帕立骨化醇治疗维持性血液透析患者继发性甲状旁腺功能亢进的疗效观察

目的观察帕立骨化醇对维持性血液透析患者继发性甲状旁腺功能亢进症的治疗效果。方法选择2018年7月至2019年7月对非选择性维生素D受体激动剂(VDRA)疗效不佳或不能耐受拟钙剂或不愿手术治疗的继发性甲状旁腺功能亢进(SHPT)的维持性血液透析患者56例,根据血液全段甲状旁腺素(iPTH)水平将所有患者分为三个组别:A组(300 pg/mL≤iPTH<600 pg/mL)、B组(600 pg/mL≤iPTH<800 pg/mL)、C组(iPTH≥800 pg/mL)。根据体重给予不同剂量的静脉帕立骨化醇注射液,分别检测患者治疗前、初始使用1个月以及达到帕立骨化醇维持剂量时,iPTH、血钙、血磷、钙磷乘积的变化情况。结果患者骨痛、瘙痒、疲乏等症状明显改善。所有患者初始治疗1个月,iPTH达标率为51.8%(29/56),达到帕立骨化醇注射液维持治疗剂量百分比为57.1%(32/56)。患者初始治疗1个月与治疗前相比,iPTH水平显著下降[(718.76±457.56)pg/mL vs.(956.68±375.61)pg/mL,P<0.001],血钙、血磷以及钙磷乘积无明显改变[(2.28±0.23)mmol/L vs.(2.23±0.27)mmol/L,(2.15±0.49)mmol/L vs.(2.29±0.48)mmol/L,(58.49±17.71)mg^2/dl2 vs.(62.90±13.93)mg^2/dl2,P>0.05]。进入维持治疗阶段的患者,维持治疗与初始治疗相比,iPTH水平仍有下降趋势,但差异无统计学意义[(424.82±221.23)pg/mL vs.(517.55±325.77)pg/mL,P>0.05],血钙、血磷以及钙磷乘积比较差异无统计学意义[(2.33±0.20)mmol/L vs.(2.31±0.24)mmol/L,(2.13±0.44)mmol/L vs.(2.00±0.42)mmol/L,(61.24±12.25)mg^2/dl2 vs.(55.76±15.66)mg^2/dl2,P>0.05]。结论帕立骨化醇对非选择性VDRA疗效不佳或不能耐受拟钙剂或不愿手术治疗的维持性血液透析患者SHPT有较好的疗效,明显缓解患者骨痛、瘙痒、疲乏等症状,显著降低iPTH水平,且不增加高钙血症的发生风险。     

Inhibition of parathyroid hormone: a dose equivalency study of paricalcitol and doxercalciferol

INTRODUCTION: Paricalcitol and doxercalciferol are effective in reducing parathyroid hormone PTH concentrations in patients with secondary hyperparathyroidism. The purpose of this study was to determine the relative dose of doxercalciferol (compared to paricalcitol) required to maintain equivalent PTH concentrations in dialysis patients. METHODS: Chronic hemodialysis patients treated with a stable dose of paricalcitol for at least 3 months were randomized to receive doxercalciferol at either 35, 50, or 65% of the paricalcitol dose for 6 weeks. Serum iPTH, calcium, phosphorus, and albumin were determined at baseline and monitored every 2 weeks. A linear regression analysis of percent change in iPTH values by dose group was performed to determine the conversion factor. RESULTS: 27 patients were enrolled. Initial iPTH, adjusted serum calcium, serum phosphorus, and CaxP were similar among the treatment groups. Linear regression analysis demonstrated a conversion factor of 0.57 for the dose of doxercalciferol relative to paricalcitol resulting in equivalent suppression of iPTH. Corrected serum calcium, phosphorus, CaxP product, as well as incidence of hypercalcemia, hyperphosphatemia and CaxP >50 were similar for all groups. CONCLUSION: In patients on a maintenance dose of paricalcitol, dosing doxercalciferol at 55-60% of the paricalcitol dose results in comparable inhibition of PTH.     

Early initiation of cinacalcet for the treatment of secondary hyperparathyroidism in hemodialysis patients: a three-year clinical experience

