Survival predictability of time-varying indicators of bone disease in maintenance hemodialysis patients

Management of phosphorus load in CKD patients

Disturbances in mineral and bone metabolism play a critical role in the pathogenesis of cardiovascular complications in patients with chronic kidney disease (CKD). The term "renal osteodystrophy" has recently been replaced with "CKD-mineral and bone disorder (CKD-MBD)", which includes vascular calcification as well as bone abnormalities. In Japan, proportions of the aged and long-term dialysis patients are increasing which makes management of vascular calcification and parathyroid function increasingly more important. There are three main strategies to manage phosphate load: phosphorus dietary restriction, administration of phosphate binder and to ensure in the CKD 5D setting, an adequate dialysis.

Association between the Achievement of Target Range CKD-MBD Markers and Mortality in Prevalent Hemodialysis Patients in Taiwan by Using the Kidney Disease: Improving Global Outcomes Clinical Guidelines

Background. This study evaluated the association between achieving target chronic kidney disease-mineral and bone disorder (CKD-MBD) marker levels and mortality in Taiwanese hemodialysis (HD) patients. Target levels were based on the Kidney Disease: Improving Global Outcomes (KDIGO) guidelines. Methods. We performed a retrospective medical record review of 1126 HD patients between 2009 and 2013. A logistic regression model was used to evaluate the relationship between achieving target marker levels and the risk for all-cause and cardiovascular (CV) mortality. Reference target ranges were 7.9 ≤ calcium (Ca) ≤ 9.9 mg/dL, 2.4 ≤ phosphate (P) ≤ 4.7 mg/dL, and 144 ≤ intact parathyroid hormone (iPTH) ≤ 648 pg/mL. Results. Achievement of target P levels was associated with a lower risk for all-cause mortality compared to achievement of either target Ca or iPTH levels. Achieving target P + iPTH levels (OR 1.32) was associated with a lower odds ratio for all-cause mortality compared to achieving target Ca + P (OR 1.66) and Ca + iPTH (OR 1.43) levels. Similar trends were observed for CV mortality risk. Conclusions. The present study demonstrated that achieving serum P levels within the KDIGO target range is the most important factor for lowering mortality in HD patients.

Pin1 and secondary hyperparathyroidism of chronic kidney disease: gene polymorphisms and protein levels

BACKGROUND

Peptidyl-prolyl cis/trans isomerase NIMA-interacting 1 (Pin1) is a key regulator of PTH mRNA stability. Secondary hyperparathyroidism (SHPT), which is characterized by elevated serum PTH levels, is a common complication of CKD. We investigated the possible associations between CKD with SHPT (CKD SHPT) and single-nucleotide polymorphisms of the Pin1 gene and compared the levels of the Pin1 protein in the CKD SHPT patients with those of the controls.

METHODS

The study group included 251 CKD SHPT patients and 61 controls. One putative functional SNP (single nucleotide polymorphism) in the Pin1 promoter (rs2233679C > T: c.-667C > T) is the main object. Genotyping was performed on purified DNA using polymerase chain reaction-restriction (PCR) and restriction fragment length polymorphisms (RFLP). The levels of Pin1 were measured in serum using an enzyme-linked immunosorbent assay.

RESULTS

Genotyping showed that CT + TT in the Pin1 promoter was significantly more common in the CKD SHPT group than in the control group (p<.05). The correlation analysis demonstrated that a significant difference in the C to T transition in the Pin1 promoter contributed to CKD SHPT (χ²=12.47, p<.05; Odds ratios (OR) = 1.26, 95% confidence (CI) intervals =1.06-1.49). The multivariate logistic regression analysis reported that the OR and 95%CI were 12.693 and 2.029-75.819 (p<.05), respectively, in the Pin1 gene promoter -667T variant genotypes (CT + TT) after adjusting for other factors, and those values in Pin1 were 0.310 and 0.122-0.792 (p<.05).

CONCLUSION

The -667T genetic variants in the Pin1 promoter contribute to an increased risk of CKD SHPT and may be biomarkers of susceptibility to CKD SHPT.

The role of phosphate in kidney disease

The importance of phosphate homeostasis in chronic kidney disease (CKD) has been recognized for decades, but novel insights - which are frequently relevant to everyday clinical practice - continue to emerge. Epidemiological data consistently indicate an association between hyperphosphataemia and poor clinical outcomes. Moreover, compelling evidence suggests direct toxicity of increased phosphate concentrations. Importantly, serum phosphate concentration has a circadian rhythm that must be considered when interpreting patient phosphate levels. Detailed understanding of dietary sources of phosphate, including food additives, can enable phosphate restriction without risking protein malnutrition. Dietary counselling provides an often underestimated opportunity to target the increasing exposure to dietary phosphate of both the general population and patients with CKD. In patients with secondary hyperparathyroidism, bone can be an important source of serum phosphate, and adequate appreciation of this fact should impact treatment. Dietary and pharmotherapeutic interventions are efficacious strategies to lower phosphate intake and serum concentration. However, strong evidence that targeting serum phosphate improves patient outcomes is currently lacking. Future studies are, therefore, required to investigate the effects of modern dietary and pharmacological interventions on clinically meaningful end points.

Analysis of the kinetics of the parathyroid hormone, and of associated patient outcomes, in a cohort of haemodialysis patients

Background

Observational studies have recently associated a decrease in serum parathyroid hormone (PTH) level with a higher rate of mortality among hemodialysis (HD) patients. Decreases in PTH level can result from medical intervention (MPD) and surgical parathyroidectomy (PTX), or may occur spontaneously, usually associated with an underlying malnutrition-inflammation syndrome (SPD). The aim of our study was to prospectively identify the incidence of decreases in PTH level in a cohort of HD patients and the frequency distribution of the different causes (MPD, PTX and SPD), as well as to evaluate the survival outcomes for each PTH group (MPD, PTX and SPD) compared to patients who did not experience a PTH decrease over the first 36 months of the study (NPD).

Methods

The 197 patients receiving HD at our center in January 2010, and meeting our eligibility criteria, were enrolled in our prospective study, and were observed for a period of 60 months. A decrease in PTH level >50 % between two successive PTH measurements obtained within an interval <3 months was defined as a significant event. MPD referred to a decrease in PTH due to an increased oral calcium intake, increased dialysate calcium concentration (DCC), increased alfacalcidol use, or use of cinacalcet therapy. A surgical 7/8 PTX was performed in young patients or in patients in whom cinacalcet therapy failed. SPD referred to a decrease in PTH related to a medical or surgical event. Baseline characteristics among patients in each group (MPD, PTX, SPD, and NPD) were evaluated using Fisher’s exact test. The 60-month survival was evaluated using Kaplan-Meier and Cox multivariable proportional hazards models. Univariate and multivariate Cox analyzes were used identify variables with mortality. The relative risk of mortality was expressed as a hazard ratio (HR).

