Administered paricalcitol dose and survival in hemodialysis patients: a marginal structural model analysis

Efficacy and safety of paricalcitol in patients undergoing hemodialysis: a meta-analysis

Background

The elevated calcium and phosphorus levels in patients undergoing hemodialysis may increase the risk of all-cause mortality. Paricalcitol, as a new vitamin D receptor activator (VDRA), seemed to be effective in reducing the calcium and phosphorus levels.

Objectives

The aim of this study was to compare the efficacy and safety of paricalcitol with other VDRAs in patients undergoing hemodialysis.

Methods

PubMed, Embase, and Web of Science database were systematically reviewed.

Selection criteria

Studies that focused on the use of paricalcitol for hemodialysis patients were eligible for inclusion.

Data collection and analysis

Two independent investigators performed the literature search, data extraction, and assessment of methodological quality. The outcomes were expressed with standard mean difference (SMD), HR, or risk ratio (RR) with 95% CI.

Results

Thirteen studies involving 112,695 patients were included in this meta-analysis. Among these studies, four studies were cohort studies and nine studies were randomized controlled trials (RCTs). For cohort studies, they were regarded as being of high quality; for RCTs, only one was classified as being at low risk of bias; and the remaining eight studies were at being unclear risk of bias. Compared with other VDRAs, paricalcitol significantly improved the overall survival (HR =0.86, 95% CI: 0.80, 0.92; P<0.001) and reduced the intact parathyroid hormone (iPTH) (SMD =-0.53, 95% CI: -0.90, -0.17; P=0.004). Paricalcitol offered similar effect with other VDRAs in the control of calcium (SMD =0.32, 95% CI: -0.04, 0.67; P=0.078) and phosphorus (SMD =0.06, 95% CI: -0.26, 0.37; P=0.727) levels. However, the serum change in calcium phosphate product was greater in the paricalcitol group than in the other VDRA group (SMD =2.13, 95% CI: 0.19, 4.07; P=0.031). There was no significant difference in the incidence of adverse events between the two groups (RR =1.02, 95% CI: 0.93, 1.12; P=0.674).

Conclusion

Paricalcitol was crucial in reducing the mortality in patients undergoing hemodialysis. Moreover, both paricalcitol and other VDRAs were effective in control of the serum iPTH, calcium, and phosphorus levels. Given the potential limitations in this study, more prospective large-scale, well-conducted RCTs are needed to confirm these findings.

Assessing the effect of oral activated vitamin D on overall survival in hemodialysis patients: a landmark analysis

BACKGROUND

Patients with end stage renal disease have a high all-cause and cardiovascular mortality. Secondary hyperparathyroidism and vitamin D deficiency are considered part of the mechanism for the excess mortality observed. We aimed to evaluate the relationship between vitamin D use and all-cause mortality.

METHODS

In this retrospective cohort study, we included all incident patients who started hemodialysis in Taiwan between 2001 and 2009. Patients were followed from landmark time, i.e., the 360th day from hemodialysis initiation, through the end of 2010 or death. We evaluated the association between activated vitamin D use or not before landmark time and all-cause mortality using conditional landmark analysis with Cox regression. We used group-based trajectory model to categorize high-dose versus average-dose users to evaluate dose-response relationships.

RESULTS

During the median follow-up of 1019 days from landmark time, vitamin D users had a lower crude mortality rate than non-users (8.98 versus 12.93 per 100 person-years). Compared with non-users, vitamin D users was associated with a lower risk of death in multivariate Cox model (HR 0.91 [95% CI, 0.87-0.95]) and after propensity score matching (HR 0.94 [95% CI, 0.90-0.98]). High-dose vitamin D users had a lower risk of death than conventional-dose users, HR 0.75 [95% CI, 0.63-0.89]. The association of vitamin D treatment with reduced mortality did not alter when we re-defined landmark time as the 180th day or repeated analyses in patients who underwent hemodialysis in the hospital setting.

CONCLUSIONS

Our findings supported the survival benefits of activated vitamin D among incident hemodialysis patients.

