Mineral metabolism management in hemodialysis patients with secondary hyperparathyroidism in Japan: baseline data from the MBD-5D

Associations of vitamin D receptor activators and calcimimetics with falls and effect modifications by physical activity: A prospective cohort study on the Japan Dialysis Outcomes and Practice Patterns Study

INTRODUCTION

This study aimed to examine the associations of vitamin D receptor activators (VDRA) and calcimimetics use with falls.

METHODS

This is a prospective cohort study on hemodialysis patients in the Japan Dialysis Outcomes and Practice Patterns Study. We excluded those who were unable to walk. The associations of VDRA or calcimimetics use with falls and effect modifications by physical activity were analyzed using marginal structural models.

RESULTS

In total, 1875 patients were included. VDRA and calcimimetics use was not associated with falls (risk ratio [95% CI]: 1.13 [0.84-1.51] and 1.02 [0.72-1.44]). The risk ratio for falls associated with VDRA use was lower among those with poor physical activity (p for interaction <0.1).

CONCLUSIONS

Although vitamin D receptor activators and calcimimetics use was not associated with falls, the lower risk ratio for falls with vitamin D receptor activators use among those with poor physical activity suggests that vitamin D receptor activators use might be beneficial among these patients.

Dialysate calcium, alfacalcidol, and clinical outcomes: A post-hoc analysis of the J-DAVID trial

The selection of dialysate calcium concentration (D-Ca) is still controversial among chronic hemodialysis (HD) regimens. We examined the trajectories of CKD MBD parameters among the J-DAVID trial participants to see the effect of D-Ca and alfacalcidol. The trial was an open-label randomized clinical trial including 976 HD patients with intact PTH of 180 pg/mL or lower which compared the users of vitamin D receptor activator (oral alfacalcidol) and non-users over a median of 4 years. The main D-Ca used at baseline were 3.0 mEq/L in 70% and 2.5 mEq/L in 25%, respectively. The primary endpoint was the composite of fatal and non-fatal cardiovascular events and the secondary endpoint was all-cause mortality. Multivariable Cox proportional hazard regression analyses in which D-Ca was included as a possible effect modifier and serum laboratory data as time-varying covariates showed no significant effect modification for composite cardiovascular events or all-cause mortality. This post hoc analysis showed that the effects of alfacalcidol on cardiovascular outcomes were not significantly modified by D-Ca.

Calcium balance in hemodialysis: More uncertainty than certainty

There is controversy about the choice of dialysate calcium concentration (DCa), with strong arguments both in favor of and against the use of a low or high DCa, as they can both be potentially harmful. Evidence suggests that calcium mass balance is positive with a DCa 3.5 mEq/L, negative or neutral with the use of DCa 2.5 mEq/L, whereas both positive and negative balances have been observed with the use of DCa 3.0 mEq/L. Overall, the use of DCa >2.5 mEq/L is usually associated with an increase in serum calcium level and a decrease in serum PTH level and use of lower vitamin D analogue dose, with the opposite effects usually observed with the use of lower DCa. Most of the available evidence is from small-sized and crossover studies; hence, evidence should be regarded with caution and applied in a patient-specific manner. As there are a lot of significant unanswered questions regarding calcium balance and the optimal DCa in hemodialysis patients, further high-quality research is needed to clarify many still unclear aspects of calcium homeostasis and balance in these patients. In conclusion, with the existing evidence the choice of DCa needs to be individualized and contextualized in the setting of each patient's calcium balance needs and homeostatic response, taking also into account oral calcium intake (dietary and medicinal), any other relevant therapy administered, such as vitamin D analogues, the type of renal mineral bone disorder, and associated cardiovascular comorbidity.

Mineral and bone disorder management in hemodialysis patients: comparing PTH control practices in Japan with Europe and North America: the Dialysis Outcomes and Practice Patterns Study (DOPPS)

Background

High-circulating level of parathyroid hormone (PTH) is associated with elevated mortality in dialysis patients. The Japanese Society for Dialysis Therapy guideline suggests a lower PTH target than other international guidelines; thus, PTH control may differ in Japan compared with other regions, and be associated with mortality.

Methods

We analyzed data from hemodialysis patients with ≥3 measurements of PTH during the first 9 months after enrollment in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 4–5 (2009–2015). PTH control was assessed by the mean, slope, and mean squared error (MSE) of all PTH measurements over the 9-month run-in period. Distribution of each PTH control was assessed by regions (Europe/Australia/New Zealand [Eur/ANZ], Japan and North America) and dialysis vintage. Mortality rates were compared across PTH control categories using Cox regression models.

