Andreas Kribben

Eculizumab for Atypical Hemolytic–Uremic Syndrome

To the Editor: Atypical hemolytic–uremic syndrome is a disease of uncontrolled complement activation associated with a high mortality rate, and most cases progress to end-stage renal disease.1 Abou...

Nephrogenic Systemic Fibrosis: Pathogenesis, Diagnosis, and Therapy

Nephrogenic systemic fibrosis (NSF) is a newly recognized disorder occurring exclusively in patients with renal failure. Exposure to gadolinium-based magnetic resonance (MR) contrast media has been associated with subsequent development of NSF. Nephrogenic systemic fibrosis is characterized by skin induration preferentially affecting the extremities. In addition, involvement of internal organs occurs, which leads ultimately to death. Skin biopsy is important for confirmation of the diagnosis. The main therapeutic goal is restoration of renal function. To reduce the risk of NSF, renal function must be determined before exposure to gadolinium-containing MR contrast agents. Gadolinium-based MR contrast media should be avoided in the presence of advanced renal failure with estimated glomerular filtration rate below 30 ml/min/1.73 m2, unless the diagnostic information is essential and not available with noncontrast magnetic resonance imaging techniques. The recommended dose of contrast agent should not be exceeded. In addition, a sufficient period of time for elimination of the contrast agent from the body should be allowed before readministration of the contrast agent.

Best supportive care and therapeutic plasma exchange with or without eculizumab in Shiga-toxin-producing E. coli O104:H4 induced haemolytic–uraemic syndrome: an analysis of the German STEC-HUS registry

BACKGROUND May 22nd marks the beginning of a Shiga-toxin-producing Escherichia coli (STEC) O104:H4 outbreak in Northern Germany. By its end on 27 July, it had claimed 53 deaths among 2987 STEC and 855 confirmed haemolytic-uraemic syndrome (HUS) cases. METHODS To describe short-term effectiveness of best supportive care (BSC), therapeutic plasma exchange (TPE) and TPE with eculizumab (TPE-Ecu) in 631 patients with suspected HUS treated in 84 hospitals in Germany, Sweden and the Netherlands using the web-based registry of the DGfN (online since 27 May). RESULTS Of 631 entries, 491 fulfilled the definition of HUS (median age 46 years; 71% females). The median (inter-quartile range) hospital stay was 22 (14-31) days. Two hundred and eighty-one (57%) patients underwent dialysis and 114 (23%) mechanical ventilation. Fifty-seven patients received BSC, 241 TPE and 193 TPE-Ecu. Treatment strategy was dependent on disease severity (laboratory signs of haemolysis, thrombocytopenia, peak creatinine level, need for dialysis, neurological symptoms, frequency of seizures) which was lower in BSC than in TPE and TPE-Ecu patients. At study endpoint (hospital discharge or death), the median creatinine was lower in BSC [1.1 mg/dL (0.9-1.3)] than in TPE [1.2 mg/dL (1.0-1.5), P < 0.05] and TPE-Ecu [1.4 mg/dL (1.0-2.2), P < 0.001], while need for dialysis was not different between BSC (0.0%, n = 0), TPE (3.7%; n = 9) and TPE-Ecu (4.7%, n = 9). Seizures were absent in BSC and rare in TPE (0.4%; n = 1) and TPE-Ecu (2.6%; n = 5) patients. Total hospital mortality in HUS patients was 4.1% (n = 20) and did not differ significantly between the TPE and TPE-Ecu groups. CONCLUSIONS Despite frequent renal impairment, advanced neurological disorders and severe respiratory failure, short-term outcome was better than expected when compared with previous reports. Within the limitations of a retrospective registry analysis, our data do not support the notion of a short-term benefit of Ecu in comparison to TPE alone in the treatment of STEC-HUS. A randomized trial comparing BSC, TPE and Ecu seems to be prudent and necessary prior to establishing new treatment guidelines for STEC-HUS.