Estimating Treatment Effects for Recurrent Events in the Presence of Rescue Medications: An Application to the Immune Thrombocytopenia Study

In many clinical studies, patients may experience the same type of event of interest repeatedly over time. However, the assessment of treatment effects is often complicated by the rescue medication uses due to ethical reasons. For example, in the motivating trial in studying the Immune Thrombocytopenia (ITP), when the interest lies in evaluating the treatment benefit of investigational product (IP) on reducing patient's repeated bleeding, rescue medication such as platelet transfusions may be allowed to raise platelet counts. Both the intention-to-treat analysis and treating the intermediate rescue medication as covariate tend to attenuate the treatment benefit, and the estimates can be biased if interpreted as causal. In this paper, we propose a general causal framework when intermediate rescue medications are informative. We adopt the inverse weighted estimation approach to estimate the treatment effect, where weights are constructed to reflect time-dependent medication use probabilities. The proposed estimators are shown to be asymptotically normal and are demonstrated to perform well in small-sample simulation studies. The application to the ITP studies reveals a stronger benefit of using IP in reducing bleeding.

Vitamin D and methylarginines in chronic kidney disease (CKD)

Background

Vitamin D associates with the plasma concentration of the endogenous inhibitor of the nitric oxide system asymmetric dimethyl arginine (ADMA) and cross-sectional studies in CKD patients treated with the vitamin D receptor activator paricalcitol show that plasma ADMA is substantially less than in those not receiving this drug.

Methods

In the frame of a randomized, double-blind, placebo controlled trial, the Paracalcitol and ENdothelial fuNction in chronic kidneY disease (PENNY), we investigated whether vitamin D receptor activation by paricalcitol (2 μg/day x 12 weeks) affects the plasma concentration of ADMA and symmetric dimethyl arginine (SDMA) in 88 patients with stage 3 to 4 CKD.

Results

Paricalcitol produced the expected small rise in serum calcium and phosphate and a marked PTH suppression. However, ADMA [Paricalcitol: baseline 0.75 μMol/L (95%CI: 0.70–0.81), 12 week 0.72 μMol/L (95%CI: 0.66–0.78); Placebo: baseline 0.75 μMol/L (95%CI: 0.70–0.90) 12 weeks 0.70 μMol/L (95%CI: 0.66–0.74)] and SDMA [Paricalcitol: baseline 0.91 μMol/L (95%CI: 0.82–1.00), 12 week 0.94 μMol/L (95%CI: 0.82–0.1.06); Placebo: baseline 0.91 μMol/L (95%CI: 0.82–1.06) 12 weeks 0.99 μMol/L (95%CI: 0.88–1.10)] remained unchanged during the trial and 2 weeks after stopping these treatments.

Conclusions

Paricalcitol does not modify plasma ADMA and SDMA in patients with stage 3–4 CKD. The apparent beneficial effects of paricalcitol on ADMA registered in cross-sectional studies is likely attributable to confounding by indication rather than to a true effect of this drug on ADMA metabolism.

Comparative efficacy and safety of paricalcitol versus vitamin D receptor activators for dialysis patients with secondary hyperparathyroidism: a meta-analysis of randomized controlled trials

Background

Secondary hyperparathyroidism (SHPT) is a severe complication for dialysis patients. Vitamin D receptor activators (VDRAs) are used to treat SHPT, but the comparative efficacy and safety between paricalcitol and other vitamin D receptor activators for management of SHPT in dialysis patients has been unproven.

Methods

We searched PubMed, Embase, and the Cochrane Library for the time period through June 2017 to identify randomized controlled trials that evaluated paricalcitol compared with other VDRAs for treatment of SHPT. The primary outcome was the percentage of patients with target reduction of intact parathyroid hormone (iPTH) from baseline. Secondary outcomes included incidences of hypercalcemia and hyperphosphatemia. The random-effects model was used to estimate relative risks (RRs) with 95% confidence intervals (CIs).

Results

Eight studies (N = 759) were eligible for final inclusion. Compared with other VDRAs, no significant differences were found in the percentage of patients with target reduction of intact parathyroid hormone (iPTH) from baseline for paricalcitol treatment of SHPT in dialysis patients (RR, 1.01; 95% CI, 0. 87–1.18; p = 0.85). There were no differences in the incidence of hypercalcemia (RR, 0.95; 95% CI, 0.74–1.21; p = 0. 65) and hyperphosphatemia (RR, 0.94; 95% CI, 0.77–1.16; p = 0.58).

