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

Paricalcitol and Extended-Release Calcifediol for Treatment of Secondary Hyperparathyroidism in Non-Dialysis Chronic Kidney Disease: Results From a Network Meta-Analysis

CONTEXT

Secondary hyperparathyroidism (SHPT) is a complication of chronic kidney disease (CKD) affecting mineral and bone metabolism and characterized by excessive parathyroid hormone (PTH) production and parathyroid hyperplasia.

OBJECTIVE

The objective of this analysis was to compare the efficacy and adverse effects of extended-release calcifediol (ERC) and paricalcitol (PCT) by assessing their effect on the biomarkers PTH, calcium, and phosphate in patients with non-dialysis CKD (ND-CKD).

METHODS

A systematic literature research was performed in PubMed to identify randomized control trials (RCTs). Quality assessment was done with the GRADE method. The effects of ERC vs PCT were compared using random effects in a frequentist setting.

RESULTS

Nine RCTs comprising 1426 patients were included in the analyses. The analyses were performed on 2 overlapping networks, due to nonreporting of outcomes in some of the included studies. No head-to-head trials were identified. No statistically significant differences in PTH reduction were found between PCT and ERC. Treatment with PCT showed statistically significant increases in calcium compared with ERC (0.2 mg/dL increase; 95% CI, -0.37 to -0.05 mg/dL). No differences in effects on phosphate were observed.

CONCLUSION

This network meta-analysis showed that ERC is comparable in lowering PTH levels vs PCT. ERC displayed avoidance of potentially clinically relevant increases in serum calcium, offering an effective and well-tolerated treatment option for the management of SHPT in patients with ND-CKD.

A comparative analysis of the efficacy and safety of paricalcitol versus other vitamin D receptor activators in patients undergoing hemodialysis: A systematic review and meta-analysis of 15 randomized controlled trials

Paricalcitol, a new vitamin D receptor activator (VDRA), is reported to be more effective than other VDRAs in reducing calcium and phosphorus levels in patients undergoing hemodialysis. However, the efficacy and safety of paricalcitol remain controversial. This analysis compares paricalcitol with other VDRAs in patients undergoing hemodialysis. We searched the Cochrane Library, PubMed, EMBASE, Web of Science, and CNKI up to April 22, 2019. Standardized mean difference (SMD), risk ratio (RR) and 95% confidence interval (CI) values were estimated to compare the outcomes of the groups. Two reviewers extracted data and assessed trial quality independently. All statistical analyses were performed using the standard statistical procedures of RevMan 5.2 and Stata 12.0. Fifteen studies (N = 110,544) were included in this meta-analysis. Of these studies, 11 were randomized controlled trials (RCTs) and 4 were non-randomized studies of interventions (NRSIs). Patients receiving paricalcitol experienced better overall survival (OS) than patients receiving other VDRAs, with a pooled hazard ratio of 0.86 (95% CI 0.80–0.91; P < 0.00001). Intact parathyroid hormone (iPTH) levels were significantly reduced in the paricalcitol group compared to the group receiving other VDRAs, with a pooled SMD of -0.53 (95% CI -0.89– -0.16; P = 0.004). There was a significant increase in serum calcium levels from baseline in the paricalcitol group compared to the other VDRAs group when limiting the analysis to RCTs, with a pooled SMD of 2.14 (95% CI 0.90–3.38; P = 0.0007). Changes in serum calcium levels were significantly lower in the paricalcitol group when the analysis was limited to NRSIs, with a pooled SMD of -0.85 (95% CI -1.34–-0.35; P = 0.0008). The NSRI analysis also showed a significant reduction in serum phosphorus levels in the paricalcitol group, with a pooled SMD of -0.57 (95% CI -1.00–-0.13; P = 0.01). No significant differences were observed in the incidence of hypercalcemia, hyperphosphatemia, or adverse events. Generally, paricalcitol seems superior to other VDRAs in reducing mortality and iPTH levels in patients undergoing hemodialysis. However, the comparative effectiveness of paricalcitol in reducing serum calcium and phosphorus levels needs further exploration. No significant difference was found in the rate of adverse events.

Efficacy and safety of cinacalcet and active vitamin D in the treatment of secondary hyperparathyroidism in patients with chronic kidney disease: a network meta-analysis

Background

We conducted a network meta-analysis (NMA) to evaluate the efficacy and safety of cinacalcet, active vitamin D and cinacalcet plus active vitamin D in the treatment of secondary hyperparathyroidism (SHPT) in patients with chronic kidney disease (CKD).

