Oral paricalcitol for the treatment of secondary hyperparathyroidism in patients on hemodialysis or peritoneal dialysis

Effects of Paricalcitol on Body Composition in Vitamin D-Deficient Rats

Background

Paricalcitol has been proposed for the treatment of secondary hyperparathyroidism in patients with renal failure and vitamin D deficiency (VDD); however, VDD is related to a range of clinical complaints. We aimed to investigate the effects of paricalcitol on body composition in VDD rats.

Methods

Thirty adult male rats aged 10 weeks were randomly divided into three groups of 10, comprising control, VDD, and VDD plus paricalcitol (32 ng/rat intraperitoneal injection) (VDD+P), at the Animal Lab of the Endocrinology and Metabolism Research Center, Shiraz, Iran, in 2020. Body composition was assessed after three weeks via serum biochemical tests and dual-energy X-ray absorptiometry. Finally, the data were analyzed by using the paired-sample t test, the one-way ANOVA, and the Tukey post hoc test.

Results

Global lean mass and fat mass were lower in the VDD and VDD+P groups than in the controls (P<0.001). Global fat percentage was reduced significantly in the VDD+P group (P=0.029).

Conclusion

Paricalcitol reduced global fat mass and fat percentage in a rat model with VDD. Evaluation of insulin and adiponectin levels is suggested to clarify the physiology of paricalcitol in VDD states.

Paricalcitol vs. cinacalcet for secondary hyperparathyroidism in chronic kidney disease: A meta-analysis

Paricalcitol and cinacalcet have been recommended to reduce parathyroid hormone (PTH) levels for patients with secondary hyperparathyroidism (SHPT) and chronic kidney disease (CKD), and they are able to reduce the risk of hypercalcemia and hyperphosphatemia. However, to date, it has remained uncertain which is the better drug. The aim of the present meta-analysis was to evaluate the effects on PTH, calcium and phosphorus metabolism between the two drugs. The PubMed, the Cochrane Library and Embase databases were searched from inception to June 1, 2019 and eligible studies comparing paricalcitol and cinacalcet for SHPT were included. Data were analysed using Review Manager version 5.3. A total of 7 trials from six articles, comprising 456 patients in the paricalcitol group and 412 patients in the cinacalcet group, were included in the meta-analysis. There were no differences in PTH levels [mean difference (MD): 71.82, 95% CI: -185.20-328.85, P=0.58] and phosphorus levels (standard MD: 0.59, 95% CI: -0.82-2.00, P=0.41). The calcium levels in the paricalcitol group were significantly higher than those in the cinacalcet group (MD: 1.10, 95% CI: 0.92-1.28, P<0.05). In conclusion, paricalcitol and cinacalcet exhibited no difference in their efficacy to control of PTH levels, as they were similarly effective in decreasing the PTH levels. They also had comparable efficacy in the management of phosphorus levels. However, cinacalcet produced a significantly greater reduction in serum calcium levels. More large multicentre randomized controlled trials are necessary to confirm the conclusions of the present analysis.

A Bayesian network analysis on comparative efficacy of treatment strategies for dialysis patients with secondary hyperparathyroidism

For dialysis patients with end-stage kidney disease and secondary hyperparathyroidism (SHPT), there are three therapeutic treatment options: Cinacalcet, paricalcitol and cinacalcet plus low-dose vitamin D analogues. However, their comparative efficacy remains unclear at present. Thus, in the current study, a Bayesian network analysis was conducted to evaluate the relative efficacy and safety of these three therapeutic regimens. A comprehensive literature database query was performed. The primary outcome was the treatment effect on serum parathyroid hormone (PTH) levels. Secondary outcomes included the occurrence of nausea and hypocalcaemia. A total of 20 randomized clinical trials, including 5,390 dialysis patients, were entered into the analysis. Paricalcitol, cinacalcet plus vitamin D analogue and cinacalcet were significantly more efficacious in controlling PTH levels compared with conventional therapy (which comprises calcium-based phosphate binders, non-calcium-based phosphate binders and vitamin D analogues) [odds ratio (OR)=3.99, 2.91 and 2.47, respectively] and placebo (OR=20.32, 14.89 and 12.56, respectively). Paricalcitol was identified as the most efficacious of the three treatments. According to a ranking analysis, patients treated with cinacalcet had a higher possibility of frequently developing nausea and hypocalcaemia compared with patients treated with cinacalcet plus low-dose active vitamin D analogues. All three therapeutic treatment options were efficacious for the treatment of dialysis patients with SHPT in controlling PTH levels. Paricalcitol had the highest possibility of being the most optimal one. Thus, paricalcitol therapy may be the most optimal regimen in controlling PTH levels, but this should be confirmed by further study.

Comparison of Paricalcitol and Calcitriol in Dialysis Patients With Secondary Hyperparathyroidism: A Meta-Analysis of Randomized Controlled Studies

Paricalcitol and calcitriol are widely used for the treatment of secondary hyperparathyroidism in dialysis patients. We conducted a systematic review and meta-analysis to compare the efficacy and safety of paricalcitol and calcitriol for secondary hyperparathyroidism in dialysis patients. PubMed, EMbase, Web of Science, EBSCO, and Cochrane library databases were systematically searched. Randomized controlled trials (RCT) assessing the efficacy of paricalcitol and calcitriol for secondary hyperparathyroidism in dialysis patients are included. Two investigators independently searched articles, extracted data, and assessed the quality of included studies. Meta-analysis was carried out using the random-effect model. Six randomized controlled trials are included in the meta-analysis. Overall, compared with calcitriol treatment for secondary hyperparathyroidism in dialysis patients, paricalcitol treatment has comparable ≥50% reduction of parathyroid hormone (risk ratio [RR] = 1.33; 95% CI = 0.93-1.91; P = 0.12), calcium concentration (standard mean difference [Std. MD] = -0.21; 95% CI = -0.94 to 0.52; P = 0.58), phosphate concentration (Std. MD = -0.17; 95% CI = -0.58 to 0.24; P = 0.42), calcium phosphate (Std. MD = -0.08; 95% CI = -0.49-0.34; P = 0.71), alkaline phosphatase (Std. MD = -0.21; 95% CI = -0.73-0.31; P = 0.43), hypercalcemia (RR = 1.43; 95% CI = 0.51 to 3.98; P = 0.49), adverse events (RR = 0.79; 95% CI = 0.42-1.49; P = 0.47), and serious adverse events (RR = 0.78; 95% CI = 0.47-1.30; P = 0.33). Paricalcitol and calcitriol result in similar ≥50% reduction of parathyroid hormone, calcium concentration, phosphate concentration, calcium phosphate, alkaline phosphatase, hypercalcemia, adverse events, and serious adverse events for secondary hyperparathyroidism in dialysis patients.