Despite the availability of standard therapy (vitamin D sterols and phosphate binders) for the treatment of secondary hyperparathyroidism (SHPT) in hemodialyzed (HD) patients, a significant percentage of patients still fail to achieve targets recommended by the Kidney Disease Outcomes Quality Initiative (K/DOQI) of the National Kidney Foundation for parathyroid hormone (PTH), calcium, and phosphorus. The calcimimetic cinacalcet (CN) has been shown to be an effective treatment for SHPT, significantly reducing serum PTH while simultaneously lowering calcium, phosphorus, and calcium-phosphorus product levels, thus increasing the proportion of patients achieving the K/DOQI targets for bone mineral parameters. The aim of this study was to evaluate if early treatment with CN had beneficial effects in HD patients with mild-to-moderate SHPT in whom conventional treatments had failed to achieve NKF-K/DOQI targets for PTH, serum-corrected calcium, and phosphorus while minimizing the risk of paradoxical hypercalcemia and/or hyperphosphatemia. Clinical practice data were collected monthly, starting from 6 months prior to, and up to 36 months after, the start of CN therapy. CN was started at a dose of 30 mg daily or every other day, and titrated thereafter to achieve intact PTH (iPTH) <300 pg/mL. The dose of concomitant vitamin D and phosphate binders were also adjusted in order to achieve K/DOQI targets. Data from 32 patients were collected, 28 of whom had been treated with CN for at least 36 months at the time of data analysis. At baseline, patients had serum iPTH >300 pg/mL (570 ± 295 pg/mL) and/or serum-corrected calcium >9.5 mg/dL. CN induced significant decreases in iPTH, calcium, and calcium-phosphorus product with respect to baseline levels. The percentage of patients within K/DOQI target levels at baseline, 12, 24, and 36 months was 0, 81.2, 83.3, and 86.2% for iPTH; 34.4, 65.6, 86.6, and 89.6% for serum-corrected calcium; 40.6, 56.2, 69.6, and 72.4% for phosphorus; and 37.5, 62.5, 80, and 82.7% for calcium-phosphorus product. The mean dose of CN at the end of the observation period was 38 mg/day. The mean dose of concomitant medication (calcitriol, Al-containing phosphate binders, and sevelamer) decreased from baseline to 36 months. Early treatment with CN in HD patients with SHPT increases the proportion of patients achieving and maintaining K/DOQI targets with a low dose of CN (38 mg/day). These results suggest that the metabolic control obtained with low-dose CN administered early in the course of SHPT can be maintained or increased over time.     

Nicotinamide suppresses hyperphosphatemia in hemodialysis patients

BACKGROUND: The use of calcium- or aluminum-based phosphate binders against hyperphosphatemia is limited by the adverse effects of hypercalcemia or aluminum toxicity in long-term hemodialysis. Because nicotinamide is an inhibitor of sodium-dependent phosphate cotransport in rat renal tubule and small intestine, we examined whether nicotinamide reduces serum levels of phosphorus and intact parathyroid hormone (iPTH) in patients undergoing hemodialysis. METHODS: Sixty-five hemodialysis patients with a serum phosphorus level of more than 6.0 mg/dL after a 2-week washout of calcium carbonate were enrolled in this study. Nicotinamide was administered for 12 weeks. The starting dose was 500 mg/day, and the dose was increased by 250 mg/day every 2 weeks until serum phosphorus levels were well controlled at less than 6.0 mg/dL. A 2-week posttreatment washout period followed the cessation of nicotinamide. Blood samples were collected every week for measurement of serum calcium, phosphorus, lipids, iPTH, and blood nicotinamide adenine dinucleotide (NAD). RESULTS: The mean dose of nicotinamide was 1080 mg/day. The mean blood NAD concentration increased from 9.3 +/- 1.9 nmol/105 erythrocytes before treatment to 13.2 +/- 5.3 nmol/105 erythrocytes after treatment (P < 0.01). The serum phosphorus concentration increased from 5.4 +/- 1.5 mg/dL to 6.9 +/- 1.5 mg/dL with the pretreatment washout, then decreased to 5.4 +/- 1.3 mg/dL after the 12-week nicotinamide treatment (P < 0.0001), and rose again to 6.7 +/- 1.6 mg/dL after the posttreatment washout. Serum calcium levels decreased during the pretreatment washout from 9.1 +/- 0.8 mg/dL to 8.7 +/- 0.7 mg/dL with the cessation of calcium carbonate. No significant changes in serum calcium levels were observed during nicotinamide treatment. Median serum iPTH levels increased with pretreatment washout from 130.0 (32.8 to 394.0) pg/mL to 200.0 (92.5 to 535.0) pg/mL and then decreased from the maximum 230.0 (90.8 to 582.0) pg/mL to 150.0 (57.6 to 518.0) pg/mL after the 12-week nicotinamide treatment (P < 0.05). With nicotinamide, serum high-density lipoprotein (HDL) cholesterol concentrations increased from 47.4 +/- 14.9 mg/dL to 67.2 +/- 22.3 mg/dL (P < 0.0001) and serum low-density lipoprotein (LDL) cholesterol concentrations decreased from 78.9 +/- 18.8 mg/dL to 70.1 +/- 25.3 mg/dL (P < 0.01); serum triglyceride levels did not change significantly. CONCLUSION: Nicotinamide may provide an alternative for controlling hyperphosphatemia and hyperparathyroidism without inducing hypercalcemia in hemodialysis patients.     

