Evaluation of changes in ferritin levels during sucroferric oxyhydroxide treatment

Background

A sub-analysis of a Phase III study was conducted to identify factors that might predict increased ferritin levels during long-term sucroferric oxyhydroxide (SO) treatment in hemodialysis patients.

Methods

The open-label, multicenter, Phase III study assessed the efficacy and safety of SO 750–3000 mg/day for 52 weeks in Japanese patients with chronic renal failure and hyperphosphatemia. A total of 125 of 161 patients from the Phase III trial, and who had data for ferritin levels after 28 weeks of SO treatment, were evaluated.

Results

Baseline ferritin was the strongest contributor (P < 0.0001) to ferritin increases during SO treatment. By Week 28, there were significant differences (P < 0.05/3) in ferritin increases between patients with higher [quartile 4 (Q4)] versus lower (Q1, Q2 and Q3) baseline ferritin. An erythropoiesis-stimulating agent dosage reduction was observed in patients with the lowest baseline ferritin level (Q1), and only slight reductions were noted in the other patient subsets. SO dosages administered to patients in baseline ferritin quartiles Q2, Q3 and Q4 were comparable throughout the study with slight fluctuations. SO dosages in Q1 were considerably lower than those in the other quartiles.

Conclusions

In summary, of the baseline variables found to predict increased ferritin, and changes in iron-related parameters, during SO treatment in Japanese chronic kidney disease patients undergoing hemodialysis, baseline ferritin was the most relevant variable.

Anemia in conventional hemodialysis: Finding the optimal treatment balance

Renal anemia is a serious and common complication in hemodialysis (HD) patients. The introduction of erythropoiesis-stimulating agents (ESAs) has dramatically improved hemoglobin levels and outcomes. Several interventional studies reported that excessive correction of anemia and the massive use of ESA can trigger cardiovascular disease (CVD), and consequently may worsen the prognosis of patients undergoing HD. Therefore, it has been widely recognized that large doses of ESA should be used with caution. An effective use of iron preparations is required to yield the optimal effect of ESA. It is well-known that iron utilization is inhibited under pathological conditions, such as chronic inflammation, resulting in ESA resistance. It is postulated that a new class of therapeutic agents for renal anemia, hypoxia inducible factor prolyl hydroxylase (HIF-PH) inhibitors, will have beneficial treatment effects in patients on HD. HIF is induced by hypoxia and promotes erythropoietin production. In the absence of a hypoxic state, HIF is decomposed by the HIF catabolic enzyme. HIF-PH inhibitors inhibit this degrading enzyme and stimulate endogenous erythropoietin production via HIF induction. Additionally, HIF-PH inhibitors promote effective utilization of iron and raise erythropoietin to physiological concentrations. Accordingly, HIF-PH inhibitors improve anemia and iron metabolism. It appears that this effect persists irrespective of chronic inflammatory conditions. HIF-PH inhibitors do not overshoot erythropoietin above physiological concentrations like ESAs. Therefore, it is hypothesized that HIF-PH inhibitors would not increase the risk of CVD in patients undergoing HD.

A mutation in transcription factor MAFB causes Focal Segmental Glomerulosclerosis with Duane Retraction Syndrome

Focal segmental glomerulosclerosis (FSGS) is a leading cause of end-stage renal disease in children and adults. Genetic factors significantly contribute to early-onset FSGS, but the etiologies of most adult cases remain unknown. Genetic studies of monogenic syndromic FSGS exhibiting extra-renal manifestations have uncovered an unexpected biological role for genes in the development of both podocytes and other cellular lineages. To help define these roles, we studied two unrelated families with FSGS associated with Duane Retraction Syndrome, characterized by impaired horizontal eye movement due to cranial nerve malformation. All four affected individuals developed FSGS and Duane Retraction Syndrome in their first to second decade of life, manifested as restricted abduction together with globe retraction and narrowed palpebral fissure on attempted adduction. Hypoplasia of the abducens nerves and hearing impairment occurred in severely affected individuals. Genetic analyses revealed that affected individuals harbor a rare heterozygous substitution (p.Leu239Pro) in MAFB, a leucine zipper transcription factor. Luciferase assays with cultured monocytes indicated that the substitution significantly reduced transactivation of the F4/80 promoter, the known MAFB recognition element. Additionally, immunohistochemistry indicated reduced MAFB expression in the podocytes of patients. Structural modeling suggested that the p.Leu239Pro substitution in the DNA-binding domain possibly interferes with the stability of the adjacent zinc finger. Lastly, podocytes in neonatal mice with p.Leu239Pro displayed impaired differentiation. Thus, MAFB mutations impair development and/or maintenance of podocytes, abducens neurons and the inner ear. The interactions between MAFB and regulatory elements in these developing organs are likely highly specific based on spatiotemporal requirements.