Conclusions

The presently available evidence is insufficient to draw a conclusion regarding whether paricalcitol therapy has a comparative efficacy and safety over other VDRAs for treating dialysis patients with SHPT. Large-sample, well-conducted, high-quality RCTs with patient-level outcomes (i.e., mortality) are urgently needed.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0691-6) contains supplementary material, which is available to authorized users.

The Obesity Paradox in Kidney Disease: How to Reconcile it with Obesity Management

Obesity, a risk factor for de novo chronic kidney disease (CKD), confers survival advantages in advanced CKD. This so-called obesity paradox is the archetype of the reverse epidemiology of cardiovascular risks, in addition to the lipid, blood pressure, adiponectin, homocysteine, and uric acid paradoxes. These paradoxical phenomena are in sharp contradistinction to the known epidemiology of cardiovascular risks in the general population. In addition to advanced CKD, the obesity paradox has also been observed in heart failure, chronic obstructive lung disease, liver cirrhosis, and metastatic cancer, as well as in the elderly. These are populations in whom protein-energy wasting and inflammation are strong predictors of early death. Both larger muscle mass and higher body fat provide longevity in these patients, whereas thinner body habitus and weight loss are associated with higher mortality. Muscle mass appears to be superior to body fat in conferring an even greater survival. The obesity paradox may be the result of a time discrepancy between competing risk factors, i.e., overnutrition as the long-term killer versus undernutrition as the short-term killer. Hemodynamic stability of obesity, lipoprotein defense against circulating endotoxins, protective cytokine profiles, toxin sequestration of fat mass, and antioxidation of muscle may play important roles. Despite claims that obesity paradox is a statistical fallacy and a result of residual confounding, the consistency of data and other causality clues suggest a high biologic plausibility. Examining the causes and consequences of the obesity paradox may help discover important pathophysiologic mechanisms leading to improved outcomes in patients with CKD.

Moderator's view: Higher serum bicarbonate in dialysis patients is protective

Several observational studies have reported an association between higher serum bicarbonate level and high mortality risk in dialysis patients. However, in such studies mere discovery of associations does not allow one to infer causal relationships. This association may be related to inadequate dietary protein intake that may lead to less acid generation and hence a higher serum bicarbonate level. Since undernutrition is a strong predictor of death in hemodialysis patients, the observed association may be an epiphenomenon and not a biologically plausible relationship. Higher protein and fluid intake between two subsequent hemodialysis treatments may lead to lower serum bicarbonate level. This low bicarbonate level may appear protective, as patients with higher food intake and better appetite generally exhibit greater survival. In the contemporary three-stream proportioning system of hemodialysis treatment, the bicarbonate concentrate is separate from the acid concentrate, and the contribution of the acid concentrate organic acid (acetate, citrate or diacetate) to the delivered bicarbonate pool of the patient is negligible. The concept of 'total buffer' that assumes that the combination of bicarbonate and acetate concentrations in the dialysate are added equally as bicarbonate equivalents is likely wrong and based on the misleading notion that the acetate of the acid concentrate is fully metabolized to bicarbonate in the dialysate. Given these uncertainties it is prudent to avoid excessively high or low bicarbonate levels in dialysis patients.

Examining the robustness of the obesity paradox in maintenance hemodialysis patients: a marginal structural model analysis

BACKGROUND

The inverse association between body mass index (BMI) and mortality observed in patients treated with maintenance hemodialysis (MHD), also known as the obesity paradox, may be a result of residual confounding. Marginal structural model (MSM) analysis, a technique that accounts for time-varying confounders, may be more appropriate to investigate this association. We hypothesize that after applying MSM, the inverse association between BMI and mortality in MHD patients is attenuated.

METHODS

We examined the associations between BMI and all-cause mortality among 123 624 adult MHD patients treated during 2001-6. We examined baseline and time-varying BMI using Cox proportional hazards models and MSM while considering baseline and time-varying covariates, including demographics, comorbidities and markers of malnutrition and inflammation.

RESULTS

The patients included 45% women and 32% African Americans with a mean age of 61(SD 15) years. In all models, BMI showed a linear incremental inverse association with mortality. Compared with the reference (BMI 25 to <27.5 kg/m(2)), a BMI of <18 kg/m(2) was associated with a 3.2-fold higher death risk [hazard ratio (HR) 3.17 (95% CI 3.05-3.29)], and mortality risks declined with increasing BMI with the greatest survival advantage of 31% lower risk [HR 0.69 (95% CI 0.64-0.75)] observed with a BMI of 40 to <45 kg/m(2).

