Meta-Analysis of Biochemical and Patient-Level Effects of Calcimimetic Therapy

Pathophysiology and therapies of CKD-associated secondary hyperparathyroidism

Uremic secondary hyperparathyroidism (SHP) refers to the biochemical abnormalities that characterize CKD-MBD. However, historically parathyroid hormone (PTH) is identified as the key culprit hormone and the essential biomarker of secondary hyperparathyroidism. SHP represents the adaptive response to several mineral abnormalities that initiate and maintain increased PTH secretion through classical mineral derangements and more recently elucidated hormonal dysregulations. Among classic factors involved in the pathogenesis of SHP, phosphate, calcium, and calcitriol have a prominent role. The discovery of new pathogenetic factors involved in the development of SHP (and the eventual CKD-MBD) including fibroblast growth factor-23 (FGF23) and klotho provides new hypothesis and perspectives to our understanding of this complex metabolic disturbance. Recently more than serum phosphate a critical role in regulating FGF23 synthesis and the progression of CKD is ascribed to phosphate pool, reflected by production of glycerol-3-phosphate and the formation of excessive CPP-2. Finally, also skeletal resistance to PTH action, due to dysregulation of the Wnt-β-catenin system and intestinal dysbiosis, affecting the PTH actions on bone are causal factor of SHP. Identifying all the actors at play is mandatory to allow the most precise therapeutic prescription in the individual patient. This paper aims to review, in particular, the pathophysiology of SHP, which is essential to envisage the eventual therapeutic options for the associated MBD.

The Effectiveness of Alternate-day Cinacalcet Therapy for Secondary Hyperparathyroidism in Noncompliant Hemodialysis Patients

Chronic kidney disease (CKD) is defined as an abnormality of the kidney's structure or function that is present for more than 3 months. Secondary hyperparathyroidism is a consequence of CKD, which eventuates with a decrease in the glomerular filtration rate. This study aimed to evaluate the effectiveness of alternate-day cinacalcet in noncompliant dialysis patients compared with a daily dose. The effects on the levels of intact parathyroid hormone (iPTH), calcium, and phosphorus were measured, and the compliance of patients with our protocol was observed. We followed the patients' (n = 134) iPTH levels every 3 months and their serum calcium and phosphorous monthly for 6 months and compared the results with 6 months of data from patients receiving daily doses of cinacalcet. The patients' mean age was 49.54 ± 16.17 years, the mean duration of dialysis was 6.44 ± 5.10 years, and 37.3% had diabetic nephropathy. The mean dose of alternate-day cinacalcet was 61.92 ± 26.59 mg. The level of iPTH before and after the change was 924.63 ± 474.132 pg/mL and 787.87 ± 496.49 pg/mL, respectively (P = 0.001), and the mean serum calcium level before and after was 8.56 ± 1.91 mg/dL and 8.85 ± 1.25 mg/dL, respectively (P = 0.035). The level of serum phosphorous before and after the change was 4.81 ± 1.32 mg/dL and 5.08 ± 2.3 mg/dL, respectively (P = 0.204). Cinacalcet produced significant reductions in iPTH with intermittent (three times per week) doses and thus was more cost-effective and had better compliance.

Clinical outcomes of parathyroidectomy versus cinacalcet in the clinical management of secondary hyperparathyroidism

Parathyroidectomy (PTX) is the standard treatment for secondary hyperparathyroidism (SHPT); however, the administration of cinacalcet has gained prominence as a noninvasive treatment. We aimed to determine whether PTX or cinacalcet is more effective in preventing morbidity and mortality through reviewing follow-up data concerning surgical management of SHPT. We retrospectively analyzed and divided 209 patients with SHPT into two treatment groups: PTX (n = 78) and cinacalcet (n = 131) groups. We compared clinical features, the over-the-target range rate during pre- and post-intervention periods, new cardiovascular events, and all-cause mortality between both groups. Almost all biochemical parameters were well controlled in the post-intervention period, and were within the recommended target range for the PTX group but not for the cinacalcet group. A significant difference was observed in the over-the-target range rate during the post-intervention period between the groups. PTX and cinacalcet interventions significantly lowered the over-the-target range rates for serum intact parathyroid hormone (iPTH) (>300 pg/mL), corrected calcium (>10.5 mg/mL), serum phosphorus (>5.5 mg/dL), and calcium-phosphorus product (>55) in both groups (p = 0.001). PTX reduced the risk of new cardiovascular events by 86% compared to cinacalcet (p = 0.001); however, all-cause mortality did not differ significantly (14.1% vs. 7.6%, p = 0.132). For patients with SHPT, PTX helps prevent cardiovascular events through normalizing biochemical variables, according to recommended guidelines. PTX should be considered before cinacalcet treatment to prevent new cardiovascular events. Early PTX for appropriate patients can help prevent immediate postoperative complications and mortality.

Treatment of secondary hyperparathyroidism in patients on hemodialysis using a novel synthetic peptide calcimimetic, etelcalcetide: a short-term clinical study

Objective

Secondary hyperparathyroidism (SHPT) is a major complication in patients with chronic kidney disease (CKD). SHPT is related to chronic kidney disease-mineral bone disorder, leading to increased morbidity and mortality. Etelcalcetide is intravenously administered at the end of hemodialysis (HD). Etelcalcetide differs from the oral calcimimetic cinacalcet because it reduces gastrointestinal adverse events, thereby improving therapeutic effects. Etelcalcetide has only been approved by the U.S. Food and Drug Administration for several months. Therefore, there have only been a few reports regarding treatment of SHPT using etelcalcetide. This study aimed to evaluate the efficacy of etelcalcetide in patients on HD with SHPT.

Methods

Nine patients on HD (four men and five women, aged 58 ± 10 years) were enrolled in this study. All of the patients received etelcalcetide (5–10 mg, three times a week after HD). The observation period was 4.4 ± 1.0 months.

Results

All of the patients showed a significant reduction in serum parathyroid hormone levels during the observation period (−59% ± 20%). No significant adverse effects were observed.

Conclusions

Although this study had an uncontrolled small group and a short observation period, our results suggest that etelcalcetide could be a promising agent for SHPT treatment.