Methods

A systematic literature search was performed using the Cochrane Library, PubMed, EMBASE, Web of Science, Google Scholar, China National Knowledge Internet (CNKI) and Wanfang databases. In total, eight randomized controlled trials (RCTs) with 1,443 patients were eligible for this meta-analysis. Pairwise meta-analysis was performed to evaluate the compliance of intact parathyroid hormone (iPTH), Ca, P, etc., and the mortality and safety of cinacalcet plus active vitamin D and active vitamin D alone. Then, NMA was used to estimate the safety and efficacy of the administration of active vitamin D and different drugs in the control group.

Results

The results of the pairwise meta-analysis revealed that compared with active vitamin D monotherapy, cinacalcet plus active vitamin D did not improve the survival of patients but significantly improved the blood calcium compliance rate [relative risk (RR) =1.82, 95% confidence interval (CI): 1.51-2.21, P<0.00001]. Furthermore, it is worth noting that compared with the corresponding incidence with other treatments, the incidence of vomiting was significantly increased with cinacalcet plus active vitamin D treatment (RR =2.07, 95% CI: 1.18-3.65, P=0.01). Through direct and indirect comparisons, the NMA revealed the following results: (I) compared with oral or intravenous (IV) administration of vitamin D, the solely oral administration of active vitamin D increased mortality, and (II) cinacalcet monotherapy increased the risk of hypocalcemia, and that risk was even higher for cinacalcet plus active vitamin D. However, the results should be treated with caution because the prediction interval (PrI) crossed the invalid line.

Conclusions

This pairwise meta-analysis and NMA provided a comprehensive analysis of the currently utilized CKD-SHPT treatment interventions. This network identified some highly ranked interventions through analyses that were included in a small number of trials; these interventions merit further examination on a larger scale in the context of well-designed RCTs.

Changes in microparticle profiles by vitamin D receptor activation in chronic kidney disease - a randomized trial

Background

Microparticles (MPs) are biomarkers and mediators of disease through their expression of surface receptors, reflecting activation or stress in their parent cells. Endothelial markers, ICAM-1 and VCAM-1, are implicated in atherosclerosis and associated with cardiovascular risk. Chronic kidney disease (CKD) patients have endothelial dysfunction and high levels of endothelial derived MPs. Vitamin D treatment has been reported to ameliorate endothelial function in CKD patients. We aimed to examine cell specific MP profiles and concentrations of MPs expressing the atherosclerotic markers ICAM-1 and VCAM-1 after treatment with paricalcitol in patients with CKD stage 3–4.

Methods

Sub-study of the previously reported SOLID trial where 36 patients were randomly assigned to placebo, 1 or 2 μg paricalcitol, for 12 weeks. MPs were measured by flow cytometry after labelling with antibodies against endothelial (CD62E), platelet (CD62P, CD41, CD154) leukocyte (CD45) and vascular (CD54, CD106) markers.

Results

Patients had a mean age of 65 years with a mean eGFR of 40 mL/min/1.73m². Concentrations of ICAM-1 positive MPs were significantly reduced by treatment (repeated measures ANOVA p = 0.04). Repeated measures MANOVA of concentrations of endothelial, platelet and leukocyte MPs showed sustained levels in the 2 μg treatment group (p = 0.85) but a decline in the 1 μg (p = 0.04) and placebo groups (p = 0.005).

Conclusions

Treatment with paricalcitol reduces concentrations of ICAM-1 positive MPs. This is accompanied by sustained concentrations of all cell specific MPs in the 2 μg group, and decreasing concentrations in the other groups, possibly due to a more healthy and reactive endothelium with paricalcitol treatment.

Treating endothelial dysfunction with vitamin D in chronic kidney disease: a meta-analysis

Background

Vitamin D deficiency is common in patients with chronic kidney disease (CKD), and is associated with endothelial dysfunction and cardiovascular disease. We performed a meta-analysis to assess the effect of vitamin D treatment on flow mediated vasodilation (FMD) in CKD patients.