Practice pattern of physician's directions of exercise restriction in patients with chronic kidney disease: results from the Chronic Kidney Disease Japan Cohort study

Background

The practice patterns of exercise restrictions for patients with chronic kidney disease have not been adequately evaluated yet; thus, we examined them using a cross-sectional design and explored the factors related with those restrictions.

Methods

The Chronic Kidney Disease Japan Cohort study was a multicentre cohort study of Japanese patients (age 20–75 years) living in Japan. We used the information in the questionnaire on the restriction of physical activities offered by physicians to the patients during enrolment. We initially considered and used the following data as the clinical factors that the physician used for decision making on the directions of restriction of physical activities: age, sex, cause of chronic kidney disease (CKD), comorbid diseases, body mass index (BMI), systolic blood pressure, estimated glomerular filtration rate (eGFR) and urine albumin. The logistic regression model was used to explore the factors and estimate their adjusted odds ratio with regard to physician’s direction of restriction of physical activities.

Results

Physician’s direction of exercise restrictions was implemented in 9.9% of the participants. In 17 facilities, the proportion of physician’s direction of exercise restriction ranged from 2.9 to 17.8%. The logistic regression analysis showed that the proportion of the factors such as younger age, cardiovascular disease, congestive heart failure and lower eGFR was higher in patients with physician’s direction of exercise restrictions.

Conclusions

The findings from this study suggested the factors related with prescribing exercise restrictions. Further studies examining which patients with CKD need direction of exercise restrictions are needed.

Efficacy and Safety of Sucroferric Oxyhydroxide and Calcium Carbonate in Hemodialysis Patients

INTRODUCTION

In this phase III, open-label, single-arm, multi-center 12-week study, we evaluated the efficacy and safety of combination therapy with sucroferric oxyhydroxide (PA21) and calcium carbonate for hemodialysis patients with hyperphosphatemia.

METHODS

We enrolled 35 subjects aged ≥ 20 years with end-stage kidney disease and serum phosphorus 3.5-6.0 mg/dl who were undergoing hemodialysis 3 times weekly and taking calcium carbonate and sevelamer hydrochloride. Patients switched from sevelamer hydrochloride and calcium carbonate to sucroferric oxyhydroxide and calcium carbonate. Sucroferric oxyhydroxide was orally administered 3 times daily within 750 mg/d (250 mg per dose) to 3000 mg/d (1000 mg per dose), immediately before every meal, for 12 weeks. Calcium carbonate was orally administered 3 times daily after every meal. Outcomes were serum phosphorus concentration, safety, and satisfaction with bowel movements.

RESULTS

Mean (SD) serum phosphorus concentrations were 5.01 (0.63) mg/dl at week 0 and 4.89 (1.14) mg/dl at the end of treatment, after patients switched from sevelamer hydrochloride to sucroferric oxyhydroxide. The incidence of adverse drug reactions was 31.4% (11/35), with diarrhea being the most frequent (31.4%). More sucroferric oxyhydroxide-treated patients were satisfied with their bowel movements. More patients with constipation, as well as those who experienced diarrhea, were satisfied with their bowel movements at the end of the study.

CONCLUSION

Combined administration of sucroferric oxyhydroxide and calcium carbonate at low doses was effective in maintaining serum phosphorus concentrations within the target range, and patients' gastrointestinal status improved. Sucroferric oxyhydroxide maintained its serum phosphorus-lowering effect with a decreased pill burden, and its concomitant administration with calcium carbonate was well tolerated.

Efficacy and safety of sucroferric oxyhydroxide compared with sevelamer hydrochloride in Japanese haemodialysis patients with hyperphosphataemia: A randomized, open-label, multicentre, 12-week phase III study

Aim

We aimed to investigate the non‐inferiority of PA21 (sucroferric oxyhydroxide) to sevelamer hydrochloride (sevelamer) in terms of efficacy and safety in Japanese haemodialysis patients with hyperphosphataemia.