Results

Mean PTH was lower in Japan than in other regions across dialysis vintage categories. In patients with dialysis vintage < 90 days, PTH level was more likely to decline > 5% per month in Japan (48% of patients) versus Eur/ANZ (35%) and North America (35%). In patients with dialysis vintage > 1 year, Japanese patients maintained steady PTH, while patients in Eur/ANZ and North America were more likely to experience a PTH increase. Mean PTH was associated with mortality in the overall samples (highest mortality rate for PTH > 600 pg/mL, hazard ratio, 1.35; 95% confidence interval, 1.20 to 1.52 vs PTH 200–399 pg/mL), and the association was obvious in the prevalent patients (hazard ratio, 1.44; 95% confidence interval, 1.26 to 1.65). PTH slope and MSE did not show significant association with mortality in the overall sample as well as in subjects stratified both by region and dialysis vintage.

Conclusion

PTH control in hemodialysis patients, as measured by keeping a stable PTH level over 9 months, was observed in Japan contrasted with other regions. High PTH mean, but not increased PTH slope and MSE, was associated with mortality especially in prevalent patients.

Higher dialysate calcium concentration is associated with incident myocardial infarction among diabetic patients with low bone turnover: a longitudinal study

This is a longitudinal study on 53,560 hemodialysis patients from the Japan Renal Data Registry. Predictor was D[Ca] ≥3.0 vs 2.5 mEq/L. Outcomes were the first CV events during 1-year observation period. Association of D[Ca] with CV events and effect modifications were tested using multivariate logistic regression analyses. Diabetes mellitus (DM) was a significant effect modifier for association of higher D[Ca] and myocardial infarction (MI) (OR: 1.26 (1.03-1.55) among DM and 0.86 (0.72-1.03) among non-DM, p for interaction <0.01). The effect size was not affected by further adjustment for serum albumin-corrected Ca or intact parathyroid hormone (iPTH) levels, but was attenuated by adjustment for intradialytic change in serum Ca concentration (ΔCa) (1.16 [0.89-1.51]). Among DM, D[Ca] ≥3.0 mEq/L was significantly associated with MI in the first tertile of corrected Ca or iPTH ≤60 pg/ml (p for interaction 0.03 and 0.03, respectively). In conclusion, higher D[Ca] was associated with incident MI in DM, especially with low serum Ca or iPTH levels. Attenuation of the effect size by adjustment for ΔCa and stratified analyses suggest that larger Ca influx during dialysis with higher D[Ca] in patients suggestive of low bone turnover leads to vascular calcification and subsequent MI in DM.

The cardiothoracic ratio and all-cause and cardiovascular disease mortality in patients undergoing maintenance hemodialysis: results of the MBD-5D study

BACKGROUND

The cardiothoracic ratio (CTR) is a non-invasive left ventricular hypertrophy index. However, whether CTR associates with cardiovascular disease (CVD) and mortality in hemodialysis (HD) populations is unclear.

METHODS

Using a Mineral and Bone disorder Outcomes Study for Japanese CKD Stage 5D Patients (MBD-5D Study) subcohort, 2266 prevalent HD patients (age 62.8 years, female 38.0%, HD duration 9.4 years) with secondary hyperparathyroidism (SHPT) whose baseline CTR had been recorded were selected. We evaluated associations between CTR and all-cause death, CVD death, or composite events in HD patients.

RESULTS

CTR was associated significantly with various background and laboratory characteristics. All-cause death, CVD-related death, and composite events increased across the CTR quartiles (Q). Adjusted hazard risk (HR) for all-cause death was 1.4 (95% confidential interval, 0.9-2.1) in Q2, 1.9 (1.3-2.9) in Q3, and 2.6 (1.7-4.0) in Q4, respectively (Q1 as a reference). The corresponding adjusted HR for CVD-related death was 1.8 (0.8-4.2), 3.1 (1.4-6.8), and 3.5 (1.6-7.9), and that for composite outcome was 1.2 (1.0-1.6), 1.7 (1.3-2.2), and 1.8 (1.5-2.3), respectively. Exploratory analysis revealed that there were relationships between CTR and age, sex, body mass index, comorbidity of CVD, dialysis duration and intact parathyroid hormone, phosphorus, hemoglobin, and usage of phosphate binder [corrected].

CONCLUSION

CTR correlated with all-cause death, CVD death, and composite events in HD patients with SHPT.

Clinical features of CKD-MBD in Japan: cohort studies and registry

Randomized controlled trials (RCTs) are essential for evidence-based medicine; however, cohort studies and registries provide an important information about risk factors and, hence, shed light on the target of laboratory parameters. The uniqueness of the current Japanese CKD-MBD guidelines lies in the lower target range of intact parathyroid hormone levels than those used in other countries, which is based on analyses of the nationwide Japan Renal Data Registry. Cohort studies were also useful in exploring risk factors of renal outcome in predialysis patients. It was revealed that low vitamin D status (very prevalent in Japan) and high fibroblast growth factor 23 (FGF23) levels predict poor renal outcome. The reported association of FGF23 levels with left ventricular hypertrophy (LVH) and heart failure observed in cohort studies may support the idea of adding the 4th component of CKD-MBD, namely, "LVH" to the three original components. When it is not feasible to conduct RCTs regarding intervention, we have no choice but to rely on observational studies with sophisticated analysis methods, such as facility-level analysis and marginal structural model minimizing indication bias. Observational studies conducted in Japan revealed that the side effects of medications for CKD-MBD, resultant compliance, and effective doses in terms of hard outcome in Japanese patients were found to be different from those in other countries. For example, the MBD-5D study confirmed the benefit of cinacalcet in terms of mortality despite its median dose of only 25 mg/day. These data are very helpful for future guidelines specific to Japanese patients with CKD.