Results

The distribution of the 197 patients forming our four study groups was 34 % in the NPD group, 35 % in the SPD group, 25 % in the MSD group and 6 % in the PTX group. Among patients in the SPD group, the main acute comorbid conditions were peripheral vascular and cardiac complications, sepsis, fractures, and cancers with an increase in serum CRP level (from 14.3 ± 18 to 132 ± 90 mg/L) and a decrease in serum albumin (from 33 ± 4.5 to 28.6 ± 4 g/L). In the MPD group, the main therapeutic change was an increase in DCC, either independently or in association with cinacalcet therapy. The median survival rate among patients was 10 months for SPD, compared to 22 months among patients in the MPD group (p < 0.001). Using multivariable Cox model and taking the NPD group as reference, the risk of mortality was lower among patients in the MPD group (HR, 0.42[0.2-0.87] p = 0.01), with survival being comparable for the SPD and NPD groups (HR, 1.3 [0.75-2.2]). No mortality was observed in the PTX group.

Conclusion

The poor outcomes associated with SPD, related to acute comorbid conditions, should not lead to undertreat secondary hyperparathyroidism whose appropriate medical or surgical therapies are associated with better outcomes.

Chronic Kidney Disease-Mineral Bone Disorder in the Elderly Peritoneal Dialysis Patient

PURPOSE

The purpose of this paper was to review the literature concerning the treatment of chronic kidney disease-mineral bone disorder (CKD-MBD) in the elderly peritoneal dialysis (PD) patient.

RESULTS

Chronic kidney disease-mineral bone disorder is a major problem in the elderly PD patient, with its associated increased fracture risk, vascular calcification, and accelerated mortality fracture risk. Peritoneal dialysis, however, bears a lower risk than hemodialysis (HD). The approach to CKD-MBD prophylaxis and treatment in the elderly PD patient is similar to other CKD patients, with some important differences. Avoidance of hypercalcemia, hyperphosphatemia, and hyperparathyroidism is important, as in other CKD groups, and is generally easier to attain. Calcium-free phosphate binders are recommended for normocalcemic and hypercalcemic patients. Normalization of vitamin D levels to > 75 nmol/L (> 30 pg/L) and low-dose active vitamin D therapy is recommended for all patients. Hyperparathryoidism is to be avoided by using active vitamin D and cinacalcet. Particular attention should be paid to treating protein malnutrition. Fracture prophylaxis (exercise, use of walkers, dwelling modifications) are important. Hypomagnesemia is common in PD and can be treated with magnesium supplements. Vitamin K deficiency is also common and has been identified as a cause of vascular calcification. Accordingly, warfarin treatment for this age group is problematic.

CONCLUSION

While treatment principles are similar to other dialysis patient groups, physicians should be aware of the special problems of the elderly group.

Low serum intact parathyroid hormone level is an independent risk factor for overall mortality and major adverse cardiac and cerebrovascular events in incident dialysis patients

Abnormal bone dynamics is a major risk factor for cardiovascular disease in patients with chronic kidney disease. The level of serum intact parathyroid hormone (iPTH) is widely used as a bone dynamic marker. We investigated the effect of the mean level of serum iPTH on overall mortality and cardiovascular outcomes in incident dialysis patients.

PURPOSE

Chronic kidney disease-mineral bone disorder (CKD-MBD) is a major risk factor for cardiovascular disease (CVD) in patients with end-stage renal disease (ESRD). CKD-MBD is classified as low- or high-turnover bone disease according to the bone dynamics; both are related to vascular calcification in ESRD. To evaluate the prognostic value of abnormal serum parathyroid hormone (PTH) levels on ESRD patients, we investigated the effects of time-averaged serum intact PTH (TA-iPTH) levels on overall mortality and major adverse cardiac and cerebrovascular events (MACCEs) in incident dialysis patients.

METHODS

Four hundred thirteen patients who started dialysis between January 2009 and September 2013 at Yonsei University Health System were enrolled. The patients were divided into three groups according to TA-iPTH levels during the 12 months after the initiation of dialysis: group 1, <65 pg/ml; group 2, 65-300 pg/ml; and group 3, >300 pg/ml. Cox regression analyses were performed to determine the prognostic value of TA-iPTH for overall mortality and MACCEs.

RESULTS

The mean age of the patients was 57 ± 15 years, and 222 patients (54 %) were men. During the median follow-up of 40.8 ± 29.3 months, 49 patients (12 %) died, and MACCEs occurred in 55 patients (13 %). The multivariate Cox regression analyses demonstrated that a low TA-iPTH level was an independent risk factor for both overall mortality (group 2 as reference; group 1: hazard ratio (HR) = 2.06, 95 % confidence interval (CI) = 1.11-3.83, P = 0.023) and MACCEs (HR = 1.82, 95 % CI = 1.04-3.20, P = 0.036) in incident dialysis patients after adjustment for confounding factors.

CONCLUSION

Low serum TA-iPTH is a useful clinical marker of both overall mortality and MACCEs in patients undergoing incident dialysis, mediated by vascular calcification.

The role of bone biopsy for the diagnosis of renal osteodystrophy: a short overview and future perspectives

Chronic kidney disease (CKD) patients present specific bone and mineral metabolism disturbances, which account for important morbidity and mortality. The term renal osteodystrophy, classically used for the nomination of CKD-associated bone disorder, has been limited to the histologic description of bone lesions, requiring the use of bone biopsy. Biochemical markers and imaging tools do not adequately predict the complex bone changes that are observed in renal osteodystrophy. Parathyroid hormone, which is a universally used biomarker of bone turnover in clinical practice, lacks specificity and sensitivity. Therefore, tetracycline double-labelled transiliac bone biopsy, with bone histology and histomorphometric evaluation, remains the best clinical tool to discriminate bone turnover and to evaluate the other dimensions of renal osteodystrophy. This review will focus on the value of classic bone histomorphometric analysis of trabecular bone in CKD patients and unfold new perspectives of this diagnostic tool, including cortical bone evaluation and bone tissue immunohistochemistry.

Modified Nutritional Recommendations to Improve Dietary Patterns and Outcomes in Hemodialysis Patients

The renal diet has traditionally been regarded as one of the most complex medical nutrition therapies to teach, understand, and implement. Specifically, patients are instructed to limit fruits, vegetables, nuts, legumes, dairy, and whole grains because of both phosphorus and potassium concerns. Furthermore, hemodialysis patients are often encouraged to decrease fluid intake to control interdialytic weight gain. These restrictions can result in frustration, lack of autonomy, and the perception that there is nothing left to eat. It is possible that the traditional renal diet may be liberalized, with a focus on whole foods low in sodium and phosphorus additives, to afford patients greater choices and ultimately improved outcomes. Therefore, the objective of this review is to concisely assess the evidence in support of a renal diet focused primarily on reducing the intake of sodium and inorganic phosphorus. Finally, the limited evidence for restrictions on dietary potassium intake is summarized.

Hyperparathyroidism of Renal Disease

Renal hyperparathyroidism (rHPT) is a common complication of chronic kidney disease characterized by elevated parathyroid hormone levels secondary to derangements in the homeostasis of calcium, phosphate, and vitamin D. Patients with rHPT experience increased rates of cardiovascular problems and bone disease. The Kidney Disease: Improving Global Outcomes guidelines recommend that screening and management of rHPT be initiated for all patients with chronic kidney disease stage 3 (estimated glomerular filtration rate, < 60 mL/min/1.73 m(2)). Since the 1990s, improving medical management with vitamin D analogs, phosphate binders, and calcimimetic drugs has expanded the treatment options for patients with rHPT, but some patients still require a parathyroidectomy to mitigate the sequelae of this challenging disease.