Old and new calcimimetics for treatment of secondary hyperparathyroidism: impact on biochemical and relevant clinical outcomes

Secondary hyperparathyroidism (SHPT) is associated with increased bone turnover, risk of fractures, vascular calcifications, and cardiovascular and all-cause mortality. The classical treatment for SHPT includes active vitamin D compounds and phosphate binders. However, achieving the optimal laboratory targets is often difficult because vitamin D sterols suppress parathyroid hormone (PTH) secretion, while also promoting calcium and phosphate intestinal absorption. Calcimimetics increase the sensitivity of the calcium-sensing receptor, so that even with lower levels of extracellular calcium a signal can still exist, leading to a decrease of the set-point for systemic calcium homeostasis. This enables a decrease in plasma PTH levels and, consequently, of calcium levels. Cinacalcet was the first calcimimetic to be approved for clinical use. More than 10 years since its approval, cinacalcet has been demonstrated to effectively reduce PTH and improve biochemical control of mineral and bone disorders in chronic kidney patients. Three randomized controlled trials have analysed the effects of treatment with cinacalcet on hard clinical outcomes such as vascular calcification, bone histology and cardiovascular mortality and morbidity. However, a final conclusion on the effect of cinacalcet on hard outcomes remains elusive. Etelcalcetide is a new second-generation calcimimetic with a pharmacokinetic profile that allows thrice-weekly dosing at the time of haemodialysis. It was recently approved in Europe, and is regarded as a second opportunity to improve outcomes by optimizing treatment for SHPT. In this review, we summarize the impact of cinacalcet with regard to biochemical and clinical outcomes. We also discuss the possible implications of the new calcimimetic etelcalcetide in the quest to improve outcomes.

Dynamics of cinacalcet use and biochemical control in hemodialysis patients: a retrospective New-user cohort design

Background

Cinacalcet is used to treat secondary hyperparathyroidism among hemodialysis patients. Large-scale epidemiologic studies describing patterns of cinacalcet use, effects on parathyroid hormone (PTH), calcium, and phosphorous levels, and predictors of discontinuation have not been previously reported.

Methods

This retrospective cohort study used a clinical database of a large U.S. dialysis provider (2007–2010) merged with administrative data from the United States Renal Data System. Among new users of cinacalcet with Medicare coverage, trends in PTH, calcium, and phosphorus were measured in 30-day intervals following cinacalcet initiation.

Results

Seventeen thousand seven hundred sixty-three eligible initiators contributed 111,047 30-day follow-up intervals. Of these, 56 % discontinued cinacalcet by month 4. Of those discontinuing, 76.3 % reinitiated. Mean values of PTH, calcium, and phosphorus decreased to recommended levels within 4 months following initiation. Proximal PTH levels <150 pg/mL were associated with discontinuation: HR = 1.23 (95 % CI: 1.12, 1.36), whereas low calcium (<7.5 mg/dL) was suggestive of an association, HR = 1.09 (95 % CI 0.91, 1.32). Being in the Part D gap period increased discontinuation risk: HR = 1.09 (95 % CI: 1.03, 1.16). Low-income subsidy status decreased discontinuation risk: HR = 0.77 (95 % CI 0.69, 0.86). Predictors of reinitiation included low-income subsidy, HR = 1.32 (95 % CI 1.22, 1.43); higher albumin level, HR = 1.23 (95 % CI 1.10, 1.36) and higher calcium level, HR = 1.26 (95 % CI 1.19, 1.33).

Conclusions

Substantial and expected declines in laboratory values occurred following cinacalcet initiation. Early discontinuation and reinitiation of cinacalcet were common and may have occurred for clinical and economic reasons.

Electronic supplementary material

The online version of this article (doi:10.1186/s12882-015-0174-6) contains supplementary material, which is available to authorized users.

Calcimimetics for secondary hyperparathyroidism in chronic kidney disease patients

BACKGROUND

Calcimimetic agents lower abnormal serum parathyroid hormone (PTH) levels in people who have chronic kidney disease (CKD), but the benefits and harms on patient-level outcomes are uncertain. Since this review was first published in 2006 showing that evidence for calcimimetics was largely restricted to biochemical outcomes, additional studies have been conducted. This is an update of a review first published in 2006.

OBJECTIVES

To evaluate the benefits and harms of cinacalcet on patient-level outcomes in adults with CKD.

SEARCH METHODS

MEDLINE, EMBASE, CENTRAL and conference proceedings were searched for randomised controlled trials (RCTs) evaluating any calcimimetic against placebo or another agent in adults with CKD (persistent albuminuria > 30 mg/g with or without reduced glomerular filtration rate (GFR) (below 60 mL/min/1.73 m²)). We updated searches to 7 February 2013 including the Cochrane Renal Group's Specialised Register to complete this update.

SELECTION CRITERIA

We included all RCTs of a calcimimetic administered to patients with CKD for the treatment of elevated serum PTH levels.

DATA COLLECTION AND ANALYSIS

Data were extracted on all relevant patient-centred and surrogate outcomes. We summarised treatment estimates using random effects and expressed treatment effects as a risk ratio (RR) or mean difference (MD) with 95% confidence intervals (CI).

MAIN RESULTS

Eighteen studies (7446 participants) compared cinacalcet in addition to standard therapy with no treatment or placebo plus standard therapy. In adults with GFR category G5 (GFR below 15 mL/min/1.73 m²) treated with dialysis, routine cinacalcet treatment had little or no effect on all-cause mortality (RR 0.97, 95% CI 0.89 to 1.05), imprecise effects on cardiovascular mortality (RR 0.67, 95% CI 0.16 to 2.87), and prevented surgical parathyroidectomy (RR 0.49, 95% CI 0.40 to 0.59) and hypercalcaemia (RR 0.23, 95% CI 0.05 to 0.97), but increased hypocalcaemia (RR 6.98, 95% CI 5.10 to 9.53), nausea (RR 2.02, 95% CI 1.45 to 2.81) and vomiting (RR 1.97, 95% CI 95% CI 1.73 to 2.24). Cinacalcet decreased serum PTH (MD -281.39 pg/mL, 95% CI -325.84 to -234.94) and calcium (MD -0.87 mg/dL, 95% CI -0.96 to -0.77) levels, but had little or no effect on serum phosphorous levels (MD -0.23 mg/dL, 95% CI -0.58 to 0.12).Data were sparse for adults with GFR categories G3a to G4 (GFR 15 to 60 mL/min/1.73 m²) and kidney transplant recipients.Overall, based on GRADE criteria, evidence for cinacalcet in adults with GFR category G5 treated with dialysis (mortality, parathyroidectomy, hypocalcaemia, and nausea) is of high or moderate quality. High quality evidence suggests "further research is very unlikely to change our confidence in the estimate of treatment effect" and moderate quality evidence is "further research is likely to have an important impact on our confidence in the estimate of effect and may change the estimate". Information for adults with less severe CKD GFR category G3a to G4 is of low or very low quality. This means that further research is very likely to have an important impact on our confidence in the estimate of effect and is likely to change the estimate