Methods

In this Phase III, open‐label, multicentre study, 213 haemodialysis patients with hyperphosphataemia were randomized to PA21 or sevelamer treatment for 12 weeks. The primary outcome was adjusted serum phosphorus concentration at the end of treatment; the non‐inferiority of PA21 was confirmed if the upper limit of the two‐sided 95% confidence interval (CI) is ≤0.32 mmol/L. Secondary outcomes were corrected serum calcium and intact‐parathyroid hormone concentrations. Adverse events (AEs) and adverse drug reactions (ADRs) were evaluated.

Results

The adjusted mean serum phosphorus concentration at the end of treatment confirmed the non‐inferiority of PA21 for lowering serum phosphorus compared with sevelamer (1.62 vs 1.72 mmol/L; difference, −0.11 mmol/L; 95% CI, −0.20 to −0.02 mmol/L). The mean daily tablet intake was 5.6 ± 2.6 and 18.7 ± 7.1 tablets in the PA21 and sevelamer groups, respectively. The incidences of AEs and ADRs were not significantly different between the two groups.

Conclusion

The non‐inferiority of PA21 to sevelamer was confirmed for the treatment of Japanese haemodialysis patients with hyperphosphataemia. PA21 was effective, safe, and well tolerated, while having a considerably lower pill burden than sevelamer.

This short‐term randomized trial of PA21 (sucroferric oxyhydroxide) performed in Japanese haemodialysis patients was able to demonstrate non‐inferiority for phosphorus lowering with a significantly lower pill burden.

Management of phosphorus load in CKD patients

Disturbances in mineral and bone metabolism play a critical role in the pathogenesis of cardiovascular complications in patients with chronic kidney disease (CKD). The term "renal osteodystrophy" has recently been replaced with "CKD-mineral and bone disorder (CKD-MBD)", which includes vascular calcification as well as bone abnormalities. In Japan, proportions of the aged and long-term dialysis patients are increasing which makes management of vascular calcification and parathyroid function increasingly more important. There are three main strategies to manage phosphate load: phosphorus dietary restriction, administration of phosphate binder and to ensure in the CKD 5D setting, an adequate dialysis.

Cardiac effect of vitamin D receptor modulators in uremic rats

Vitamin D receptor (VDR) modulators (VDRMs) are commonly used to control secondary hyperparathyroidism (SHPT) associated with chronic kidney disease, and are associated with beneficial outcomes in cardiovascular disease. In this study, we compared the cardiac effect of VS-105, a novel VDRM, with that of paricalcitol in 5/6 nephrectomized uremic rats. Male Sprague-Dawley rats were 5/6 nephrectomized, fed a standard diet for 4 weeks to establish uremia, and then treated (intraperitoneally, 3 times/week) with vehicle (propylene glycol), paricalcitol (0.025 and 0.15μg/kg), or VS-105 (0.05 and 0.3μg/kg) for 4 weeks. In uremic rats, neither VDRM (low and high doses) altered serum creatinine and phosphorus levels. Serum calcium was significantly higher with high dose paricalcitol compared to sham rats. PTH levels were significantly decreased with low dose paricalcitol and VS-105, and were further reduced in the high dose groups. Interestingly, serum FGF23 was significantly higher with high dose paricalcitol compared to sham rats, whereas VS-105 had no significant effect on FGF23 levels. Left ventricle (LV) weight and LV mass index determined by echocardiography were significantly suppressed in both high dose VDRM groups. This suppression was more evident with VS-105. Western blotting showed significant decreases in a fibrosis marker TGF-β1 in both high dose VDRM groups (vs. vehicle) and Masson trichrome staining showed significant decreases in cardiac fibrosis in these groups. These results suggest that VS-105 is less hypercalcemic than paricalcitol and has favorable effects on SHPT and cardiac parameters that are similar to those of paricalcitol in uremic rats. The cardioprotective effect is a noteworthy characteristic of VS-105.

Dose-response efficacy and safety of PA21 in Japanese hemodialysis patients with hyperphosphatemia: a randomized, placebo-controlled, double-blind, Phase II study

Background

Hyperphosphatemia is common in chronic kidney disease (CKD) and associated with mortality and morbidity. We aimed to evaluate the dose-dependent efficacy and safety of PA21 (sucroferric oxyhydroxide), an iron-based phosphate binder, in Japanese hemodialysis patients with hyperphosphatemia.