Association of bone mineral density with biochemical markers of bone turnover in hemodialysis children

Introduction: Although some descriptive and cross-sectional studies have been reported about bone mass in chronic kidney disease (CKD) children, only a few studies investigated markers of bone turnover and the bone mass measurements.

Objectives: The aim of this study was to evaluate the association between bone mineral density (BMD) and biochemical markers of bone turnover in hemodialysis (HD) children.

Patients and Methods: The children who had received dialysis for at least the preceding 6‐month were included. BMD was measured for total body, the lumbar spine and the femoral neck and the blood samples were tested to assess biochemical bone turnover markers.

Results: The study group was comprised of 27 patients with CKD, 9 males (33%) and 18 females (67%) with the mean±SD age of the subjects 14.9±4.5 years. Positive significant correlations of parathyroid hormone (PTH) with total body bone densitometry Z-score, lumbar spine and femoral neck Z-score(r=0.43, P=0.06; r=0.41, P=0.08 and r=0.45, P=0.05, respectively) was noted. In addition, positive significant correlations calcium and total body, lumbar spine and femoral neck Z-score (r=0.52, P=0.02; r=0.28, P=0.23 and r=0.36, P=0.12, respectively) was seen. Interestingly, a positive significant correlation between alkaline phosphatase (ALP) and lumbar spine Z-score was found (r=0.46, P=0.04), while the correlation of this parameter with total body and femoral neck Z-score was not significant (P>0.05).

Conclusion: In our study, majority of patients with CKD had low level of BMD. In addition, lower levels of calcium (Ca), phosphorus (P), PTH and 25 (OH) vitamins D in patients with abnormal BMD Z-scores were detected.

PTH-dependence of the effectiveness of cinacalcet in hemodialysis patients with secondary hyperparathyroidism

Cinacalcet lowers parathyroid hormone levels. Whether it can prolong survival of people with chronic kidney disease (CKD) complicated by secondary hyperparathyroidism (SHPT) remains controversial, in part because a recent randomized trial excluded patients with iPTH <300 pg/ml. We examined cinacalcet’s effects at different iPTH levels. This was a prospective case-cohort and cohort study involving 8229 patients with CKD stage 5D requiring maintenance hemodialysis who had SHPT. We studied relationships between cinacalcet initiation and important clinical outcomes. To avoid confounding by treatment selection, we used marginal structural models, adjusting for time-dependent confounders. Over a mean of 33 months, cinacalcet was more effective in patients with more severe SHPT. In patients with iPTH ≥500 pg/ml, the reduction in the risk of death from any cause was about 50% (Incidence Rate Ratio [IRR] = 0.49; 95% Confidence Interval [95% CI]: 0.29–0.82). For a composite of cardiovascular hospitalization and mortality, the association was not statistically significant, but the IRR was 0.67 (95% CI: 0.43–1.06). These findings indicate that decisions about using cinacalcet should take into account the severity of SHPT.

Development and Evaluation of the Psychometric Properties of the CKD-MBD Knowledge and Behavior (CKD-MBD-KB) Questionnaire for Patients With Chronic Kidney Disease

CONTEXT

Chronic kidney disease-mineral and bone disorder (CKD-MBD) is one of the most complicated morbidities among patients with end-stage renal disease. At present, a specific questionnaire assessing relevant knowledge and behavior for patients with CKD-MBD is still unavailable.

OBJECTIVES

To develop and evaluate a valid and reliable questionnaire specific to patients with CKD-MBD.

METHODS

Both quantitative and qualitative analyses were combined to develop and estimate the CKD-MBD knowledge and behavior (CKD-MBD-KB) questionnaire. Three hundred thirteen and 295 patients, respectively, participated in the investigation during the period from November 2013∼October 2014. Reliability and validity testing were conducted to analyze the psychometric properties of questionnaire.

RESULTS

The final version of the CKD-MBD-KB questionnaire encompasses two domains, five facets, and 50 items. Reliability analysis showed that the Cronbach alpha of the five facets ranged from 0.578 to 0.854. Retest correlation coefficients of the five facets ranged from 0.825 to 0.944. Nine common factors were extracted from exploratory factor analysis that interpreted the cumulative variation of 64.1%, and factor loadings of all items were greater than 0.4. The results of confirmatory factor analysis indicated that the model had a satisfactory goodness of fit; the root mean square error of approximation = 0.070. Meanwhile, a significant correlation was found between each item and its facet.