A long-term, multicenter study of the efficacy and safety of paricalcitol in end-stage renal disease.

BACKGROUND: Paricalcitol is a vitamin D analog approved for the prevention and treatment of secondary hyperparathyroidism associated with chronic renal failure. This study was designed to evaluate the long-term efficacy and safety of paricalcitol. Additional analysis evaluated the effects of paricalcitol in hypocalcemic and hyperphosphatemic subpopulations. PATIENTS AND METHODS: One hundred sixty-four end-stage renal disease (ESRD) patiesnts on hemodialysis were treated in an open-label, multicenter study lasting up to 13 months in duration. After a baseline or washout period, an initial starting dose of 0.04-0.393 microg/kg was given 2-3 times per week. This dose was adjusted at the discretion of the investigator according to the patient's intact parathyroid hormone level (iPTH), calcium level, and calcium-phosphorus (Ca x P) product. The therapy was intended to reproduce expected clinical use of paricalcitol. Patients represented a wide cross-section of the ESRD population, and were not excluded from the study based on age or underlying disease. RESULTS: The mean paricalcitol dose level throughout the study was 0.10 microg/kg. The mean iPTH levels (baseline mean 628.3 +/- 27.65 pg/ml) decreased rapidly during the first 4 months of therapy, and reached the designated target range (100-300 pg/ml) by month 5 (mean 295.3 +/- 25.69 pg/ml). A maximum mean decrease in iPTH level of 409 +/- 35.01 pg/ml was seen at month 13. Throughout the course of the study, the mean normalized calcium level was maintained well within the normal range (9.44-9.94 mg/dl). The mean phosphorus level was maintained in an acceptable range throughout the study (5.92-6.53 mg/dl). Mean Ca x P product was maintained between 52 and 65. Mean alkaline phosphatase levels decreased significantly from baseline with a maximum mean decrease of 62 +/- 17.3 U/l observed at month 9. In 34 initially hypocalcemic patients (mean of 7.7 mg/dl) iPTH levels decreased from baseline, on average, by 443 +/- 81.86 pg/ml while mean calcium levels rose by 1.2 +/- 0.23 mg/dl to reach the normal range. In 35 initially hyperphosphatemic patients (mean of 8.0 mg/dl) iPTH levels decreased, on average, by 515 +/- 103.31 pg/ml with an associated mean decrease in phosphorus of 0.57 +/- 0.52 mg/dl. Adverse events that were considered by the investigator to have a possible. probable, or definite relationship to study drug occurred in 26% of patients. Other than expected temporary effects of hypercalcemia and hyperphosphatemia. the only possible trends for causally-related adverse events were for nausea/vomiting and metallic taste. CONCLUSIONS: This long-term study of paricalcitol demonstrates that it rapidly and effectively suppresses iPTH levels in a wide spectrum of ESRD patients and caused no unexpected adverse events.     

A comparison of sevelamer hydrochloride with calcium acetate on biomarkers of bone turnover in hemodialysis patients

OBJECTIVE: To evaluate the influence of sevelamer hydrochloride and calcium acetate on biomarkers of bone turnover in patients with hyperphosphatemia receiving hemodialysis. METHODS: In this prospective, open-label, randomized, active-controlled study, 70 patients (38 men and 32 women) with hyperphosphatemia (serum phosphorus level >6.0 mg/dL) underwent a two-week washout period and were randomly selected to receive sevelamer hydrochloride (n = 37) or calcium acetate (n = 33) for eight weeks. Changes in serum levels of intact parathyroid hormone (iPTH), alkaline phosphatase (Alk-P), phosphorus, and calcium were measured and compared. RESULTS: After eight weeks of treatment, calcium acetate lowered iPTH levels significantly more than sevelamer hydrochloride did (-178.0 vs. -69.0 pg/mL, p = 0.0019). Levels of Alk-P were significantly elevated in patients given sevelamer hydrochloride compared with levels in those given calcium acetate treatment (24.09 vs. 7.45 U/L, p = 0.0014). Changes in serum phosphorus levels did not differ between sevelamer hydrochloride (-1.93 mg/dL) and calcium acetate (-2.5 mg/dL) at the end of the study (p = 0.0514). Changes in the calcium and phosphorous product did not significantly differ between the sevelamer-hydrochloride group (-18.06 mg2/dL2) and the calcium-acetate group (-19.05 mg2/dL2, p = 0.6764). Fifteen patients (45.5%) treated with calcium acetate had hypercalcemia (serum-adjusted calcium level >10.5 mg/dL); the rate was significantly higher than that of patients treated with sevelamer (five [13.5%] of 37, p = 0.0039). CONCLUSION: Treatment with sevelamer hydrochloride had the advantage of maintaining stable iPTH levels and elevating Alk-P levels while lowering serum phosphorus levels and calcium-phosphorous product.     

