Association of changes in bone mineral parameters with mortality in haemodialysis patients: insights from the ARO cohort

The effect of parathyroid hormone lowering by etelcalcetide therapy on calcification propensity and calciprotein particles in hemodialysis patients

Background

This study investigated whether parathyroid hormone (PTH) lowering with etelcalcetide, and the consequent effects on mineral and bone metabolism, could improve serum calcification propensity (T50 time) and decrease calciprotein particle (CPP) load in hemodialysis patients with secondary hyperparathyroidism.

Methods

In this single-arm, prospective, dose-escalation proof-of-principle study, hemodialysis patients received etelcalcetide at 2.5 mg/dialysis session with increments of 2.5 mg every 4 weeks to a maximum dose of 15 mg three times a week or until a pre-specified safety endpoint was reached, followed by an 8-week wash-out phase.

Results

Out of 36 patients recruited (81% male, 62 ± 13 years), 16 patients completed the study per protocol with a mean maximum tolerated dose of etelcalcetide of 9.5 ± 2.9 mg/dialysis session. With escalating doses of etelcalcetide, PTH and serum calcium levels significantly decreased (P < 0.0001). While there was no significant change in T50 times or serum phosphate levels, etelcalcetide did yield significant and consistent reductions in serum levels of endogenous calciprotein monomers [-35.4 (-44.4 to -26.5)%, P < 0.0001], primary [-22.4 (-34.5 to -10.3)%, P < 0.01] and secondary CPP [-29.1 (-45.7 to -12.4)%, P < 0.01], an effect that was reversed after therapy withdrawal. Serum levels of osteoclastic markers significantly decreased with escalating doses of etelcalcetide, while levels of the osteoblastic marker remained stable.

Conclusions

Lowering of PTH with etelcalcetide did not result in statistically significant changes in T50. By contrast, homogenous reductions in serum levels of calciprotein monomers, primary and secondary CPP were observed.

Alkaline Phosphatase and Parathyroid Hormone Levels: International Variation and Associations With Clinical Outcomes in the DOPPS

Introduction

Secondary hyperparathyroidism (SHPT) increases the risk of fractures and cardiovascular (CV) disease in patients on hemodialysis (HD). The relationship between parathyroid hormone (PTH) and outcomes has been inconsistent, possibly due to variable bone responsiveness to PTH. The KDIGO guideline suggests monitoring total alkaline phosphatase (ALP), but the role of ALP versus PTH in the management of mineral and bone disorder (MBD) is not clear.

Methods

The analysis included 28,888 patients on HD in 9 countries in Dialysis Outcomes and Practice Patterns Study (DOPPS) phase 3 to 7 (2005-2021). The primary exposures of interest were normalized ALP and PTH, which are raw values divided by facility upper normal limit, measured at study enrollment. Cox models were used to estimate hazard ratios of all-cause or CV mortality and any or hip fracture adjusted for potential confounders. Linear mixed models, adjusted for potential confounders, were employed to investigate the relationship between normalized ALP levels and patient characteristics.

Results

Normalized PTH showed a J-shaped association with all-cause or CV mortality, and a weak linear association with fracture. In contrast, normalized ALP showed a strong association with all outcomes. Factors associated with higher ALP levels after controlling for PTH included Black race, longer dialysis vintage, diabetes mellitus, hypocalcemia, hypophosphatemia, elevated C-reactive protein (CRP), and the use of cinacalcet.

Conclusion

Total ALP is a more robust exposure of adverse outcomes than PTH in patients on HD. PTH responsiveness is affected by race, primary renal disease, comorbidities, and mineral metabolism and therapy. Our results indicate that it may be useful to evaluate target organ response, rather than PTH alone when considering the consequences of (SHPT).