CONCLUSION

This CKD-MBD-KB questionnaire has been confirmed to have adequate psychometric properties (good reliability and validity) and may be useful in the assessment of patient-related knowledge, intervention programs, and treatment protocols.

Relationship between parathyroid mass and parathyroid hormone level in hemodialysis patients with secondary hyperparathyroidism

Background

To evaluate the influence of parathyroid mass on the regulation of parathyroid hormone (PTH) secretion, we investigated the relationship between the resected parathyroid gland in total parathyroidectomy and the parathyroid hormone level in hemodialysis patients with secondary hyperparathyroidism.

Methods

From January 2009 to July 2014, 223 patients undergoing total parathyroidectomy were included. The size and the weight of parathyroid gland were measured during the operation.

Results

874 parathyroid glands were removed. A positive correlation was identified between the size and the weight of resected parathyroid glands. We found that both the preoperative PTH and the reduction of PTH were significantly correlated with the size and the weight of parathyroid glands in a positive manner. However, in the subgroup of patients with PTH < 1000 pg/ml, no significant correlation was found.

Conclusions

Larger parathyroid gland secretes more PTH and high level of serum PTH usually indicated that surgical removal might be required. However, since PTH levels could be influenced by the pharmaceutical drug, the large size of parathyroid gland might be used as a much more appropriate guide that indicates the requirement of surgery treatment even when the parathyroid hormone was less than 1000 pg/ml.

Dialysate Calcium Concentration, Mineral Metabolism Disorders, and Cardiovascular Disease: Deciding the Hemodialysis Bath

Patients with end-stage kidney disease treated with dialysis are at increased risk to experience fractures and cardiovascular events than similar-aged people from the general population. The enhanced risk for these outcomes in dialysis patients is not completely explained by traditional risk factors for osteoporosis and cardiovascular disease. Mineral metabolism abnormalities are almost universal by the time patients require dialysis therapy, with most patients having some type of renal osteodystrophy and vascular calcification. These abnormalities have been linked to adverse skeletal and cardiovascular events. However, it has become clear that the treatment regimens used to modify the serum calcium, phosphate, and parathyroid hormone levels almost certainly contribute to the poor outcomes for dialysis patients. In this article, we focus on one aspect of mineral metabolism management; dialysate calcium concentration and the relationships among dialysate calcium concentrations, mineral and bone disorder, and cardiovascular disease in hemodialysis patients.

Use of renin-angiotensin system inhibitors is associated with reduction of fracture risk in hemodialysis patients

Background

Patients with chronic kidney disease, especially those undergoing dialysis treatment and having secondary hyperparathyroidism, have a high risk of bone fracture. The renin-angiotensin system (RAS) is associated with osteoclastic bone resorption. We aimed to examine whether the use of RAS inhibitors reduces the incidence of fracture in hemodialysis patients.

Methods and Findings

This was a multicenter, 3-year, prospective, observational study. From 2008 to 2011, maintenance hemodialysis patients with secondary hyperparathyroidism (N = 3,276) treated with angiotensin converting enzyme inhibitor (ACEI)/angiotensin II receptor blocker (ARB) at baseline were followed for a mean of 2.7 years. The association between the use of ACEI/ARB and hospitalization rate owing to fracture was examined by using Cox regression models. Effect modifications by the severity of secondary hyperparathyroidism (intact parathyroid hormone [iPTH] level), sex, and systolic blood pressure were also examined. The incidence proportion of fracture-related hospitalization was 5.42% throughout the observation period. ACEI/ARB use was associated with a lower rate of fracture-related hospitalization (adjusted hazard ratio, 0.65; 95% confidence interval [CI], 0.45–0.92). This association was not significantly affected by sex (P = 0.56) or systolic blood pressure levels (P = 0.87). The hazard ratios adjusted by iPTH levels were qualitatively different, but not statistically significant (P = 0.11): 0.77 (95% CI, 0.42–1.39), 0.38 (95% CI, 0.20–0.73), 0.59 (95% CI, 0.29–1.21), and 1.29 (95% CI, 0.58–2.42) for the first, second, third and fourth quartiles of iPTH, respectively.

Conclusions

Use of RAS inhibitors is associated with a lower rate of fracture-related hospitalization in hemodialysis patients with secondary hyperparathyroidism.

Trial Registration

ClinicalTrials.gov NCT00995163

Associations between the levels of sclerostin, phosphate, and fibroblast growth factor-23 and treatment with vitamin D in hemodialysis patients with low intact PTH level

Serum sclerostin levels could be closely associated with serum phosphate and fibroblast growth factor-23 levels in hemodialysis patients with low intact parathyroid hormone (PTH) levels. Further study is required to indicate whether these close associations are present in patients with spontaneously low PTH levels without any vitamin D treatment.