Methods

PubMed/Medline, Web of Science, Embase and Cochrane trials and reviews were searched systematically for randomized controlled trials (RCT:s) using any vitamin D compound, at any stage of CKD, with FMD as outcome. Fixed and random effects models were performed using the standardized mean difference effect size post treatment for each trial. Heterogeneity was assessed by I² statistics.

Results

4 trials were included, comprising 305 patients. One used both 1 and 2 μg for two intervention groups and was therefore split in two during the analysis. Patients in the included trials had a mean age of 44–65 years and were all in CKD 3 to 4. One study used cholecalciferol, the others all used paricalcitol as treatment. Study duration was 12–16 weeks. Intervention with vitamin D was associated with ameliorated FMD (STANDmean ES 0.78, 95% CI 0.55–1.01) in a fixed model. Heterogeneity was substantial (I² = 84%). Secondary analysis with random model analysis also showed significant results.

Conclusions

Short term intervention with vitamin D is associated with improvements in endothelial function, as measured by FMD. This indicates positive effects of vitamin D on vascular disease in CKD. Limitations of this meta-analysis are the small number of studies performed, and the short duration of intervention.

Electronic supplementary material

The online version of this article (10.1186/s12882-018-1042-y) contains supplementary material, which is available to authorized users.

NUTRITIONAL OR ACTIVE VITAMIN D FOR THE CORRECTION OF MINERAL METABOLISM ABNORMALITIES IN NON-DIALYSIS CHRONIC KIDNEY DISEASE PATIENTS?

Context

Benefits of vitamin D therapies in chronic kidney disease (CKD) are debated.

Objective

To compare the effects of medium-term native (VitD) and active (VDRA) vitamin D on parameters of mineral metabolism and arterial function in non-dialysis CKD.

Design

Open-label, active comparator, randomized study.

Subjects and Methods

Forty-eight adult patients, vitamin D naïve, CKD stage 3 to 5 with increased parathyroid hormone (iPTH) were randomized to receive either oral cholecalciferol 1000UI/day (n=24) or paricalcitol 1mcg/day (n=24) for 6 months. Median changes at end of study vs. baseline in serum calcidiol, iPTH, total alkaline phosphatase (ALP), and cardio-ankle vascular index (CAVI) were the efficacy parameters.

Results

Higher increase in calcidiol (15.5 [95%CI 13.3; 17.2] vs. 0.4 [95%CI -6.1; 3.7]ng/mL, p<0.001) were found in VitD group. Conversely, the decline of iPTH (-35.2 [95%CI -83; 9] vs. 13.3 [95%CI -8.1; 35]pg/mL, p=0.008) and ALP (-34 [95%CI -58; -11] vs. -10 [95%CI -23; -2]U/L, p=0.02) were greater after paricalcitol. More subjects experienced iPTH decrease in VDRA group (71% vs. 39%, p=0.03). The variation in CAVI and the incidence of hypercalcemia and hyperphosphatemia were similar.

Conclusions

It seems that secondary hyperparathyroidism was more efficiently treated by VDRA, whereas cholecalciferol better corrected the calcidiol deficiency in non-dialysis CKD.

Total parathyroidectomy with forearm auto-transplantation improves the quality of life and reduces the recurrence of secondary hyperparathyroidism in chronic kidney disease patients

BACKGROUND

Our study aims to explore the effect of total parathyroidectomy (PTX) with forearm autotransplantation (FAT) on the quality of life and recurrence of secondary hyperparathyroidism (SHPT) in chronic kidney disease patients.

METHODS

A total of 104 chronic kidney disease patients with SHPT were enrolled and divided into the PTX (n = 62) and PTX + FAT (n = 42) groups. The operation efficacy was evaluated by analyzing preoperative and postoperative values, including levels of intact parathyroid hormone (iPTH), serum phosphorus, serum calcium, alkaline phosphatase (ALP), calcium-phosphorus product, signs and symptoms, and MOS 36-item short-form health survey (SF-36) scores. Moreover, complications and recurrences were followed up for 12 months after the operation. Binary logistic regression was to present the risk factors for the recurrence of chronic kidney disease patients with SHPT.