Phosphate Binding Therapy to Lower Serum Fibroblast-Growth-Factor-23 Concentrations in Chronic Kidney Disease: Rationale and Study Design of the Sevelamer on FGF23 Trial (SoFT)

BACKGROUND

Increased levels of phosphate and fibroblast growth factor-23 (FGF23) are strong predictors of cardiovascular morbidity and mortality in patients with chronic kidney disease (CKD). Preliminary data suggest that interventions lowering gastro-intestinal phosphate uptake lowers serum FGF23 concentrations and improves cardiovascular risk and subsequently survival. However, data are lacking about the magnitude of effects, the effect in different stages of CKD and whether there is a dose-effect relationship.

METHODS

Therefore, the Sevelamer on FGF23 Trial (SoFT) is designed as an open-label, single-arm, clinical pilot study aiming to demonstrate the feasibility of a phosphate-restricted diet in combination with the phosphate binder sevelamer to induce an effective, predictable and sustained decrease in FGF23 level in patients with an estimated glomerular filtration rate (eGFR) of 15-90 or >90 ml/min/1.73 m2 with proteinuria >1.0 g in 24 h urine collection, despite optimally dosed RAAS blockade, without inducing hypophosphatemia using a forced uptitration treatment regimen aimed at restricting phosphate uptake.

Dose-response efficacy and safety of PA21 in Japanese hemodialysis patients with hyperphosphatemia: a randomized, placebo-controlled, double-blind, Phase II study

Background

Hyperphosphatemia is common in chronic kidney disease (CKD) and associated with mortality and morbidity. We aimed to evaluate the dose-dependent efficacy and safety of PA21 (sucroferric oxyhydroxide), an iron-based phosphate binder, in Japanese hemodialysis patients with hyperphosphatemia.

Methods

In this double-blind, multicenter, Phase II study, 183 patients were randomized to placebo or PA21 at doses of 250, 500, 750, or 1000 mg (based on iron content) three times/day for 6 weeks. The primary efficacy endpoint was the mean change in serum phosphorus levels from baseline to end of treatment in each group. Adverse reactions were evaluated.

Results

The change in serum phosphorus level was significantly greater in each PA21 group than in the placebo group (analysis of covariance: P < 0.001 for all groups). A dose-dependent change in serum phosphorus levels was observed in the PA21 groups. A notable decrease in mean serum phosphorus levels to the target level of ≤6 mg/dL was shown starting at Week 1 in all PA21 groups. The cumulative achievement rates for target serum phosphorus level at the end of treatment were generally >80 % in all PA21 groups. The major adverse reaction reported was diarrhea; however, most cases were mild.

Conclusions

PA21 was an effective and safe treatment that decreased serum phosphorus levels starting at 1 week of treatment when administered as one 250-mg tablet three times/day. PA21 demonstrated a dose-dependent phosphorus lowering effect up to 3000 mg/day. PA21 may be a new treatment alternative with relatively low pill burden for Japanese hemodialysis patients with hyperphosphatemia.

Preclinical studies of VS-505: a non-absorbable highly effective phosphate binder

BACKGROUND AND PURPOSE

Phosphate imbalance is often present in chronic kidney disease (CKD), and it contributes to a higher cardiovascular mortality rate. A phosphate binder is typically part of a treatment strategy for controlling phosphate imbalance. However, safety concerns and low compliance are two well-recognized disadvantages of on-market phosphate binders. This report describes the preclinical studies of VS-505, a non-absorbable, calcium- and aluminum-free, plant-derived polymer currently being evaluated in haemodialysis patients in Australia.

EXPERIMENTAL APPROACH

Normal Sprague Dawley (SD) rats or uraemic SD rats induced by 5/6 nephrectomy fed a high-phosphate diet were treated with VS-505 or sevelamer (0.05-10% in food) for 5 and 28 days respectively.

KEY RESULTS

Urinary and serum phosphate levels were significantly elevated in untreated rats, and were decreased by VS-505 and sevelamer. VS-505 increased faecal phosphate levels in a dose-dependent manner. High-phosphate diet also caused an increase in serum FGF-23 and parathyroid hormone in nephrectomized (NX) rats, effects prevented by VS-505 or sevelamer. Significant aortic calcification was observed in NX rats treated with 5% sevelamer, whereas VS-505 at all doses tested did not show effects. VS-505 had no effects on small intestine histomorphology and intestinal sodium-dependent phosphate cotransporter gene expression. In vitro characterizations showed that VS-505 has a relatively high density and low expansion volume when exposed to simulated gastric fluid.

CONCLUSIONS AND IMPLICATIONS

VS-505 is a safe and effective phosphate binder and may offer the advantage of having a reduced pill burden and minimal GI side effects for CKD patients.

Prevalence and severity of disordered mineral metabolism in patients with chronic kidney disease: A study from a tertiary care hospital in India

BACKGROUND

Disordered mineral metabolism is common complications of chronic kidney disease (CKD). However, there are limited data on the pattern of these disturbances in Indian CKD population.

MATERIALS AND METHODS

This was a prospective observational study of CKD-mineral and bone disorder (CKD-MBD) over a period of 3 years. The biochemical markers of CKD-MBD, namely, calcium, phosphorus, alkaline phosphatase, intact parathyroid hormone (iPTH), and 25-hydoxyvitamin Vitamin D3 (25OHD), were measured in newly diagnosed CKD Stage 3-5 and prevalent CKD Stage 5D adult patients.

RESULTS

A total of 462 patients of CKD Stage 3-5D were studied. The frequency of various biochemical abnormalities was hypocalcemia (23.8%), hypercalcemia (5.4%), hypophosphatemia (2.8%), hyperphosphatemia (55.4%), raised alkaline phosphatase (56.9%), secondary hyperparathyroidism (82.7%), and hypoparathyroidism (1.5%). 25OHD was done in 335 (72.5%) patients and 90.4% were found to have Vitamin D deficiency. About 70.6% of the patients had iPTH levels were above kidney disease outcomes quality initiative (KDOQI) target range. Nondiabetic CKD as compared to diabetic CKD had a higher alkaline phosphatase (P = 0.016), a higher iPTH (P = 0.001) a higher proportion of patients with iPTH above KDOQI target range (P = 0.09), and an elevated alkaline phosphatase (P = 0.004). The 25OHD levels were suggestive of severe Vitamin D deficiency in 33.7%, Vitamin D deficiency in 45.4%, and Vitamin D insufficiency in 11.3% patients. There was a significant positive correlation between iPTH with alkaline phosphatase (r = 0.572, P = 0.001), creatinine (r = 0.424, P = 0.001), and phosphorus (r = 0.241, P = 0.001) and a significant negative correlation with hemoglobin (r = -0.325, 0.001), age (r = -0.169, P = 0.002), and 25OHD (r = -0.126, P = 0.021). On multivariate logistic regression analysis, an elevated alkaline phosphatase was a significant predictor of hyperparathyroidism (odds ratio 9.7, 95% confidence interval 4.9-19.2, P = 0.001).

CONCLUSIONS

There was a high prevalence of CKD-MBD in Indian CKD patients. CKD-MBD is more common and more severe and has an early onset as compared to the western populations.

Dialyzing women and men: does it matter? An observational study

BACKGROUND

Application and consequences of hemodialysis treatment may differ between genders; focusing on these differences may be useful to optimize outcomes.