INTRODUCTION

Intact parathyroid hormone (iPTH) is involved in the interaction between sclerostin and phosphate/fibroblast growth factor-23 (FGF23) in animal models. However, their relationship in patients on hemodialysis (HD) is unclear.

METHODS

Data of 102 HD patients were collected regarding clinical and laboratory parameters and mineral bone disorder medications. The patients were divided into subgroups according to the iPTH level (A, <70 pg/mL; B, 70-150 pg/mL; C, 150-300 pg/mL; and D, ≥ 300 pg/mL).

RESULTS

The sclerostin level was significantly and positively correlated with phosphate and log of FGF23 levels in subgroups A, B, and combined A and B. Multiple linear regression analysis in the combined A and B subgroup revealed that male sex (t = 3.24, P = 0.01; 95% confidence interval [CI] 11.78 to 50.43) and phosphate level (t = 2.13, P = 0.04; 95% CI, 1.08 to 36.91) were independent factors for serum sclerostin level. The log of serum FGF23 level (t = 1.90, P = 0.06, 95% CI -1.85 to 63.50) appeared to be an important factor for serum sclerostin level. The frequency of patients using vitamin D treatment was not significantly different among subgroups A (93.1%), B (88.0%), C (85.2%), and D (90.5%).

CONCLUSION

Serum sclerostin levels were associated with serum phosphate and FGF23 levels in patients with low iPTH levels. Further study is required to indicate whether these close associations are present in patients with spontaneously low iPTH levels without vitamin D treatment.

Association of serum bicarbonate with bone fractures in hemodialysis patients: the mineral and bone disorder outcomes study for Japanese CKD stage 5D patients (MBD-5D)

BACKGROUND/AIMS

Bone fracture is often complicated in hemodialysis (HD) patients. Metabolic acidosis is related to bone disease and muscle wasting, but it is not known whether acid-base disturbance is associated with the risk of bone fractures. The aim of this study was to clarify the association of serum bicarbonate level with bone fracture in HD patients.

METHODS

Using a subcohort of the Mineral and Bone Disorder Outcomes Study for Japanese CKD Stage 5D Patients (MBD-5D), 890 prevalent HD patients (age: 62 years old, male: 62.8%, duration of dialysis: 8.3 years) with secondary hyperparathyroidism were studied. After measuring predialysis serum bicarbonate at a 2-day interdialytic interval, we prospectively followed them every 3 months, and examined the occurrence of any type of bone fracture or hospitalization due to fracture over a 3-year observation period.

RESULTS

Seventy-four bone fractures and 47 hospitalizations due to fracture were observed during the follow-up period. HD patients with serum bicarbonate <20 mmol/l had a 1.93 (95% CI 1.01-3.71)-fold higher risk for all-cause fractures than those with serum bicarbonate of 20.0-21.9 mmol/l. A higher bicarbonate level (≥22 mmol/l) was also related to an increased risk of bone fracture. A restricted cubic regression spline disclosed that the higher or the lower than 21.0 mmol/l of serum bicarbonate, the greater the risk for bone fracture.

CONCLUSION

Both a lower level and a higher level of predialysis bicarbonate concentration were associated with risk of bone fracture in HD patients with secondary hyperparathyroidism.

A Japanese approach for CKD-MBD

Disturbances in mineral and bone metabolism have a critical role in the pathogenesis of cardiovascular complications in patients with chronic kidney disease (CKD). The term ‘renal osteodystrophy' has recently been replaced by ‘CKD-mineral and bone disorder (CKD-MBD)', which includes abnormalities in bone and mineral metabolism and vascular calcification. The Japanese Society for Dialysis Therapy clinical practice guideline for the management of secondary hyperparathyroidism in chronic dialysis patients was originally published in Japanese in 2006, then in English in 2008. During the past 5 years, this first guideline has contributed to a considerably better understanding and control of secondary hyperparathyroidism in CKD patients by physicians, other medical professionals, and the patients themselves. However, since its publication several new therapeutic modalities have become available for Japanese dialysis patients, which added more evidence to this area. Thus, we revised the guideline to include several new policies, and the new guideline was published in Japanese in 2012. This article contains the new guideline text, and clinical significance of CKD-MBD in Japan.

