, our study does not show any benefit of the silver ring in preventing catheter-related infections in PD patients. Thus, prevention of infection-related method failure in PD still has to rely on conventional antibiotic treatment strategies and less so on alternative methods.

International renal-cell-cancer study. VI. the role of medical and family history.

A number of medical conditions have been linked with renal-cell cancer, although the evidence is not consistent in every case. In a large international case-control study of renal-cell cancer, we examined, among other hypotheses, associations with a personal history of certain medical conditions and a family history of cancer of the kidney or thyroid. Relative risks (RR), adjusted for the effects of age, gender, body-mass index, tobacco smoking and study centre, were significantly increased by a history of kidney stones or thyroid or kidney disease. The RR were not altered by additional adjustment for hypertension, or when diagnoses were restricted to those made at least 5 or 10 years before 1987 (the usual "cut-off" date). The link with kidney injury is particularly likely to be affected by recall bias. Increased RR of borderline significance were found for kidney infection (RR, 1.2) and diabetes (RR, 1.4). Having one first-degree relative with kidney cancer was associated with a significantly increased risk of renal-cell cancer (RR, 1.6; 95% Cl, 1.1-2.4). Seven cases reported 2 first-degree relatives with kidney cancer. No controls had first-degree relatives with kidney cancer. None of our participants reported having von Hippel-Lindau disease. The data suggests that a few conditions of the kidney are strongly associated with renal-cell cancer and that heredity plays a role in a small proportion of cases.

International renal-cell cancer study. VIII. Role of diuretics, other anti-hypertensive medications and hypertension.

Risk of renal-cell cancer in relation to use of diuretics, other anti-hypertensive medications and hypertension was assessed in a multi-center, population-based, case-control study conducted in Australia, Denmark, Germany, Sweden and the United States, using a shared protocol and questionnaire. A total of 1,732 histologically confirmed cases and 2,309 controls, frequency-matched to cases by age and sex, were interviewed. The association between renal-cell cancer and the drugs was estimated by relative risks (RRs) and 95% confidence intervals (CIs). Risks were increased among users of diuretics and other anti-hypertensive medications. After adjustment for hypertension, risk for diuretics was reduced to unity, except among long-term (15+ years) users. Risk for use of non-diuretic anti-hypertensive drugs remained significantly elevated and increased further with duration of use. Overall risk was not enhanced when both classes of medications were used. Excess risk was not restricted to any specific type of diuretic or anti-hypertensive drug and no trend was observed with estimated lifetime consumption of any particular type of product. The RR for hypertension after adjustment for diuretics and other anti-hypertensive medications was 1.4 (95% CI = 1.2-1.7), although among non-users of any anti-hypertensive medications, there was little excess risk associated with a history of hypertension. Exclusion of drug use that first occurred within 5 years of cancer diagnosis or interview did not alter the associations. Our findings suggest small effects on renal-cell cancer risk associated with hypertension and use of diuretics and other anti-hypertensive medications. However, because of potential misclassifications of these highly correlated variables, it is difficult to distinguish the effect of treatment from its indication, hypertension.

International renal-cell cancer study. I. Tobacco use.

The relationship between renal-cell cancer (RCC) and tobacco use was investigated in an international, multicenter, population-based case-control study. Coordinated studies were conducted in Australia, Denmark, Germany, Sweden and the United States using a shared protocol and questionnaire. A total of 1,732 cases (1,050 men, 682 women) and 2,309 controls (1,429 men, 880 women) were interviewed for the study. No association was observed between risk and use of cigars, pipes or smokeless tobacco. A statistically significant association was observed for cigarette smoking, with current smokers having a 40% increase in risk [relative risk (RR) = 1.4, 95% confidence interval (CI) 1.2-1.7]. Risk increased with intensity (number of cigarettes) and duration (years smoked). Among current smokers the RR for pack-years rose from 1.1 (95% CI 0.8-1.5) for < 15.9 pack years to 2.0 (95% CI 1.6-2.7) for > 42 pack years (p for trend < 0.001). Long-term quitters (> 15 years) experienced a reduction in risk of about 15-25% relative to current smokers. Those who started smoking late (> 24 years of age) had about two-thirds the risk of those who started young (< or = 12 years of age). Overall, the findings of this pooled analysis confirm that cigarette smoking is a causal factor in the etiology of RCC.

International renal-cell cancer study. II. Analgesics.