Paricalcitol versus calcitriol in the treatment of secondary hyperparathyroidism

BACKGROUND: Management of secondary hyperparathyroidism has included the use of active vitamin D or vitamin D analogs for the suppression of parathyroid hormone (PTH) secretion. Although, these agents are effective, therapy is frequently limited by hypercalcemia, hyperphosphatemia, and/or elevations in the calcium-phosphorus (Ca x P) product. In clinical studies, paricalcitol was shown to be effective at reducing PTH concentrations without causing significant hypercalcemia or hyperphosphatemia as compared to placebo. A comparative study was undertaken in order to determine whether paricalcitol provides a therapeutic advantage to calcitriol. METHODS: A double-blind, randomized, multicenter study comparing the safety and effectiveness of intravenous paricalcitol and calcitriol in suppressing PTH concentrations in hemodialysis patients was performed. A total of 263 randomized patients were enrolled at domestic and international sites. Following the baseline period, patients with serum Ca x P < 75, and a PTH level > or =300 pg/mL were randomly assigned to receive either paricalcitol or calcitriol in a dose-escalating fashion for up to 32 weeks. Dose adjustments were based on laboratory results for PTH, calcium, and Ca x P. The primary end point was the greater than 50% reduction in baseline PTH. Secondary end points were the occurrence of hypercalcemia and elevated Ca x P product. RESULTS: Paricalcitol-treated patients achieved a > or =50% reduction from baseline PTH significantly faster than did the calcitriol-treated patients (P = 0.025) and achieved a mean reduction of PTH into a desired therapeutic range (100 to 300 pg/mL) at approximately week 18, whereas the calcitriol-treated patients, as a group, were unable to achieve this range. Moreover, paricalcitol-treated patients had significantly fewer sustained episodes of hypercalcemia and/or increased Ca x P product than calcitriol patients (P = 0.008). CONCLUSION: Paricalcitol treatment reduced PTH concentrations more rapidly with fewer sustained episodes of hypercalcemia and increased Ca x P product than calcitriol therapy.     

Intravenous calcitriol versus paricalcitol in haemodialysis patients with severe secondary hyperparathyroidism

Aim:   Secondary hyperparathyroidism (SHPT) is common among haemodialysis patients. Intensive treatment with calcitriol is often complicated by hypercalcaemia, hyperphosphataemia and elevated calcium phosphorus (Ca X PO₄) product. Paricalcitol is a vitamin D analogue developed to overcome some of the limitations of calcitriol therapy. The study objectives were to compare the response of intact parathyroid hormone (iPTH) and the incidence of hypercalcaemia, hyperphosphataemia and elevated Ca X PO₄ product in patients with severe SHPT treated with either i.v. calcitriol or i.v. paricalcitol.
Methods:   This was a single centre randomized open label study. Patients with serum intact iPTH of 50 pmol/L or more were randomized to receive either i.v. calcitriol (0.01 ug/kg) or i.v. paricalcitol (0.04 ug/kg) during every haemodialysis treatment. Serum iPTH, calcium, phosphorus and alkaline phosphatase were measured at the beginning of the study and every 3 weeks for 12 weeks.
Results:   Twenty-five patients were enrolled into the study – 12 were randomized into the calcitriol group and 13 into the paricalcitol group. There were no differences in the baseline study parameters between both groups. Serum iPTH levels were significantly reduced ( P  = 0.003) only in the paricalcitol group but not in the calcitriol group ( P  = 0.101). On the other hand, serum calcium levels were significantly increased only in the calcitriol group ( P  = 0.004 vs P  = 0.242). Serum phosphorus, alkaline phosphatase and Ca X PO₄ product were not different.
Conclusion:   Intravenous paricalcitol may be superior to i.v. calcitriol for the treatment of severe SHPT in our chronic haemodialysis population. A larger randomized controlled trial is indicated to confirm these initial findings.     

Calcitriol resistance in hemodialysis patients with secondary hyperparathyroidism