Long-Term Therapy Outcomes When Treating Chronic Kidney Disease Patients with Paricalcitol in German and Austrian Clinical Practice (TOP Study)

Paricalcitol is approved for prevention and therapy of secondary hyperparathyroidism (sHPT) in patients with chronic kidney disease (CKD), with only short-term data in clinical routine settings. A 12-month observational study was conducted in Germany and Austria (90 centers, 761 patients) from 2008 to 2013. Laboratory values, demographical, and clinical data were documented in 629 dialysis patients and 119 predialysis patients. In predialysis patients, median intact parathormone (iPTH) was 180.0 pg/mL (n = 105) at the start of the study, 115.7 pg/mL (n = 105) at last documentation, and 151.8 pg/mL (n = 50) at month 12, with 32.4% of the last documented iPTH values in the KDOQI (Kidney Disease Outcomes Quality Initiative) target range. In dialysis patients, median iPTH was 425.5 pg/mL (n = 569) at study start, 262.3 pg/mL (n = 569) at last documentation, and 266.1 pg/mL (n = 318) at month 12, with 36.5% of dialysis patients in the KDOQI target range. Intravenous paricalcitol showed more homogenous iPTH control than oral treatment. Combined analysis of all dialysis patients indicated comparable and stable mean serum calcium and phosphate levels throughout the study. Clinical symptoms, such as itching, bone pain, and fatigue, were improved compared with study entry. The spectrum and frequency of adverse events mirrored the known pattern for patients on dialysis. Paricalcitol is efficacious and has a consistent safety profile in sHPT over 12 months.

Comparison of the Pharmacological Effects of Paricalcitol Versus Calcitriol on Secondary Hyperparathyroidism in the Dialysis Population

Management of secondary hyperparathyroidism (SHPT) in dialysis population includes the use of active vitamin D forms, among which paricalcitol was shown to be more effective at reducing parathyroid hormone (PTH) concentrations. A prospective randomized study comparing the effectiveness and safety of peroral paricalcitol and calcitriol in suppressing PTH concentrations in 20 hemodialysis patients was performed comparing the influence of agents on PTH suppression, calcium (Ca) and phosphate (P) level and calcium-phosphorus product (C×P). The study was performed in an "intent to treat" manner with primary end point in reduction of PTH level in the target area of 150 > PTH < 300 ng/L after 3 months. At the time point 3 months after therapy induction paricalcitol and calcitriol were equally efficient at correcting PTH levels, with paricalcitol showing significantly less calcemic effect than calcitriol.

Effects of paricalcitol on cardiovascular outcomes and renal function in patients with chronic kidney disease : A meta-analysis

BACKGROUND

Paricalcitol, a selective activator of the vitamin D receptor (VDR), influences calcium and phosphorus homeostasis and bone metabolism. Whether paricalcitol reduces cardiovascular risk and protects renal function remains unclear. To systematically evaluate this in patients with chronic kidney disease (CKD), we conducted a meta-analysis of published randomized controlled trials (RCTs).

METHODS

We searched MEDLINE, Embase, the Cochrane Library, and reference lists for RCTs comparing paricalcitol with placebo in stage 2-5 CKD (including pre-dialysis and renal replacement patients). The Cochrane quality assessment method was used to evaluate study quality. Results were summarized as risk ratios (RRs) for dichotomous outcomes or mean differences (MD) for continuous outcomes.

RESULTS

We included 21 studies comprising 1894 patients. Compared to placebo, paricalcitol reduced the risk of cardiovascular events (RR 0.55; 95% CI 0.35-0.87; p = 0.01), but the RR of hypercalcemia associated with paricalcitol was 6.50 (95% CI 3.21-13.15; p < 0.00001). Paricalcitol cannot significantly change systolic blood pressure and cardiac structure. Although proteinuria reduction was achieved more frequently with paricalcitol (RR 1.51; 95% CI 1.25-1.82; p < 0.0001), it did not significantly reduce proteinuria level compared to placebo. Paricalcitol could not protect renal function to delay CKD progression, since it reduced the glomerular filtration rate (MD -3.15; 95% CI -4.35--1.96; p < 0.0001) and elevated serum creatinine (MD 0.93; 95% CI 0.10-0.68; p = 0.008).

CONCLUSION

Paricalcitol reduces the risk of cardiovascular events in CKD patients but increases the risk of hypercalcemia and cannot improve cardiac structure. Meanwhile, it cannot significantly reduce proteinuria level or protect renal function.

Early introduction of oral paricalcitol in renal transplant recipients. An open-label randomized study

In stable renal transplant recipients with hyperparathyroidism, previous studies have indicated that vitamin D agonist treatment might have anti-proteinuric effects. Animal studies indicate possible anti-fibrotic and anti-inflammatory effects. Early introduction of paricalcitol in de novo renal transplant recipients might reduce proteinuria and prevent progressive allograft fibrosis. We performed a single-center, prospective, randomized, open-label trial investigating effects of paricalcitol 2 μg/day added to standard care. Participants were included 8 weeks after engraftment and followed for 44 weeks. Primary end point was change in spot urine albumin/creatinine ratio. Exploratory microarray analyses of kidney biopsies at study end investigated potential effects on gene expression. Secondary end points included change in glomerular filtration rate (GFR), pulse wave velocity (PWV), and endothelial function measured by peripheral arterial tonometry as reactive hyperemia index (RHI). Seventy-seven de novo transplanted kidney allograft recipients were included, 37 receiving paricalcitol. Paricalcitol treatment lowered PTH levels (P = 0.01) but did not significantly reduce albuminuria (P = 0.76), change vascular parameters (PWV; P = 0.98, RHI; P = 0.33), or influence GFR (P = 0.57). Allograft gene expression was not influenced. To summarize, in newly transplanted renal allograft recipients, paricalcitol reduced PTH and was well tolerated without negatively affecting kidney function. Paricalcitol did not significantly reduce/prevent albuminuria, improve parameters of vascular health, or influence allograft gene expression.

Pharmacological Management of Secondary Hyperparathyroidism in Patients with Chronic Kidney Disease

Secondary hyperparathyroidism (SHPT) is a common complication of chronic kidney disease (CKD) and is part of the CKD-mineral bone disorder (CKD-MBD). SHPT is associated with increased risk of fracture and mortality; thus, SHPT control is recommended as kidney function declines. Effective SHPT management becomes more difficult once skeletal and cardiovascular adverse effects associated with severe SHPT have become established. However, interventional studies to lower parathyroid hormone (PTH) have so far shown inconsistent results in improving patient-centred outcomes such as mortality, cardiovascular events and fracture. Pharmacological treatment effect on PTH level is also inconsistent between pre-dialysis CKD and dialysis patients, which adds to the complexity of SHPT management. This review aims to give an overview on the pathophysiology, pharmacological and non-pharmacological treatment for SHPT in CKD including some of the limitations of current therapeutic options.

Effect of paricalcitol on mineral bone metabolism in kidney transplant recipients with secondary hyperparathyroidism

INTRODUCTION

Secondary hyperparathyroidism is highly prevalent in kidney transplant recipients, and commonly results in hypercalcaemia; an association to osteopenia and bone fractures has also been observed. Paricalcitol has proved effective to control secondary hyperparathyroidism in chronic kidney disease in both dialysed and non-dialysed patients, with a low hypercalcaemia incidence. Currently available experience on paricalcitol use in kidney transplant recipients is scarce. Our main aim was to show the effect of paricalcitol on mineral bone metabolism in kidney transplant recipients with secondary hyperparathyroidism.

MATERIAL AND METHODS

A retrospective multicentre study in kidney transplant recipients aged>18 years with a 12-month or longer post-transplantation course, stable renal function, having received paricalcitol for more than 12 months, with available clinical follow-up for a 24-month period.