METHODS

Data from 1 999 648 hemodialysis sessions performed in 10 984 (3316 incident and 7668 prevalent) patients, treated in 55 centers of the European Clinical Database (EuCliD)-Turkey, were analyzed, and various demographic, clinical, biochemical, therapeutic and prognostic parameters were compared.

RESULTS

There were 1905 male and 1411 female incident and 4339 male and 3329 female prevalent patients. For females, the mean age in incident (61.8 ± 14.9 years) and prevalent (58.3 ± 15.2 years) patients was higher than for males (60.2 ± 14.8 and 56.5 ± 14.9 years, respectively) (P < 0.001 for both analyses). Also, body mass index was higher, while the hemoglobin level, and the percentage of interdialytic weight gain and arteriovenous fistula were lower. Serum phosphorus was similar in both genders in incident cases, while it was lower in prevalent female patients. Serum parathyroid hormone levels were lower in incident, but higher in prevalent male cases. Erythropoiesis-stimulating agents and vitamin D preparations were more frequently used in female incident and prevalent patients. Hospitalization was more frequent in prevalent females, while it did not differ significantly in the incident cases. Overall, no significant difference was observed in survival rates at 3 years in both incident and prevalent male and female patients.

CONCLUSIONS

Many parameters differ significantly between female and male dialysis patients. Considering the effects of sex on several parameters may be a valuable approach for achieving better outcomes when formulating treatment strategies in this patient population.

Hidden Hypercalcemia and Mortality Risk in Incident Hemodialysis Patients

CONTEXT

Neither uncorrected- nor albumin-corrected total calcium reliably predict ionized calcium in patients with end-stage renal disease. However, little is known about the consequences of inaccurate assessment of calcium concentration using total calcium.

OBJECTIVE

We hypothesized that hidden hypercalcemia (ie, elevated ionized calcium with normal total calcium) and apparent hypercalcemia (ie, elevated ionized calcium with elevated total calcium) are both associated with increased mortality risk.

DESIGN, SETTING, AND PATIENTS

We identified 874 incident hemodialysis patients with measured serum ionized calcium, total calcium, albumin, phosphorus, and bicarbonate from October 2007 to December 2011, using data from a large dialysis organization in the United States.

EXPOSURES

Serum concentrations of ionized calcium and total calcium were measured.

MAIN OUTCOME MEASURE

The primary outcome was all-cause mortality.

RESULTS

There was only fair interindex agreement with calcium status between ionized calcium and uncorrected or corrected total calcium (κ = 0.32 and 0.27, respectively). Among patients with high ionized calcium (>1.32 mmol/liter), 88% and 70% patients were incorrectly categorized as being normocalcemic using uncorrected and corrected total calcium, respectively, and were thus considered to have "hidden hypercalcemia." Compared to patients with low-normal ionized calcium (1.16-1.24 mmol/liter), patients with high ionized calcium had a significantly higher mortality risk (adjusted hazard ratio, 1.77; 95% confidence interval, 1.13-2.75). Furthermore, compared to patients with normocalcemia (ionized calcium 1.16-1.32 mmol/liter), those with hidden hypercalcemia by uncorrected and corrected total calcium also had a higher risk for death (adjusted hazard ratio 1.75 [95% confidence interval 1.11-2.75] and 1.80 [95% confidence interval, 1.11-2.90], respectively).

CONCLUSION

The majority of end-stage renal disease patients with elevated ionized calcium are incorrectly categorized as normocalcemic using conventional total calcium measurements; these patients have a higher death risk. Future research is needed to establish whether reducing ionized calcium concentrations in these patients improves clinical outcomes.

Association Between Blood Cadmium Levels and Mortality in Peritoneal Dialysis

The negative impact of environmental exposure of cadmium has been well established in the general population. However, the effect of cadmium exposure in chronic peritoneal dialysis (PD) patients remains uncertain.A total of 306 chronic PD patients were included in this 36-month observational study. Patients were stratified into 3 groups by the tertile of baseline blood cadmium levels (BCLs): high (>0.244 μg/L, n = 101), middle (0.130-0.244 μg/L, n = 102), and low (<0.130 μg/L, n = 103) for cross-sectional analyses. Mortality rates and cause of death were recorded for longitudinal analyses.Patients in the high-BCL group were older, more likely to have diabetes mellitus, had lower levels of serum albumin and lower percentage of lean body mass than patients in the low-BCL group. A multivariate logistic regression analysis revealed that logarithmic transformed BCL was independently associated with a higher risk of low turnover bone disease (odds ratio = 3.8, P = 0.005). At the end of the 36-month follow-up, 66 (21.6%) patients died. Mortality rates increased with higher BCLs (P for trend = 0.005). A Cox multivariate analysis showed that, using the low-BCL group as the reference, the high-BCL group had increased hazard ratios (HR) for all-cause mortality in chronic PD patients after adjusting for related variables (HR = 2.469, 95% confidence interval = 1.078-5.650, P = 0.043).In conclusion, BCL showed significant association with malnutrition and low turnover bone disease in chronic PD patients. Furthermore, BCL is an important determinant of mortality. Our findings suggest that avoiding environmental exposure to cadmium as much as possible is warranted in chronic PD patients.

Successful Conversion From Parenteral Paricalcitol to Pulse Oral Calcitriol for the Management of Secondary Hyperparathyroidism in Hemodialysis Patients

OBJECTIVE

The management of hyperparathyroidism in hemodialysis patients involves the administration of phosphate binders, vitamin D receptor activators, and calcimimetics. Intravenous paricalcitol has been preferred over oral calcitriol as it may cause less hypercalcemia and hyperphosphatemia. However, there is little data looking at the efficacy and tolerability of oral calcitriol in the calcimimetic era particularly in a real practice-based experience. The University of California, Irvine free-standing dialysis center converted from routine intravenous paricalcitol to oral calcitriol due to pharmacy purchasing preferences. We report the efficacy, safety, and cost of such a change.

SUBJECTS

Ninety-three preconversion intravenous paricalcitol and 91 postconversion oral calcitriol.

INTERVENTION

Conversion to in-center, pulse, oral calcitriol (0.25 mcg = 1 mcg paricalcitol) 3 times a week from intravenous paricalcitol. Additional dose adjustments were made by the nephrologists based on clinical indications.

MAIN OUTCOME MEASURE

Five-month average serum calcium, phosphorous, and intact parathyroid hormone levels and cardiovascular events pretransition and posttransition.

RESULTS

There were 93 patients on intravenous paricalcitol between April 2013 and August 2013, of which 74 converted to oral calcitriol and were included in the postconversion group evaluated between October 2013 and February 2014. An additional 17 new patients had initiated calcitriol such that 91 patients were on oral therapy in the postconversion period. Sevelamer use increased from 41 (44.1%) patients preconversion to 48 (52.7%) postconversion, whereas calcium acetate use significantly dropped from 62 (66.7%) to 46 (50.5%) (P = .026). Cinacalcet use dropped slightly from 37 (39.7%) patients preconversion to 35 (38.4%) postconversion. Average serum calcium, phosphorus, and intact parathyroid hormone levels remained unchanged after conversion. Percent of values within Kidney Disease Outcome Quality Initiative guidelines were similarly maintained. Estimated vitamin D cost savings were $564 per person/year. No increase in the incidence of cardiovascular events was observed.