CONCLUSIONS

The linear inverse relationship between BMI and mortality is robust across models including MSM analyses that more completely account for time-varying confounders and biases.

The uses and abuses of Vitamin D compounds in chronic kidney disease-mineral bone disease (CKD-MBD)

Vitamin D is of paramount importance to skeletal development, integrity and health. Vitamin D homeostatis is typically deranged in a number of chronic conditions, of which chronic kidney disease is one of the most important. The use of vitamin D based therapy to target secondary hyperparathyroidism is now several decades old, and there is a large body of clinical practice, experience, guidelines and research to underpin this. However, there are many unknowns, of significant clinical relevance. Amongst which is what "species" of vitamin D we should be using, in what patient, and, under what conditions. Sadly, there has been a real dearth of randomised controlled trials, and trials with outputs of clinical relevance, which means our clinical practice has not developed and refined adequately ove the last 4 decades. This article will discuss the vexed but critical questions of which vitamin D therapies might suit which kidney patients, and will high-light the many important clinical questions which urgently require answering.

Antidepressant treatment and suicide attempts and self-inflicted injury in children and adolescents

PURPOSE

In the 2004, FDA placed a black box warning on antidepressants for risk of suicidal thoughts and behavior in children and adolescents. The purpose of this paper is to examine the risk of suicide attempt and self-inflicted injury in depressed children ages 5-17 treated with antidepressants in two large observational datasets taking account time-varying confounding.

METHODS

We analyzed two large US medical claims databases (MarketScan and LifeLink) containing 221,028 youth (ages 5-17) with new episodes of depression, with and without antidepressant treatment during the period of 2004-2009. Subjects were followed for up to 180 days. Marginal structural models were used to adjust for time-dependent confounding.

RESULTS

For both datasets, significantly increased risk of suicide attempts and self-inflicted injury were seen during antidepressant treatment episodes in the unadjusted and simple covariate adjusted analyses. Marginal structural models revealed that the majority of the association is produced by dynamic confounding in the treatment selection process; estimated odds ratios were close to 1.0 consistent with the unadjusted and simple covariate adjusted association being a product of chance alone.

CONCLUSIONS

Our analysis suggests antidepressant treatment selection is a product of both static and dynamic patient characteristics. Lack of adjustment for treatment selection based on dynamic patient characteristics can lead to the appearance of an association between antidepressant treatment and suicide attempts and self-inflicted injury among youths in unadjusted and simple covariate adjusted analyses. Marginal structural models can be used to adjust for static and dynamic treatment selection processes such as that likely encountered in observational studies of associations between antidepressant treatment selection, suicide and related behaviors in youth.

Ability of vitamin D receptor activator to prevent pulmonary congestion in advanced chronic kidney disease

BACKGROUND

Vitamin D deficiency is common among patients with chronic kidney disease (CKD). However, the benefits of vitamin D supplementation versus vitamin D receptor activator (VDRA) administration have yet to be established. Recently, an association between activated vitamin D and cardiovascular factors was reported. To evaluate the benefits of VDRA in advanced CKD, we analyzed the association between VDRA administration and the prevalence of pulmonary congestion.

METHODS

This retrospective, cross-sectional analysis included patients initiated on dialysis between October 2011 and September 2013 at 17 Japanese institutions. Data from 952 participants were analyzed using a multivariate logistic regression model and a linear regression model. We also analyzed subgroup data for groups classified by selection of peritoneal dialysis or hemodialysis.

RESULTS

Of the 952 participants, 303 patients received VDRA. VDRA administration was associated with a low prevalence of pulmonary congestion in the multivariate logistic regression model (odds ratio [OR], 0.64; 95 % confidence interval [CI], 0.44-0.94; P = 0.02). There was no significant association between VDRA administration and systolic blood pressure, diastolic blood pressure, or pulse pressure. Subgroup analysis revealed a tendency that VDRA administration was associated with low prevalence of pulmonary congestion in both groups.