RESULTS

A total of 69 patients with a 120 ± 92-month post-transplantation course were included. Baseline creatinine was 2.2 ± 0.9 mg/dl y GFR-MDRD was 36 ± 20 ml/min/1.73 m(2). Paricalcitol doses were gradually increased during the study: baseline 3.8 ± 1.9 μg/week, 12 months 5.2 ± 2.4 μg/week; 24 months 6.0 ± 2.9 μg/week (P<.001). Serum PTH levels showed a significant fast decline: baseline 288 ± 152 pg/ml; 6 months 226 ± 184 pg/ml; 12 months 207 ± 120; 24 months 193 ± 119 pg/ml (P<.001). Reduction from baseline PTH was ≥30% in 42.4% of patients at 12 months y in 65.2% of patients at 24 months. Alkaline phosphatase showed a significant decrease in first 6 months followed by a plateau: baseline 92 ± 50 IU/l; 6 months 85 ± 36 IU/l, 12 months 81 ± 39 IU/l (P<.001). Overall, no changes were observed in serum calcium and phosphorus, and in urine calcium excretion. PTH decline was larger in patients with higher baseline levels. Patients with lower baseline calcium levels showed significantly increased levels (mean increase was 0.5-0.6 mg/dl) but still within normal range, whereas patients with baseline calcium>10mg/dl showed gradually decreasing levels. Fifteen (21.7%) patients had received prior calcitriol therapy. When shifted to paricalcitol, such patients required paricalcitol doses significantly larger than those not having received calcitriol. Paricalcitol was used concomitantly to cinacalcet in 11 patients with significant PTH reductions being achieved; clinical course was similar to other patients and paricalcitol doses were also similar.

CONCLUSIONS

Paricalcitol is an effective therapy for secondary hyperparathyroidism in kidney transplant recipients. Overall, no significant changes were observed in calcium and phosphorus levels or urinary excretion. Patients having previously received calcitriol required higher paricalcitol doses. When used in patients receiving cinacalcet, paricalcitol results in a significant PTH fall, with paricalcitol doses being similar to those used in patients not receiving cinacalcet.

Ranking adverse drug reactions with crowdsourcing

BACKGROUND

There is no publicly available resource that provides the relative severity of adverse drug reactions (ADRs). Such a resource would be useful for several applications, including assessment of the risks and benefits of drugs and improvement of patient-centered care. It could also be used to triage predictions of drug adverse events.

OBJECTIVE

The intent of the study was to rank ADRs according to severity.

METHODS

We used Internet-based crowdsourcing to rank ADRs according to severity. We assigned 126,512 pairwise comparisons of ADRs to 2589 Amazon Mechanical Turk workers and used these comparisons to rank order 2929 ADRs.

RESULTS

There is good correlation (rho=.53) between the mortality rates associated with ADRs and their rank. Our ranking highlights severe drug-ADR predictions, such as cardiovascular ADRs for raloxifene and celecoxib. It also triages genes associated with severe ADRs such as epidermal growth-factor receptor (EGFR), associated with glioblastoma multiforme, and SCN1A, associated with epilepsy.

CONCLUSIONS

ADR ranking lays a first stepping stone in personalized drug risk assessment. Ranking of ADRs using crowdsourcing may have useful clinical and financial implications, and should be further investigated in the context of health care decision making.

Achievement of NKF/K-DOQI recommended target values for bone and mineral metabolism in incident hemodialysis patients: results of the FARO-2 cohort

BACKGROUND

Mineral Bone Disorders (MBD) is prevalent in hemodialysis (HD) patients and associated with increased cardiovascular mortality. The FARO-2 study evaluated the achievement of the NKF/K-DOQI guidelines on recommended target values for serum calcium (Ca), phosphorous (P) and intact parathyroid hormone (PTH) levels on survival in incident HD patients.

METHODS

Data were collected by questionnaire from 568 incident HD patients followed prospectively over a 3-year period from 26 Italian dialysis units. The cumulative probability of time-to-death for CKD-MBD treatment characteristics was determined by the Kaplan-Meier curves.

RESULTS

Serum PTH levels (median values at 6 months vs. 36 months; 225 vs. 254 pg/ml), Ca (8.8 vs. 8.9 g/dl) and P (5.1 vs. 4.8 mg/dl) were not significantly different at 6 months versus follow-up. The majority of incident HD patients (60-70%) who were followed up for 36 months did not achieve the NKF/K-DOQI recommended target values. Survival rates were higher in patients on target for three parameters versus patients off target (survival at 24 months: at target 95.7% (95% CI: 84.0-98.9) versus not on target 71.1% (95% CI: 66.3-75.4, p < 0.01)). The 30.1% of patients on target for three MBD parameters at least once during the follow-up period had better survival rates compared to those not reaching these targets (survival at 24 months: at least once 88.0% (95% CI: 81.9-92.1); 67.7% (95% CI: 61.9-72.8, p < 0.01)).

CONCLUSION

Our findings indicate that incident HD patients who achieved target levels (for three MBD parameters) for at least one visit have a lower risk of mortality.

Paricalcitol for secondary hyperparathyroidism in renal transplantation

Secondary hyperparathyroidism contributes to post-transplant CKD mineral and bone disorder. Paricalcitol, a selective vitamin D receptor activator, decreased serum parathyroid hormone levels and proteinuria in patients with secondary hyperparathyroidism. This single-center, prospective, randomized, crossover, open-label study compared the effect of 6-month treatment with paricalcitol (1 μg/d for 3 months and then uptitrated to 2 µg/d if tolerated) or nonparicalcitol therapy on serum parathyroid hormone levels (primary outcome), mineral metabolism, and proteinuria in 43 consenting recipients of renal transplants with secondary hyperparathyroidism. Participants were randomized 1:1 according to a computer-generated sequence. Compared with baseline, median (interquartile range) serum parathyroid hormone levels significantly declined on paricalcitol from 115.6 (94.8-152.0) to 63.3 (52.0-79.7) pg/ml (P<0.001) but not on nonparicalcitol therapy. At 6 months, levels significantly differed between treatments (P<0.001 by analysis of covariance). Serum bone-specific alkaline phosphatase and osteocalcin decreased on paricalcitol therapy only and significantly differed between treatments at 6 months (P<0.001 for all comparisons). At 6 months, urinary deoxypyridinoline-to-creatinine ratio and 24-hour proteinuria level decreased only on paricalcitol (P<0.05). L3 and L4 vertebral mineral bone density, assessed by dual-energy x-ray absorption, significantly improved with paricalcitol at 6 months (P<0.05 for both densities). Paricalcitol was well tolerated. Overall, 6-month paricalcitol supplementation reduced parathyroid hormone levels and proteinuria, attenuated bone remodeling and mineral loss, and reduced eGFR in renal transplant recipients with secondary hyperparathyroidism. Long-term studies are needed to monitor directly measured GFR, ensure that the bone remodeling and mineral effects are sustained, and determine if the reduction in proteinuria improves renal and cardiovascular outcomes.