Impact of cinacalcet introduction on MBD management: the MBD-5D study in Japan

Chronic kidney disease-mineral and bone disorder (CKD-MBD) has recently attracted attention in light of its association with clinical outcomes, such as fracture, cardiovascular disease, and mortality. Management of CKD-MBD has therefore come to have a central role in dialysis practice. Cinacalcet, a newly developed drug, has changed prescription patterns in many centers based on different changes in MBD markers than those observed with active vitamin D derivatives. As physicians require real-world evidence to guide their treatment decisions with respect to MBD management, we conducted the Mineral and Bone Disorder Outcomes Study for Japanese CKD Stage 5D Patients (MBD-5D), a 3-year observational study involving prevalent hemodialysis patients with secondary hyperparathyroidism (SHPT). Here, we review the results from the MBD-5D and discuss issues of MBD management in the cinacalcet era. Three years since the introduction of cinacalcet, 40% of hemodialysis patients with SHPT have come to use cinacalcet, enjoying marked improvement in management of circulating MBD markers, such as intact parathyroid hormone (PTH), phosphorus, and calcium. Combination therapy with cinacalcet and a vitamin D receptor activator (VDRA) may allow physicians to choose more suitable prescription patterns based on patient characteristics and therapeutic purposes. We observed an additive association between ‘starting cinacalcet' and ‘increased VDRA dose,' with marked improvement in the control of intact PTH levels. Further, the combination pattern of ‘starting cinacalcet' and ‘decreased VDRA dose' was associated with better achievement of target serum phosphorus and calcium levels. Future studies should examine the effect of different prescription patterns for SHPT treatment on clinical outcomes.

Age-dependent parathormone levels and different CKD-MBD treatment practices of dialysis patients in Hungary--results from a nationwide clinical audit

Background

Achieving target levels of laboratory parameters of bone and mineral metabolism in chronic kidney disease (CKD) patients is important but also difficult in those living with end-stage kidney disease. This study aimed to determine if there are age-related differences in chronic kidney disease-mineral and bone disorder (CKD-MBD) characteristics, including treatment practice in Hungarian dialysis patients.

Methods

Data were collected retrospectively from a large cohort of dialysis patients in Hungary. Patients on hemodialysis and peritoneal dialysis were also included. The enrolled patients were allocated into two groups based on their age (<65 years and ≥65 years). Characteristics of the age groups and differences in disease-related (epidemiology, laboratory, and treatment practice) parameters between the groups were analyzed.

Results

A total of 5008 patients were included in the analysis and the mean age was 63.4±14.2 years. A total of 47.2% of patients were women, 32.8% had diabetes, and 11.4% were on peritoneal dialysis. Diabetes (37.9% vs 27.3%), bone disease (42.9% vs 34.1%), and soft tissue calcification (56.3% vs 44.7%) were more prevalent in the older group than the younger group (p<0.001 for all). We found an inverse relationship between age and parathyroid hormone (PTH) levels (p<0.001). Serum PTH levels were lower in patients with diabetes compared with those without diabetes below 80 years (p<0.001). Diabetes and age were independently associated with serum PTH levels (interaction: diabetes × age groups, p=0.138). Older patients were more likely than younger patients to achieve laboratory target ranges for each parameter (Ca: 66.9% vs 62.1%, p<0.001; PO₄: 52.6% vs 49.2%, p<0.05; and PTH: 50.6% vs 46.6%, p<0.01), and for combined parameters (19.8% vs 15.8%, p<0.001). Older patients were less likely to receive related medication than younger patients (66.9% vs 79.7%, p<0.001).

Conclusions

The achievement of laboratory target ranges for bone and mineral metabolism and clinical practice in CKD depends on the age of the patients. A greater proportion of older patients met target criteria and received less medication compared with younger patients.

Avaliação da capacidade da Escala Internacional de Eficácia de Quedas em discriminar risco de quedas em pacientes com doença renal crônica submetidos à hemodiálise

O objetivo deste estudo foi avaliar a capacidade da Escala Internacional de Eficácia de quedas (FES-I), dos níveis séricos de paratormônio (PTH) e do tempo de tratamento hemodialítico (TTH) de discriminar pacientes com doença renal crônica (DRC) em tratamento hemodialítico caidores de não caidores. Foi realizado estudo transversal com 64 pacientes, com idade média de 44,2±14,8 anos. Foram coletados dados antropométricos, níveis séricos de PTH, histórico e risco de quedas (Escala Internacional de Eficácia de Quedas - FES-I), TTH e o nível de atividade física (Questionário Internacional de Atividade Física - IPAQ). Foram encontrados níveis séricos de PTH elevados em 64,1% dos pacientes, e 17,2% deles relataram histórico de queda no último ano. O tempo médio de TTH foi 50,3±37,5 meses. Nível de atividade física leve foi encontrado em 64,1%. Foi encontrada correlação positiva entre o PTH e o TTH (r=0,47; p<0,001). Não foram encontradas correlação entre o FES-I e o PTH (p<0,131), entre o FES-I e o TTH (p<0,153) nem entre o PTH (valor baixo/normal <450 pg/mL e valor elevado >450 pg/mL) e o risco de queda (caidores e não caidores) (p<0,158). No estudo, o instrumento FES-I mostrou-se capaz de discriminar hemodialíticos caidores de não caidores. Concluímos que a FES-I apresentou bom desempenho de avaliação entre caidores e não caidores, no entanto não foi observada associação entre caidores com os níveis séricos do PTH e com o TTH.