AUTHORS' CONCLUSIONS

Routine cinacalcet therapy reduced the need for parathyroidectomy in adults treated with dialysis and elevated PTH levels but does not improve all-cause or cardiovascular mortality. Cinacalcet increases risks of nausea, vomiting and hypocalcaemia, suggesting harms may outweigh benefits in this population.

Mineral metabolic abnormalities and mortality in dialysis patients

The survival rate of dialysis patients, as determined by risk factors such as hypertension, nutritional status, and chronic inflammation, is lower than that of the general population. In addition, disorders of bone mineral metabolism are independently related to mortality and morbidity associated with cardiovascular disease and fracture in dialysis patients. Hyperphosphatemia is an important risk factor of, not only secondary hyperparathyroidism, but also cardiovascular disease. On the other hand, the risk of death reportedly increases with an increase in adjusted serum calcium level, while calcium levels below the recommended target are not associated with a worsened outcome. Thus, the significance of target levels of serum calcium in dialysis patients is debatable. The consensus on determining optimal parathyroid function in dialysis patients, however, is yet to be established. Therefore, the contribution of phosphorus and calcium levels to prognosis is perhaps more significant. Elevated fibroblast growth factor 23 levels have also been shown to be associated with cardiovascular events and death. In this review, we examine the associations between mineral metabolic abnormalities including serum phosphorus, calcium, and parathyroid hormone and mortality in dialysis patients.

Educational paper: Progression in chronic kidney disease and prevention strategies

Chronic kidney disease (CKD) in children is a rare but devastating condition. Once a critical amount of nephron mass has been lost, progression of CKD is irreversible and results in end-stage renal disease (ESRD) and need of renal replacement therapy. The time course of childhood CKD is highly variable. While in children suffering from congenital anomalies of the kidneys and the urinary tract, progression of CKD in general is slow, in children with acquired glomerulopathies, disease progression can be accelerated resulting in ESRD within months. However, irrespective of the underlying kidney disease, hypertension and proteinuria are independent risk factors for progression. Thus, in order to prevent progression, the primary objective of treatment should always aim for efficient control of blood pressure and reduction of urinary protein excretion. Blockade of the renin-angiotensin-aldosterone system preserves kidney function not only by lowering blood pressure, but also by reducing proteinuria and exerting additional anti-proteinuric, anti-fibrotic, and anti-inflammatory effects. Besides, intensified blood pressure control, aiming for a target blood pressure below the 50th percentile, may exert additive renoprotective effects. Additionally, other modifiable risk factors, such as anemia, metabolic acidosis, dyslipidemia, and altered bone-mineral homeostasis may also contribute to CKD progression. In conclusion, beyond strict blood pressure control and reduction of urinary protein excretion, identification and treatment of both, renal disease-related and conventional risk factors are mandatory in children with CKD in order to prevent deterioration of kidney function.

Effects and safety of calcimimetics in end stage renal disease patients with secondary hyperparathyroidism: a meta-analysis

Purpose

Secondary hyperparathyroidism (SHPT) is one of the most common abnormalities of mineral metabolism in patients with chronic kidney disease. We performed a meta-analysis to determine the effect and safety of cinacalcet in SHPT patients receiving dialysis.

Methods

The meta-analysis was performed to determine the effect and safety of cinacalcet in SHPT patients receiving dialysis by using the search terms ‘cinacalcet’ or ‘mimpara’ or ‘sensipar’ or ‘calcimimetic’ or ‘R586’ on MEDLINE and EMBASE (January 1990 to February 2012).

Results

Fifteen trials were included, all of which were performed between 2000 and 2011 enrolling a total of 3387 dialysis patients. Our study showed that calcimimetic agents effectively ameliorated iPTH levels(WMD, −294.36 pg/mL; 95% CI, −322.76 to −265.95, P<0.001) in SHPT patients and reduced serum calcium (WMD, −0.81 mg/dL; 95% CI, −0.89 to −0.72, P<0.001) and phosphorus disturbances(WMD, −0.29 mg/dL; 95% CI, −0.41 to −0.17, P<0.001). The percentage of patients in whom there was a 30% decrease in serum iPTH levels by the end of the dosing was higher in cinacalcet group than that in control group(OR = 10.75, 95% CI: 6.65–17.37, P<0.001). However, no significant difference was found in all-cause mortality and all adverse events between calcimimetics and control groups(OR = 0.86, 95% CI: 0.46–1.60, P = 0.630; OR = 1.30, 95% CI: 0.78–2.18, P = 0.320, respectively). Compared with the control therapy, there was a significant increase in the episodes of hypocalcemia (OR = 2.46, 95% CI: 1.58–3.82, P<0.001), nausea (OR = 2.45, 95% CI: 1.29–4.66, P = 0.006), vomiting(OR = 2.78, 95% CI: 2.14–3.62, P<0.001), diarrhea(OR = 1.51, 95% CI: 1.04–2.20, P = 0.030) and upper respiratory tract infection (OR = 1.79, 95% CI: 1.20–2.66, P = 0.004)in calcimimetics group.

Conclusions

Calcimimetic treatment effectively improved biochemical parameters of SHPT patients receiving dialysis without increasing all-cause mortality and all adverse events.

[Cinacalcet treatment for secondary hyperparathyroidism in dialysis patients in real-world clinical practice - the ECHO observational study: French experience]

In chronic kidney disease patients with secondary hyperparathyroidism (SHPT), the recommended K/DOQI™ target serum levels of parathyroid hormone (PTH), calcium (Ca) and phosphorus (P) are difficult to reach and maintain stable. We present the results of the French cohort from the European study ECHO which investigated the use and effectiveness of cinacalcet in real-world clinical practice.