Effects of vitamin D on parathyroid hormone and clinical outcomes in peritoneal dialysis: a narrative review

Vitamin D deficiency is very prevalent in dialysis and peritoneal dialysis (PD) patients show lower levels of cholecalciferol (25(OH)D3) than hemodialysis patients. We conducted a systematic narrative review to assess the effects of vitamin D therapy on control of secondary hyperparathyroidism and clinical outcomes induced by vitamin D pleiotropic effects. Medline database was searched for cohort and intervention studies reporting data on vitamin D (all sterols including synthetic analogs) and peritoneal dialysis without language restriction. Two authors independently extracted data. Twenty-nine observational and eleven interventional studies were identified for inclusion (1,036 subjects). PTH levels decreased in twenty-nine studies, increased in one study and remained stable in ten studies. Thirty-three studies analyzed the oral route for vitamin D administration, ten the intraperitoneal, one the subcutaneous and one the intravenous. A significant decrease of peritonitis risk was observed in two studies. Proteinuria decreased in four studies and remained stable in one study. Peritoneal protein loss decreased in one study and was stable in two studies. Studies on the therapeutic effects of vitamin D in PD are limited and describe small population samples. Moreover, vitamin D compounds do not consistently reduce PTH levels. The administration of active vitamin D in PD may have interesting pleiotropic effects such as decreasing proteinuria and peritoneal protein loss. According to these effects, vitamin D could help to preserve residual renal function and ensure efficient peritoneal membrane dialysance.

A randomized multicenter trial of paricalcitol versus calcitriol for secondary hyperparathyroidism in stages 3-4 CKD

BACKGROUND AND OBJECTIVES

Calcitriol is used to treat secondary hyperparathyroidism in patients with CKD. Paricalcitol is less calcemic and phosphatemic in preclinical studies and in some trials in dialysis patients, but head-to-head comparisons in nondialysis patients are lacking. A large meta-analysis of trials concluded that these agents did not consistently reduce parathyroid hormone (PTH) and increased the risk of hypercalcemia and hyperphosphatemia. Therefore, the objective of this multicenter trial was to compare the rate of hypercalcemia between calcitriol and paricalcitol, while suppressing PTH 40%-60%.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Patients with stages 3-4 CKD (n=110) with a PTH level >120 pg/ml were recruited and randomized to 0.25 μg/d of calcitriol or 1 μg/d of paricalcitol between April 2009 and July 2011. Subsequent dose adjustments were by protocol to achieve 40%-60% PTH suppression below baseline. The primary endpoint was the rate of confirmed hypercalcemia of >10.5 mg/dl between groups.

RESULTS

Forty-five patients in each group completed the 24 weeks of treatment. Both agents suppressed PTH effectively (-52% with paricalcitol and -46% with calcitriol; P=0.17), although the paricalcitol group reached a 40% reduction in PTH sooner at a median 8 weeks (interquartile range [IQR], 4, 12) versus 12 weeks (IQR, 8, 18; P=0.02) and had a lower pill burden of 240 (IQR, 180, 298) versus 292 (IQR, 231, 405; P=0.01). Confirmed hypercalcemia was very low in both groups (three with paricalcitol and one with calcitriol) and was not significantly different (P=0.36). Both groups had small increases in calcium and phosphorus levels (0.3-0.4 mg/dl in each electrolyte) and significant decreases in alkaline phosphatase, a marker of high bone turnover, with no significant differences between groups.

CONCLUSIONS

These results show that both calcitriol and paricalcitol achieved sustained PTH and alkaline phosphatase suppression in stages 3-4 CKD, with small effects on serum calcium and phosphorus and a low incidence of hypercalcemia.

Mortality rates do not differ among patients prescribed various vitamin D agents

BACKGROUND

Limited well-controlled research exists examining the impact of different formulations of oral vitamin D on clinical outcomes in dialysis patients, specifically those on peritoneal dialysis. For this retrospective mortality analysis, we compared mortality rates of patients on 3 of the most commonly prescribed vitamin D agents.

METHODS

We examined 2 years (7/1/2008 to 6/30/2010) of oral medication records of peritoneal dialysis patients from a large US dialysis organization. Patients were identified whose physicians prescribed a single form of vitamin D (calcitriol, paricalcitol, or doxercalciferol) for ≥ 90% of all patient-months. We excluded incident patients (< 90 days on dialysis) and patients whose physicians treated < 5 peritoneal dialysis patients at a dialysis facility, and we assessed mortality.

RESULTS

The analysis inclusion criteria identified 1,707 patients. The subset in this analysis included 12.6% of all prevalent peritoneal dialysis patients and 11.8% of prevalent patient-months. Patients with physicians who predominately prescribed calcitriol had a lower mortality rate: 9.33 (confidence interval (CI) 7.06, 11.60) deaths per 100 patient-years than the doxercalciferol, 12.20 (CI 9.34, 15.06) or paricalcitol, 12.27 (CI 9.27, 15.28) groups. However, these differences were not statistically significant. A Cox proportional hazards model, adjusting for differences in age, vintage, gender, race, body mass index, and comorbidities also showed no significant differences.

CONCLUSIONS

For this peritoneal dialysis population, instrumental variable analyses showed no significant difference in mortality in patients taking the most common oral vitamin D formulations (calcitriol, doxercalciferol, paricalcitol).

Paricalcitol treatment of secondary hyperparathyroidism in hemodialysis patients: a German-Austrian, single-arm, open-label, prospective, noninterventional, observational study

BACKGROUND

Safety and efficacy of paricalcitol in hemodialysis patients with secondary hyperparathyroidism (sHPT) was investigated under routine clinical practice in German and Austrian dialysis centers.

METHODS

Hemodialysis patients with sHPT initiating intravenous paricalcitol were enrolled in this noninterventional study regardless of concomitant sHPT treatment. Prior active vitamin D therapy was discontinued. Clinical laboratory values, including intact parathyroid hormone (iPTH), total serum calcium (Ca), phosphorus (P), Ca × P product, and alkaline phosphatase (AP), were recorded for 6 months following initiation of paricalcitol treatment.

RESULTS

1,313 patients (Austria, n = 280; Germany, n = 1,033) from 169 dialysis centers were enrolled. Most patients (n = 932; 79.1%) had received dialysis for ≥1 year. Median iPTH fell from 518.9 pg/ml [55.0 pmol/l] at baseline to 264.0 pg/ml [28.0 pmol/l] after 6 months (p < 0.0001). After 6 months of treatment, ≥30 and ≥60% reductions in iPTH were observed in 63.0 and 35.9% of patients, respectively. At 6 months, 27.2% of patients achieved iPTH levels between 150 and <300 pg/ml [15.9 and <31.8 pmol/l] compared with 9.7% at baseline. Ca, P, and Ca × P levels remained stable in the majority of patients. AP levels declined from a median of 98 U/l at baseline to 83 U/l (p < 0.0001) at 6 months. Monitoring of adverse events and clinical laboratory assessments identified no unexpected safety signals for paricalcitol.

CONCLUSIONS

Paricalcitol is an effective and well-tolerated treatment option for the control of iPTH levels in hemodialysis patients with sHPT. The results of this study support the results of previous trials under real-time clinical practice conditions in Austria and Germany.

Comparative cost analysis of management of secondary hyperparathyroidism with paricalcitol or cinacalcet with low-dose vitamin D in hemodialysis patients

OBJECTIVE

The objective of this analysis was to compare costs of paricalcitol or cinacalcet plus low dose vitamin D, and of phosphate binders, in patients in the IMPACT SHPT study; and to extrapolate those to estimate expected annual maintenance costs.