RESULTS

Compared with the preoperative values, the PTX and PTX + FAT groups showed decrease postoperative levels of iPTH, serum phosphorus, serum calcium, calcium-phosphorus product, bone pain, and skin pruritus at all time periods. The PTX and PTX + FAT groups demonstrated decreased ALP, fracture or deformity, and coronary artery calcification at 1 month, decreased short stature at 3 months after the operation but increased SF-36 score after operation. Compared with the PTX group, the level of iPTH decreased and the levels of serum calcium, calcium-phosphorus product increased at 3, 6, and 12 months after the operation in the PTX + FAT group. The levels of ALP, fracture or deformity, short stature, and SF-36 decreased separately at 1 week and 6 and 12 months after the operation, along with the decrease of coronary artery calcification and the recurrence rate, respectively, at 6 and 12 months after the operation in the PTX + FAT group when compared with those in the PTX group. Logistic regression analysis evidenced that the preoperative iPTH level, SF-36 score, and operation type were the risk factors for the recurrence of chronic kidney disease with SHPT.

CONCLUSION

Total PTX combined with FAT is more effective in improving the quality of life and reducing the recurrence of chronic kidney disease with SHPT than PTX alone.

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.

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.

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.

Clinical practice recommendations for treatment with active vitamin D analogues in children with chronic kidney disease Stages 2-5 and on dialysis

In patients with chronic kidney disease (CKD), renal synthesis of active vitamin D [1,25-dihydroxyvitamin D (1,25(OH)2D)] declines and is associated with hypocalcaemia, secondary hyperparathyroidism and the spectrum of CKD-mineral and bone disorder (MBD). In advanced CKD, active vitamin D analogues, including alfacalcidol, calcitriol and paricalcitol, are routinely administered. There are few studies on the use of vitamin D analogues in children with CKD and on dialysis. It is difficult to define bone-specific outcomes that can guide treatment with active vitamin D analogues in children with CKD-MBD. A core working group (WG) of the European Society for Paediatric Nephrology (ESPN) CKD-MBD and Dialysis WGs has developed recommendations for the use of active vitamin D therapy in children with CKD and on dialysis. A second document in parallel with this one covers treatment recommendations for native vitamin D therapy. The WGs have performed an extensive literature review to include systematic reviews and randomized controlled trials in adults and children with CKD and prospective observational studies in children with CKD. The Grading of Recommendation, Assessment, Development and Evaluation (GRADE) system was used to develop and grade the recommendations. In the absence of applicable study data, the opinion of experts from the ESPN CKD-MBD and Dialysis WGs is provided, but clearly GRADE-ed as such and must be carefully considered by the treating physician and adapted to individual patient needs as appropriate.

Stirring the Pot: Can Dietary Modification Alleviate the Burden of CKD?

Diet is one of the largest modifiable risk factors for chronic kidney disease (CKD)-related death and disability. CKD is largely a progressive disease; however, it is increasingly appreciated that hallmarks of chronic kidney disease such as albuminuria can regress over time. The factors driving albuminuria resolution remain elusive. Since albuminuria is a strong risk factor for GFR loss, modifiable lifestyle factors that lead to an improvement in albuminuria would likely reduce the burden of CKD in high-risk individuals, such as patients with diabetes. Dietary therapy such as protein and sodium restriction has historically been used in the management of CKD. Evidence is emerging to indicate that other nutrients may influence kidney health, either through metabolic or haemodynamic pathways or via the modification of gut homeostasis. This review focuses on the role of diet in the pathogenesis and progression of CKD and discusses the latest findings related to the mechanisms of diet-induced kidney disease. It is possible that optimizing diet quality or restricting dietary intake could be harnessed as an adjunct therapy for CKD prevention or progression in susceptible individuals, thereby reducing the burden of CKD.

Comparison between paricalcitol and active non-selective vitamin D receptor activator for secondary hyperparathyroidism in chronic kidney disease: a systematic review and meta-analysis of randomized controlled trials

PURPOSE

The goal of this systematic review is to evaluate the efficacy and safety of paricalcitol versus active non-selective vitamin D receptor activators (VDRAs) for secondary hyperparathyroidism (SHPT) management in chronic kidney disease (CKD) patients.

METHODS

PubMed, EMBASE, Cochrane Central Register of Controlled Trials (CENTRAL), clinicaltrials.gov (inception to September 2015), and ASN Web site were searched for relevant studies. A meta-analysis of randomized controlled trials (RCTs) and quasi-RCTs that assessed the effects and adverse events of paricalcitol and active non-selective VDRA in adult CKD patients with SHPT was performed using Review Manager 5.2.