METHODS

An observational study of the SHPT management in dialysis patients, partially retrospective (from 6 months prior to cinacalcet initiation) and partially prospective (up to 12 months of cinacalcet treatment).

RESULTS

Four hundred and eighty-five French patients were enrolled from 44 centres. Cinacalcet was given in combination with active vitamin D treatment (39%) and phosphate binders (87%). After 12 months, the proportion of patients reaching recommended K/DOQI™ target levels had increased from 2.5% to 28.8% for PTH, from 46.8% to 50.1% for Ca, from 40.0% to 49.9% for P and 54.8% to 77.7% for the CaxP product. The proportions of patients using active vitamin D and sevelamer decreased by 6% and 20% respectively. Adverse events were reported in 37 (7.6%) patients, mainly nausea (2.1%), vomiting (2.1%) and dyspepsia (1.2%).

CONCLUSIONS

The results of this study are consistent with data from controlled and randomized studies showing that cinacalcet increases the proportion of patients achieving the K/DOQI™ targets for PTH, Ca, P and CaxP in real-world clinical practice.

Surgical parathyroidectomy versus cinacalcet therapy: in the management of secondary hyperparathyroidism

OBJECTIVES

The aim of this study was to compare the clinical effectiveness of surgery with calcimimetics as treatment strategies for managing the biochemical abnormalities that characterize secondary hyperparathyroidism (2HPTH), resistant to optimal conventional therapy in patients with end-stage renal failure (ESRF).

STUDY DESIGN

A historical cohort study.

SETTING

Maxillofacial Department, Morriston Hospital, Swansea, United Kingdom.

SUBJECTS AND METHODS

Fifty-four patients with 2HPTH resistant to optimal conventional medical management were studied. One cohort of 20 patients was treated with surgical parathyroidectomy, the other cohort of 34 patients with cinacalcet. Serum parathyroid hormone (PTH) and bone profile were measured before and at monthly intervals after intervention.

RESULTS

Both cohorts were comparable in their demographic profile, pretreatment comorbidities, baseline PTH, and bone profile. In all 20 surgical patients, the 1-week postoperative PTH had decreased by 97% (P < .001); in the medical cohort after 4 months of daily cinacalcet, the PTH decreased by 48% (P < .001) from baseline. This reduction was maintained at 18 months. In all but 1 surgical patient, alkaline phosphatase (ALP) decreased to normal levels, whereas on cinacalcet, there was no statistically significant reduction. Patients who underwent parathyroidectomy had a more significant decrease in PTH (P < .001) and ALP (P < .0014) than did patients on cinacalcet therapy. All patients managed surgically who complained of preoperative symptoms of pruritis and bone pain expressed complete resolution or significant improvement after parathyroidectomy (P < .001, P < .003, respectively).

CONCLUSION

Surgery was superior to "medical" parathyroidectomy in controlling PTH and ALP.

Derangements in phosphate metabolism in chronic kidney diseases/endstage renal disease: therapeutic considerations

The changes in phosphate (PO(4)) metabolism across the spectrum of chronic kidney disease (CKD) and specific strategies to address these abnormalities by reducing PO(4) loads are discussed in this review. This review also addresses briefly the evidence for specific PO(4) serum targets in CKD and endstage renal disease (ESRD) and the potential for other biomarkers such as fibroblast growth factor-23 (FGF-23) to define disease and monitor the effectiveness of therapy. As renal function declines, single nephron excretion of PO(4) must increase to maintain PO(4) balance. Abnormalities in PO(4) metabolism occur early in CKD. Compensatory changes in renal PO(4) handling are sufficient to maintain a normal serum PO(4) level in early stages of CKD, but in more advanced CKD, these processes no longer suffice and overt hyperphosphatemia develops. The resulting increased PO(4) burden contributes directly to development of secondary hyperparathyroidism. The FGF-23 increases early in CKD, likely in response to abnormal PO(4) metabolism, and mediates processes that help restore serum PO(4) levels to normal in CKD stage 3 and in early stage 4. The increased PO(4) burden and subsequent overt hyperphosphatemia are associated with increased mortality and morbidity. Dietary PO(4) restriction, modification of dialysis prescriptions, and administration of oral PO(4) binders can restore PO(4) balance. As CKD progresses, population-based studies demonstrate that diet alone is typically not able to prevent or treat hyperphosphatemia. Dialysis modalities that are currently used often fail to remove sufficient PO(4) to prevent hyperphosphatemia in patients with an inadequately controlled dietary PO(4) load. This is particularly likely among patients without significant residual renal function. Thus, in the majority of ESRD patients, PO(4) binders remain the mainstay of therapy for hyperphosphatemia. All currently available PO(4) binders can restore serum PO(4) to the required level when administered appropriately and in conjunction with dietary PO(4) restrictions. PO(4) binders differ regarding their potential side-effects and impact on long-term patient-centered outcomes. Which of the PO(4) binders might result in the most favorable survival and cardiovascular morbidity profiles and which remain uncertain, remains a subject of considerable clinical investigation. Compelling observational and more limited randomized controlled trial (RCT) evidence support the view that PO(4) binders might differ in their effects on mortality and/or morbidity. The limited evidence from RCTs is mostly congruent with the findings from large observational studies. In particular, evidences from both epidemiologic and RCT support the view that excess calcium administration may independently increase the risk of cardiovascular disease in individuals with normal renal function and in patients with CKD and ESRD. Additional RCT evidence might help determine the degree at which any increased risk from oral calcium exposure can be mitigated with the use of noncalcium-based PO(4) binders. Judicious control of PO(4) early in CKD, possibly monitored by measures of FGF-23, could potentially reduce the risk of development of renal secondary hyperparathyroidism and all of the adverse clinical consequences of poorly controlled CKD-mineral and bone disorder. The mainstays of therapy are likely to include a balance of dietary restriction and PO(4) binders to reduce PO(4) input, and in ESRD patients, dialysis modalities to augment PO(4) output.