Prescription patterns and mineral metabolism abnormalities in the cinacalcet era: results from the MBD-5D study

BACKGROUND AND OBJECTIVES

Prescription patterns for hemodialysis patients with secondary hyperparathyroidism have varied widely since market introduction of cinacalcet. This study examined associations between prescription patterns and subsequent laboratory values.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Using a Mineral and Bone Disorder Outcomes Study for Japanese CKD Stage 5D Patients subcohort, 1716 prevalent hemodialysis patients (4048 sets for repeated measures between January 2008 and July 2009) with an intact parathyroid hormone (iPTH) level >180 pg/ml who used intravenous vitamin D receptor activator (VDRA) without cinacalcet were selected. Prescription patterns were defined based on cinacalcet administration (starting or not) and VDRA dosage change (decreased [<-25%], stable [-25% to 25%], or increased [>25%]). Proportion differences (PDs) were determined for decreasing iPTH levels by at least one category (<180, 180-299, 300-499, and ≥500 pg/ml) and for achieving target phosphorus (3.5-6.0 mg/dl) and calcium (8.4-10.0 mg/dl) levels, adjusting for potential confounders.

RESULTS

The starting cinacalcet and increased VDRA patterns were associated with decreasing iPTH levels (PD, 0.25 and 0.13; 95% confidence intervals [95% CIs], 0.19-0.31 and 0.09-0.17, respectively); combination use had an additive association (PD, 0.34; 95% CI, 0.20-0.42). The starting cinacalcet and decreased VDRA combination was associated with simultaneously achieving target phosphorus (PD, 0.12; 95% CI: 0.04-0.20) and calcium (PD, 0.09; 95% CI, 0.01-0.17) levels.

CONCLUSIONS

Certain combinations of cinacalcet and VDRA were associated with decreasing iPTH and achieving targets for phosphorus and calcium. Combinations may prove advantageous versus VDRA alone in managing secondary hyperparathyroidism.

Oral activated charcoal suppresses hyperphosphataemia in haemodialysis patients

AIM

Hyperphosphataemia is almost inevitable in end stage renal disease (ESRD) patients and is associated with increased morbidity and mortality. In this study we examined whether oral activated charcoal (oAC) reduces serum phosphate level in haemodialysis patients.

METHODS

This was an open-label, prospective, uncontrolled study. One hundred and thirty-five haemodialysis patients were included in this study, with cessation of treatment with any phosphate binders during a 2 week washout period. Patients with serum phosphate levels greater than 5.5 mg/dL during the washout period were included for treatment with oAC. oAC was started at a dose of 600 mg three times per day with meals and was administered for 24 weeks. oAC dose was titrated up during the 24 week period to achieve phosphate control (3.5-5.5 mg/dL). A second 2 week washout period followed the end of oAC treatment.

RESULTS

In the 114 patients who successfully completed the trial, the mean dose of activated charcoal was 3190 ± 806 mg/day. oAC reduced mean phosphate levels to below 5.5 mg/dL, with mean decreases of 2.60 ± 0.11 mg/dL (P < 0.01) and 103 (90.4%) of the patients reached the phosphate target. After the second washout period the phosphate levels increased to 7.50 ± 1.03 mg/dL (P < 0.01). Serum intact parathyroid hormone (iPTH) levels declined from 338.75 ± 147.77 pg/mL to 276.51 ± 127.82 pg/mL (P < 0.05) during the study. oAC had no influence on serum prealbumin, total cholesterol, triglycerides, serum ferritin, haemoglobin or platelet levels and the levels of 1,25-dihydroxyvitamin D were stable during the study.

CONCLUSION

In this open-label uncontrolled study, oAC effectively controls hyperphosphataemia and hyperparathyroidism in haemodialysis patients. The safety and efficacy of oAC needs to be assessed in a randomized controlled trial.

Role of uremic toxins and oxidative stress in the development of chronic kidney disease-mineral and bone disorder

The kidney plays an important role in the regulation of mineral metabolism. As kidney function declines, there is a progressive deterioration in mineral homeostasis, along with various abnormalities, including bone disease and vascular calcification, which has recently been named as "Chronic Kidney Disease-Mineral and Bone Disorder (CKD-MBD)." Although the precise mechanisms of this systemic disorder remain to be elucidated, accumulating evidence suggest that uremic toxins contribute substantially to the development of CKD-MBD, partly through evoking oxidative stress in the bone and cardiovascular systems. This brief review summarizes recent work on the role of uremic toxins and oxidative stress in the development of CKD-MBD.

Cost-effectiveness of cinacalcet hydrochloride for hemodialysis patients with severe secondary hyperparathyroidism in Japan

BACKGROUND

Cinacalcet effectively reduces elevated levels of parathyroid hormone (PTH) in patients with secondary hyperparathyroidism (SHPT), even those with severe disease for whom parathyroidectomy can be the treatment of choice. The objective of this study was to estimate the cost-effectiveness of cinacalcet treatment in hemodialysis patients with severe SHPT in Japan.