Recommended calcium intake in adults and children with chronic kidney disease-a European consensus statement

Mineral and bone disorders (MBD) are common in patients with chronic kidney disease (CKD), contributing to significant morbidity and mortality. For several decades, the first-line approach to controlling hyperparathyroidism in CKD was by exogenous calcium loading. Since the turn of the millennium, however, a growing awareness of vascular calcification risk has led to a paradigm shift in management and a move away from calcium-based phosphate binders. As a consequence, contemporary CKD patients may be at risk of a negative calcium balance, which, in turn, may compromise bone health, contributing to renal bone disease and increased fracture risk. A calcium intake below a certain threshold may be as problematic as a high intake, worsening the MBD syndrome of CKD, but is not addressed in current clinical practice guidelines. The CKD-MBD and European Renal Nutrition working groups of the European Renal Association (ERA), together with the CKD-MBD and Dialysis working groups of the European Society for Pediatric Nephrology (ESPN), developed key evidence points and clinical practice points on calcium management in children and adults with CKD across stages of disease. These were reviewed by a Delphi panel consisting of ERA and ESPN working groups members. The main clinical practice points include a suggested total calcium intake from diet and medications of 800-1000 mg/day and not exceeding 1500 mg/day to maintain a neutral calcium balance in adults with CKD. In children with CKD, total calcium intake should be kept within the age-appropriate normal range. These statements provide information and may assist in decision-making, but in the absence of high-level evidence must be carefully considered and adapted to individual patient needs.

Abdominal aortic calcification score can predict all-cause and cardiovascular mortality in maintenance hemodialysis patients

Purpose: Abdominal aortic calcification (AAC) assessed by using standard lateral lumbar radiographs can be graded, and composite summary scores (range, 0-24) have been shown to be highly predictive of subsequent cardiovascular morbidity and mortality in hemodialysis (HD) patients. However, few studies have sought to determine the optimal AAC score cutoff values for the prediction of mortality among HD patients.Methods: This retrospective cohort study included 408 hemodialysis patients. AAC severity was quantified by the AAC score, which was measured by lateral lumbar radiography with complete follow-up data from January 2015 to December 2021. We used receiver operating characteristic (ROC) analysis to find the cutoff AAC value for the prediction of mortality. The Kaplan-Meier method was used to analyze all-cause and cardiovascular mortality.Results: The cutoff calcification score for the prediction of mortality was 4.5 (sensitivity, 67.3%; specificity, 70.4%). The patients with AAC scores above 4.5 had significantly higher all-cause (log-rank p < 0.001) and cardiovascular (log-rank p < 0.001) mortality rates than those with AAC scores below 4.5. In the multivariate regression analyses, an AAC score above 4.5 was a significant factor associated with all-cause mortality (HR: 2.079, p = 0.002) and cardiovascular mortality (HR: 2.610, p < 0.001).Conclusions: AAC is a reliable aortic calcification marker. HD patients with an AAC score > 4.5 have significantly elevated all-cause and cardiovascular mortality compared with those with an AAC score ≤ 4.5. AAC was a better predictor than cardiac valve calcification for mortality in HD patients.

Association between CKD-MBD and mortality in older patients with advanced CKD-results from the EQUAL study

BACKGROUND

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a common complication of CKD; it is associated with higher mortality in dialysis patients, while its impact in non-dialysis patients remains mostly unknown. We investigated the associations between parathyroid hormone (PTH), phosphate and calcium (and their interactions), and all-cause, cardiovascular (CV) and non-CV mortality in older non-dialysis patients with advanced CKD.

METHODS

We used data from the European Quality study, which includes patients aged ≥65 years with estimated glomerular filtration rate ≤20 mL/min/1.73 m2 from six European countries. Sequentially adjusted Cox models were used to assess the association between baseline and time-dependent CKD-MBD biomarkers and all-cause, CV and non-CV mortality. Effect modification between biomarkers was also assessed.