Association of cinacalcet adherence and costs in patients on dialysis

OBJECTIVE

In addition to negative impacts on clinical effectiveness in treating secondary hyperparathyroidism, low adherence to cinacalcet may have negative impacts on healthcare costs. This study assessed the relationship between medication adherence and healthcare costs among US patients on dialysis given cinacalcet to manage secondary hyperparathyroidism.

METHODS

Retrospective cohort study of patients who were receiving dialysis with an initial cinacalcet prescription between January 2004 and April 2010 and who survived ≥12 months. Longitudinal, integrated medical, and pharmacy claims data from the MarketScan? database were used to calculate medication possession ratios (MPR) over 12 months and to examine the association of adherence with inpatient, outpatient, emergency room, outpatient medication, and total costs while controlling for patient characteristics, co-morbid medical conditions, and concomitant medication MPR in a multivariate regression model. Patients were dichotomized as adherent (<180 days refill gap) or non-adherent (≥180 day refill gap). Adherent patients were further dichotomized as low adherent (<0.8 MPR) and high adherent (≥0.8 MPR).

RESULTS

The final study cohort included 4923 patients. After 12 months, 46% were non-adherent, 27% were low adherent, and 28% were high adherent. Greater cinacalcet adherence was associated with significantly lower inpatient costs with cost-savings of a greater magnitude than the increased medication costs.

CONCLUSIONS

This study demonstrated that low adherence to cinacalcet, which may be associated with undesirable clinical and health-economic outcomes, is common. Despite limitations inherent in retrospective studies of claims databases, such as unobserved confounding, non-discrimination between prescription fill and actual use, and not knowing the reasons for non-adherence, these results suggest that inpatient cost savings of $8899, more than offset higher medication costs of $5858 associated with increased cinacalcet adherence.

[Treatment of secondary hyperparathyroidism resistant to conventional therapy and tertiary hyperparathyroidism with Cinacalcet: an efficiency strategy]

INTRODUCTION

The treatment of secondary hyperparathyroidism (SHPT) in dialysis patients has changed with the introduction of cinacalcet (CC), which represents a medical alternative to surgical parathyroidectomy (PTX). The aim of our study is to prospectively assess the tolerance and efficacy of CC in patients, treated in one centre using long haemodialysis, with SHPT who do not respond to conventional therapy.

PATIENTS AND METHODS

We prospectively observed all patients treated with CC between September 2004 and 2009. The characteristics of the patients were compared with that recorded for the patients non treated with CC. Biological factors and the efficacy of the treatment in the patients were compared before (T-0) and after (T-End) CC therapy. The haemodialysis (HD) schedule was 3 x 5 to 3 x 8 h per week. The biological criteria for CC prescription were a serum PTH level greater than 300 pg/ml, calcium level greater than 2.45 mmol/l and bone alkaline phosphatase level greater than 20 microg/l or, in cases of tertiary hyperparathyroidism (THPT), a calcium level greater than 2.55 mmol/l.

RESULTS

Eighty-one (14.7%) among the 550 HD patients were treated with CC. As compared to the untreated population, these patients were younger and had higher body mass index (BMI) and higher protein-catabolic rate (nPCR). The treatment failed in 6.1% of the treated patients; 12.3% had severe gastrointestinal side effects and 10% underwent PTX. The treatment was successful in 81.4% patients who were prescribed a mean final CC dosage of 51+/-30 mg/day. Between T-0 and T-End (18+/-15) months), the serum PTH levels decreased by 77%, calcaemia levels decreased by 10% and phosphataemia levels decreased by 14%. Therefore, the percentage of patients with normal biological parameters increased significantly : serum PTH (150-300 pg/ml: 0 to 50%), calcaemia (2.1-2.37 mmol/l: 6 to 77%) and phosphataemia (1.15-1.78 mol/l: 58 to 84%). After 12 months, eight patients (10%) successfully weaned from CC therapy. No episodes of hypocalcaemia (<2.0 mmol/l) occurred. Treatments with alfacalcidol (68 to 40%) and sevelamer (72 to 50%) decreased, treatments with CaCO(3) remained stable (20%), those with native vitamin D increased (55 to 95%).

CONCLUSION

The treatment of HD patients having SHPT and THPT with CC and vitamin D derivatives was efficacious and well tolerated in a majority of cases after the failure of conventional therapies. These treatments improved mineral metabolism significantly.

Vitamin D compounds for people with chronic kidney disease requiring dialysis

BACKGROUND

Clinical guidelines recommend vitamin D compounds to suppress serum parathyroid hormone (PTH) in chronic kidney disease (CKD), however treatment may be associated with increased serum phosphorus and calcium, which are associated with increased mortality in observational studies. Observational data also indicate vitamin D therapy may be independently associated with reduced mortality in CKD.

OBJECTIVES

We assessed the effects of vitamin D compounds on clinical, biochemical, and bone outcomes in people with CKD and receiving dialysis.

SEARCH STRATEGY

We searched The Cochrane Renal Group's specialised register, Cochrane's Central Register of Controlled Trials (CENTRAL), MEDLINE, EMBASE, and reference lists of retrieved articles.

SELECTION CRITERIA

Randomised controlled trials (RCTs) in subjects with CKD and requiring dialysis that assessed treatment with vitamin D compounds.

DATA COLLECTION AND ANALYSIS

Data was extracted by two authors. Results are summarised as risk ratios (RR) for dichotomous outcomes or mean differences (MD) for continuous outcomes, with 95% confidence intervals (CI).

MAIN RESULTS

Sixty studies (2773 patients) were included. No formulation, route, or schedule of administration was associated with altered risks of death, bone pain, or parathyroidectomy. Marked heterogeneity in reporting of outcomes resulted in few data available for formal meta-analysis. Compared with placebo, vitamin D compounds lowered serum PTH at the expense of increasing serum phosphorus. Trends toward increased hypercalcaemia and serum calcium did not reach statistical significance but may be clinically relevant. Newer vitamin D compounds (paricalcitol, maxacalcitol, doxercalciferol) lowered PTH compared with placebo, with increased risks of hypercalcaemia, although inadequate data were available for serum phosphorus. Intravenous vitamin D may lower PTH compared with oral treatment, and be associated with lower serum phosphorus and calcium levels, although limitations in the available studies precludes a conclusive statement of treatment efficacy. Few studies were available for intermittent versus daily and intraperitoneal versus oral administration or directly comparative studies of newer versus established vitamin D compounds.