Cystatin C: Efficacy as Screening Test for Reduced Glomerular Filtration Rate

Serum cystatin C, a cysteine proteinase inhibitor, has been proposed as a marker of glomerular filtration rate (GFR). Serum cystatin C, serum creatinine and creatinine clearance were measured in 226 patients with various nephropathies, covering the entire range of renal function, to evaluate the efficacy of cystatin C as a screening test to detect reduced creatinine clearance in comparison to creatinine. Subgroups of 53 patients with glomerular and 26 patients with tubular impairment were compared to assess whether cystatin C performed differently in either glomerular or tubular impairment. Cystatin C detected reduced creatinine clearance with higher sensitivity (97 vs. 83%), and higher negative predictive value (96 vs. 87%) compared to creatinine. In parallel, 95% sensitivity of cystatin C as derived from receiver-operating characteristic plot was significantly higher (p < 0.05). In the subgroups with glomerular or tubular impairment, cystatin C and creatinine did not significantly differ with regard to efficacy. Serum cystatin C is as efficacious as serum creatinine to detect reduced GFR as measured by creatinine clearance. The efficacy of cystatin C as a screening test may even be superior compared to creatinine. In addition, the efficacy of cystatin C is independent of either glomerular or tubular impairment.

Serum cystatin C : a superior marker of rapidly reduced glomerular filtration after uninephrectomy in kidney donors compared to creatinine

AIMS Acute renal failure (ARF), defined by a rapid decrease of glomerular filtration rate (GFR), is associated with high mortality. Early and accurate detection of decreasing GFR is critical to prevent the progression of ARF and to potentially improve its outcome. Serum creatinine, the conventional GFR marker, has major limitations. We prospectively evaluated whether serum cystatin C detected a rapid GFR decrease earlier and more accurately than serum creatinine. METHODS In ten patients undergoing nephrectomy for living related kidney transplantation, serum creatinine and cystatin C were determined daily. The decrease of GFR was quantitated preoperatively by creatinine clearance and MAG3 scintigraphy. The GFR decrease was defined by a 50-100% increase of cystatin C or creatinine from preoperative values. Ten patients without renal impairment served as controls. RESULTS Initially, patients had a creatinine clearance of 105 +/- 14 ml/min/1.73 m2. Due to nephrectomy, patients lost 45 +/- 3% of their renal function. Serum cystatin C significantly increased already one, serum creatinine two days after nephrectomy. Cystatin C demonstrated an increase by 50-100% 1.4 +/- 0.9 days earlier than creatinine (p = 0.009). Serum cystatin C performed well detecting the GFR decrease with higher diagnostic values compared to creatinine. This was indicated by a sensitivity of 50, 70 and 80% of cystatin C to detect the GFR decrease on the three days following nephrectomy. CONCLUSIONS Serum cystatin C detects rapid GFR decreases one to two days earlier than creatinine. Cystatin C is an early and accurate marker to detect rapid GFR decreases as in ARF.

Measurement of urinary cystatin C by particle-enhanced nephelometric immunoassay: precision, interferences, stability and reference range

Background: Urinary excretion of the low molecular weight protein cystatin C is a marker of renal disorders and a good predictor of the severity of acute tubular necrosis. We evaluated the measurement of urinary cystatin C and determined its reference range. Methods: Measurement of urinary cystatin C by particle-enhanced nephelometric immunoassay (PENIA) in 102 patients with various renal disorders and 133 healthy controls. We assessed the influence of pH and temperature, interferences on urinary cystatin C measurement, as well as cystatin C adsorption to plastic. Results: The upper reference value for urinary cystatin C was 0.28 mg/L, independent of age and gender. Accuracy and linearity (r 2=0.996) were excellent. Intra- and inter-assay precision were ≤4.8% and ≤5.2%, respectively. Albumin (≤160 g/L), bilirubin (≤500 µmol/L) and haemoglobin (≤210 µmol/L) did not show interferences. Urinary cystatin C was stable, at urine pH≥5, at -20°C and 4°C for 7 days, and at 20°C for 48 h. Freezing and thawing did not influence urinary cystatin C concentration. There was no adsorption of cystatin C to plastic. Conclusion: Urinary cystatin C measurement by PENIA is precise. High stability and no interference add to the practicability of urinary cystatin C as a routine biochemical test.