There has been concern about the role of analgesics in the development of renal-cell cancer, although a few studies have reported moderately elevated risks with regular or long-term use. In a large international case-control study of renal-cell cancer we examined, among other hypotheses, the effect of phenacetin-containing and of other types of analgesics: paracetamol (acetaminophen), salicylates (mainly aspirin) and pyrazolones (e.g., antipyrine or phenazone). Relative risks, adjusted for the effects of age, sex, body-mass index, tobacco smoking and study centre, were not significantly increased with intake of phenacetin, either when lifetime consumption was categorized at the level of > or = 0.1 kg or when subjects were subdivided further by amount. Nor were paracetamol, salicylates or pyrazolones linked with renal-cell cancer. No consistently increasing risks with consumption level was found. The lack of association was not altered by restricting analgesic use to that which occurred 5 or 10 years before the defined "cut-off" date or when analysis was restricted to exclusive users of a particular type of analgesic. Neither was the risk influenced by the rate of consumption or whether the consumption had occurred at a young age. Our study provides clear evidence that aspirin is unrelated to renal-cell cancer risk, and our findings do not support the hypothesis that analgesics containing phenacetin or paracetamol increase the risk, although the number of "regular" users and the amount of these types of analgesic consumed were too small to confidently rule out a minor carcinogenic effect of phenacetin and paracetamol.

International renal-cell cancer study. III. Role of weight, height, physical activity, and use of amphetamines.

Although numerous studies have identified obesity or high relative weight as a risk factor for renal-cell cancer in women, the degree to which this effect is present in men remains unclear. A multicenter population-based case-control study concerning incident cases of histologically verified renal-cell cancer (n = 1,732) and age- and sex-matched controls (n = 2,309) was conducted in Australia, Denmark, Germany (2 centers), Sweden and the United States. Relative weight was estimated by the body mass index, and the association between this factor and other factors, such as height, physical activity and use of amphetamines, was measured by the relative risk estimated in logistic regression models. Body mass index was found to be a risk factor among women and, to a lesser extent, among men. A 3-fold increased risk (RR = 3.6, 95% CI = 2.3-5.7) was observed for women with a relative weight in the top 5% compared with those in the lowest quartile. Rate of weight change (estimated as weight change per annum in kilograms) appeared to be an independent risk factor among women but not among men. Physical activity and height were unrelated to risk of renal-cell cancer regardless of level of BMI, while use of amphetamines was associated with an increased risk among men, although no dose or duration effect was seen. Our findings verify the link between high relative weight and risk of renal-cell cancer, particularly among women. The mechanism that underlies this association is, however, still unclear, although the rate of weight change may play a role.

Evaluation of diagnostic criteria for analgesic nephropathy in patients with end-stage renal failure: results of the ANNE study. Analgesic Nephropathy Network of Europe.

It was found that in Belgium, renal imaging techniques, demonstrating a decreased renal mass of both kidneys combined with either bumpy contours or papillary calcifications, were the only methods to reliably diagnose analgesic nephropathy (AN) in patients with end-stage renal failure. However, these criteria were selected in an area with a high prevalence of this disease (15.6% of the dialysis population at December 1990). To evaluate the criteria selected to diagnose AN in populations with lower or unknown prevalences of AN, the Analgesic Nephropathy Network of Europe (ANNE) was formed, consisting of 23 dialysis units from 14 European countries and Brazil. During 1991-1992, 598 new patients with equivocal diagnosis of renal disease (excluding biopsy-proven glomerulonephritis, polycystic disease, diabetic nephropathy and other systemic diseases) and who began renal replacement therapy in the ANNE centres were evaluated by a short questionnaire and two renal imaging techniques: sonography and either tomography or computed tomography (CT) scan. A comparison of 82 abusers (daily use of analgesic mixtures for at least 5 years) and 495 controls corroborated the excellent diagnostic performance of the renal imaging techniques for AN. We recommend the use of these renal imaging criteria in all patients without a clear renal diagnosis in order to obtain a more reliable insight into the magnitude of the AN problem in different countries.

Vancomycin dosing in haemodialysis patients and Bayesian estimate of individual pharmacokinetic parameters.

A dose reduction of vancomycin to 1000 mg once a week usually is recommended for haemodialysis patients. Our modified dosing schedule consists of a loading dose of 1000 mg and a maintenance dose of 500 mg administered 3 times a week after haemodialysis. Different vancomycin regimens were retrospectively evaluated by therapeutic drug monitoring and bayesian parameter estimates in 39 dialysis patients. The mean (+/- SD) trough level in 7 patients receiving only the conventional dosage regimen was significantly lower than in 17 patients strictly treated by the modified schedule (7 +/- 4 versus 17 +/- 8 mg/L; p = 0.001). The corresponding peaks were low in both groups and no different (23 +/- 10 versus 27 +/- 12 mg/L). The one week average vancomycin clearance was significantly lower in the conventional dosage group compared to the modified dosage group (6 +/- 3 versus 10 +/- 3 ml/min; p = 0.001). High-flux dialysers were not used in the conventional dosage group but for 30 percent of the procedures in the modified dosage group, where the vancomycin one week average elimination half-life was 66 hours (+/- 18) and the volume of distribution 50 litres (+/- 5). As compared to the bayesian programme, NONMEM calculated comparable pharmacokinetic parameters but could be applied only in 5 cases with a sufficient number of concentration measurements. Ototoxicity occurred in 1 patient, whereas vancomycin treatment was judged as ineffective against infection in 5 of the 39 patients. Their troughs were below 15 mg/L.(ABSTRACT TRUNCATED AT 250 WORDS)