STUDY DESIGN

Cost-effectiveness analysis.

SETTING & POPULATION

Patients with severe SHPT (intact PTH >500 pg/mL) who were receiving hemodialysis in Japan.

MODEL, PERSPECTIVE, & TIMEFRAME

A Markov model was constructed from the health care system perspective in Japan. Patients were followed up over their lifetime. Dialysis costs were not included in the base case.

INTERVENTION

Cinacalcet as an addition to conventional treatment compared to conventional treatment alone. In both arms, patients underwent parathyroidectomy if intact PTH level was >500 pg/mL for 6 months and they were eligible for surgery.

OUTCOMES

Costs, quality-adjusted life-years (QALYs), and incremental cost-effectiveness ratios (ICERs).

RESULTS

ICERs for cinacalcet for those who were eligible for surgery and those who were not were $352,631/QALY gained and $21,613/QALY gained, respectively. Sensitivity and scenario analyses showed that results were fairly robust to variations in model parameters and assumptions. In the probabilistic sensitivity analysis, cinacalcet was cost-effective in only 0.9% of simulations for those eligible for surgery, but in more than 99.9% of simulations for those ineligible for surgery, if society would be willing to pay $50,000 per additional QALY.

LIMITATIONS

Data for the long-term effect of cinacalcet on patient-level outcomes are limited. The model predicted rates for clinical events using data for the surrogate biochemical end points.

CONCLUSIONS

The use of cinacalcet to treat severe SHPT is likely to be cost-effective for only those who cannot undergo parathyroid surgery for medical or personal reasons.

Decreases in PTH in Japanese hemodialysis patients with secondary hyperparathyroidism: associations with changing practice patterns

BACKGROUND AND OBJECTIVES

Control of serum concentrations of calcium (Ca), phosphorus (P), and parathyroid hormone (PTH) is essential for management of secondary hyperparathyroidism (SHPT).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This is a planned interim analysis of a longitudinal cohort study. The settings are dialysis facilities in Japan. Eligible patients comprise all those who were receiving hemodialysis at one of 86 participating facilities and who have SHPT. Using data from a random sample (n = 3276) of the participants from January 2008 through June 2009, we measured changes in the percentages of patients who were within the national guideline-specified target ranges of Ca (8.4 to 10 mg/dl), P (3.5 to 6.0 mg/dl), and intact PTH (iPTH) (60 to 180 pg/ml), and changes in prescriptions of drugs targeting SHPT. We used regression models to identify factors affecting the achievement of the guideline-specified targets.

RESULTS

There were no notable changes in the percentage of patients who were within the guideline for Ca, P, or both. The percentage who were within the iPTH guideline increased from 14.5% to 43.3% (P < 0.001). There were no remarkable changes in the percentage of patients receiving vitamin D or phosphate binders. The percentage who received cinacalcet increased from 0% to 29%. Prescription of cinacalcet was associated with improvement or target-achievement for iPTH and for Ca by 16.8 percentage points (95% CI: 8.1 to 17.0) and by 12.6 percentage points (13.7 to 19.9), respectively.

CONCLUSIONS

In the routine care of hemodialysis patients, increasing use of cinacalcet was associated with better control of SHPT.

Cinacalcet treatment and serum FGF23 levels in haemodialysis patients with secondary hyperparathyroidism

BACKGROUND

Elevated fibroblast growth factor 23 (FGF23) is associated with adverse clinical outcomes and development of secondary hyperparathyroidism (SHPT) refractory to active vitamin D. Cinacalcet hydrochloride is effective in treating SHPT, but little is known as to whether treatment with cinacalcet alters these levels and whether pretreatment FGF23 levels predict response to this therapy.

METHODS

We measured serum full-length FGF23 levels in 55 haemodialysis patients, who participated and completed the 52-week, multicentre, open-label single-arm trial that examined the effectiveness of cinacalcet for treating SHPT. In the study, alteration of vitamin D dosage was not permitted except for the case in which serum calcium could not be managed by calcium carbonate adjustment alone.

RESULTS

After 12 weeks of cinacalcet treatment, FGF23 levels decreased significantly concomitantly with a significant reduction in intact parathyroid hormone (PTH) levels. These responses were sustained >52 weeks. In multivariate regression analyses, changes from baseline in serum FGF23 were associated with changes in serum calcium and phosphorus but not with intact PTH at each time point of measurements (Week-12, Week-24 and Week-52). Baseline FGF23 was not associated with the likelihood of achieving an intact PTH <180 pg/mL at the study end.

CONCLUSIONS

Cinacalcet lowers serum FGF23 in haemodialysis patients with SHPT independently of the effects of active vitamin D. Pretreatment FGF23 cannot predict treatment response to cinacalcet in this setting. The precise mechanism of FGF23 reduction by cinacalcet and its clinical impact on outcomes in patients remain to be investigated.