METHODS

IMPACT SHPT was a 28-week, randomized, open-label trial. Subjects from 12 countries received intravenous (IV) or oral paricalcitol, or oral cinacalcet plus fixed IV doxercalciferol or oral alfacalcidol. The primary end-point was the proportion of subjects who achieved a mean intact parathyroid hormone (iPTH) value of 150-300 pg/mL during weeks 21-28 (evaluation period). This study compares the costs of study drugs and phosphate binders among participants during the study and annualized. This analysis includes only those subjects that reached the evaluation period (134 in each group).

RESULTS

The mean total drug costs over the study period were €2606 (SD = €2000) in the paricalcitol group and €3034 (SD = €3006) in the cinacalcet group (difference €428, p = 0.1712). The estimated annualized costs were €5387 (SD = €4139) in the paricalcitol group and €6870 (SD = €6256) in the cinacalcet group (difference €1492, p = 0.0395). In addition, a significantly greater proportion (p = 0.010) of subjects in the paricalcitol arm (56.0%) achieved an iPTH of 150-300 pg/mL during the evaluation period compared to the cinacalcet arm (38.2%).

LIMITATIONS

This was a secondary analysis of the IMPACT SHPT study which was not designed or powered for costs as an outcome. The dosing of study drugs and phosphate binders in the IMPACT study may not reflect actual practice, and patients were followed for 28 weeks, while the treatment of SHPT is long-term.

CONCLUSION

Patients with SHPT requiring hemodialysis who were treated with a paricalcitol-based regimen for iPTH control had lower estimated annual drug costs compared to those treated with cinacalcet plus low-dose vitamin D.

Randomized controlled trial to compare the efficacy and safety of oral paricalcitol with oral calcitriol in dialysis patients with secondary hyperparathyroidism

AIM

The objective of the study was to compare the efficacy and safety of oral paricalcitol with oral calcitriol for treating secondary hyperparathyroidism.

METHODS

We conducted the first multicenter open-labelled parallel group randomized controlled trial in 66 patients on dialysis. Patients were randomized to paricalcitol or calcitriol at a 3:1 dose ratio and adjusted to maintain intact parathyroid hormone (iPTH) level between 150-300 pg/mL, serum calcium ≤2.74 mmol/L and calcium-phosphate product ≤5.63 mmol(2) /L(2). The primary end point was the proportion of patients who achieved >30% reduction in iPTH.

RESULTS

At 24 weeks, 22 (61.1%) patients in the paricalcitol and 22 (73.3%) in the calcitriol group had achieved the primary end-point (P-value = 0.29). The cumulative proportion of patients who achieved the end-point at 6 weeks, 12 weeks and 24 weeks were 50%, 80.6% and 86.1%, respectively, in paricalcitol and 53.3%, 86.7% and 86.7%, respectively, in the calcitriol group (P-value = 0.67). Median time to the end-point was 6 weeks in both groups. There were no significant differences in iPTH level at any time during the study. The median reduction in iPTH at 24 weeks was 48.4% in the paricalcitol group and 41.9% in the calcitriol group (P-value = 0.6). The median maximal iPTH reduction was 77.1% (paricalcitol) and 83.7% (calcitriol), P-value = 0.3. Serum calcium and incidence of hypercalcaemia did not differ between groups. 16.7% of patients in both groups had at least one episode of hypercalcaemia (serum calcium >2.74 mmol/L). Other adverse events were similar between groups.

CONCLUSION

Our study suggests that oral paricalcitol has similar efficacy and safety to oral calcitriol.

Oral paricalcitol versus oral calcitriol in continuous ambulatory peritoneal dialysis patients with secondary hyperparathyroidism

BACKGROUND

Secondary hyperparathyroidism (SHPT) is common in end-stage renal disease. Our primary objective was to evaluate the efficacy of oral paricalcitol versus oral calcitriol on serum intact parathyroid hormone (iPTH) and mineral bone parameters in continuous ambulatory peritoneal dialysis (CAPD) patients with SHPT. The secondary objective was to analyze highly sensitive C-reactive protein (hsCRP) and peritoneal membrane function in both groups.

METHODS

This was a prospective randomized control trial. CAPD patients with SHPT were randomized to paricalcitol or calcitriol for 15 weeks. Serum intact iPTH, calcium, phosphate and alkaline phosphatase (ALP) were measured at baseline and every 3 weeks. Serum hsCRP and peritoneal membrane functions were measured at baseline and at week 15.

RESULTS

A total of 26 patients were enrolled and randomized-12 to paricalcitol and 14 to calcitriol. Serum iPTH reduced significantly in both groups and there was no difference in the incidence of ≥50 % reduction of iPTH between both groups. There was a significant increase in serum calcium in both groups but there were no differences in serum phosphorus across the visits. The incidence of hypercalcemia was the same in both groups. Serum calcium-phosphorus (Ca × P) product increased in the paricalcitol group but decreased in the calcitriol group. Serum ALP decreased significantly in both groups. There were also no differences in pre- and post-treatment serum hsCRP and peritoneal function test (PFT) in both groups.

CONCLUSION

Both oral paricalcitol and calcitriol were equally efficacious in reducing serum iPTH but were associated with significantly higher serum calcium. Serum Ca × P product increased in the paricalcitol group and decreased in the calcitriol group. Serum hsCRP level and PFT were not affected by either treatment. A larger randomized controlled trial is indicated to confirm these initial findings.

Effects of paricalcitol on calcium and phosphate metabolism and markers of bone health in patients with diabetic nephropathy: results of the VITAL study

Background

Chronic kidney disease (CKD) is associated with elevations in serum phosphate, calcium–phosphorus product and bone-specific alkaline phosphatase (BAP), with attendant risks of cardiovascular and bone disorders. Active vitamin D can suppress parathyroid hormone (PTH), but may raise serum calcium and phosphate concentrations. Paricalcitol, a selective vitamin D activator, suppressed PTH in CKD patients (stages 3 and 4) with secondary hyperparathyroidism (SHPT) with minimal changes in calcium and phosphate metabolism.

Methods

The VITAL study enrolled patients with CKD stages 2–4. We examined the effect and relationship of paricalcitol to calcium and phosphate metabolism and bone markers in a post hoc analysis of VITAL. The study comprised patients with diabetic nephropathy enrolled in a double-blind, placebo-controlled, randomized trial of paricalcitol (1 or 2 μg/day). Urinary and serum calcium and phosphate, serum BAP, and intact PTH (iPTH) concentrations were measured throughout the study.

Results

Baseline demographics and calcium, phosphate, PTH (49% with iPTH <70 pg/mL), and BAP concentrations were similar between groups. A transient, modest yet significant increase in phosphate was observed for paricalcitol 2 μg/day (+0.29 mg/dL; P < 0.001). Dose-dependent increases in serum and urinary calcium were observed; however, there were few cases of hypercalcemia: one in the 1-μg/day group (1.1%) and three in the 2-μg/day group (3.2%). Significant reductions in BAP were observed that persisted for 60 days after paricalcitol discontinuation (P < 0.001 for combined paricalcitol groups versus placebo). Paricalcitol dose-dependent reductions in iPTH were observed. Paricalcitol in CKD patients (±SHPT) was associated with modest increases in calcium and phosphate.