RESULTS

In 1294 patients, the prevalence of CKD-MBD at baseline was 94%. Both PTH [adjusted hazard ratio (aHR) 1.12, 95% confidence interval (CI) 1.03-1.23, P = .01] and phosphate (aHR 1.35, 95% CI 1.00-1.84, P = .05), but not calcium (aHR 1.11, 95% CI 0.57-2.17, P = .76), were associated with all-cause mortality. Calcium was not independently associated with mortality, but modified the effect of phosphate, with the highest mortality risk found in patients with both hypercalcemia and hyperphosphatemia. PTH level was associated with CV mortality, but not with non-CV mortality, whereas phosphate was associated with both CV and non-CV mortality in most models.

CONCLUSIONS

CKD-MBD is very common in older non-dialysis patients with advanced CKD. PTH and phosphate are independently associated with all-cause mortality in this population. While PTH level is only associated with CV mortality, phosphate seems to be associated with both CV and non-CV mortality.

Mineral and bone metabolism markers and mortality in diabetic patients on haemodialysis

BACKGROUND

Diabetic patients on haemodialysis have a higher risk of mortality than non-diabetic patients. The aim of this COSMOS (Current management of secondary hyperparathyroidism: a multicentre observational study) analysis was to assess whether bone and mineral laboratory values [calcium, phosphorus and parathyroid hormone (PTH)] contribute to this risk.

METHODS

COSMOS is a multicentre, open-cohort, 3-year prospective study, which includes 6797 patients from 227 randomly selected dialysis centres in 20 European countries. The association between mortality and calcium, phosphate or PTH was assessed using Cox proportional hazard regression models using both penalized splines smoothing and categorization according to KDIGO guidelines. The effect modification of the association between the relative risk of mortality and serum calcium, phosphate or PTH by diabetes was assessed.

RESULTS

There was a statistically significant effect modification of the association between the relative risk of mortality and serum PTH by diabetes (P = .011). The slope of the curve of the association between increasing values of PTH and relative risk of mortality was steeper for diabetic compared with non-diabetic patients, mainly for high levels of PTH. In addition, high serum PTH (>9 times the normal values) was significantly associated with a higher relative risk of mortality in diabetic patients but not in non-diabetic patients [1.53 (95% confidence interval 1.07-2.19) and 1.17 (95% confidence interval 0.91-1.52)]. No significant effect modification of the association between the relative risk of mortality and serum calcium or phosphate by diabetes was found (P = .2 and P = .059, respectively).

CONCLUSION

The results show a different association of PTH with the relative risk of mortality in diabetic and non-diabetic patients. These findings could have relevant implications for the diagnosis and treatment of chronic kidney disease-mineral and bone disorders.

[Diagnosis and treatment of osteoporosis in patients with chronic kidney disease : Joint guidelines of the Austrian Society for Bone and Mineral Research (ÖGKM), the Austrian Society of Physical and Rehabilitation Medicine (ÖGPMR) and the Austrian Society of Nephrology (ÖGN)]

DEFINITION AND EPIDEMIOLOGY

Chronic kidney disease (CKD): abnormalities of kidney structure or function, present for over 3 months. Staging of CKD is based on GFR and albuminuria (not graded). Osteoporosis: compromised bone strength (low bone mass, disturbance of microarchitecture) predisposing to fracture. By definition, osteoporosis is diagnosed if the bone mineral density T‑score is ≤ -2.5. Furthermore, osteoporosis is diagnosed if a low-trauma (inadequate trauma) fracture occurs, irrespective of the measured T‑score (not graded). The prevalence of osteoporosis, osteoporotic fractures and CKD is increasing worldwide (not graded). PATHOPHYSIOLOGY, DIAGNOSIS AND TREATMENT OF CHRONIC KIDNEY DISEASE-MINERAL AND BONE DISORDER (CKD-MBD): Definition of CKD-MBD: a systemic disorder of mineral and bone metabolism due to CKD manifested by either one or a combination of the following: abnormalities of calcium, phosphorus, PTH, or vitamin D metabolism; renal osteodystrophy; vascular calcification (not graded). Increased, normal or decreased bone turnover can be found in renal osteodystrophy (not graded). Depending on CKD stage, routine monitoring of calcium, phosphorus, alkaline phosphatase, PTH and 25-OH-vitamin D is recommended (2C). Recommendations for treatment of CKD-MBD: Avoid hypercalcemia (1C). In cases of hyperphosphatemia, lower phosphorus towards normal range (2C). Keep PTH within or slightly above normal range (2D). Vitamin D deficiency should be avoided and treated when diagnosed (1C).