CONCLUSIONS

In this study, VDRA administration was associated with a low prevalence of pulmonary congestion in patients initiated on dialysis. Appropriate VDRA administration may prevent pulmonary congestion.

Dose of hemodialysis and survival: a marginal structural model analysis

BACKGROUND

Observational studies have consistently demonstrated the survival benefits of a greater dialysis dose in maintenance hemodialysis (MHD) patients, whereas randomized controlled trials have shown conflicting results. The possible causal impact of dialysis dose on mortality needs to be investigated using rich cohort data analyzed with novel statistical methods such as marginal structural models (MSMs) that account for time-varying confounding and exposure.

METHODS

We quantified the effect of delivered dose of hemodialysis (HD) [single-pool Kt/V (spKt/V)] on mortality risk in a contemporary cohort of 68,110 patients undergoing HD 3 times weekly (7/2001- 9/2005). We compared conventional Cox proportional hazard and MSM survival analyses, accounting for time-varying confounding by applying longitudinally modeled inverse-probability-of-dialysis-dose weights to each observation.

RESULTS

In conventional Cox models, baseline spKt/V showed a weak negative association with mortality, while higher time-averaged spKt/V was strongly associated with lower mortality risk. In MSM analyses, compared to a spKt/V range of 1.2 - <1.4, a spKt/V range of <1.2 was associated with a higher risk of mortality [HR (95% CI) 1.67 (1.54 - 1.80)], whereas mortality risks were significantly lower with higher spKt/V [HRs (95% CI): 0.74 (0.70-0.78), 0.63 (0.59-0.66), 0.56 (0.52-0.60), and 0.56 (0.52-0.61) for spKt/V ranges of 1.4 - <1.6, 1.6-<1.8, 1.8 - <2.0, and ≥2.0, respectively]. Thus, MSM analyses showed that the greatest survival advantage of a higher dialysis dose was observed for a spKt/V range of 1.8-<2.0, and the dialysis dose-mortality relationship was robust in almost all subgroups of patients.

CONCLUSIONS

Higher HD doses were robustly associated with greater survival in MSM analyses that more fully and appropriately accounted for time-varying confounding.

Mortality of combined serum phosphorus and parathyroid hormone concentrations and their changes over time in hemodialysis patients

BACKGROUND

Mineral and bone disorder (MBD) is common and associated with mortality in patients with chronic kidney disease (CKD) Given that disarrays in serum phosphorus (P) and parathyroid hormone (PTH) levels and their changes over time are closely interrelated, modeling mortality-predictability of their combinations may help improve CKD patient management.

METHODS

A historical cohort study was undertaken to evaluate the joint effect of serum P and PTH levels on mortality in 107,299 chronic hemodialysis (HD) patients. Changes in serum P and PTH levels over 6months, in particular discordant changes, were also modeled with mortality.

RESULTS

HD patients were 64±15 (mean±SD)years old and included 45% women, 33% African-American, and 59% diabetic. Compared with serum P level ≥7.0mg/dL and PTH level ≥600pg/mL, adjusted hazard ratio (HR) tended to be lowest in patients with serum P level of 3.5-<5.5mg/dL combined with PTH level of 150-<300pg/mL (HR 0.64, 95% confidence interval 0.61-0.67). A change over time in serum P level towards the 3.5-<5.5mg/dL range from higher or lower ranges was associated with a decreased mortality, whereas only change in PTH level from <150pg/mL to 150-<300pg/mL range was associated with a lower risk of mortality. Upon discordant changes of PTH and P, i.e., decrease in one of the two measures while the other increased, no change in mortality risk was observed.

CONCLUSION

In CKD-MBD management, patent survival is the greatest with controlling both serum P and PTH levels in balance. Tailoring an individualized treatment strategy in CKD-MBD may benefit patients. Further studies are needed.

Application of marginal structural models in pharmacoepidemiologic studies: a systematic review

PURPOSE

We systematically reviewed pharmacoepidemiologic studies published in 2012 that used inverse probability weighted (IPW) estimation of marginal structural models (MSM) to estimate the effect from a time-varying treatment.

METHODS

Potential studies were retrieved through a citation search within Web of Science and a keyword search within PubMed. Eligibility of retrieved studies was independently assessed by at least two reviewers. One reviewer performed data extraction, and a senior epidemiologist confirmed the extracted information for all eligible studies.