CONCLUSIONS

We conclude that in-center distributed pulse oral calcitriol may be an effective, safe, and economical treatment option for the management of hyperparathyroidism in hemodialysis patients.

Changes in Markers of Mineral and Bone Disorders and Mortality in Incident Hemodialysis Patients

BACKGROUND

Abnormalities in mineral and bone disorder (MBD) markers are common in patients with chronic kidney disease. However, previous studies have not accounted for their changes over time, and it is unclear whether these changes are associated with survival.

METHODS

We examined the association of change in MBD markers (serum phosphorus (Phos), albumin-corrected calcium (Ca(Alb)), intact parathyroid hormone (iPTH) and alkaline phosphatase (ALP)) during the first 6 months of hemodialysis (HD) with all-cause mortality across baseline MBD strata using survival models adjusted for clinical characteristics and laboratory measurements in 102,754 incident HD patients treated in a large dialysis organization between 2007 and 2011.

RESULTS

Across all MBD markers (Phos, Ca(Alb), iPTH and ALP), among patients whose baseline MBD levels were higher than the reference range, increase in MBD levels was associated with higher mortality (reference group: MBD level within reference range at baseline and no change at 6 months follow-up). Conversely, decrease in Phos and iPTH, among baseline Phos and iPTH levels lower than the reference range, respectively, were associated with higher mortality. An increase in ALP was associated with higher mortality across baseline strata of ALP ≥80 U/l. However, patients with baseline ALP <80 U/l trended towards a lower risk of mortality irrespective of the direction of change at 6 months follow-up.

CONCLUSIONS

There is a differential association between changes in MBD markers with mortality across varying baseline levels in HD patients. Further study is needed to determine if consideration of both baseline and longitudinal changes in the management of MBD derangements improves outcomes in this population.

Exploring Problems in Following the Hemodialysis Diet and Their Relation to Energy and Nutrient Intakes: The BalanceWise Study

OBJECTIVE

To identify the problems experienced by hemodialysis (HD) patients in attempting to follow the HD diet and their relation to energy and nutrient intakes.

DESIGN

Cross-sectional analysis of baseline data from the BalanceWise Study.

SUBJECTS

Participants included community-dwelling adults recruited from outpatient HD centers. After excluding participants with incomplete dietary analyses (n = 50), 140 African American and white (40/60%) men and women (52/48%) on chronic intermittent HD for at least 3 months (median 3 years) were included.

INTERVENTION

Participant responses, on a 5-point Likert scale ranging from "not at all a problem" to "a very important problem for me," to 34 questions pertaining to potential barriers to following the HD diet in the previous 2 months were classified as either a problem (1) or not a problem (2-5).

MAIN OUTCOME MEASURE

Energy and nutrient intakes determined using the Nutrition Data System for Research® based on 3, non-consecutive, unscheduled, 2-pass 24-hour dietary recalls collected on 1 dialysis and 1 non-dialysis weekday, and 1 non-dialysis weekend day.

RESULTS

More than half of participants reported having problems related to specific behavioral factors (e.g., feeling deprived), technical difficulties (e.g., tracking nutrients), and physical condition (e.g., appetite), but issues of time and food preparation and behavioral factors tended to be most deterministic of reported dietary intakes. Longer duration of HD was associated with lower intakes of protein, potassium, and phosphorus (P < .05).

CONCLUSION

Registered dietitian nutritionists should consider issues of time and food preparation, and behavioral factors in their nutrition assessment of HD patients and should continually monitor HD patients for changes in protein intake that may occur over time.

Serum PTH reference values established by an automated third-generation assay in vitamin D-replete subjects with normal renal function: consequences of diagnosing primary hyperparathyroidism and the classification of dialysis patients

OBJECTIVE

To determine parathyroid hormone (PTH) reference values in French healthy adults, taking into account serum 25-hydroxyvitamin D (25OHD), renal function, age, gender, and BMI.

PARTICIPANTS AND MAIN BIOLOGICAL MEASUREMENTS

We studied 898 healthy subjects (432 women) aged 18-89 years with a normal BMI and estimated glomerular filtration rate (eGFR), 81 patients with surgically proven primary hyperparathyroidism (PHPT), and 264 dialysis patients. 25OHD and third-generation PTH assays were implemented on the LIAISON XL platform.

RESULTS

Median PTH and 25OHD values in the 898 healthy subjects were 18.8  ng/l and 23.6  ng/ml respectively. PTH was lower in subjects with 25OHD ≥30  ng/ml than in those with lower values. Among the 183 subjects with 25OHD ≥30  ng/ml, those aged ≥60 years (n=31) had higher PTH values than younger subjects, independent of 25OHD, BMI, and eGFR (P<0.001). Given the small number of subjects aged ≥60 years, we adopted the 95% CI of PTH values for the entire group of 183 vitamin D-replete subjects (9.4-28.9  ng/l) as our reference values. With 28.9  ng/l as the upper limit of normal (ULN) rather than the manufacturer's ULN of 38.4  ng/l, the percentage of PHPT patients with 'high' PTH values rose to 90.1% from 66.6% (P<0.001), and 18.6% of the dialysis patients were classified differently in view of the KDIGO target range (two to nine times the ULN).

CONCLUSION

When only subjects with 25OHD ≥30  ng/ml were included in the reference population, the PTH ULN fell by 22.4%, diagnostic sensitivity for PHPT improved, and the classification of dialysis patients was modified.

Markers of increased atherosclerotic risk in patients with chronic kidney disease: a preliminary study

BACKGROUND

The prevalence of chronic kidney disease is rising continuously. Cardiovascular disease is among leading causes of death and premature mortality of patients with chronic kidney disease. Even the earliest stages of chronic kidney disease are associated with higher risk of subsequent coronary heart disease. The aim of this study was to determine markers of increased risk of atherosclerosis in CKD.

METHODS

The study group consisted of a total of 80 patients (20 patients with stage I/II CKD, 20 with stage III CKD, 20 stage IV CKD and 20 stage V/dialysis) and 24 healthy volunteers. Levels of proteins (osteoprotegerin, osteopontin, osteocalcin, matrix γ-carboxyglutamic acid protein, fetuin A, MMP-2, MMP-9, TIMP-1, TIMP-2) and biochemical parameters were measured to analyse their influence on atherosclerosis risk in CKD patients. Cardiac echocardiography was performed to assess structural integrity and function, presence of left ventricular hypertrophy and systolic and diastolic function dysfunction.

RESULTS

This study shows that the prevalence of ventricular hypertrophy (95.3 %) and diastolic dysfunction (93.2 %) in CKD patients is high. Also E/E' ratio was significantly higher (13.6 ± 4.4, p = 0.001), tricuspid insufficiency (27.3 in CKD I/II vs. 71.4 in CKD V, p = 0.016), contractile dysfunction (33.3 in CKD I/II vs. 78.9 in CKD V, p = 0.040), mitral valve calcification (0 in CKD I/II vs. 28.6 in CKD V, p = 0.044) and aortic valve calcification (0 in CKD I/II vs. 61.9 in CKD V, p = 0.0008) were significantly more frequent in patients with CKD stage V/dialysis than in other groups. Only MMP-2, MMP-2/TIMP-2 ratio and TIMP-1 differed significantly between groups.