Nonselective vitamin D receptor activators (VDRA), such as calcitriol and alfacalcidol, have been successfully used in the treatment of secondary hyperparathyroidism (SHPT) in hemodialysis. Despite their beneficial effects on the control of serum PTH levels, their use has been limited by intolerance (development of hypercalcemia and hyperphosphatemia with consecutive cardiovascular toxicity). Apart from becoming intolerant, in 20–30 % of patients who use nonselective VDRA, serum PTH levels do not decrease appropriately despite increasing doses of these agents. These patients are considered calcitriol-resistant patients. Thus, calcitriol resistance and intolerance are two sides of the same coin: active vitamin D failure. Despite the clinical relevance of active vitamin D failure, definitions of resistance and intolerance are imprecise and have varied over time. More selective VDRA claim to produce less hypercalcemia and hyperphosphatemia and could help clinicians to overcome intolerance. Also, some studies have also shown that paricalcitol can be even useful in resistant patients. Significant limitations of iPTH as a reliable and useful clinical biomarker have been increasingly appreciated. There is evidence that intact PTH concentration must differ by 72 % between any two measurements before it can be considered a significant change. VDR polymorphisms could be involved in the development of SHPT in CKD patients. Interestingly, a higher incidence of the b allele of the VDR BsmI gene variant has been shown to be present in SHPT. The BsmI genotype can also affect the response of hemodialysis to IV calcitriol. A challenge for the future will be to establish biomarkers such as laboratory determinations or ultrasound findings that can help us to early identify those patients who will not respond appropriately to calcitriol or exhibit intolerable side effects .     

Paricalcitol versus calcitriol treatment for hyperparathyroidism in pediatric hemodialysis patients

Secondary hyperparathyroidism (SHPT) remains a treatment dilemma in pediatric dialysis patients. Recent experience with paricalcitol (P), a vitamin D analogue, in adults with SHPT has shown equal efficacy and improved survival compared to traditional treatment with calcitriol (C). We present our experience with (C) compared to (P) treatment in our pediatric dialysis patients with SHPT. Twenty-one patients (mean age 11.5±5 years) with SHPT (intact parathyroid hormone (iPTH) averaging 1,228±496 pg/ml) were studied. Seventeen received (C) followed by (P); while an additional four were treated with either (C=1) or (P=3) alone. After 26±8 weeks, average percent (%) decrease in iPTH was similar with (C) and (P) (−60.4±34% versus −65.4±28%, respectively; p=0.6). In the (P) group, the effective dose in children was greater than in adult trials based on kilogram weight. Episodes of hypercalcemia between the treatment groups were not different. However, episodes of elevated calcium × phosphorus product (Ca×P)≥70 mg²/dl² occurred more frequently in the (C) group (odds ratio=1.5; p=0.01). Paricalcitol appears to be safe and effective in pediatric patients. Data suggest that dosing should be gauged according to degree of SHPT. This should serve as impetus for future pharmacokinetic studies in pediatric dialysis patients.     

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

Background

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

Methods

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

Results

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

Conclusion

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

Once-weekly intravenous paricalcitol in the treatment of secondary hyperparathyroidism in hemodialysis patients

BACKGROUND: Paricalcitol, a vitamin D analog, is commonly administered three times weekly to control secondary hyperparathyroidism in hemodialysis patients. Less frequent dosing would be more convenient, require less nursing time, and be an option in other dialysis modalities. No studies have examined the efficacy of once-weekly dosing of paricalcitol. METHODS: Chronic hemodialysis patients receiving a stable dose of paricalcitol three times weekly with intact PTH (iPTH) 100-500 ng/l were monitored during a two-week baseline, then were converted to a single mid-week paricalcitol dose equal to the previous cumulative weekly dose. Serum calcium and phosphorus were monitored weekly and iPTH levels determined during study Weeks 4 and 8. A single paricalcitol dose adjustment was made during study Week 5 based on iPTH to achieve a target value of 150-300 ng/l. Phosphate binders and calcium dialysate bath were kept constant during the study. RESULTS: In the 25 patients, mean iPTH was 295 +/- 107 ng/l at baseline, and not significantly different at Week 4 (307 +/- 111 ng/l) or Week 8 (285 +/- 98 ng/l). Paricalcitol dose increases mid-study were almost exclusively in patients with iPTH > 300 ng/l. Calcium, phosphorus, and calcium x phosphorus product were not significantly different on weekly therapy. (Only one patient developed a calcium > 2.55 mmol/l during the study.) CONCLUSION: Once-weekly dosing of paricalcitol is an effective option in treatment of secondary hyperparathyroidism. Less frequent dosing may better allocate nursing time and potentially benefit other patient populations with CKD and ESRD.     

Assessment of phosphorus and calcium metabolism and its clinical management in hemodialysis patients in the community of Valencia