RESULTS

Twenty pharmacoepidemiologic studies were eligible for data extraction. The majority of reviewed studies did not report whether the positivity assumption was checked. Six studies performed intention-to-treat analyses, but none of them reported adherence levels after treatment initiation. Eight studies chose an as-treated analytic strategy, but only one of them reported modeling the multiphase of treatment use. Almost all studies performing as-treated analyses chose the most recent treatment status as the functional form of exposure in the outcome model. Nearly half of the studies reported that the IPW estimate was substantially different from the estimate derived from a standard regression model.

CONCLUSIONS

The use of IPW method to control for time-varying confounding is increasing in medical literature. However, reporting of the application of the technique is variable and suboptimal. It may be prudent to develop best practices in reporting complex methods in epidemiologic research.

Revisiting the association between altitude and mortality in dialysis patients

It was recently reported that residential altitude is inversely associated with all-cause mortality among incident dialysis patients; however, no adjustment was made for key case-mix and laboratory variables. We re-examined this question in a contemporary patient database with comprehensive clinical and laboratory data. In a contemporary 8-year cohort of 144,892 maintenance dialysis patients from a large dialysis organization, we examined the relationship between residential altitude and all-cause mortality. Using data from the US Geological Survey, the average residential altitudes per approximately 43,000 US zip codes were compiled and linked to the residential zip codes of each patient. Mortality risks for these patients were estimated by Cox proportional hazard ratios. The study population's mean ± standard deviation age was 61 ± 15 years. Forty-five percent of patients were women, and 57% of patients had diabetes. In fully adjusted analysis, those residing in the highest altitude strata (≥ 6000 ft) had a lower all-cause mortality risk in fully adjusted analyses: death hazard ratio: 0.92 (95% confidence interval, 0.86-0.99), as compared with patients in the reference group (<250 ft). Residential altitude is inversely associated in all-cause mortality risk in maintenance dialysis patients notwithstanding the unknown and unmeasured confounders.

Bone and mineral disorders after kidney transplantation: therapeutic strategies

Mineral and bone diseases (MBD) are common in patients with chronic kidney disease who undergo kidney transplantation. The incidence, types and severity of MBD vary according to the duration of chronic kidney disease, presence of comorbid conditions and intake of certain medications. Moreover, multiple types of pathology may be responsible for MBD. After successful reversal of uremia by kidney transplantation, many bone and mineral disorders improve, while immunosuppression, other medications, and new and existing comorbidities may result in new or worsening MBD. Chronic kidney disease is also common after kidney transplantation and may impact bone and mineral disease. In this article, we reviewed the prevalence, pathophysiology, and impact of MBD on post-transplant outcomes. We also discussed the diagnostic approach; immunosuppression management and potential treatment of MBD in kidney transplant recipients.

Angiotensin-converting enzyme inhibitor, angiotensin receptor blocker use, and mortality in patients with chronic kidney disease

OBJECTIVES

The study objective was to assess the association between angiotensin-converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB) use and mortality in patients with chronic kidney disease (CKD).

BACKGROUND

There is insufficient evidence about the association of ACEI or ARBs with mortality in patients with CKD.

METHODS

A logistic regression analysis was used to calculate the propensity of ACEI/ARB initiation in 141,413 U.S. veterans with nondialysis CKD who were previously unexposed to ACEI/ARB treatment. We examined the association of ACEI/ARB administration with all-cause mortality in patients matched by propensity scores using the Kaplan-Meier method and Cox models in "intention-to-treat" analyses and in generalized linear models with binary outcomes and inverse probability of treatment weights in "as-treated" analyses.

RESULTS

The age of the patients at baseline was 75 ± 10 years, 8% of patients were black, and 22% were diabetic. ACEI/ARB administration was associated with a significantly lower risk of mortality both in the intention-to-treat analysis (hazard ratio: 0.81, 95% confidence interval: 0.78 to 0.84; p < 0.001) and the as-treated analysis with inverse probability of treatment weights (odds ratio: 0.37, 95% confidence interval: 0.34 to 0.41; p < 0.001). The association of ACEI/ARB treatment with lower risk of mortality was present in all examined subgroups.

CONCLUSIONS

In this large contemporary cohort of nondialysis-dependent patients with CKD, ACEI/ARB administration was associated with greater survival.

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.