Conclusion

Paricalcitol reduces BAP levels, which may be beneficial for reducing vascular calcification.

Trial registration

Trial is registered with ClinicalTrials.gov, number NCT00421733.

Safety and tolerability of paricalcitol in patients with chronic kidney disease

INTRODUCTION

Secondary hyperparathyroidism (SHPT) is a complication of chronic kidney disease (CKD). Beyond skeletal complications, uncontrolled SHPT is associated with cardiovascular mortality. Vitamin D receptor activators (VDRAs) are a mainstay of therapy for SHPT; however, use is limited by hypercalcemia, though less so with calcitriol analogs such as paricalcitol and there is emerging experience with oral formulations for non-SHPT indications. The role of VDRAs in the treatment of SHPT becomes a complex question as alternative strategies have developed.

AREAS COVERED

This review summarizes trials that established the safety and efficacy of paricalcitol for SHPT. Comparative experience with paricalcitol as against other VDRAs will be reviewed as will the experience with paricalcitol in non-dialysis CKD and comparative experience with non-VDRA-based therapy.

EXPERT OPINION

VDRA therapy is considered first-line therapy for treatment of SHPT. Paricalcitol has demonstrated superiority to calcitriol with respect to parathyroid hormone suppression and calcium-phosphorus balance. Oral formulations of paricalcitol appear to be similarly effective for SHPT. While there is evidence to suggest adjunctive antiproteinuria benefit with the use of VDRAs, efficacy of these agents to slow the progression of CKD or to reduce cardiovascular risk has not yet been demonstrated.

Comparison between calcitriol and calcitriol plus low-dose cinacalcet for the treatment of moderate to severe secondary hyperparathyroidism in chronic dialysis patients

Aim: Uremic hyperparathyroidism (UHPT) has been shown to contribute to the development and progression of chronic kidney disease—mineral bone disorder. UHPT is frequently observed in chronic dialysis patients, and patients with UHPT are associated with increased risk of all-cause and cardiovascular mortality. Cinacalcet is a novel agent that increases sensitivity to the calcium-sensing receptor and is approved for control of UHPT. Nevertheless, cinacalcet is costly and information regarding efficacy of low-dose cinacalcet on UHPT is limited. Methods: We conducted a retrospective study to evaluate treatment with either low-dose calcitriol combined with low-dose cinacalcet (25 mg) (d-Cinacalcet) or calcitriol alone (VitD) in dialysis patients with moderate to severe UHPT. A total of 81 dialysis patients were enrolled (40 subjects in d-Cinacalcet group and 41 subjects in VitD group). Demographic data including age, gender, duration on dialysis and biochemical data were reviewed and recorded. Results: At the end of the study, the intact parathyroid hormone (iPTH) levels of the d-Cinacalcet group declined significantly (from 1166.0 ± 469.3 pg/mL to 679.8 ± 421.6 pg/mL, p < 0.0001), while there was no significant change in the VitD group. Significant decrease of serum calcium (Ca: 9.9 ± 0.6 mg/dL vs. 9.6 ± 0.8 mg/dL, p = 0.002), phosphorus (P: 5.9 ± 1.3 mg/dL vs. 4.9 ± 0.9 mg/dL, p < 0.0001) and calcium phosphate product (Ca × P: 58.7 ± 15.0 mg²/dL² vs. 46.9 ± 8.9 mg²/dL², p < 0.0001) were observed in the d-Cinacalcet group. In addition, the subjects in the d-Cinacalcet group had a greater proportion to achieve Kidney Disease Outcomes Quality Initiative (KDOQI)-recommended biochemical targets than the subjects in the VitD group (Ca: 48% vs. 24%; P: 78% vs. 32%; Ca × P: 85% vs. 37%; iPTH: 15% vs. 0%). Conclusions: We conclude that combination therapy of low-dose cinacalcet and calcitriol is more effective than calcitriol alone as a treatment for moderate and severe UHPT in chronic dialysis patients. Furthermore, this therapy is associated with improvement in hyperphosphatemia and hypercalcemia.

Treatment with oral paricalcitol in daily clinical practice for patients with chronic kidney disease stage 3-4: a preliminary study

Background

Active vitamin D is an effective treatment for secondary hyperparathyroidism (SHPT) in chronic kidney disease (CKD) patients often complicated by hypercalcaemia and hyperphosphataemia. Treatment with paricalcitol, a selective vitamin D receptor activator, has shown benefits by adequately reducing parathyroid hormone (PTH) levels with minimal changes in serum calcium (Ca) and phosphorus (P). The purpose of this study is to present data on the use of oral paricalcitol in real-life clinical practice in patients with CKD stage 3–4 and SHPT.

Methods

We studied 43 patients, M/F: 25/18, median age: 74 years (47–87), CKD stage 3/4: 16/27, with SHPT, who were prescribed oral paricalcitol at recommended doses for 6 months. Monthly measurements of serum intact PTH (iPTH), Ca, P, alkaline phosphatase (ALP), haemoglobin, albumin (ALB), lipid profile, proteinuria and 24-h urine creatinine clearance were performed 3 months before and 6 months after treatment initiation.

Results

Paricalcitol induced a significant, early and sustained, through the end of follow-up period, decrease in iPTH and ALP levels and an increase in serum ALB. No significant increase in Ca and P levels as well as in Ca × P product was observed during the study period. No significant changes were found in protein excretion, kidney function and the other measured parameters between baseline and last evaluation. Paricalcitol final median dose was 5 μg/week ranging between 3 and 7 μg/week.

Conclusions

In the context of real-life clinical practice, oral paricalcitol for 6 months is an effective, well-tolerated treatment of SHPT in CKD stage 3–4 with minimal effects on calcium and phosphorus metabolism.

Potential new treatments for diabetic kidney disease

Antifibrotic agents, antioxidant agents, ET-a receptor antagonists, and a few other agents with nonspecific or multifaceted mechanisms of action have been evaluated and progressed to small clinical studies in human subjects. Although there are limited data at the present time, these early evaluations have produced some favorable results that at least warrant further investigation. There is certainly not enough compelling evidence to justify the routine use of any of these products specifically for DKD at the moment; however, more well-controlled and adequately powered studies in several hundred patients will help determine which of these may have a place in the DKD treatment armamentarium of the future.

Meta-analysis: the efficacy and safety of paricalcitol for the treatment of secondary hyperparathyroidism and proteinuria in chronic kidney disease

Introduction. Previous studies have demonstrated the safety and efficacy of using Paricalcitol for the treatment of secondary hyperparathyroidism (SHPT) in patients on dialysis. The aim of the current meta-analysis was to assess the safety and efficacy of Paricalcitol for the management of SHPT in patients with chronic kidney disease (CKD) not yet on dialysis. A secondary aim was to determine if sufficient data was available to assess the effect of Paricalcitol for the management of proteinuria. Methods. A meta-analysis was conducted using the Cochrane Collaboration's RevMan 4.2 software. Results. Paricalcitol is effective in lowering PTH in patients with CKD not yet on dialysis and is also effective in lowering proteinuria in diabetic CKD patients. However, we uncovered a safety signal identifying an elevated calcium phosphate product and a trend towards the development of hypercalcemia. A phosphate elevation was not demonstrated because the target used in the clinical studies was a P > 5.5 mg/dl, a value appropriate for dialysis patients and not CKD patients. Conclusion. Although Paricalcitol is effective in lowering PTH, we advise caution in the use of any active Vitamin D analogues in patients with CKD because of the potential risk of exacerbating vascular calcification.

