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Introduction: The achievement of erythropoiesis in hemodialysis (HD) patients is typically managed with erythropoiesis-stimulating-agents (ESA's) and intravenous iron (IV-iron). Using this treatment strategy, HD patients frequently show an elevated fraction of red blood cells (RBC) with hemoglobin (Hb) content per cell that is below the normal range, called hypochromic RBC. The low Hb content per RBC is the result of the clinical challenge of providing sufficient iron content to the bone marrow during erythropoiesis. Vitamin C supplements have been used to increase Hb levels in HD patients with refractory anemia, which supports the hypothesis that vitamin C mobilizes iron needed for Hb synthesis., Methods: We conducted a cross-sectional survey in 149 prevalent HD patients of the percent hypochromic RBC, defined as RBC with Hb < 300 ng/uL of packed RBC, in relation to plasma vitamin C levels. We also measured high-sensitivity CRP, (hs-CRP), iron, and ferritin levels. and calculated ESA dose., Findings: High plasma levels of vitamin C were negatively associated with hypochromic RBC (P < 0.003), and high ESA doses were positively associated (P < 0.001). There was no significant association of hs-CRP with percent hypochromic RBC., Discussion: This finding supports the hypothesis that vitamin C mobilizes iron stores, improves iron delivery to the bone marrow, and increase the fraction of RBC with normal Hb content. Further research is warranted on development of protocols for safe and effective use of supplemental vitamin C for management of renal anemia., (© 2016 International Society for Hemodialysis.)

Peritoneal dialysis (PD) invariably induces sclerotic changes in the peritoneal membrane. The impact of these changes on the well-being of PD patients has not been studied sufficiently. In a matched-pair analysis, the gastrointestinal life quality of patients with a history of PD was compared with end-stage renal disease patients who never performed PD, using a standardized questionnaire (gastrointestinal life-quality index [GLQI]). We identified all patients in our dialysis unit who underwent PD between 1989 and 2001 and who were alive in October 2001 (PD patients; n=53). Patients who were treated by hemodialysis (HD patients) were recruited as pairs. Hemodialysis and PD patients did not differ in gastrointestinal life quality (GLQI: HD 106.0+/-16.4 points; PD 104.0+/-16.7 points; p=0.70). Gastrointestinal life quality was neither correlated with the number of peritonitis episodes, nor with the duration of PD treatment. Peritoneal dialysis treatment is not associated with a long-term impairment of gastrointestinal life quality.

Hyperphosphatemia is a well recognized risk factor for cardiovascular mortality in dialysis patients. Despite advanced technology and regular and efficient dialysis treatment the prevalence of hyperphosphatemia is still high. The goal of normalization of serum phosphorus (iP) levels can only be reached by optimization of dialysis prescription in combination with individualized dietary and medical strategies. Due to the unique characteristics of intradialytic iP kinetics, dialysis treatment time and frequency are the most effective factors governing intradialytic iP removal. Although the combination of diffusive and convective removal by hemodiafiltration allows a further increase in iP mass removal, a neutral phosphorus balance without dietary restrictions and the use of phosphate binders has only be achieved by daily nocturnal hemodialysis. Strict dietary phosphate restriction bears the risk of inadequate protein intake and the development of protein/calorie malnutrition. Although phosphate binders (PB) can effectively lower serum iP levels into the normal range, this is rarely achieved in clinical practice probably due to inadequate relation of PB dose to dietary phosphorus intake. Developing methods to enable patients to self-adjust phosphate binder dose to individual meal phosphate content, similar to adjusting insulin dose to carbohydrate intake, may lead to further improvements in phosphate management.

Apart from its well-known functions in calcium homeostasis and parathyroid hormone regulation, 1,25-(OH)2D3 and its synthetic analogs are being increasingly recognized for their potent antiproliferative, pro-differentiative and immunomodulating activities. The effects of these drugs are exerted either via vitamin D receptor-dependent genomic, or cell-surface receptor-mediated, non-genomic pathways. Several vitamin D analogs with fewer hypercalcemic side effects have been developed for use in secondary hyperparathyroidism. These analogs may potentially improve treatment of autoimmune disorders and graft rejection, and in dialysis patients may open a new opportunity for amelioration of the chronic inflammatory status. It has recently been shown that hemodialysis (HD) patients treated with paricalcitol have lower total and cardiovascular mortality and morbidity rates and experience improved hospitalization outcomes compared with HD patients treated with calcitriol, suggesting a potential beneficial effect in chronic inflammation and the development of cardiovascular disease. Specific studies on the immunomodulating effects of vitamin D are needed in the HD population.

Mortality rates among hemodialysis patients differ greatly among the United States, Europe, and Japan and it has been hypothesized that this is mainly due to differences in practice patterns. Results from the international DOPPS study, however, indicate that differences in practice patterns among the United States, Japan, and Europe are small and not alone explanatory for the differences in mortality rates. Ethnic variability in predisposition to atherosclerotic cardiovascular disease in the general population may lead to significant differences in background cardiovascular mortality in the United States, Japan, and Europe. It is our hypothesis that cardiovascular mortality in dialysis patients is to a great extent dependent on cardiovascular background mortality of the general population. We are currently studying the relationship between all-cause and cardiovascular death rates in countries worldwide using the WHO database. Preliminary data from 35 countries show that all-cause and cardiovascular death rates differ significantly among regions, with Eastern European countries reporting four- to sevenfold higher death rates than Asian countries. A strong linear relationship between cardiovascular and all-cause death rates is observed among these countries. The next step of our study will be to compare country-specific cardiovascular death rates of dialysis populations with those of the respective general populations. Ethnic differences in cardiovascular morbidity and mortality may be explained by genetic variability based upon polymorphism of genes involved in the pathogenesis of atherosclerosis and myocardial infarction.