Background and objectives: Vitamin D deficiency is highly prevalent in chronic kidney disease. The aim of this study was to evaluate the effects of oral cholecalciferol supplementation on mineral metabolism, inflammation, and cardiac dimension parameters in long-term hemodialysis (HD) patients. Design, setting, participants, & measurements: This 1-year prospective study included 158 HD patients. Serum levels of 25-hydroxyvitamin D [25(OH)D], 1,25-dihydroxyvitamin D [1,25(OH)₂D], intact parathyroid hormone, and plasma brain natriuretic peptide as well as circulating bone metabolism and inflammation parameters were measured before and after supplementation. Baseline 25(OH)D and 1,25(OH)₂D levels were measured twice (end of winter and of summer, respectively). Therapy with paricalcitol, sevelamer, and darbepoietin was evaluated. Results: There was an increase in serum 25(OH)D and 1,25(OH)₂D levels after supplementation. Conversely, serum calcium, phosphorus, and intact parathyroid hormone were decreased. There was a reduction in the dosage and in the number of patients who were treated with paricalcitol and sevelamer. Darbepoietin use was also reduced, with no modification of hemoglobin values. Serum albumin increased and C-reactive protein decreased during the study. Brain natriuretic peptide levels and left ventricular mass index were significantly reduced at the end of the supplementation. Conclusions: Oral cholecalciferol supplementation in HD patients seems to be an easy and cost-effective therapeutic measure. It allows reduction of vitamin D deficiency, better control of mineral metabolism with less use of active vitamin D, attenuation of inflammation, reduced dosing of erythropoiesis-stimulating agents, and possibly improvement of cardiac dysfunction.

Background: Hypomagnesaemia is a cardiovascular (CV) risk factor in the general population. The aim of this study was to evaluate the relationship between pre-dialysis magnesium (Mg) and CV risk markers, [including pulse pressure (PP), left ventricular mass index (LVMI) and vascular calcifications (VC)], and mortality in haemodialysis (HD) patients. Methods: We performed a 48-month prospective study in 206 patients under pre-dilution haemodiafiltration with a dialysate Mg concentration of 1 mmol/l. Results: Lower Mg concentrations were predictors of an increased PP (≥65 mm Hg) (p = 0.002) and LVMI (≥140 g/m2) (p = 0.03) and of a higher VC score (≥3) (p = 0.01). Patients with Mg <1.15 mmol/l had a lower survival at the end of the study (p = 0.01). Serum Mg <1.15 mmol/l was an independent predictor of all-cause (p = 0.01) and CV mortality (p = 0.02) when adjusted for multiple CV risk factors. Conclusions: Lower Mg levels seem to be associated with increased CV risk markers, like PP, LVMI and VC, and with higher mortality in HD patients.

Albuminuria was widely considered as the first clinical sign of diabetic kidney disease (DKD), which is why it has traditionally been used as a screening test for DKD. However, increasing evidence has shown that a significant number of type 2 diabetes mellitus (DM) patients have a decreased glomerular filtration rate (GFR) without significant albuminuria, known as non-albuminuric DKD (NA-DKD). The aim of this study was to determine the prevalence and the demographic and clinical characteristics of patients with NA-DKD. This was a 1-year retrospective study that included 146 type 2 diabetic patients with GFR<75mL/min followed-up in a diabetes outpatient department. Patients were divided into two groups according to their ACR status - NA-DKD and albuminuric DKD (A-DKD). Of the 146 patients included in the study, 53.4% had A-DKD and 46.6% had NA-DKD. According to the multivariable analysis performed, patients with NA-DKD tended to be older (p=0.021), female (p=0.045) and with a lower GFR (p=0.004) than A-DKD patients. There was no difference between the groups in terms of body mass index, metabolic control of DM, duration of DM diagnosis and prevalence of metabolic syndrome. The majority of patients with DKD had albuminuria, but a significant proportion had a non-albuminuric phenotype (46.6% in this population). These patients exhibit distinct clinical features that could have screening, therapeutic and prognosis implications.

Magnesium and vitamin D play important roles in most cells of the body. These nutrients act in a coordinated fashion to maintain physiologic functions of various organs, and their abnormal balance could adversely affect these functions. Therefore, deficient states of both nutrients may lead to several chronic medical conditions and increased cardiovascular and all-cause mortality. Chronic kidney disease (CKD) patients have altered metabolism of both magnesium and vitamin D. Some studies indicate that magnesium could have a role in the synthesis and metabolism of vitamin D, and that magnesium supplementation substantially reversed the resistance to vitamin D treatment in some clinical situations. Recent observational studies also found that magnesium intake significantly interacted with vitamin D status and, particularly with the risk of cardiovascular mortality. It is therefore essential to ensure adequate levels of magnesium to obtain the optimal benefits of vitamin D supplementation in CKD patients. In this review, we discuss magnesium physiology, magnesium and vitamin D metabolism in CKD, potential metabolic interactions between magnesium and vitamin D and its clinical relevance, as well as the possible role of magnesium supplementation to assure adequate vitamin D levels.

Incremental peritoneal dialysis (IPD) is a strategy of RRT that is based on the prescription of a lower dose rather than the standard full dose of peritoneal dialysis (PD). The clearance goals are achieved through the combination of residual kidney function (RKF) and peritoneal clearance. The dialysis prescription should be increased as the RKF declines. IPD has been associated with clinical, economic, and environmental advantages. We emphasize possible better quality of life, fewer mechanical symptoms, lower costs, slight adverse metabolic effects, and less plastic waste and water consumption. The potential benefits for RKF preservation and the lower risk of peritonitis have also been discussed. There are some concerns regarding this strategy, such as inadequate clearance of uremic toxins and/or severe electrolyte disturbances due to undetected loss of RKF, lower clearance of medium-sized molecules (such as β-2-microglobulin) which mostly depends on the total PD dwell time, and patients' reluctance to dose adjustments. Current clinical evidence is based on moderate-quality to low-quality studies and suggests that the outcomes of IPD will be at least identical to those of full dose. This review aims to define IDP, discuss strategies for prescription, and review its advantages and disadvantages according to the current evidence.