AIM: The objective of the study was to determine the situation concerning mineral metabolism and bone disease in hemodialysis (HD) patients living in the community of Valencia (Spain), as well as the clinical practices for bone disease control in relation to the laboratory targets recommended in the National Kidney Foundation Dialysis Outcomes Quality Initiative (K/DOQI) guidelines. METHODS: In December 2003, a cross-sectional study was performed including 2392 patients (1485 males and 907 females) from 43 different centers in the council of Valencia (the entire HD population). Mean age was 65.8 +/- 14 yrs. Cut-off levels for the study of calcium, phosphorus, calcium-phosphorus product (Ca x P) and parathyroid hormone (PTH) were performed following the recommendations of the K/DOQI guidelines. RESULTS: The mean values for calcium were 9.57 +/- 0.7 mg/dL, phosphorus 4.97 +/- 1.5 mg/dL, intact PTH (iPTH) 297 +/- 353 pg/mL, Ca x P 47.5 +/- 15 mg2/dL2. Hypocalcemia (<8.4 mg/dL) was present in 5% of patients, whereas 17.8% of patients presented hypercalcemia (>10.2 mg/dL), 60.3% of whom received vitamin D. Hypophosphoremia (<3.5 mg/dL) was present in 16% of patients, and 29% of patients presented hyperphosphoremia (>5.5 mg/dL). Ca x P was <55 mg2/dL2 in 73% of patients. Thirty one percent of patients presented secondary hyperparathyroidism (HPTH >300 pg/mL), being severe in 12% (>600 pg/mL); 43% of patients presented iPTH <150 pg/mL. Only 7.3% of patients achieved the four recommendations provided in the K/DOQI guidelines. Vitamin D treatment was administered in 48% of patients. CONCLUSIONS: The population undergoing dialysis in the community of Valencia achieved targets based on the clinical recommendations of the K/DOQI guidelines as follows: 45% of patients achieved targets for calcium, 55% for phosphorus, 73% for Ca x P and 26% for iPTH levels. Surprisingly, only 7.3% of patients achieved all four targets.     

Normalization of intraoperative parathyroid hormone does not predict normal postoperative parathyroid hormone levels

BACKGROUND: Intraoperative intact parathyroid hormone (iPTH) is being used to confirm complete excision of hyperfunctioning parathyroid tissue. It is uncertain whether normalization of intraoperative iPTH levels accurately predicts long-term postoperative iPTH values. METHODS: Fifty-two consecutive patients with primary or secondary hyperparathyroidism underwent parathyroidectomy with measurement of intraoperative iPTH. Ten patients were excluded due to incomplete laboratory follow-up. Follow-up serum calcium and iPTH levels were measured at 1- and 3-month intervals. RESULTS: Before operation, the mean serum iPTH level was 249 pg/mL (SD=208) and mean serum calcium level was 11.4 +/- 0.9 mg/dL (+/- SD). In all but 4 patients, final intraoperative iPTH levels normalized to less than 67 +/- 41 pg/mL (mean, 35 pg/mL). One week after operation, serum calcium levels had returned to normal (mean, 9.4 +/- 1.1 pg/mL), which directly correlated with the final intraoperative serum iPTH values (Pearson correlation, r = -.434; P <.01). By 1 month, all but 2 patients were normocalcemic (mean, 9.4 +/- 0.9 pg/mL) with a mean iPTH level of 74.8 +/- 82 pg/mL. There was no correlation between final intraoperative and postoperative serum iPTH values (r =.099; P <.533). Both patients with persistent hypercalcemia at 1 month had appropriate intraoperative decreases in iPTH values. CONCLUSIONS: Intraoperative serum iPTH levels significantly correlate with postoperative serum calcium levels but not with postoperative serum iPTH levels. There was a 4.8% failure rate in the correction of postoperative serum calcium levels and a 29% failure rate in the normalization of postoperative serum iPTH levels.     

A Comparison of Sevelamer Hydrochloride with Calcium Acetate on Biomarkers of Bone Turnover in Hemodialysis Patients

Objective. To evaluate the influence of sevelamer hydrochloride and calcium acetate on biomarkers of bone turnover in patients with hyperphosphatemia receiving hemodialysis. Methods. In this prospective, open-label, randomized, active-controlled study, 70 patients (38 men and 32 women) with hyperphosphatemia (serum phosphorus level >6.0 mg/dL) underwent a two-week washout period and were randomly selected to receive sevelamer hydrochloride (n = 37) or calcium acetate (n = 33) for eight weeks. Changes in serum levels of intact parathyroid hormone (iPTH), alkaline phosphatase (Alk-P), phosphorus, and calcium were measured and compared. Results. After eight weeks of treatment, calcium acetate lowered iPTH levels significantly more than sevelamer hydrochloride did (?178.0 vs. ?69.0 pg/mL, p = 0.0019). Levels of Alk-P were significantly elevated in patients given sevelamer hydrochloride compared with levels in those given calcium acetate treatment (24.09 vs. 7.45 U/L, p = 0.0014). Changes in serum phosphorus levels did not differ between sevelamer hydrochloride (?1.93 mg/dL) and calcium acetate (?2.5 mg/dL) at the end of the study (p = 0.0514). Changes in the calcium and phosphorous product did not significantly differ between the sevelamer-hydrochloride group (?18.06 mg²/dL²) and the calcium-acetate group (?19.05 mg²/dL², p = 0.6764). Fifteen patients (45.5%) treated with calcium acetate had hypercalcemia (serum-adjusted calcium level >10.5 mg/dL); the rate was significantly higher than that of patients treated with sevelamer (five [13.5%] of 37, p = 0.0039). Conclusion. Treatment with sevelamer hydrochloride had the advantage of maintaining stable iPTH levels and elevating Alk-P levels while lowering serum phosphorus levels and calcium-phosphorous product.     

