Jadranka Buturovic Ponikvar

Comparison of the Pharmacological Effects of Paricalcitol Versus Calcitriol on Secondary Hyperparathyroidism in the Dialysis Population.

Management of secondary hyperparathyroidism (SHPT) in dialysis population includes the use of active vitamin D forms, among which paricalcitol was shown to be more effective at reducing parathyroid hormone (PTH) concentrations. A prospective randomized study comparing the effectiveness and safety of peroral paricalcitol and calcitriol in suppressing PTH concentrations in 20 hemodialysis patients was performed comparing the influence of agents on PTH suppression, calcium (Ca) and phosphate (P) level and calcium‐phosphorus product (C×P). The study was performed in an “intent to treat” manner with primary end point in reduction of PTH level in the target area of 150 > PTH < 300 ng/L after 3 months. At the time point 3 months after therapy induction paricalcitol and calcitriol were equally efficient at correcting PTH levels, with paricalcitol showing significantly less calcemic effect than calcitriol.

Phosphate or Phosphorus Removal During Nocturnal Hemodialysis: Are We Using Correct Terms?

Dear Editor, Last year we published an article regarding phosphate removal during nocturnal hemodialysis (1). It has recently been kindly brought to our attention in a personal correspondence from Professor John T. Daugirdas, that our measured results differ significantly from the results of a kineticmodel he has developed (2), and that we might have made a calculation error. We have therefore looked at the results and calculations again and found that while the results “per se” are correct, they can still be misunderstood and misleading, and therefore we wish to publish a correction. The main issue is the way phosphate intake and removal is reported in the literature. While often in the literature on phosphate in chronic kidney disease and dialysis (3,4) the term “phosphate” (PO4 , the form in which “phosphorus”[P] occurs in humans) is used, what is actually reported is the amount of phosphorus. While there is no difference when reported in SI units (mmol), the difference is threefold when phosphorus and phosphate are expressed in conventional units (mg). Although both terms are often considered synonymous in the literature, the usage of the term phosphate, when actually referring to phosphorus, is incorrect from the chemical point of view and misleading (5). This inconsistency is also the reason our data can be misunderstood. In our article we have reported a mean removal of phosphate to be 5195 ± 1898 mg per dialysis procedure (54.7 mmol). This is “per se” correct, as we were referring to the phosphate, meaning literally the PO4 ion. We would kindly ask for a correction, as a more conventional way would be to express it as phosphorus, which is then 1696 ± 575 mg per procedure for the whole group, 1510 ± 507 mg per procedure for on-line HDF and 2253 ± 453 mg per procedure for high-flux HD, P = 0.21. Although the difference is threefold and we have cited amounts expressed as phosphorus in the discussion, the content of the discussion nevertheless remains valid. We would like to thank Professor Daugirdas for bringing this issue to our attention.

Citrate Anticoagulation in Tandem Membrane Plasma-Exchange or Immunoadsorption and Hemodialysis in Patients With Immunological Diseases and Dialysis-Dependence.

In 1996 we performed tandem membrane plasma exchange‐hemodialysis in a 3‐year‐old girl and tandem immunoadsorption‐hemodialysis with citrate as the only anticoagulant in a patient with Goodpastures syndrome. In the present study, we evaluated the feasibility, efficacy and safety of 24 tandem plasma exchange/immunoadsorption hemodialysis procedures in four different circuit setups with citrate as the only anticoagulant. In two setups, the tandem procedures were connected in series (plasma exchange hemodialysis and immunoadsorption hemodialysis), while in the other two setups they were in parallel (plasma exchange hemodialysis with independent blood circuits and plasma exchange hemodialysis with independent arterial blood lines, but with a common return line). All tandem procedures were feasible, efficient and safe. No serious side‐effects were recorded. The most elegant setup was the procedure with independent, parallel blood circuits. However, serial tandem procedures provided for the elimination of citrate and normalization of electrolytes before blood was returned to the patient.