Paricalcitol versus cinacalcet plus low-dose vitamin D therapy for the treatment of secondary hyperparathyroidism in patients receiving haemodialysis: results of the IMPACT SHPT study

BACKGROUND

Optimal treatment for secondary hyperparathyroidism (SHPT) has not been defined. The IMPACT SHPT (ClinicalTrials.gov identifier: NCT00977080) study assessed whether dose-titrated paricalcitol plus supplemental cinacalcet only for hypercalcaemia is superior to cinacalcet plus low-dose vitamin D in controlling intact parathyroid hormone (iPTH) levels in patients with SHPT on haemodialysis.

METHODS

In this 28-week, multicentre, open-label Phase 4 study, participants were randomly selected to receive paricalcitol or cinacalcet plus low-dose vitamin D. Randomization and analyses were stratified by mode of paricalcitol administration [intravenous (IV) or oral]. The primary efficacy end point was the proportion of subjects who achieved a mean iPTH value of 150-300 pg/mL during Weeks 21-28.

RESULTS

Of 272 subjects randomized, 268 received one or more dose of study drug; 101 in the IV and 110 in the oral stratum with two or more values during Weeks 21-28 were included in the primary analysis. In the IV stratum, 57.7% of subjects in the paricalcitol versus 32.7% in the cinacalcet group (P = 0.016) achieved the primary end point. In the oral stratum, the corresponding proportions of subjects were 54.4% for paricalcitol and 43.4% for cinacalcet (P = 0.260). Cochran-Mantel-Haenszel analysis, controlling for stratum, revealed overall superiority of paricalcitol (56.0%) over cinacalcet (38.2%; P = 0.010) in achieving iPTH 150-300 pg/mL during Weeks 21-28. Hypercalcaemia occurred in 4 (7.7%) and 0 (0%) of paricalcitol-treated subjects in the IV and oral strata, respectively. Hypocalcaemia occurred in 46.9% and 54.7% of cinacalcet-treated subjects in the IV and oral strata, respectively.

CONCLUSION

Paricalcitol versus cinacalcet plus low-dose vitamin D provided superior control of iPTH, with low incidence of hypercalcaemia.

Cardiorenal syndrome and vitamin D receptor activation in chronic kidney disease

Cardiorenal syndrome (CRS) refers to a constellation of conditions whereby heart and kidney diseases are pathophysiologically connected. For clinical purposes, it would be more appropriate to emphasize the pathophysiological pathways to classify CRS into: (1) hemodynamic, (2) atherosclerotic, (3) uremic, (4) neurohumoral, (5) anemic–hematologic, (6) inflammatory–oxidative, (7) vitamin D receptor (VDR) and/or FGF23-, and (8) multifactorial CRS. In recent years, there have been a preponderance data indicating that vitamin D and VDR play an important role in the combination of renal and cardiac diseases. This review focuses on some important findings about VDR activation and its role in CRS, which exists frequently in chronic kidney disease patients and is a main cause of morbidity and mortality. Pathophysiological pathways related to suboptimal or defective VDR activation may play a role in causing or aggravating CRS. VDR activation using newer agents including vitamin D mimetics (such as paricalcitol and maxacalcitol) are promising agents, which may be related to their selectivity in activating VDR by means of attracting different post-D-complex cofactors. Some, but not all, studies have confirmed the survival advantages of D-mimetics as compared to non-selective VDR activators. Higher doses of D-mimetic per unit of parathyroid hormone (paricalcitol to parathyroid hormone ratio) is associated with greater survival, and the survival advantages of African American dialysis patients could be explained by higher doses of paricalcitol (>10 μg/week). More studies are needed to verify these data and to explore additional avenues for CRS management via modulating VDR pathway.

Paricalcitol versus cinacalcet plus low-dose vitamin D for the treatment of secondary hyperparathyroidism in patients receiving haemodialysis: study design and baseline characteristics of the IMPACT SHPT study

Background. Paricalcitol and cinacalcet are common therapies for patients on haemodialysis with secondary hyperparathyroidism (SHPT). We conducted a multi-centre study in 12 countries to compare the safety and efficacy of paricalcitol and cinacalcet for the treatment of SHPT.

Methods. Patients aged ≥18 years with Stage 5 chronic kidney disease receiving maintenance haemodialysis and with intact parathyroid hormone (iPTH) 300–800 pg/mL, calcium 8.4–10.0 mg/dL (2.09–2.49 mmol/L) and phosphorus ≤6.5 mg/dL (2.09 mmol/L) were randomized within two strata defined by the mode of paricalcitol administration to treatment with paricalcitol- (intra-venous, US and Russian sites, IV stratum; oral, non-US and non-Russian sites, oral stratum) or cinacalcet-centred therapy. The primary endpoint is the proportion of patients in each treatment group who achieve a mean iPTH value of 150–300 pg/mL during Weeks 21–28 of treatment. Assuming efficacy response rates of 36 and 66% for cinacalcet and paricalcitol, respectively, and a 20% discontinuation rate, 124 subjects in each stratum were estimated to provide 81% power to detect a 30% absolute difference in the primary endpoint.

Results. Of 746 patients screened, 272 (mean age, 63 years; mean iPTH, 509 pg/mL) were randomized. Mean duration of haemodialysis at baseline was 3.7 years. Comorbidities included hypertension (90.4%), Type 2 diabetes (40.4%), congestive heart failure (17.3%), coronary artery disease (34.6%) and gastrointestinal disorders (75%).

Conclusions. The study participants are representative of a multinational cohort of patients on haemodialysis with elevated iPTH. The study results will provide valuable information on the best available treatment of SHPT in patients on haemodialysis.

Bone alkaline phosphatase and mortality in dialysis patients

BACKGROUND AND OBJECTIVES

Serum alkaline phosphatase (AP) is associated with vascular calcification and mortality in hemodialysis patients, but AP derives from various tissues of origin. The aim of this study was to assess the effect of bone-specific AP (BAP) on morbidity and mortality in dialysis patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

From a prospective cohort study of incident dialysis patients in The Netherlands, all patients with measured BAP at 12 months after the start of dialysis (baseline) were included in the analysis (n = 800; mean age, 59 ± 15 years; mean BAP = 18 ± 13 U/L). By Cox regression analyses, we assessed the impact of BAP levels on short-term mortality (6 months) and longer-term mortality (4-year follow-up).

RESULTS

High levels of BAP strongly affected short-term mortality. After adjustment for confounders, patients in the highest BAP tertile had a 5.7-fold increased risk of death within 6 months compared with patients in the lowest tertile. The effect applied to both cardiovascular and noncardiovascular mortality. Furthermore, high levels of BAP were associated with increased cardiovascular mortality in the longer term. In comparison with total AP, the effect sizes related to clinical outcomes were much higher for BAP.

CONCLUSIONS

High levels of BAP were strongly associated with short-term mortality in dialysis patients, pointing out the important impact of bone turnover. Longitudinal assessments of BAP may be useful for the treatment monitoring in clinical practice in dialysis patients.