RESULTS

A total of 10 trials involving 734 patients were identified for this review. The quality of included trials was limited, and very few trials reported all-cause mortality or cardiovascular calcification without any differences between two groups. Compared with active non-selective VDRAs, paricalcitol showed no significant difference in both PTH reduction (MD -7.78, 95% CI -28.59-13.03, P = 0.46) and the proportion of patients who achieved the target reduction of PTH (OR 1.27, 95% CI 0.87-1.85, P = 0.22). In addition, no statistical differences were found in terms of serum calcium, episodes of hypercalcemia, serum phosphorus, calcium × phosphorus products, and bone metabolism index.

CONCLUSIONS

Current evidence is insufficient, showing paricalcitol is superior to active non-selective VDRAs in lowering PTH or reducing the burden of mineral loading. Further trials are required to prove the tissue-selective effect of paricalcitol and to overcome the limitation of current research.

Potential of vitamin D in treating diabetic cardiomyopathy

Cardiovascular disease is the leading cause of morbidity and mortality in patients with diabetes mellitus (DM), and patients with DM frequently develop diabetic cardiomyopathy. Currently, effective treatments for diabetic cardiomyopathy are limited. Vitamin D exerts pleiotropic effects on the cardiovascular system and is associated with DM. The purpose of this review was to evaluate published research on vitamin D in diabetic cardiomyopathy by searching PubMed databases. Herein, we reviewed vitamin D metabolism; evaluated the molecular, cellular, and neuroendocrine effects in native and bioactive vitamin D; and evaluated the role of vitamin D in treating cardiovascular disease and DM. Some evidence suggests that vitamin D may improve cardiovascular outcomes in diabetes through anti-inflammatory, antioxidative, antihypertrophic, antifibrotic, and antiatherosclerotic activities and by regulating advanced glycation end-product signaling, the renin-angiotensin system, and cardiac metabolism. This clinical and laboratory evidence suggests that vitamin D may be a potential agent in treating diabetic cardiomyopathy. However, using vitamin D entails possible adverse risks of hypercalcemia, hyperphosphatemia, and vascular calcifications. Therefore, future studies should be conducted that clarify the potential benefits of vitamin D through large-scale randomized clinical trials in well-defined groups of diabetic patients.

Vitamin D resistance in chronic kidney disease (CKD)

BACKGROUND

Previous studies have shown that treatment with ergocalciferol in patients with CKD stage 3 + 4 is not effective with less than 33% of patients achieving a 25-OH vitamin D target of >30 ng/ml. The aim of this study was to test the response to cholecalciferol in CKD. We attempted to replete 25-OH vitamin D to a target level of 40-60 ng/ml using the response to treatment and PTH suppression as an outcome measure.

METHODS

This retrospective cohort study identified patients (Stages 2-5 and Transplant) from 2001-2010 who registered at the Chronic Kidney Disease Clinic. Patients received cholecalciferol 10,000 IU capsules weekly as initial therapy. When levels above 40 ng/ml were not achieved, doses were titrated up to a maximum of 50,000 IU weekly. Active vitamin D analogs were also used in some Stage 4-5 CKD patients per practice guidelines. Patients reaching at least one level of 40 ng/mL were designated RESPONDER, and if no level above 40 ng/mL they were designated NON-RESPONDER. Patients were followed for at least 6 months and up to 5 years.

RESULTS

352 patients were included with a mean follow up of 2.4 years. Of the CKD patients, the initial 25-OH vitamin D in the NON-RESPONDER group was lower than the RESPONDER group (18 vs. 23 ng/ml) (p = 0.03). Among all patients, the initial eGFR in the RESPONDER group was significantly higher than the NON-RESPONDER group (36 vs. 30 ml/min/1.73 m2) (p < 0.001). Over time, the eGFR of the RESPONDER group stabilized or increased (p < 0.001). Over time, the eGFR in the NON-RESPONDER group decreased toward a trajectory of ESRD. Proteinuria did not impact the response to 25-OH vitamin D replacement therapy. There were no identifiable variables associated with the response or lack of response to cholecalciferol treatment.

CONCLUSIONS

CKD patients treated with cholecalciferol experience treatment resistance in raising vitamin D levels to a pre-selected target level. The mechanism of vitamin D resistance remains unknown and is associated with progressive loss of eGFR. Proteinuria modifies but does not account for the vitamin D resistance.