AUTHORS' CONCLUSIONS

We confirm that vitamin D compounds suppress PTH in people with CKD and requiring dialysis although treatment is associated with clinical elevations in serum phosphorus and calcium. All studies were inadequately powered to assess the effect of vitamin D on clinical outcomes and until such studies are conducted the relative importance of changes in serum PTH, phosphorus and calcium resulting from vitamin D therapy remain unknown. Observational data showing vitamin D compounds may be associated with improved survival in CKD need to be confirmed or refuted in specifically designed RCTs.

Review article: Patient-level outcomes: the missing link

Treatment of chronic kidney disease (CKD) may be life-saving, but can disrupt every aspect of a patient's life and the lives of family members. Many patients with CKD are elderly with significant comorbidities and sometimes therapies to improve survival may be less important than those that improve or maintain quality of life. In this setting, patient-level benefits become particularly important goals of therapy. Randomized controlled trials (RCT) are also essential to justify expensive therapies, such as medications used in the treatment of CKD mineral and bone disorders. Surprisingly, data to support the efficacy of these drugs for patient-level outcomes remains limited. In fact, fewer RCT are conducted in renal medicine than in any other medical specialty and reliance is often placed on association data and the assessment of intermediate and biochemical end-points. While some of these may prove to be valid surrogates for clinically important outcomes, some may not. Inclusion of patient-level outcomes in clinical research provides a missing link that can inform a more comprehensive approach to clinical practice and patient care. Incorporating measures of health-related quality of life into clinical trials can make outcomes more relevant and may be relatively simple. This paper provides examples of reliable, validated instruments to measure health-related quality of life domains and functional status, together with practical instructions for their use. Most could be incorporated into RCT of CKD mineral and bone disorder treatments. Inclusion of outcomes that are perceived by patients to be significant should become standard practice in renal medicine and in clinical renal research.

Simultaneous control of PTH and CaxP Is sustained over three years of treatment with cinacalcet HCl

BACKGROUND & OBJECTIVES

Chronic kidney disease (CKD) is commonly complicated by secondary hyperparathyroidism (SHPT), leading to increased risk of morbidity and mortality. SHPT is a progressive disease often requiring long-term therapy to control parathyroid hormone (PTH) and mineral imbalances. Vitamin D sterols and phosphate binders, used as traditional therapies to lower PTH and phosphorus, may provide inadequate long-term control for many dialysis patients. Cinacalcet, by simultaneously lowering PTH, calcium, phosphorus, and calcium-phosphorus levels, may maintain PTH and mineral balance in these individuals. However, as with traditional therapies, long-term data are limited. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENT: Dialysis subjects from at least one of five lead-in studies (double-blind placebo-controlled, including one extension trial) completing up to 52 wk of either cinacalcet or placebo were eligible for this open-label extension study, including an 8-wk dose titration (initiated at 30 mg/d), followed by 24-wk maintenance and up to 132 wk of follow-up. Final efficacy analysis was at week 180.

RESULTS

Three hundred thirty-four of 589 enrolled subjects received cinacalcet from the beginning of the lead-in study. Weekly median PTH values were < or =300 pg/ml (weeks 16 through 180) and median CaxP values were < or =55 mg(2)/dl(2) (weeks 4 through 180). Similar results were exhibited in the 255 subjects who initially received placebo. Among the patients exposed to cinacalcet from the beginning of the lead-in study, 3% of subjects exhibited treatment-related serious adverse events.

CONCLUSIONS

Cinacalcet effectively maintained PTH, Ca and P reductions in dialysis subjects for up to 180 wk.

HMG CoA reductase inhibitors (statins) for people with chronic kidney disease not requiring dialysis

BACKGROUND

Dyslipidaemia occurs frequently in chronic kidney disease (CKD) patients and contributes both to cardiovascular disease and worsening renal function. Statins are widely used in non-dialysis dependent CKD patients (pre-dialysis) even though evidence favouring their use is lacking.

OBJECTIVES

To evaluate the benefits and harms of statins in CKD patients who were not receiving renal replacement therapy.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, CENTRAL (in The Cochrane Library), and hand-searched reference lists of textbooks, articles and scientific proceedings.

SELECTION CRITERIA

Randomised controlled trials (RCTs) and quasi-RCTs comparing statins with placebo, no treatment or other statins in adult pre-dialysis CKD patients.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed study quality and extracted data. Results were expressed as mean difference (MD) for continuous outcomes (lipids, creatinine clearance and proteinuria) and risk ratio (RR) for dichotomous outcomes (all-cause mortality, cardiovascular mortality, fatal and non-fatal cardiovascular events, elevated liver enzymes, rhabdomyolysis and withdrawal rates) with 95% confidence intervals (CI).

MAIN RESULTS

Twenty six studies (25,017 participants) comparing statins with placebo were identified. Total cholesterol decreased significantly with statins (18 studies, 1677 patients: MD -41.48 mg/dL, 95% CI -49.97 to -33.99). Similarly, LDL cholesterol decreased significantly with statins (16 studies, 1605 patients: MD -42.38 mg/dL, 95% CI -50.71 to -34.05). Statins decreased both the risk of all-cause (21 RCTs, 18,781 patients, RR 0.81, 95% CI 0.74, 0.89) and cardiovascular deaths (20 studies, 18,746 patients: RR 0.80, 95% CI 0.70 to 0.90). Statins decreased 24-hour urinary protein excretion (6 studies, 311 patients: MD -0.73 g/24 h, 95% CI -0.95 to -0.52), but there was no significant improvement in creatinine clearance - a surrogate marker of renal function (11 studies, 548 patients: MD 1.48 mL/min, 95% CI -2.32 to 5.28).The incidence of rhabdomyolysis, elevated liver enzymes and withdrawal rates due to adverse events (well known complications of statins use), were not significantly different between patients receiving statins and placebo.

AUTHORS' CONCLUSIONS

Statins significantly reduced the risk of all-cause and cardiovascular mortality in CKD patients who are not receiving renal replacement therapy. They do not impact on the decline in renal function as measured by creatinine clearance, but may reduce protein excretion in urine. Statins appear to be safe in this population. Guidelines recommendations on hyperlipidaemia management in CKD patients could therefore be followed targeting higher proportions of patients receiving a statin, with appropriate monitoring of adverse events.