DIAGNOSIS AND RISK STRATIFICATION OF OSTEOPOROSIS IN CKD

Densitometry (using dual X‑ray absorptiometry, DXA): low T‑score correlates with increased fracture risk across all stages of CKD (not graded). A decrease of the T‑score by 1 unit approximately doubles the risk for osteoporotic fracture (not graded). A T-score ≥ -2.5 does not exclude osteoporosis (not graded). Bone mineral density of the lumbar spine measured by DXA can be increased and therefore should not be used for the diagnosis or monitoring of osteoporosis in the presence of aortic calcification, osteophytes or vertebral fracture (not graded). FRAX can be used to aid fracture risk estimation in all stages of CKD (1C). Bone turnover markers can be measured in individual cases to monitor treatment (2D). Bone biopsy may be considered in individual cases, especially in patients with CKD G5 (eGFR < 15 ml/min/1.73 m2) or CKD 5D (dialysis).

SPECIFIC TREATMENT OF OSTEOPOROSIS IN PATIENTS WITH CKD

Hypocalcemia should be treated and serum calcium normalized before initiating osteoporosis therapy (1C). CKD G1-G2 (eGFR ≥ 60 ml/min/1.73 m2): treat osteoporosis as recommended for the general population (1A). CKD G3-G5D (eGFR < 60 ml/min/1.73 m2 to dialysis): treat CKD-MBD first before initiating osteoporosis treatment (2C). CKD G3 (eGFR 30-59 ml/min/1.73 m2) with PTH within normal limits and osteoporotic fracture and/or high fracture risk according to FRAX: treat osteoporosis as recommended for the general population (2B). CKD G4-5 (eGFR < 30 ml/min/1.73 m2) with osteoporotic fracture (secondary prevention): Individualized treatment of osteoporosis is recommended (2C). CKD G4-5 (eGFR < 30 ml/min/1.73 m2) and high fracture risk (e.g. FRAX score > 20% for a major osteoporotic fracture or > 5% for hip fracture) but without prevalent osteoporotic fracture (primary prevention): treatment of osteoporosis may be considered and initiated individually (2D). CKD G4-5D (eGFR < 30 ml/min/1.73 m2 to dialysis): Calcium should be measured 1-2 weeks after initiation of antiresorptive therapy (1C).

PHYSICAL MEDICINE AND REHABILITATION

Resistance training prioritizing major muscle groups thrice weekly (1B). Aerobic exercise training for 40 min four times per week (1B). Coordination and balance exercises thrice weekly (1B). Flexibility exercise 3-7 times per week (1B).

Investigation on maintenance hemodialysis patients with mineral and bone disorder in Anhui province, China

BACKGROUND

Chronic kidney disease-mineral bone disorder (CKD-MBD) is a common comorbidity in patients with CKD. The study aims to describe the control rates of serum-corrected calcium (Ca), phosphate (P) and intact parathyroid hormone (iPTH) and its risk factors among maintenance hemodialysis (MHD) patients in Anhui Province of China.

METHODS

The study was conducted in 27 hemodialysis centers of Anhui Province between January 1st 2020 and December 31th 2020. Chi-square test was used to compare the control rates of serum-corrected Ca, P and iPTH between the present study and DOPPS 4 or Anhui Province in 2014. Binary logistic regression analysis was used to explore the risk factors of the control rates of serum-corrected Ca, P and iPTH.

