BackgroundHigh Cut-Off (HCO) dialysis membranes efficiently reduce serum free light chain (FLC) concentrations and may improve renal recovery and survival from multiple myeloma (MM) associated renal failure with cast nephropathy. However, clinical trials comparing dialysis with HCO versus conventional filters are lacking. The aim of this study was to assess clinical outcomes and economic impact of HCO dialyzers compared to conventional hemodialysis membranes in cast nephropathy.MethodsMulticenter retrospective analysis of 19 patients treated for renal failure from FLC associated cast nephropathy with standard induction chemotherapy (bortezomib/dexamethasone). We compared hemodialysis treatment with High Cut-Off (n = 12) versus conventional dialyzers (n = 7). Primary endpoint was survival; secondary endpoints were renal recovery, renal function and treatment costs.ResultsAt 12 months, patient survival was 25% in the HCO group versus 0% in controls (p = NS). A tendency towards faster renal recovery (p = 0.066) and better renal function at 3, 6 and 12 months (p = 0.109) after diagnosis of MM was noted in the HCO group. Complete renal response rate was achieved in 10.5 and 0% of HCO and control patients, respectively, partial renal response in 15.8 and 5.3%, and minor renal response in 26.3 and 15.8%, respectively. Both patient survival and renal recovery were significantly correlated with the extent of free light chain (FLC) reduction in serum. Median treatment costs were CHF 230’000 and 223’000 (p = NS) in the HCO and control group, respectively.ConclusionsHemodialysis treatment with HCO membranes for cast nephropathy tended towards better survival as well as faster and better recovery of renal function versus conventional dialyzers. Moreover, total medical costs were comparable between groups. In the absence of results from randomized prospective trials on this topic, the use of HCO dialyzers in patients with renal failure from cast nephropathy may be recommended. Prospective randomized trials are required.

BackgroundCreatinine clearance (CrCl) based on 24 h urine collection is an established method to determine glomerular filtration rate (GFR). However, its measurement is cumbersome and the results are frequently inaccurate. The aim of this study was to develop an alternative method to predict CrCl and urinary protein excretion based on plasma creatinine and the quantification of muscle mass through bioimpedance analysis (BIA).MethodsIn 91 individuals with normal and impaired renal function CrCl was measured from 24 h urine excretion and plasma creatinine concentration. A model to predict 24 h-creatininuria was developed from various measurements assessing muscle mass such as body cell mass (BCM) and fat free mass (FFM) obtained by BIA, skinfold caliper and other techniques (training group, N = 60). Multivariate regression analysis was performed to predict 24 h-creatininuria and to calculate CrCl. A validation group (N = 31) served to compare predicted and measured CrCl.ResultsOverall (accuracy, bias, precision, correlation) the new BIA based prediction model performed substantially better compared with measured CrCl (P15 = 87 %, bias = 0, IQR of differences = 7.9 mL/min/1.73 m2, R = 0.972) versus established estimation formulas such as the 4vMDRD (P15 = 26 %, bias = -8.3 mL/min/1.73 m2, IQR = 13.7 mL/min/1.73 m2, R = 0.935), CKD-EPI (P15 = 29 %, bias = -7.0 mL/min/1.73 m2, IQR = 12.1 mL/min/1.73 m2, R = 0.932, Cockcroft-Gault equations (P15 = 55 %, bias = -4.4 mL/min/1.73 m2, IQR = 9.0 mL/min/1.73 m2, R = 0.920). The superiority of the new method over established prediction formulas was most obvious in a subgroup of individuals with BMI > 30 kg/m2 and in a subgroup with CrCl > 60 mL/min/1.73 m2. Moreover, 24 h urinary protein excretion could be estimated accurately by normalization with 24 h-creatininuria derived from BIA based BCM.ConclusionPrediction of CrCl based on estimated urinary creatinine excretion determined from measurement of BCM by BIA technique is both accurate and convenient to quantify renal function in normal and diseased states. This new method may become particularly helpful for the evaluation of patients with borderline renal insufficiency and/or with abnormal body composition.

Tumour lysis syndrome (TLS) is a constellation of meta- bolic complications due to the rapid destruction of malignant cells, causing renal, cardiac or cerebral dysfunction. Electrolyte abnormalities include hyperuricaemia, hyperphosphataemia, hyperkalaemia and hypocalcaemia. TLS-induced renal failure is mainly caused by uric acid and calcium phosphate crystal deposition and usually develops following cytotoxic chemotherapy. Here, we present a case of spontaneous TLS in a patient with chronic myelomonocytic leukaemia (CMML) with massive uric acid stone and crystal formation and rapidly worsening renal failure. Autopsy revealed underlying tumourous kidney infiltration. Risk factors for occurrence of TLS and current therapeutic management are discussed.

Conversion to extended darbepoetin-alpha dosing intervals of up to QM, with maintenance of initial Hb concentrations, was successful for the majority of stable dialysis patients.

Hypocalcaemia often occurs in patients after parathyroidectomy (PTX) due to hypoparathyroidism and/or hungry bone syndrome. To avoid hypocalcaemia, patients are substituted with large doses of calcium and vitamin D. Here, we present four patients, who developed acute renal failure with hypercalcaemia and/or histologically confirmed nephrocalcinosis after PTX due to oversubstitution with vitamin D analogues and calcium. As a consequence, serum and urinary calcium should be closely monitored after PTX, and calcium and vitamin D substitution should be continuously adapted to avoid not only hypocalcaemia but also nephrocalcinosis and hypercalcaemic renal failure.