Methods

In this double-blind, multicenter, Phase II study, 183 patients were randomized to placebo or PA21 at doses of 250, 500, 750, or 1000 mg (based on iron content) three times/day for 6 weeks. The primary efficacy endpoint was the mean change in serum phosphorus levels from baseline to end of treatment in each group. Adverse reactions were evaluated.

Results

The change in serum phosphorus level was significantly greater in each PA21 group than in the placebo group (analysis of covariance: P < 0.001 for all groups). A dose-dependent change in serum phosphorus levels was observed in the PA21 groups. A notable decrease in mean serum phosphorus levels to the target level of ≤6 mg/dL was shown starting at Week 1 in all PA21 groups. The cumulative achievement rates for target serum phosphorus level at the end of treatment were generally >80 % in all PA21 groups. The major adverse reaction reported was diarrhea; however, most cases were mild.

Conclusions

PA21 was an effective and safe treatment that decreased serum phosphorus levels starting at 1 week of treatment when administered as one 250-mg tablet three times/day. PA21 demonstrated a dose-dependent phosphorus lowering effect up to 3000 mg/day. PA21 may be a new treatment alternative with relatively low pill burden for Japanese hemodialysis patients with hyperphosphatemia.

Clinical Expectation of Online Hemodiafiltration: A Japanese Perspective

Many pieces of evidence of online hemodiafiltration (HDF) have been reported, and the clinical advantage of postdilution online HDF with sufficient substitution is now established. After the approval of online HDF in 2012, the number of online HDF patients has been dramatically increasing in Japan and reached 10% of the total dialysis population at the end of 2013. One of the marked characteristics of Japanese online HDF is a widespread use of predilution treatment and, in 2013, 90.8% of online HDFs were carried out with the predilution mode. The main reason for the wide use of predilution online HDF results from the low blood flow rate in Japan, by which it is difficult to substitute a sufficient volume during the limited treatment time. Other reasons to choose the predilution mode include the reduction of albumin loss and the suppression of membrane fouling during treatment. Contrary to postdilution treatment, adequate clinical evidence has not been reported for predilution online HDF to provide a better outcome of the patients. A further clinical trial is expected to elucidate the clinical advantages over conventional hemodialysis for predilution online HDF.

Possible prevention of dialysis-requiring congestive heart failure by angiotensin-II receptor blockers in non-dialysis Japanese patients with Stage 5 chronic kidney disease

BACKGROUND

Preventive medications for dialysis-requiring congestive heart failure (CHF) in non-dialysis Japanese patients with Stage 5 chronic kidney disease (CKD) are unknown. Our aim was to explore which CKD medication was associated with a reduced prevalence of dialysis-requiring CHF in non-dialysis Japanese patients with Stage 5 CKD.

METHODS

The present multicenter, retrospective, cross-sectional study examined the association between CKD medications and the prevalence of dialysis-requiring CHF in non-dialysis Japanese patients with Stage 5 CKD.

RESULTS

There were 1536 Japanese Stage 5 CKD patients who satisfied our inclusion criteria. We had 309 (20.1%) patients whom had developed dialysis-requiring CHF and 940 patients (60.8%) whom had been using angiotensin-II receptor blockers (ARBs) before initiating dialysis. In our multivariate analysis, only ARB use was significantly associated with a lower risk of CHF (Odds ratio (OR): 0.680, 95% confidence interval (CI): 0.516-0.897; p = 0.0064), of the CKD treatments examined in this study.

CONCLUSIONS

We found that ARB use during the pre-dialysis period is associated with a lower prevalence of CHF in the non-dialysis Japanese patients with Stage 5 CKD, suggesting a possible prevention of dialysis-requiring CHF by ARBs, in non-dialysis Japanese patients with Stage 5 CKD.