RESULTS

A total of 3 025 MHD patients were recruited in this study, with a mean age of 54.8 (SD: 12.8) years, and 60.1% were males. According to the Chinese Diagnosis and Treatment Guidelines for CKD-MBD, the control rates of serum-corrected Ca, P and iPTH in the present study were 57.9%, 20.0% and 56.0%, respectively. Based on KDOQI guidelines (2003), the control rates of the above indicators were 43.1%, 35.3% and 22.3%, respectively. The control rates of serum-corrected Ca, P and iPTH in this study were lower than those of DOPPS 4 (P < 0.001). Compared to the results of Anhui Province in 2014, the control rate of corrected Ca was higher (P < 0.001) and the control rate of iPTH was lower (P = 0.005). Age, residential area, BMI, dialysis vintage, albumin and hemoglobin levels were factors of serum-corrected Ca, P and iPTH not within target range.

CONCLUSION

The control rates of serum-corrected Ca, P and iPTH in MHD patients in Anhui Province are relatively low. Monitoring and management should be strengthened to improve the prognosis of patients undergoing dialysis.

Lower Bone Turnover and Skeletal PTH Responsiveness in Japanese Compared to European Patients on Hemodialysis

CONTEXT

Parathyroid hormone (PTH) treatment targets for patients receiving hemodialysis (HD) are lower in Japan than in Europe. Whether this translates to lower bone turnover is unknown and could depend on skeletal PTH responsiveness.

OBJECTIVE

This study investigates whether skeletal PTH responsiveness is better preserved in Japanese vs European patients receiving HD.

METHODS

This is a post hoc analysis of data from 2 prospective cohort studies, using a case-control design. Patients receiving chronic intermittent HD therapy were eligible for inclusion. Participating Belgian and Japanese patients (n = 374) were matched 1:1 by age (59 ± 12 years), sex (66% male), diabetes (34%), and dialysis duration (39 months [22-63 months]). PTH, bone-specific alkaline phosphatase (BALP), and tartrate-resistant acid phosphatase isoform 5b (TRAP5b) were measured centrally in Liège, Belgium.

RESULTS

Japanese patients had lower levels of iPTH (207 vs 268 pg/mL; P < .001), BALP (15.3 vs 24.5 μg/L; P < .001), and TRAP5b (3.35 vs 5.79 U/L; P < .001). Linear regression analyses revealed lower levels of bone turnover markers for any given level of PTH in Japanese vs Belgian patients, indicating lower skeletal PTH responsiveness. Consistently, bone turnover markers were significantly lower in Japanese vs Belgian patients when stratifying or matching according to PTH levels. Male sex, obesity, and hyperphosphatemia were the main determinants of the bone turnover marker/PTH ratios.

CONCLUSION

Japanese patients receiving HD have lower bone turnover than their European counterparts, even at similar PTH levels. The rationale for the current regional differences in PTH treatment targets remains obscure and deserves further attention.

Treatment of secondary hyperparathyroidism in non-dialysis CKD: an appraisal 2022s

The situation of secondary hyperparathyroidism (sHPT) in CKD patients not on dialysis (ND-CKD) is probably best characterised by the KDIGO CKD-MBD Update 2017 guideline 4.2.1 stating that the optimal PTH levels is not known in these stages. Furthermore, new caution became recommended with regard to the routine use of active vitamin D analogues in early CKD stages and moderate sHPT phenotypes, due to their potential risks for hypercalcaemia and hyperphosphataemia aggravation. Nevertheless, there is still a substantial clinical need to prevent the development of parathyroid gland autonomy with its associated consequences of bone and vascular damage including fracture risks and cardiovascular events. Therefore, we now attempt to review the current guideline-based and clinical practice management of sHPT in ND-CKD including their strengths and weaknesses, favouring individualised approaches respecting calcium and phosphate homeostasis. We further comment on extended-release calcifediol (ERC) as a new differential therapeutic option now also available in Europe, and on a potentially novel understanding of a required vitamin D saturation in more advanced CKD stages. There is no doubt, however, that knowledge gaps will remain in this issue unless powerful RCTs with hard and meaningful endpoints are performed.