Cinacalcet: pharmacological and clinical aspects

The calcium sensing receptor (CaSR) is expressed in cells secreting calcium-regulating hormones, in cells involved in calcium transport and in many other tissues, with an as yet not completely defined role. In parathyroid cells, the CaSR stimulation inhibits parathyroid hormone (PTH) secretion, synthesis and parathyroid cell proliferation. Cinacalcet belongs to calcimimetic type II compounds that can interact with CaSR, increasing its affinity for calcium. Clinical studies have proved cinacalcet to be effective in reducing calcium and PTH levels in primary hyperparathyroidism and in reducing PTH, calcium and phosphate in patients with secondary hyperparathyroidism owing to chronic renal failure, with a relatively safe profile, the only reported adverse events being hypocalcaemia and gastrointestinal symptoms. However, though calcimimetics do represent a real advancement in the field of the treatment of PTH secretion disturbances, there is a need for clinical trials, which should aim to demonstrate that a better control of biochemical parameters is also matched with better clinical outcomes.

Treatment of secondary hyperparathyroidism in kidney disease: what we know and do not know about use of calcimimetics and vitamin D analogs

There is a growing understanding of the pathophysiology of secondary hyperparathyroidism (SHPT) and a recent emergence of new agents for SHPT treatment in patients with advanced kidney disease. At the same time, appreciation that mineral metabolic derangements promote vascular calcification and contribute to excess mortality, along with recognition of potentially important “non-classical” actions of vitamin D, have prompted the nephrology community to reexamine the use of various SHPT treatments, such as activated vitamin D sterols, phosphate binders, and calcimimetics. In this review, the evidence for treatment of SHPT with calcimimetics and vitamin D analogs is evaluated, with particular consideration given to recent clinical trials that have reported encouraging findings with cinacalcet use. Additionally, several controversies in the pathogenesis and treatment of SHPT are explored. The proposition that calcitriol deficiency is a true pathological state is challenged, the relative importance of the vitamin D receptor and the calcium sensing receptor in parathyroid gland function is summarized, and the potential relevance of non-classical actions of vitamin D for patients with advanced renal disease is examined. Taken collectively, the balance of evidence now supports a treatment paradigm in which calcimimetics are the most appropriate primary treatment for SHPT in the majority of end stage renal disease patients, but which nevertheless acknowledges an important role for modest doses of activated vitamin D sterols.

Calcimimetics or vitamin D analogs for suppressing parathyroid hormone in end-stage renal disease: time for a paradigm shift?

Considerable advances have been made in the understanding of the pathogenesis and treatment of secondary hyperparathyroidism (SHPT) in chronic kidney disease (CKD). These include the discovery that the calcium-sensing receptor has an important role in the regulation of parathyroid gland function, the development of calcimimetics to target this receptor, the recognition that vitamin D receptor activation has important functions beyond the regulation of mineral metabolism, the identification of the phosphaturic factor fibroblast growth factor 23 and the contribution of this hormone to disordered phosphate and vitamin D metabolism in CKD. However, despite the availability of calcimimetics, phosphate binders, and vitamin D analogs, control of SHPT remains suboptimal in many patients with advanced kidney disease. In this Review, we explore several unresolved issues regarding the pathogenesis and treatment of SHPT. Specifically, we examine the significance of elevated circulating fibroblast growth factor 23 levels in CKD, question the proposition that calcitriol deficiency is truly a pathological state, explore the relative importance of the vitamin D receptor and the calcium-sensing receptor in parathyroid gland function and evaluate the evidence to support the treatment of SHPT with calcimimetics and vitamin D analogs. Finally, we propose a novel treatment framework in which calcimimetics are the primary therapy for suppressing parathyroid hormone production in patients with end-stage renal disease.

Cinacalcet is efficacious in pediatric dialysis patients

Secondary hyperparathyroidism (high-turnover bone disease, or HTBD) is manifested by elevated parathyroid hormone (PTH) levels. Control of HTBD may be achieved by maintaining low serum phosphorous levels and administering vitamin D therapy, although some patients continue to exhibit high PTH levels. We report the results of the efficacy of the calcimimetic cinacalcet in six hemodialysis (HD) and three peritoneal dialysis (PD) pediatric patients with HTBD, age 14.5 +/- 1.0 (range 7.5-17.5) years. Six patients received 30 mg/day, one required 60 mg/day, and two received 120 mg/day. Treatment with cinacalcet resulted in a 61% decline in intact PTH (iPTH) levels (1,070 +/- 171.5 pretreatment to 417.6 +/- 97.8 posttreatment pg/ml, p = 0.005). Serum alkaline phosphatase also declined (561.8 +/- 169.6 U/L pretreatment to 390.3 +/- 110.3 U/L posttreatment pg/ml). During therapy, serum calcium (p = 0.9) and phosphorous (p = 0.9) levels, calcium-phosphorous product (p = 0.8), systolic blood pressure (BP) (p = 1.0), diastolic BP (p = 0.8), and hemoglobin (p = 0.9) remained unchanged. The dose of oral calcitriol for the three patients on PD while receiving cinacalcet trended downward (0.8 +/- 0.2 pretreatment vs. 0.5 +/- 0.0 microg/day posttreatment pg/ml), as did the dose of paracalcitol for those receiving HD (6.6 +/- 2.3 pretreatment vs. 4.3 +/- 1.7 micrograms/day posttreatment pg/ml). We conclude that short-term treatment with the calcimimetic cinacalcet is efficacious in adolescent dialysis patients.