Indication and efficacy of PEIT in the management of secondary hyperparathyroidism

Control of secondary hyperparathyroidism (SHPT) using active vitamin D analogues becomes difficult in advanced SHPT, because the enlarged parathyroid glands (PTGs) are resistant to medical therapy. Percutaneous ethanol injection therapy (PEIT) has been widely used in Japan since the 1990s as a surgical intervention for advanced SHPT, by selectively destroying only the enlarged glands with nodular hyperplasia (i.e. >0.5 cm(3), measured by ultrasonography). If there is only one PTG with nodular hyperplasia, PEIT will be successful with a small number of injections, and it then becomes possible to maintain target levels of parathyroid hormone by treatment with active vitamin D analogues. Recent studies have demonstrated that in the advanced phase of SHPT, it is desirable to perform PEIT when it is restricted to patients with not more than one PTG larger than 0.5 cm(3) in terms of superior prognosis can be obtained including efficacy, low recurrence, and long-term remission period.

Long-term prognosis of parathyroid function in chronic dialysis patients after PEIT-a single-centre trial

Background. Secondary hyperparathyroidism (SHPT) is a common complication observed in long-term dialysis patients. Percutaneous ethanol injection therapy (PEIT) of parathyroid glands (PTGs) is now established in Japan as a treatment option for SHPT. In this study, to elucidate the factors influencing efficacy in 1 year and relapse following PEIT, we analysed the long-term prognosis of parathyroid function that is known to have the greatest effect on therapeutic results.

Methods. The study design was a retrospective cohort study. We studied 104 patients with SHPT, who underwent PEIT at Tokai University Hospital between January 1993 and December 2002, and we followed them up until January 2008. The effective group reached intact parathyroid hormone of 200 pg/ml or less, corrected calcium (Ca) of 10.5 mg/dl or less and phosphate (P) of 6.0 mg/dl or less. The ineffective group failed to achieve these criteria.

Results. Among the 104 patients, 66 patients (63%) fulfilled the criteria for the effective group within the first year of PEIT. Using the multivariate logistic regression analysis, the number of PTGs before PEIT was a significant risk factor to deviate from the criteria. At the end of the surveillance period, 31 patients (30%) fulfilled the criteria, and their SHPT was controlled with PEIT. Using the multivariate logistic regression analysis, more than three PTGs at the beginning, and the increase in PTGs during the observation period were significant risk factors to deviate from the criteria. In conclusion, superior results with PEIT are obtained in terms of efficacy, remission period and risk of relapse, regardless of the size of the gland.

Clinical significance of parathyroid intervention on CKD-MBD management

Recently published ‘Guidelines for the management of secondary hyperparathyroidism in chronic dialysis patients’ by the Japanese Society for Dialysis Therapy advocate that percutaneous ethanol injection into enlarged glands, which has been considered as the only alternative to parathyroidectomy (PTx), should be indicated in patients with a single enlarged parathyroid gland (estimated volume >500 mm³, or estimated major axis >10 mm), and that PTx should be recommended in patients with multiple enlarged glands. Cinacalcet cannot achieve optimal control of chronic kidney disease–mineral bone disorder in all patients, and parathyroid intervention will be required in a considerable number of patients with refractory secondary hyperparathyroidism.

New clinical guidelines for selective direct injection therapy of the parathyroid glands in chronic dialysis patients

In 2000, the Japanese Society for Parathyroid Intervention issued the 'Guidelines for percutaneous ethanol injection therapy of the parathyroid glands in chronic dialysis patients'. Since then, the concept of 'selective PEIT' has been well accepted and the number of patients treated by this method in Japan has increased. Recently, it has been reported that the effect of PEIT differs depending on the degree of nodular hyperplasia. Several new drugs have become available since 2000, and active vitamin D and its analogue have also been used for direct injection into the parathyroids. We present the new 'Guidelines for selective direct injection therapy of the parathyroid glands in chronic dialysis patients', a revised version of the 2000 Guidelines. We believe that these new guidelines are useful for selecting direct injection therapy in patients with advanced secondary hyperparathyroidism.

Absence of mesangial C1q deposition is associated with resolution of proteinuria and hematuria after tonsillectomy plus steroid pulse therapy for immunoglobulin a nephropathy

INTRODUCTION AND AIMS

Deposition of C1q occurs in 0 to 45% of patients with IgAN. In order to identify whether mesangial C1q deposition in IgAN is a novel marker for the response to tonsillectomy plus steroid pulse therapy (TSP), we studied the association between mesangial C1q deposition in IgAN and the remission rate after TSP therapy for IgAN.

METHODS

We conducted a retrospective cohort study at a single Japanese center. We analyzed data on 110 patients diagnosed with IgA nephropathy who received TSP between January 2003 and December 2012. Positive C1q findings were defined as diffuse mesangial C1q deposition. The study outcome was the resolution of abnormal urinary findings and was defined as negative proteinuria and negative occult blood 1 year after steroid pulse therapy.