持续质量改进对老年腹膜透析患者钙磷代谢紊乱的作用

目的:探讨应用持续质量改进(CQI)的方法纠正老年腹膜透析患者钙磷代谢紊乱的效果。方法:运用PDCA四步法,即设计、实施、检验和应用,设计并实施改善老年腹膜透析患者钙磷代谢紊乱的治疗措施。结果:45例腹膜透析时间>3个月的老年患者参与了此项研究。经9个月CQI,各种钙磷代谢紊乱总发生率由82.22%降至42.22%(P<0.05)。其中高钙血症组血钙由(2.71±0.25)mmol/L降至(2.52±0.31)mmol/L(P<0.05),低钙血症组血钙由(1.78±0.42)mmol/L升至(2.11±0.24)mmol/L(P<0.05),血磷水平由(2.13±0.62)mmol/L降至(1.67±0.53)mmol/L(P<0.05),钙磷乘积由(80.22±16.61)mg2/dl2降至(54.58±15.93)mg2/dl2(P<0.05),继发性甲状旁腺功能亢进患者的血清全段甲状旁腺素(iPTH)由(488.12±227.31)pg/ml降至(290.3±171.15)pg/ml(P<0.01),血清碱性磷酸酶水平由(108.75±35.31)U/L降至(88.75±38.14)U/L(P<0.05)。有残肾功能较无残肾功能组,虽KT/V差异不大,在CQI后纠正高磷血症、高钙血症、甲状旁腺功能亢进上差异均有统计学意义(P<0.05)。结论:持续质量改进措施显著改善了老年腹膜透析患者的钙磷代谢紊乱。     

A comparison of dosing regimens of paricalcitol capsule for the treatment of secondary hyperparathyroidism in CKD stages 3 and 4

BACKGROUND: Intermittent dosing of calcitriol for secondary hyperparathyroidism (SHPT) has been associated with greater parathyroid hormone (PTH) reduction with fewer calcemic and phosphatemic effects than daily (QD) dosing. METHODS: Secondary analyses of three randomized, double-blind, placebo-controlled multicenter studies in stage 3 and 4 chronic kidney disease (CKD) patients with SHPT were performed to compare three times per week (TIW) with QD dosing of paricalcitol. The pharmacokinetics of TIW and QD dosing of paricalcitol capsules were assessed in a separate group of healthy subjects. RESULTS: Pharmacokinetics revealed similar steady state paricalcitol exposure between dosing regimens. In CKD patients, baseline data were similar between the TIW studies (n = 72, paricalcitol; n = 73, placebo) and QD studies (n = 35, paricalcitol; n = 40, placebo). Both dosing regimens resulted in similar efficacy (91%) for the primary end point of two consecutive > or = 30% decreases in intact PTH from baseline, but the QD regimen resulted in a greater percent reduction in intact PTH from baseline. The chances for developing increased serum calcium and phosphorus levels or Ca x P product were similar between paricalcitol and placebo groups for both treatment regimens. Furthermore, no difference in the risk for these elevations was detected between the TIW and QD regimens. CONCLUSIONS: QD dosing of paricalcitol capsules is as efficacious as TIW dosing in achieving the primary end point (2 consecutive > or = 30% reductions in PTH) in stage 3 and 4 CKD patients with SHPT. Moreover, the QD regimen had no significant effect on hypercalcemia, hyperphosphatemia or Ca x P product as compared with placebo or intermittent dosing.     

Secondary hyperparathyroidism and anemia. Effects of a calcimimetic on the control of anemia in chronic hemodialysed patients. Pilot Study