CONCLUSIONS

This study shows high prevalence of ventricular hypertrophy and diastolic dysfunction in CKD patients. Contractile dysfunction, mitral and aortic valve calcification in HD patients were significantly more frequent than in patients with other CKD stages. Significantly increased levels of MMP-2, MMP-2/TIMP-2 ratio and lower TIMP-1 suggests that these factors may be involved in the pathogenesis of atherosclerosis in CKD patients.

Nutritional education for management of osteodystrophy: Impact on serum phosphorus, quality of life, and malnutrition

Introduction Osteodystrophy management includes dietary phosphorus restriction, which may limit protein intake, exacerbate malnutrition-inflammation syndrome and mortality among hemodialysis patients. Methods A multicenter randomized controlled trial was conducted in Lebanon, to test the hypothesis that intensive nutrition education focused on phosphorus-to-protein balance will improve patient outcomes. Six hemodialysis units were randomly assigned to the trained hospital dietitian (THD) protocol (210 patients). Six others (184 patients) were divided equally according to the patients' dialysis shifts and assigned to Dedicated Dietitian (DD) and Control protocols. Patients in the THD group received nutrition education from hospital dietitians who were trained by the study team on renal dietetics, but had limited time for hemodialysis patients. Patients in the DD group received individualized nutritional education on dietary phosphorus and protein management for 6 months (2-hour/patient/month) from study renal dietitians. Patients in the control group continued receiving routine care from hospital dietitians who had limited time for these patients and were blinded to the study. Serum phosphorus (mmol/L), malnutrition-inflammation score (MIS), health-related quality of life (HRQOL) index and length of hospital stay (LOS) were assessed at T0 (baseline), T1 (postintervention) and T2 (post6 month follow up). Findings Only the DD protocol significantly improved serum phosphorus (T0:1.78 ± 0.5, T1:1.63 ± 0.46, T2:1.69 ± 0.53), 3 domains of the HRQOL and maintained MIS at T1, but this protective effect resolved at T2. The LOS significantly dropped for all groups. Discussion The presence of competent renal dietitians fully dedicated to hemodialysis units was superior over the other protocols in temporarily improving patient outcomes.

Low parathyroid hormone status induced by high dialysate calcium is an independent risk factor for cardiovascular death in hemodialysis patients

Here we studied a possible association between low parathyroid hormone (PTH) status and mortality in incident patients undergoing hemodialysis . A total of 1983 patients were included at baseline and prospectively followed for 24 months. Patients were classified according to their Kidney Disease: Improving Global Outcomes PTH status at baseline and at 12 months, and mortality evaluated at 12 to 24 months using adjusted Cox analysis. Factors potentially involved in PTH status variability between baseline and 12 months were analyzed. A decrease in serum PTH from normal or high to low values between baseline and 12 months was associated with significantly increased cardiovascular mortality at 12 to 24 months (hazard ratio, 2.03; 95% confidence interval, 1.22-3.36). For patients with high or normal baseline PTH levels, the main independent factor at 6 months for a decrease to low PTH levels at 12 months was high dialysate calcium (1.75 mmol/L), whereas prescription of non-calcium-based phosphate binders was associated with a lower risk of PTH decrease. In the high cardiovascular (CV) mortality risk subgroup of patients who acquired a low PTH status at 12 months, the main independent factor at 12 months associated with significant 12- to 24-month CV mortality was high dialysate calcium (odds ratio, 5.44; 95% CI, 2.52-11.75). Thus, patients with a serum PTH decrease to low values after 1 year of hemodialysis treatment are at high risk of short-term CV death. High dialysate calcium was an important contributor to PTH oversuppression, and continued use was associated with increased CV mortality.

A New Data Analysis System to Quantify Associations between Biochemical Parameters of Chronic Kidney Disease-Mineral Bone Disease

BACKGROUND

In hemodialysis patients, deviations from KDIGO recommended values of individual parameters, phosphate, calcium or parathyroid hormone (PTH), are associated with increased mortality. However, it is widely accepted that these parameters are not regulated independently of each other and that therapy aimed to correct one parameter often modifies the others. The aim of the present study is to quantify the degree of association between parameters of chronic kidney disease and mineral bone disease (CKD-MBD).

METHODS

Data was extracted from a cohort of 1758 adult HD patients between January 2000 and June 2013 obtaining a total of 46.141 records (10 year follow-up). We used an advanced data analysis system called Random Forest (RF) which is based on self-learning procedure with similar axioms to those utilized for the development of artificial intelligence. This new approach is particularly useful when the variables analyzed are closely dependent to each other.

RESULTS

The analysis revealed a strong association between PTH and phosphate that was superior to that of PTH and Calcium. The classical linear regression analysis between PTH and phosphate shows a correlation coefficient is 0.27, p<0.001, the possibility to predict PTH changes from phosphate modification is marginal. Alternatively, RF assumes that changes in phosphate will cause modifications in other associated variables (calcium and others) that may also affect PTH values. Using RF the correlation coefficient between changes in serum PTH and phosphate is 0.77, p<0.001; thus, the power of prediction is markedly increased. The effect of therapy on biochemical variables was also analyzed using this RF.

CONCLUSION

Our results suggest that the analysis of the complex interactions between mineral metabolism parameters in CKD-MBD may demand a more advanced data analysis system such as RF.

Time-averaged serum potassium levels and its fluctuation associate with 5-year survival of peritoneal dialysis patients: two-center based study

The time-averaged serum potassium was more comprehensive to reflect the all-time changes of serum potassium levels during peritoneal dialysis (PD). However, the association of fluctuation of time-averaged serum potassium level with long-time survival of PD patients remains unknown. In this retrospective study, we included 357 incident PD patients in 2 centers from January 1, 2007 to October 31, 2012 with follow-up through October 31, 2014. Our data demonstrated that it was the lower time-averaged serum potassium level rather than baseline of serum potassium level that was associated with high risk of death. Patients with higher standard deviation (SD) had significantly poorer all-cause (p = 0.016) and cardiovascular mortality (p = 0.041). Among the patients with time-averaged serum potassium levels below 4.0 mEq/L, a lower mean value was more important than its SD to predict death risk. In contrast, the patients with time-averaged serum potassium levels above 4.0 mEq/L, those with serum potassium SD < 0.54 mEq/L, exhibited a higher 3-year and 5-year survival rate for both all-cause and cardiovascular mortality compared to the control groups. Our data clearly suggested both time-averaged serum potassium and its fluctuation contributed disproportionately to the high death risk in PD patients.

Lean Body Mass and Survival in Hemodialysis Patients and the Roles of Race and Ethnicity

BACKGROUND

Lean body mass (LBM) represents the "fat-free" muscle mass in hemodialysis (HD) patients and is an important nutritional measure. Previous studies have found that both higher LBM and body mass index (BMI) were related to greater survival in HD patients. Additional studies have shown differences in survival across racial-ethnic groups of HD patients. However, the association of LBM and mortality across racial-ethnic subgroups has not been examined.

OBJECTIVE

We hypothesize that racial differences in LBM affect the mortality in HD patients.

SETTING AND SUBJECTS

Chronic HD patients from a large dialysis organization in the United States.

PREDICTORS

Estimated LBM (eLBM), self-identified racial subgroups.

MAIN OUTCOME MEASURE

5-year survival.