Reimbursement of Dialysis: A Comparison of Seven Countries

Reimbursement for chronic dialysis consumes a substantial portion of healthcare costs for a relatively small proportion of the total population. Each country has a unique reimbursement system that attempts to control rising costs. Thus, comparing the reimbursement systems between countries might be helpful to find solutions to minimize costs to society without jeopardizing quality of treatment and outcomes. We conducted a survey of seven countries to compare crude reimbursement for various dialysis modalities and evaluated additional factors, such as inclusion of drugs or physician payments in the reimbursement package, adjustment in rates for specific patient subgroups, and pay for performance therapeutic thresholds. The comparison examines the United States, the province of Ontario in Canada, and five European countries (Belgium, France, Germany, The Netherlands, and the United Kingdom). Important differences between countries exist, resulting in as much as a 3.3-fold difference between highest and lowest reimbursement rates for chronic hemodialysis. Differences persist even when our data were adjusted for per capita gross domestic product. Reimbursement for peritoneal dialysis is lower in most countries except Germany and the United States. The United Kingdom is the only country that has implemented an incentive if patients use an arteriovenous fistula. Although home hemodialysis (prolonged or daily dialysis) allows greater flexibility and better patient outcomes, reimbursement is only incentivized in The Netherlands. Unfortunately, it is not yet clear that such differences save money or improve quality of care. Future research should focus on directly testing both outcomes.

Repaglinide in the Management of New‐Onset Diabetes Mellitus After Renal Transplantation

The purpose of this study was to investigate the use of the short‐acting insulin secretion drug repaglinide in new‐onset diabetes mellitus (NODM) after renal transplantation. Twenty‐three Caucasian patients with NODM after renal transplantation were selected to receive repaglinide therapy and were followed for at least 6 months. A control group treated with rosiglitazone was chosen for comparison. Successful repaglinide treatment was defined as a significant improvement of blood glucose concentrations and HbA1c <7% in the absence of glucosuria and without the need for the addition of further anti‐diabetic agents. After 6 months of treatment with repaglinide, 14 of the 23 patients were successfully treated. Mean HbA1c decreased from 7.6 ± 0.6% to 5.8 ± 0.6% in 14 patients treated successfully. In nine patients, hyperglycemia persisted, and they were switched to insulin treatment (HbA1c 8.5 ± 2.9% at the beginning to 7.4 ± 2.2%). Mean serum creatinine levels, cyclosporine A and tacrolimus blood levels did not change significantly following institution of repaglinide therapy. The rate of successful treatment and the degree of HbA1c decrease were similar compared to rosiglitazone‐treated control patients. The data from our observational study indicate that repaglinide can be an effective treatment option in Caucasian patients with NODM after renal transplantation.

Which patients benefit from hemodialysis therapy in hepatorenal syndrome

Background and Aim:  Hepatorenal syndrome (HRS) occurs in patients with advanced liver cirrhosis and has a poor outcome. The aim of the present study was to investigate which patients with HRS are likely to benefit from hemodialysis.

Nephrotoxicity of iso-osmolar versus low-osmolar contrast media is equal in low risk patients.

BACKGROUND Contrast media-induced nephropathy (CIN) is an increasing cause of hospital-acquired acute kidney injury and leads to a significant increase in mortality. There is uncertainty whether the use of iso-osmolar contrast media as opposed to the use of low-osmolar contrast media would be associated with a lower incidence of CIN. Therefore, we compared the nephrotoxicity of isoosmotic contrast media iodixanol with the low-osmotic contrast media iopromid in patients receiving contrast media during coronary angiography. METHODS In this prospective double-blind study we examined 221 patients with normal renal function who received up to 1,000 ml of contrast media during coronary angiography, and compared the effect of iodixanol and iopromid on inducing contrast media nephropathy. Patients received 800 ml fluid orally before contrast media administration and 1,000 ml saline i.v. thereafter. Creatinine clearance, serum creatinine and urine-N-acetyl-beta-D-glucosaminidase (NAG) concentration was obtained 24 h before and 48 h after contrast media administration. Decrease of 20% of the creatinine clearance, increase of 25% of serum creatinine and increase of 20% of the urine concentration of NAG was defined as CIN. RESULTS Incidence of CIN assessed by decreased creatinine clearance was 22.2% in the iopromid group and 19.7% in the iodixanol group. CIN defined by increased serum creatinine was 6.9% in the iopromid group and 8.6% in the iodixanol group. The difference between these two groups was not significant. Subgroup analysis of the diabetic patients or the patients that received high dose of contrast media revealed no significant difference in the incidence of CIN between the two contrast media. CONCLUSION The iso-osmolar and the low-osmolar contrast media exhibited the same incidence of CIN in our study population. If fluid administration is sufficient, the selection of either iopromid or iodixanol has no impact on the risk of developing CIN in patients with normal renal function, even when they are diabetic or receive a high dose of more than 500 ml contrast media.