The main cause of resistance to erythropoiesis-stimulating agents (ESA) used for treatment of anemia in chronic hemodialysed patients (CHP) is the iron deficiency, absolute or functional. Secondary hyperparathyroidism (SHPT) is a secondary factor of resistance. Indeed, it has been reported in the literature an improvement of anemia parameters after surgical parathyroidectomy (PTX). The objective of this study is to assess in CHP, the impact of the correction of SHPT by a calcimimetic, cinacalcet (CI), (which is considered as a pharmacological PTX) on the response to ESA, measured by the erythropoietin resistance index (ERI). Twenty-two CHP with severe SHPT documented by an intact parathyroid hormone (iPTH) above 800pg/mL were included in this prospective pilot study. Mineral bone metabolism, anemia and nutritional parameters were measured baseline and after 6 months of treatment by CI. The effect on anemia was assessed at the end of study by the ERI, the change in Hb concentration, and the proportion of patients with Hb levels above 11g/dL. RESULTS: At the end of study there was a significant decrease (M6 vs M0) in iPTH (1302 vs 674pg/mL or -48%, p=0.006), serum calcium (2.39 vs 2.15mmol/L or -10%), serum phosphate (2 vs 1.7mmol/L or -15%), serum calcium-phosphorus product (CaxP) (4.8 vs 3.8mmol(2)/L(2) or - 20% (p<0.05), and the number of patients with CaxP>4.4mmol(2)/L(2) (64 vs 32%, p<0.05). The level of bone alkaline phosphatase remained stable during the study (28 vs 27?IU/L). The Hb levels increased from 11 to 11.4g/dL, as did the proportion of patients whose Hb concentration reached 11g/dL or higher (50 vs 70%, p<0.05) without important change of the median weekly ESA dosis in the majority of patients, 18?cases (81%) vs four (19%). Two subgroups were identified from the median decreases in iPTH (delta iPTH) between M0 and M6, Group?1 (delta iPTH≥400pg/mL, n=10) and group?2 (delta iPTH<400pg/mL, n=12): in group?1, we found a correlation between the decrease in iPTH by CI and the stability or decrease in ERI (group?1), at comparable dose of dialysis, nutritional and iron intakes and inflammatory profiles; in group?2 without a significant effect of CI on PTH reduction the levels of ERI and ESA dosis were more elevated. CONCLUSION: A treatment by calcimimetic improves the control of anemia by ESA in CHP and interferes positively on a cause of secondary resistance to ESA represented by SHPT. The mechanism of these effects could be linked to the decreased of bone marrow fibrosis and inflammation and to the triptych formed by the reduction in iPTH, CaxP and phosphate.     

No difference between alfacalcidol and paricalcitol in the treatment of secondary hyperparathyroidism in hemodialysis patients: a randomized crossover trial

Alfacalcidol and paricalcitol are vitamin D analogs used for the treatment of secondary hyperparathyroidism in patients with chronic kidney disease, but have known dose-dependent side effects that cause hypercalcemia and hyperphosphatemia. In this investigator-initiated multicenter randomized clinical trial, we originally intended two crossover study periods with a washout interval in 86 chronic hemodialysis patients. These patients received increasing intravenous doses of either alfacalcidol or paricalcitol for 16 weeks, until parathyroid hormone was adequately suppressed or calcium or phosphate levels reached an upper threshold. Unfortunately, due to a period effect, only the initial 16-week intervention period for 80 patients was statistically analyzed. The proportion of patients achieving a 30% decrease in parathyroid hormone levels over the last four weeks of study was statistically indistinguishable between the two groups. Paricalcitol was more efficient at correcting low than high baseline parathyroid hormone levels, whereas alfacalcidol was equally effective at all levels. There were no differences in the incidence of hypercalcemia and hyperphosphatemia. Thus, alfacalcidol and paricalcitol were equally effective in the suppression of secondary hyperparathyroidism in hemodialysis patients while calcium and phosphorus were kept in the desired range.     

帕立骨化醇治疗维持性血液透析患者继发性甲状旁腺功能亢进症的前瞻性研究

目的 观察帕立骨化醇治疗维持性血液透析患者继发性甲状旁腺功能亢进症（secondary hyperparathyroidism,SHPT）的疗效及安全性.方法 选择我科血液净化中心进行维持性血液透析治疗的13例患者,血全段甲状旁腺素（intact parathyroid hormone,iPTH）≥33 pmol/L,血钙水平＜2.55 mmol/L,钙磷乘积＜65,根据iPTH水平使用帕立骨化醇1～18 μg治疗,于每次透析治疗后给药,共观察12周.分别于治疗前及治疗后第2、4、6、8、10、12周测定患者的iPTH、血钙、血磷水平.结果 13例患者的血清iPTH水平在治疗后第2、4周已开始下降,但与治疗前相比差异无统计学意义.从治疗后第6周开始,iPTH水平与治疗前相比存在统计学差异（P＜0.05）,治疗后第12周时下降至（46.68±38.06） pmol/L,与治疗前（78.30±52.13） pmol/L比较,有统计学差异（P＜0.01）.治疗后第2、4周血钙水平升高,与治疗前比较有统计学差异（P＜0.05）,其中治疗后第4周时血钙水平升高尤为显著（P＜0.01）.经调整帕立骨化醇剂量后,治疗后第6周患者的血钙水平逐渐恢复正常并保持稳定,血磷、钙磷乘积水平在治疗前、后均无明显统计学差异.治疗过程中,患者耐受性良好,无相关不良反应的发生.结论 使用帕立骨化醇治疗维持性血液透析患者SHPT是有效、安全的.