STUDY DESIGN

We examined the association between baseline eLBM and survival using Cox proportional hazard models adjusted for demographics, comorbidities, and laboratory measures. Associations were examined across subgroups of race-ethnicity (non-Hispanic white, African American, and Hispanic) and BMI.

RESULTS

The final cohort included 117,683 HD patients, who were 62 ± 15 (mean ± standard deviation) years old, 43% women and 59% with diabetes mellitus. Higher eLBM was linearly associated with lower mortality. Compared with the reference group (48.4-<50.5 kg), patients with the lowest eLBM (<41.3 kg) had a 1.4-fold higher risk of mortality (hazard ratio: 1.37; 95% confidence interval: 1.30-1.44) in the fully adjusted model. A similar linear association was seen among patients with BMI < 35 kg/m(2) and in non-Hispanic whites and African American subgroups. However, higher eLBM was not associated with improved survival in Hispanic patients or patients with BMI ≥ 35 kg/m(2).

LIMITATION

Potential residual confounding.

CONCLUSIONS

Higher eLBM is associated with a lower mortality risk in HD patients, especially among non-Hispanic white and African American groups. Hispanic patients do not demonstrate a similar inverse relationship. The association between LBM and mortality among different racial groups of HD patients deserves additional study.

Mineral (Mal)Adaptation to Kidney Disease--Young Investigator Award Address: American Society of Nephrology Kidney Week 2014

In the short time since its initial discovery as the cause of rare hypophosphatemic disorders, fibroblast growth factor-23 (FGF-23) has emerged as a major regulator of mineral metabolism and critical component of the bone and mineral adaptation to CKD. However, because elevated FGF-23 levels are also a novel biomarker and possible molecular mediator of increased risks of cardiovascular disease and death in CKD, the initially adaptive response to increase FGF-23 levels to maintain neutral phosphate balance in CKD may ultimately become maladaptive. Incorporating FGF-23 into understanding the complex physiology that governs normal bone and mineral metabolism and its alterations in CKD has filled critical knowledge gaps and opened a new landscape of exciting hypotheses and novel therapeutic strategies to be tested in the continued quest to alleviate the burden of CKD.

Associations among time-average mineral values, mortality and cardiovascular events in hemodialysis patients

Mineral and bone disease (CKD-MBD), disorders of mineral metabolism, is associated with mortality and cardiovascular disease in dialysis patients. However, the associations among time average mineral values (P, Ca and PTH) and clinical outcomes are not well investigated.

OBJECTIVES

This study examines the associations among mineral values and clinical outcomes from a single medical center.

METHODS

Adult patients who initiate hemodialysis in Taoyuan General Hospital from 2008 to 2013 were enrolled. We examined these associations using baseline and time-average model. The clinical outcomes included mortality, major adverse cardiovascular events (MACE) and cardiovascular events. We also examined the association between achieve K/DOQI guidelines' targets and clinical outcomes.

RESULTS

From a total of 284 hemodialysis patients, none of the baseline mineral values is associated with mortality and cardiovascular event, except hyperphosphatemia. Compared to patients achieved K/DOQI guidelines' targets, time average hyperphosphatemia is associated with MACE and first cardiovascular event [the adjusted hazard ratios (AHRs) are 6.343 and 3.278); whereas time average hypercalcemia is associated with MACE marginally (the AHR is 5.964). None of above clinical outcomes is related to hyperparathyroidism. The AHRs for mortality in those who only met PTH targets and none of the mineral value targets are 1.73 and 1.74, whereas the AHRs for cardiovascular events in those who met only Ca, only PTH, and none of the targets are 1.73, 1.81 and 2.54 (all ps < 0.05).

CONCLUSION

Time-average phosphate is associated with cardiovascular events after initiation of dialysis. Among mineral values, serum phosphate is still the strongest predictor for mortality and cardiovascular events.

ESAM predicts cardiovascular mortality in diabetic hemodialysis patients

AIM

To assess endothelial cell selective adhesion molecule (ESAM) as predictor of cardiovascular mortality in diabetic dialysis patients (DDPs).

METHODS

ESAM, clinical and laboratory parameters were assessed in 73 DDP. Cardiovascular mortality was recorded in a 2 years' prospective observational study.

RESULTS

Baseline ESAM was 17.1 (10.05-24.8) ng/ml and was correlated to phosphate (r = -0.42, p = 0.008), parathormone (r = -0.36, p = 0.048), albumin (r = -0.24, p = 0.048). ESAM significantly predicted cardiovascular death in univariate [HR = 1.03, 95% CI (1.006-1.054), p = 0.01] and multivariate [HR = 1.034, 95% CI (1.003-1.066), p = 0.03] Cox analysis. Time to cardiovascular death was shorter for patients with ESAM >12.44 ng/ml, p = 0.0045.

CONCLUSION

ESAM is an independent predictor of cardiovascular mortality in DDP.

Prevalence of CKD-MBD in pre-dialysis patients using biochemical markers in Enugu, South-East Nigeria

BACKGROUND

As kidney function declines, there is a progressive deterioration in mineral homeostasis with disruption of normal serum and tissue concentration of phosphorus and calcium, and changes in circulating levels of hormones-parathyroid hormone (PTH), calcitriol (1,25(OH)2 D), and Fibroblast growth factor-23 (FGF-23).

OBJECTIVE

This study was aimed at determining the prevalence of markers of CKD-MBD in pre-dialysis patients.

METHODS

We evaluated consecutively 168 subjects made up of 85 CKD patients and 83 healthy controls, who were attending the renal clinics and medical outpatient of University of Nigeria Teaching Hospital, Enugu. GFR was estimated and serum calcium, phosphorus, alkaline phosphatase, PTH, and 25(OH) D levels assayed.

RESULTS

The prevalence of various mineral bone disease abnormalities were 70% hyper-phosphatemia, 85% hyper-parathyroidism, and 100% low levels of 25 (OH) D among the patients. Estimated GFR correlated negatively with both serum phosphorus, and PTH. Age of the patients ranged from18-76 years with a male to female ratio of 1.7:1. Chronic Glomerulonephritis (CGN), hypertension and diabetes mellitus caused CKD in 75% of the patients. There was no significant decrease in serum calcium levels of patients compared to controls. The patients did not have pathologically raised alkaline phosphatase, although their mean level was significantly higher than that of the control group.

CONCLUSION

Low 25 (OH) D levels (insufficiency/deficiency), hyperparathyroidism, and hyper-phosphatemia were the obvious markers of CKD-MBD in our pre-dialysis patients. These should be evaluated at presentation in these patients.

The role of bone in CKD-mediated mineral and vascular disease

Cardiovascular disease is the leading cause of death in pediatric patients with chronic kidney disease (CKD), and vascular calcifications start early in the course of CKD. Based on the growing body of evidence that alterations of bone and mineral metabolism and the therapies designed to treat the skeletal consequences of CKD are linked to cardiovascular calcifications, the Kidney Disease, Improving Global Outcomes (KDIGO) working group redefined renal osteodystrophy as a systemic disorder of mineral and bone metabolism due to CKD, and this newly defined disorder is now known as "chronic kidney disease-mineral bone disorder (CKD-MBD)". Elevated fibroblast growth factor 23 (FGF23), a bone-derived protein, is the first biochemical abnormality to be associated with CKD-MBD, and high FGF23 levels correlate with increased cardiovascular morbidity and mortality, suggesting that bone is central to both initiating and perpetuating the abnormal mineral metabolism and vascular disease in CKD. The current standard therapies for CKD-MBD affect FGF23 levels differently; non-calcium-based binders with or without concurrent use of dietary phosphate restriction reduce FGF23 levels, while calcium-based binders seem to either increase or have no effect on FGF23 levels. Active vitamin D sterols increase FGF23 levels, whereas therapy with calcimimetics decreases FGF23 levels. Thus, the appropriate therapy that will minimize the rise in FGF23 and prevent cardiovascular morbidity remains to be defined.