Relationship between intact parathyroid hormone and all-cause death, cardiovascular events, and ectopic calcification in patients with diabetic kidney disease: A retrospective study

AIM

We aimed to investigate the relationship between intact parathyroid hormone (iPTH) levels and all-cause death, cardiovascular events, and ectopic calcification in patients with diabetic kidney disease (DKD).

METHODS

In this retrospective cohort study, we collected the clinical data of 508 patients with clinically diagnosed DKD. The primary and secondary outcomes were all-cause death or cardiovascular events and ectopic calcification, respectively. We used different regression methods to analyze the relationship between various clinical parameters and the two clinical outcomes.

RESULTS

We found that iPTH was a risk factor for all-cause death and cardiovascular events (hazards ration [HR]: 2.817, 95% confidence interval [CI]: 1.045-6.562, P = 0.016). Meanwhile, diabetes duration (HR: 1.090, 95% CI: 1.045-1.138, P < 0.0001), triglycerides (TG) (HR: 1.254, 95% CI: 1.049-1.499, P = 0.013), and iPTH (HR: 1.954, 95% CI: 1.001-3.813, P = 0.049) were independent risk factors for ectopic calcification. In contrast to patients with lower iPTH levels (iPTH < 31.7 pg/mL), patients with higher iPTH levels (iPTH ≥ 31.7 pg/mL) had increased ectopic calcification rate (P = 0.002) and decreased survival time (P < 0.001).

CONCLUSION

In patients with DKD, higher iPTH levels were significantly related to worsen clinical outcomes.

Serum phosphate and mortality in incident dialysis patients in Australia and New Zealand

AIM

Hyperphosphataemia is associated with increased adverse outcomes, including mortality. Re-examining this association using up-to-date data reflecting current and real-world practices, across different global regions and in both haemodialysis and peritoneal dialysis patients, is important.

METHODS

We describe the association between serum phosphate and all-cause and cardiovascular mortality in incident dialysis patients between 2008 and 2018 using the Australia and New Zealand Dialysis and Transplant (ANZDATA) Registry. Time-dependent Cox proportionate hazards models were used. Models were adjusted for available covariates and fitted for the overall cohort, and also each dialysis modality.

RESULTS

31 989 patients were followed over 97 122 person-years at risk (mean age at first dialysis 61 years, 38% female, 67% haemodialysis). We observed a U-shaped association between serum phosphate and all-cause mortality. In the fully adjusted model, categories of serum phosphate above and below 1.25-1.99 mmol/L were associated with progressively higher risk, reaching a hazard ratio of 2.13 (95% CI 1.93-2.36, p < .001) for serum phosphate ≥2.75 mmol/L, and 1.56 (95% CI 1.44-1.69, p < .001) for serum phosphate <1.00 mmol/L. Low and high levels of serum phosphate were also associated with increased risk of cardiovascular mortality, however the association with high serum phosphate was more pronounced ("J-shaped relationship"). The associations were consistent across sub-analyses of patients receiving haemodialysis and peritoneal dialysis treatment.

CONCLUSION

In this large contemporary dialysis cohort, both high and low levels of serum phosphate were independently associated with increased risk of mortality. Future studies are required to determine whether treatment of abnormal serum phosphate levels improves mortality.

Clinical Approach to Vascular Calcification in Patients With Non-dialysis Dependent Chronic Kidney Disease: Mineral-Bone Disorder-Related Aspects