Calcimimetics in CKD-results from recent clinical studies

Secondary hyperparathyroidism (sHPT) is a frequent complication in patients with chronic kidney disease (CKD) and a known contributor to the development of vascular calcification and renal osteodystrophy (CKD-BMD). Secondary hyperparathyroidism is also related to increased cardiovascular mortality in CKD patients. With the discovery that molecules can modulate the calcium-sensing receptor (CaR) of the parathyroid gland, new treatment options are now available to control sHPT. Calcimimetics activate the CaR and-by increasing its sensitivity to calcium-can effectively decrease parathyroid hormone (PTH) secretion. Calcimimetic treatment with cinacalcet has resulted in an effective lowering of PTH levels in both animal and clinical studies. Most clinical studies have been performed in dialysis patients, and only a few studies have been carried out in patients with CKD stage 3 & 4 and renal transplant patients. In haemodialysis patients with sHPT, cinacalcet treatment could increase the number of patients achieving National Kidney Foundation Kidney Disease Outcomes Quality Initiative targets (PTH, calcium, phosphate) compared to standard therapy. In stage 3 and 4 CKD patients, cinacalcet has been reported to reduce PTH levels, however, at the expense of increasing phosphate serum levels. Several small studies have reported that calcimimetics reduced PTH levels and hypercalcaemia after renal transplantation. In addition, two studies on paediatric dialysis patients with sHPT reported effective PTH lowering. This review summarizes recent clinical studies with cinacalcet treatment in CKD patients.

Parathyroidectomy Versus Cinacalcet Hydrochloride–Based Medical Therapy in the Management of Hyperparathyroidism in ESRD: A Cost Utility Analysis

BACKGROUND

Previously, patients with end-stage renal disease (ESRD) with uncontrolled hyperparathyroidism had few options other than parathyroidectomy, which was reserved for patients refractory to medical therapy. Newer calcimimetic agents, such as cinacalcet, may be an alternative, but raise the possibility of indefinite medical treatment that also would increase costs.

STUDY DESIGN

Cost utility analysis.

SETTING & POPULATION

Base case consisted of prevalent adult US patients with ESRD refractory to management with standard medical therapy. Characteristics were obtained from patients who underwent parathyroidectomy in 2001, and, for purposes of comparison, patients in whom cinacalcet was used were assigned similar characteristics. All data came from preexisting literature and trials or from US Renal Data System analysis files.

INTERVENTION

Use of cinacalcet hydrochloride versus parathyroidectomy.

PERSPECTIVE & TIME FRAME

Medicare and societal costs and quality-adjusted life-years from the date of parathyroidectomy or use of cinacalcet followed up for 2 years, respectively.

MODEL & OUTCOMES

Primary outcomes were cost (measured in US dollars) and cost utility measured using cost per quality-adjusted life-years.

RESULTS

At base-case surgical and drug costs, surgical and drug success rates, complication rates/costs, and benefit from correction of hyperparathyroidism, parathyroidectomy was found to be both less expensive and more cost-effective at 7.25 +/- 0.25 months. Parathyroidectomy became more cost-effective at 15.28 to 16.32 months at the upper limit of sensitivity analysis, when drug/surgical costs and success/complication rates/costs were maximally weighted to favor cinacalcet-based medical therapy.

LIMITATIONS

We assumed current costs of both cinacalcet and parathyroidectomy and assumed cinacalcet use would be indefinite.

CONCLUSIONS

For patients with ESRD with uncontrolled hyperparathyroidism who are good candidates for either drug therapy or surgery, cinacalcet hydrochloride is the most cost-effective modality if the patient is to remain on dialysis therapy for 7.25 +/- 0.25 months. Cinacalcet may be more optimal if used in patients who have high risk of mortality or who would expect to receive a kidney transplant quickly. For other subgroups, parathyroidectomy dominated.

Mineral metabolism and mortality in patients with chronic kidney disease

Chronic kidney disease is associated with profound alterations in mineral metabolism. A growing body of evidence, based largely on observational studies, indicates that patient mortality is associated with altered mineral metabolism. Evidence is reviewed concerning the association between mortality and high concentrations of serum phosphorus, calcium, calcium-phosphate product, and parathyroid hormone. In addition, mortality may be independently associated with dialysate calcium concentration, type of phosphate binder therapy, and use of vitamin D analogs. Practices related to management of altered mineral metabolism may prove to be a promising means of improving outcomes for patients with chronic kidney disease.

Calcimimetics for secondary hyperparathyroidism in chronic kidney disease patients

BACKGROUND

Calcimimetic agents have recently been evaluated in the treatment of secondary hyperparathyroidism (SHPT) as add-on therapy to calcitriol and vitamin D analogues and dietary phosphate binders.

OBJECTIVES

To evaluate the benefits and harms of calcimimetics for the prevention of secondary hyperparathyroid bone disease (including osteitis fibrosa cystica and adynamic bone disease) in dialysis patients with chronic kidney disease (CKD).

SEARCH STRATEGY

MEDLINE, EMBASE, the Cochrane Central Register of Controlled Trials and conference proceedings were searched for randomised controlled trials (RCTs) evaluating any calcimimetic against placebo or another agent in pre-dialysis or dialysis patients with CKD.

SELECTION CRITERIA

We included all RCTs of any calcimimetic agent, cinacalcet HCl (AMG-073, Sensipar), NPS R-467 or NPS R-568 administered to patients with CKD for the treatment of SHPT.

DATA COLLECTION AND ANALYSIS

Data were extracted on all relevant patient-centred and surrogate outcomes. Analysis was by a random effects model and results expressed as relative risk (RR) or weighted mean difference (MD) with 95% confidence intervals.

MAIN RESULTS

Eight studies (1429 patients) were identified, which compared a calcimimetic agent plus standard therapy to placebo plus standard therapy. The end of treatment values of parathyroid hormone (pg/mL) (MD -290.79, 95% CI -360.23 to -221.34), serum calcium (mg/dL) (MD -0.85, 95% CI -1.14 to -0.56), serum phosphorus (mg/dL) (MD -0.29, 95% CI -0.50 to -0.08) and the calcium by phosphorus product (mg(2)/dL(2))(MD -7.90, 95% CI -10.25 to -5.54) were significantly lower with calcimimetics compared to placebo. No significant effects on patient-based endpoints were demonstrated except for the risk of hypotension which was significantly reduced with calcimimetics compared to placebo (RR 0.53, 95%CI 0.36 to 0.79).

AUTHORS' CONCLUSIONS

Calcimimetic treatment of SHPT leads to significant improvements in biochemical parameters that observational studies have shown to be associated with increased mortality, cardiovascular risk and osteitis fibrosa, but patient-based benefits have not yet been demonstrated in trials. For patients with SHPT, the benefits of calcimimetics over standard therapy remain uncertain until further RCTs become available.