Calcium and Sudden Cardiac Death in End-Stage Renal Disease

Sudden cardiac death (SCD) accounts for a quarter of all deaths in end-stage renal disease (ESRD) patients. While causative mechanisms of SCD in this high risk population remain poorly defined, interaction of the vulnerable myocardium with dialysis-related arrhythmic triggers is thought to play a major role. Recent evidence suggests that dialysis-induced derangement of calcium concentrations contributes to the increased risk of all-cause and cardiovascular mortality, vascular calcification, and SCD. Current KDIGO guidelines recommend avoiding high dialysate calcium concentrations as a precaution against adverse outcomes of increased calcium burden and vascular calcification. Conversely, low calcium concentration is also implicated in the development of SCD via increased QT dispersion and prolonged QT interval. Consequently, the optimal dialysate calcium concentration in dialysis patients remains debated and further studies are needed to establish the best strategy for managing calcium in dialysis patients.

Vitamin D and Anaesthesia

Vitamin D is a vitamin not only associated with calcium-phosphorus metabolism but also affects many organ systems. Because of its effect on the immune system in recent years, it has attracted much attention. Vitamin D deficiency is a clinical condition that can be widely observed in the society. Thus, patients with vitamin D deficiency are often seen in anaesthesia practice. In the absence of vitamin D, prolongation of intensive care unit stay, increase in mortality and morbidity and also association of chronic diseases further increase the importance of vitamin D deficiency. The results obtained from studies have led to the question of whether poor surgical outcome is associated with vitamin D deficiency. We assessed the vitamin D deficiency and its negative consequences for the anaesthesiologist.

Socio-Economic Factors, Food Habits and Phosphorus Levels in Patients on Hemodialysis

BACKGROUND

Hyperphosphoremia is one of the most important risk factors for morbidity and mortality for chronic kidney disease (CKD) patients, and also, for the general population. Excessive dietary intake of phosphate (P) is one of the key factors. In particular, P in its inorganic form, which is contained in food additives, is more readily absorbed. Unfortunately, these food additives are mostly present in convenience so called "fast foods" (pre-cooked), soft drinks, which represent the typical food consumed by our hemodialysis (HD) population, composed by elderly people, mostly low-socio economic class, who often live alone.

OBJECTIVES

We performed an observational retrospective multicenter study to find any association between social, cultural and economic situation, as well as food habits, and P levels in a cohort of patients on HD. Secondarily; we also examined the association between the fast food consumption and increased P levels, as well as patient compliance for P binding products.

PATIENTS AND METHODS

To explore the association between socio-economic factors and serum P levels, we enrolled 100 patients on periodic HD treatment from three different units. Information on social, cultural, economic, diet habits, therapy for hyperphosphoremia and hematological and clinical parameters had been collected through specific questionnaires, administered by a physician.

RESULTS

Results showed serum P level was reduced in patients who live alone compared to patients in family (P = 0.04), in self-sufficient (P = 0.05) and in patients belonging to middle-upper class, versus low-class (P = 0.003). Fast foods intake correlates with increase in P serum levels (P = 0.002), whilst the same correlation was not found for cheese intake. Our data show that socio-economic status and food habits are useful predictors of P serum levels.

CONCLUSIONS

In conclusion, dietary counseling of patients on HD is mandatory. Interventions that consider the socio-economic situation allow delivering important messages on foods with the least amount of P and adequate protein content, and they may be a successful strategy in targeting patients at a higher risk of hyperphosphoremia.

Adynamic bone disease: from bone to vessels in chronic kidney disease

Adynamic bone disease (ABD) is a well-recognized clinical entity in the complex chronic kidney disease (CKD)-mineral and bone disorder. Although the combination of low intact parathyroid hormone (PTH) and low bone alkaline phosphatase levels may be suggestive of ABD, the gold standard for precise diagnosis is histomorphometric analysis of tetracycline double-labeled bone biopsies. ABD essentially is characterized by low bone turnover, low bone volume, normal mineralization, and markedly decreased cellularity with minimal or no fibrosis. ABD is increasing in prevalence relative to other forms of renal osteodystrophy, and is becoming the most frequent type of bone lesion in some series. ABD develops in situations with reduced osteoanabolic stimulation caused by oversuppression of PTH, multifactorial skeletal resistance to PTH actions in uremia, and/or dysregulation of Wnt signaling. All may contribute not only to bone disease but also to the early vascular calcification processes observed in CKD. Various risk factors have been linked to ABD, including calcium loading, ageing, diabetes, hypogonadism, parathyroidectomy, peritoneal dialysis, and antiresorptive therapies, among others. The relationship between low PTH level, ABD, increased risk fracture, and vascular calcifications may at least partially explain the association of ABD with increased mortality rates. To achieve optimal bone and cardiovascular health, attention should be focused not only on classic control of secondary hyperparathyroidism but also on prevention of ABD, especially in the steadily growing proportions of diabetic, white, and elderly patients. Overcoming the insufficient osteoanabolic stimulation in ABD is the ultimate treatment goal.

Hyperphosphatemia as an independent risk factor for coronary artery calcification progression in peritoneal dialysis patients

Background

Coronary artery calcification (CAC) is associated with cardiovascular mortality in end-stage renal disease (ESRD) patients. The present study aimed to identify modifiable risk factors for CAC progression in peritoneal dialysis (PD) patients.

Methods

Adult patients who received regular PD for more than 6 months and underwent a series of coronary artery calcification score (CaCS) measurements by multislice spiral computed tomography (MSCT) with an interval of ≥ 6 months were included in this observational cohort study. The demographic characteristics and clinical data, including laboratory data and adequacy of PD, were collected. Curve estimation was used to fit the straight line and obtain the slope. Binary logistic regression was performed to identify the independent risk factors for CAC progression in the PD patients, and multivariate linear regression was conducted to identify factors associated with hyperphosphatemia.

Results

A total of 207 adult patients on PD (116 men, 56.0 %) with a mean age of 59.8 ± 15.9 years were recruited to this study, and 157 of them (75.8 %) received three or more CaCS assessments. The patients were divided into a slow group (n = 137) and a rapid group (n = 70) according to the linear regression slope or the average speed of development. The follow-up time was 33.0 ± 18.8 months. Multivariate logistic regression revealed that age and serum phosphate level were independent risk factors for CAC progression after adjustments. Multivariate linear regression revealed that hyperphosphatemia was associated with elevations in the transferrin and serum albumin levels and normalized protein catabolic rate (nPCR) and reductions in the hemoglobin level, residual Ccr, and PD Ccr.

Conclusions

Hyperphosphatemia is an independent risk factor for CAC progression, and the serum phosphate level may be associated with protein intake and PD adequacy. These results provide important information for the clinical management of ESRD patients.