Chronic kidney disease (CKD) is associated with a very high morbimortality, mainly from cardiovascular origin, and CKD is currently considered in the high- or very high risk- cardiovascular risk category. CKD-mineral and bone disorders (CKD-MBDs), including vascular and/or valvular calcifications, are also associated with these poor outcomes. Vascular calcification (VC) is very prevalent (both intimal and medial), even in non-dialysis dependent patients, with a greater severity and more rapid progression. Simple X-ray based-scores such as Adragão's (AS) are useful prognostic tools and AS (even AS based on hand-X-ray only) may be superior to the classic Kauppila's score when evaluating non-dialysis CKD patients. Thus, in this mini-review, we briefly review CKD-MBD-related aspects of VC and its complex pathophysiology including the vast array of contributors and inhibitors. Furthermore, although VC is a surrogate marker and is not yet considered a treatment target, we consider that the presence of VC may be relevant in guiding therapeutic interventions, unless all patients are treated with the mindset of reducing the incidence or progression of VC with the currently available armamentarium. Avoiding phosphate loading, restricting calcium-based phosphate binders and high doses of vitamin D, and avoiding normalizing (within the normal limits for the assay) parathyroid hormone levels seem logical approaches. The availability of new drugs and future studies, including patients in early stages of CKD, may lead to significant improvements not only in patient risk stratification but also in attenuating the accelerated progression of VC in CKD.

The path to the standardization of PTH: Is this a realistic possibility? a position paper of the IFCC C-BM

Parathyroid hormone (PTH) determination is of greatest importance for patients suffering from parathyroid gland disorders and for the follow-up of bone turnover in patients suffering from chronic kidney disease (CKD). Two generations of PTH assays are simultaneously present on the market for PTH quantification. As these assays are not yet standardized, this results in a significant level of confusion in the care of CKD patients. One key objective of the IFCC Committee for Bone Metabolism is to improve this situation. In this position paper, we will highlight the current state of PTH testing and propose a pathway to ultimately overcome issues resulting from PTH assay variability.

The effect of phosphate binder therapy with sucroferric oxyhydroxide on calcification propensity in chronic haemodialysis patients: a randomized, controlled, crossover trial

BACKGROUND

Calcification propensity is associated with the risk for cardiovascular events and death in end-stage renal disease patients. Here we investigated the effect of lowering serum phosphate with oral phosphate binder therapy on calcification propensity.

METHODS

We performed an open-label, randomized, controlled, crossover study in chronic haemodialysis patients with hyperphosphataemia. Patients (n = 39) were randomized in a 1:1 ratio to either low-dose (250 mg/day) sucroferric oxyhydroxide (SO) followed by high-dose (2000 mg/day) SO or vice versa, with washout phases before and after SO treatment. The primary endpoint was changed in calcification propensity as measured by calciprotein particle formation time (T50 test) between washout and high-dose SO treatment in patients with ≥85% adherence to the prescribed SO dose (per-protocol analysis).

RESULTS

In the primary per-protocol analysis (n = 28), 2000 mg/day SO treatment resulted in a mean increase in T50 of 66 min (95% CI 49-84 min, P < 0.0001), from 243 ± 63 to 309 ± 74 min compared with phosphate binder washout. Serum phosphate decreased from 2.28 ± 0.5 to 1.63 ± 0.43 mmol/L (P < 0.0001). SO at 250 mg/day did not influence T50 (P = 0.4) or serum phosphate concentrations (P = 0.9) compared with phosphate binder washout. The secondary intention-to-treat analysis (n = 39) showed similar results: an increase in T50 of 52 min (95% CI 31-74 min, P < 0.0001) and a decrease in serum phosphate from 2.18 ± 0.5 to 1.64 ± 0.46 mmol/L. No major adverse cardiovascular event, case of calciphylaxis or death occurred during the study.

CONCLUSION

Phosphate binder treatment with SO improves serum calcification propensity of haemodialysis patients and might lead to improved outcomes.

Disorders in bone-mineral parameters and the risk of death in persons with chronic kidney disease stages 4 and 5: the PECERA study

BACKGROUND

Abnormalities of bone mineral parameters are associated with increased mortality in patients on dialysis, but their effects and the optimal range of these biomarkers are less well characterized in non-dialysis chronic kidney disease (CKD).