RESULTS

In all enrolled cases, 69 patients (62.7%) went into remission. Ten out of 24 (41.7%) C1q-positive patients experienced remission, and 59 out of 86 (68.6%) C1q-negative patients experienced remission. Multiple logistic regression model analysis showed that the absence of C1q deposition increased the odds ratio for remission (odds ratio 4.41; 95% confidence interval 1.33-15.75, p = 0.017).

CONCLUSIONS

These results suggest that the absence of diffuse C1q deposition in the mesangial area of the glomerulus in patients with IgA nephropathy is a positive predictive sign for a response to TSP and is associated with the resolution of urinary abnormalities 1 year after TSP.

Association between the Hemoglobin Level and Cardiothoracic Ratio in Patients on Incident Dialysis

BACKGROUND/AIM

The present study explores associations between hemoglobin (Hb) levels and patients with cardiac enlargement in end-stage kidney disease (ESKD) to help prevent cardiac remodeling during the predialysis phase of chronic kidney disease (CKD).

METHODS

This cross-sectional study included 2,249 patients with ESKD (age, 67 ± 13 years; male, 67%; diabetic kidney disease, 41%) who started hemodialysis (HD) between January 2006 and October 2013 at eight participating hospitals. We examined associations between Hb levels immediately before the first HD session and cardiothoracic ratios (CTRs). Clinical factors associated with the CTR were also assessed.

RESULTS

The mean Hb level was 8.7 ± 1.6 g/dl, and the mean and median CTRs were 55.0 and 54.7%, respectively. The correlation between the Hb level and the CTR was linear and negative (r = -0.129, p < 0.001). The mean CTR and the prevalence of patients with a CTR >50% obviously decreased with increasing Hb levels (both p < 0.001 for trend). Univariate logistic regression analysis revealed an approximately 20% reduction in the odds ratio for complicating CTRs >50% per 1 g/dl increase in Hb. Hb levels of <9 g/dl were significantly associated with CTRs >50%. Numerical and categorical Hb remained significantly associated with CTRs >50% after adjusting for confounding variables.

CONCLUSIONS

Lower Hb levels participate in progressive CTR enlargement in patients with ESKD, and maintaining Hb levels of >9 g/dl might help prevent cardiac remodeling during the predialysis phase of CKD.

Significance of serum magnesium as an independent correlative factor on the parathyroid hormone level in uremic patients

CONTEXT

PTH is a critical factor in mineral homeostasis, and chronic kidney disease mineral and bone metabolism disorder is a very important problem in patients with renal failure. Abnormal levels of PTH, serum phosphate, and calcium influence chronic kidney disease mineral and bone metabolism disorder, but there is little information about the influence of magnesium (Mg) on PTH.

OBJECTIVE

The aim of this study was to elucidate the correlation between magnesium and PTH levels in uremic patients just prior to beginning hemodialysis (HD) for the first time.

PATIENTS

We enrolled 1231 patients in nine Japanese facilities who had begun HD for end-stage renal disease. We investigated their serum Mg levels and the correlation between intact PTH (iPTH) and the serum Mg levels and other clinical parameters and medications.

RESULTS

The mean serum Mg was 2.2 ± 0.5 mg/dL, and hypermagnesemia was found in 663 patients (53.9%). Divided into two groups according to median iPTH level, the serum Mg levels were significantly higher in patients with low iPTH (2.3 ± 0.5 vs 2.1 ± 0.5, P < .01). Furthermore, divided into two groups according to the Mg level, iPTH levels were lower in patients with high Mg than in patients with normal serum Mg levels (277.9 ± 195.9 pg/mL vs 321.9 ± 203.7 pg/mL, P < .01). In the multiple regression analysis according to the effect of iPTH level, the serum Mg level was an independent variable after adjustment for other factors.

CONCLUSIONS

A high serum level of Mg is frequent in uremic patients with end-stage renal disease just prior to beginning HD. In the present set of patients, there was a significant correlation between the serum Mg and iPTH levels. Furthermore, the serum Mg level was an independent factor apart from the other factors regulating iPTH. These results suggest that serum Mg may be one of the factors regulating the serum PTH level in uremic patients.