Vitamin d receptor activators and clinical outcomes in chronic kidney disease

Vitamin D deficiency appears to be an underestimated risk factor for cardiovascular disease in patients with chronic kidney disease. Evidence from both basic science and clinical studies supports the possible protective role of vitamin D beyond its effect on mineral metabolism. Toxicity of pharmacologic doses of active vitamin D metabolites, in particular calcitriol, is mainly due to the possibility of positive calcium and phosphorus balance. Therefore, vitamin D analogs have been developed, which suppress PTH secretion and synthesis with reduced calcemic and phosphatemic effects. Observational studies suggest that in hemodialysis patients the use of a vitamin D receptor (VDR) activator, such as calcitriol, doxercalciferol, paricalcitol, or alfacalcidol, is associated with a reduced mortality when compared with nonusers of any VDR activator. In this article the existing literature on the topic is reviewed, although a more robust answer to the question of whether or not VDR activators have beneficial effects in hemodialysis patients will hopefully come from a randomized controlled trial.

Paricalcitol in secondary hyperparathyroidism and the survival benefit in patients with chronic kidney disease

Secondary hyperparathyroidism is a characteristic feature of chronic kidney disease, which develops early in the course of chronic kidney disease, often in a progressive way. It occurs as the renal function continues to decline and is encountered following a series of biochemical abnormalities, which are responsible for initiation and maintenance of increased parathyroid hormone (PTH) secretion. Several agents are used in the management of secondary hyperparathyroidism. Paricalcitol is a new generation selective vitamin D receptor activator that lowers PTH levels by exerting a less hypercalcaemic and hyperphosphataemic effect. In addition, there is emerging evidence of the benefit of paricalcitol in preventing intravascular calcification and proteinuria.

The effect of combined calcium and vitamin D3 supplementation on serum intact parathyroid hormone in moderate CKD

BACKGROUND

Studies addressing the effects of vitamin D(3) supplementation on secondary hyperparathyroidism in patients with moderate chronic kidney disease are scarce.

STUDY DESIGN

Post hoc analysis of the randomized clinical trial Vitamin D, Calcium, Lyon Study II (DECALYOS II) to assess effects according to baseline estimated glomerular filtration rate (eGFR).

SETTING & PARTICIPANTS

Multicenter, randomized, double-blinded, placebo-controlled study of 639 elderly women randomly assigned to calcium-vitamin D(3) fixed combination; calcium plus vitamin D(3) separate combination, or placebo.

INTERVENTIONS

Placebo or calcium (1,200 mg) and vitamin D(3) (800 IU) in fixed or separate combination.

OUTCOMES & MEASUREMENTS

Proportion of participants with a mean decrease in intact parathyroid hormone (iPTH) level of 30% or greater. eGFR was calculated using the 4-variable Modification of Diet in Renal Disease (MDRD) Study equation and categorized as 60 or greater, 45 to 59, and less than 45 mL/min/1.73 m(2).

RESULTS

610 participants had an eGFR at baseline: 288 (47.2%), 222 (36.4%), and 100 (16.4%) were in each decreasing eGFR category. Across decreasing eGFR groups, 88%, 86%, and 89% had 25-hydroxyvitamin D (25[OH]D) levels less than 15 ng/mL at baseline. On treatment, similar improvements in the proportion of participants achieving 25(OH)D levels greater than 30 ng/mL at 6 months were seen in all kidney function groups (43%, 49%, and 41%, respectively). Active regimens versus placebo increased mean 25(OH)D levels from baseline in all eGFR groups at all times (P < 0.001 for all). The proportion with a 30% or greater decrease in iPTH level at 6 months was 50% in all eGFR groups on treatment versus 6% to 9% for placebo (P < 0.001 for all). The effects of the intervention on iPTH levels did not differ according to baseline eGFR (interaction P > 0.1 for all times).

LIMITATIONS

This study included only elderly white women.

CONCLUSION

Vitamin D(3) was effective in increasing 25(OH)D and decreasing iPTH levels in patients with moderate chronic kidney disease.

Cinacalcet HCl and concurrent low-dose vitamin D improves treatment of secondary hyperparathyroidism in dialysis patients compared with vitamin D alone: the ACHIEVE study results

BACKGROUND AND OBJECTIVES

Patients with chronic kidney disease (CKD) receiving dialysis often develop secondary hyperparathyroidism with disturbed calcium and phosphorus metabolism. The National Kidney Foundation-Kidney Disease Outcomes Quality Initiative (KDOQI) was established to guide treatment practices for these disorders. The ACHIEVE study was designed to test two treatment strategies for achieving KDOQI goals.

DESIGN, SETTING, PARTICIPANTS, MEASUREMENTS

Individuals on hemodialysis treated with vitamin D sterols were enrolled in this 33-week study. Subjects were randomly assigned to treatment with either cinacalcet and low-dose vitamin D (Cinacalcet-D) or flexible vitamin D alone (Flex-D) to achieve KDOQI-recommended bone mineral targets. ACHIEVE included a 6-week screening phase, including vitamin D washout, a 16-week dose-titration phase, and an 11-week assessment phase.

RESULTS

Of 173 subjects enrolled, 83% of Cinacalcet-D and 67% of Flex-D subjects completed the study. A greater proportion of Cinacalcet-D versus Flex-D subjects had a >30% reduction in parathyroid hormone (PTH) (68% versus 36%, P < 0.001) as well as PTH <300 pg/ml (44% versus 23%, P = 0.006). The proportion of subjects simultaneously achieving targets for intact PTH (150-300 pg/ml) and calcium-phosphorus product (Ca x P) (<55 mg2/dl2) was also greater (21% versus 14%), but this was not statistically significant. This was attributable to 19% of Cinacalcet-D subjects with a PTH value below the KDOQI target range.

CONCLUSIONS

Achievement of KDOQI targets was difficult, especially with Flex-D. Maintaining calcium and phosphorus target values precluded the use of vitamin D doses necessary to lower PTH to within the narrow target range and highlighted limitations inherent to the KDOQI treatment algorithm.

Vitamin D and Peritoneal Dialysis

Chronic kidney disease – mineral and bone disorder (CKD–MBD) is a cause of significant morbidity and mortality in patients with long-standing kidney disease. Management of secondary hyperparathyroidism includes the use of phosphorus-binding agents and treatment with activated vitamin D compounds, better referred to as vitamin D receptor agonists (VDRAs). In an effort to maximize the therapeutic response while reducing the adverse effects of calcitriol, the naturally synthesized hormone, the use of intravenous administration and several selective VDRAs have been developed. Recently, oral preparations of these selective VDRAs have become available, enabling their use in the peritoneal dialysis (PD) population. The present report reviews the data concerning the use of oral VDRAs for the treatment of hyperparathyroidism in PD patients. The data, although limited, appear to support the use of oral paricalcitol as the VDRA in PD patients. In addition, traditional teaching focuses only on therapy with VDRAs, ignoring vitamin D replacement in CKD stage 5. However, given the potential benefits of calcidiol (25-OH-D) repletion and the rampant 25-OH-D deficiency in the PD population, our opinion is that screening for and treating that deficiency should extend beyond early CKD and also include PD patients.