METHODS

PECERA (Collaborative Study Project in Patients with Advanced CKD) is a 3-year, prospective multicenter, open-cohort study of 966 adult patients with non-dialyzed CKD stages 4-5 enrolled from 12 centers in Spain. Associations between levels of serum calcium (Ca) (corrected for albumin), phosphate (P), and intact parathyroid hormone (iPTH) with all-cause mortality (primary outcome) and cardiovascular mortality (secondary outcome) were examined using time-dependent Cox proportional hazards models and penalized splines analysis adjusted by demographics and comorbidities, treatments and biochemical values collected every 6 months for 3 years.

RESULTS

After a median follow-up of 29 months (IQR: 13-36 months) there were 181 deaths (19%). The association of calcium with all-cause mortality was J-shaped, with an increased risk for all-cause mortality at levels > 10.5 mg/dL. For phosphate and iPTH levels, the association was U-shaped. The serum values associated with the minimum risk of mortality were 3.8 mg/dL for phosphate and 70 pg/mL for iPTH, being the lowest risk ranges between 2.8 and 5.0 mg/dL, and between 38 and 112 pg/mL for phosphate and iPTH, respectively.

CONCLUSIONS

Our study provides evidence on the non-linear association of serum calcium, phosphate and iPTH levels with mortality in stage 4 and 5 CKD patients, and suggests potential survival benefits for controlling bone mineral parameters in this population, as previously reported for dialysis patients.

The effects of dialysis modalities on the progression of coronary artery calcification in dialysis patients

Background

Hemodialysis (HD) tend to have more hemodynamic changes than peritoneal dialysis (PD), which aggravates inflammation and oxidative stress. Whether HD and PD have different effects on the progression of vascular calcification? Therefore, we produced a study to explore the relationship of dialysis modalities and coronary artery calcification (CAC) progression.

Methods

This was a prospective cohort study. CT scans were performed at enrollment and 2 years later for each patient. Demographic and clinical data were collected. Tobit regression was used to compare delta CAC score between HD and PD patients.

Results

(1) 155 patients were enrolled, including 69 HD and 86 PD patients. (2) The baseline CAC scores were 97 (1, 744) in HD and 95 (0, 324) in PD; the follow-up CAC scores were 343 (6, 1379) in HD and 293 (18, 997) in PD. There were no significant differences in baseline, follow-up and delta CAC scores between 2 groups (P > 0.05). (3) In Tobit regression, after adjusted for variables, there was no significant difference of CAC progression in HD and PD groups (P > 0.05). (4) Logistic regression showed that older age, diabetes and higher time-averaged serum phosphate (P) were associated with faster progression of CAC (P < 0.05), but there was no evidence that HD was associated with faster CAC progression compared with PD (P = 0.879).

Conclusions

There was no evidence that different dialysis modalities have different effect on CAC progression. Old age, DM and higher time-averaged P were associated with fast CAC progression.

Modifying Phosphate Toxicity in Chronic Kidney Disease

Phosphate toxicity is a well-established phenomenon, especially in chronic kidney disease (CKD), where hyperphosphatemia is a frequent occurrence when CKD is advanced. Many therapeutic efforts are targeted at phosphate, and comprise dietary intervention, modifying dialysis schemes, treating uncontrolled hyperparathyroidism and importantly, phosphate binder therapy. Despite all these interventions, hyperphosphatemia persists in many, and its pathological influence is ongoing. In nephrological care, a somewhat neglected aspect of treatment-when attempts fail to lower exposure to a toxin like phosphate-is to explore the possibility of "anti-dotes". Indeed, quite a long list of factors modify, or are mediators of phosphate toxicity. Addressing these, especially when phosphate itself cannot be sufficiently controlled, may provide additional protection. In this narrative overview, several factors are discussed that may qualify as either such a modifier or mediator, that can be influenced by other means than simply lowering phosphate exposure. A wider scope when targeting phosphate-induced comorbidity in CKD, in particular cardiovascular disease, may alleviate the burden of disease that is the consequence of this potentially toxic mineral in CKD.