Abstract
Effect of Low-Calcium Dialysate on Serum Calcium–Phosphate Metabolism in Peritoneal Dialysis Patients
Objectives: To investigate the effects of low-Ca dialysate on serum Ca and P metabolism and to evaluate its safety in continuous ambulatory peritoneal dialysis (CAPD) patients with high serum Ca or high serum P, or both.
Methods: The study involved 45 patients treated with CAPD using standard-Ca dialysate (1.75 mmol/L) for more than 1 year. A group of 22 CAPD patients with hypercalcemia or hyperphosphatemia (or both) and intact parathyroid hormone (iPTH) < 150 pg/mL received low-Ca dialysate (1.25 mmol/L) and oral Ca carbonate (2.4 g/d). The serum levels of Ca, P, intact parathyroid hormone (iPTH), and albumin were measured every month and whenever problems occurred during the study.
Results: Serum Ca or P (or both) in the low-Ca dialysate group gradually increased and iPTH significantly decreased from the values at 1 year of standard-Ca dialysate use. After the change to low-Ca dialysate, serum Ca decreased significantly in the first month (p < 0.05 compared with standard-Ca dialysate) and maintained a normal level. Serum P was slightly lower than in patients using standard-Ca dialysate, with statistical significance in the second and third months. The level of iPTH increased significantly in the first month (p < 0.05 compared with standard-Ca dialysate), but maintained an acceptable level (200 pg/mL) afterward. No significant change in serum albumin was observed during treatment. Most patients tolerated low-Ca dialysate well (no hypotension and no hyperspasmia).
Conclusions: Hypercalcemia or hyperphosphatemia in CAPD patients is partly correlated with standard-Ca dialysate. We observed favorable changes in serum Ca, P, and iPTH in CAPD patients with high serum Ca or high serum P (or both) after treatment with low-Ca dialysate and adequate Ca carbonate intake. Dialysate with a Ca concentration of 1.25 mmol/L is safe in peritoneal dialysis patients with hypercalcemia and hyperphosphatemia with low bone turnover. Low-Ca dialysate, with adequate Ca intake, can improve Ca and P metabolism. Low-Ca dialysate effectively corrected the imbalance of Ca and P in patients with hypercalcemia, hyperphosphatemia, and hypoparathyroidism; it could also correct metastatic calcification and improve quality of life.
Survey of Peritoneal Dialysis Patients with Renal Osteodystrophy
Objectives: To identify the morbidity, diagnostic, and therapeutic status of peritoneal dialysis patients with renal osteodystrophy.
Methods: Our study enrolled 112 patients, including 54 men (mean age: 55.5 ± 27.7 years) and 58 women (mean age: 55.3 ± 19.7 years). Using blood Ca level, the patients were allocated to one of three groups: hypocalcaemia (blood Ca < 2.0 mmol/L), normocalcemia (2.0 mmol/L < blood Ca < 2.8 mmol/L), and hypocalcaemia (blood Ca > 2.8 mmol/L). Using blood P, they were also grouped into hypophosphatemia (blood P < 0.9 mmol/L), normophosphatemia (0.9 mmol/L < blood P < 1.8 mmol/L), and hyperphosphatemia (blood P > 1.8 mmol/L). And using intact parathyroid hormone (iPTH), they were classified into one of three groups (<150 pg/mL, 150–300 pg/mL, >300 pg/mL).
Results: Morbidity in the hypocalcemia, normocalcemia, and hypercalcemia groups was 24.1%, 75.8%, and 0% respectively. Morbidity in the hypophosphatemia, normophosphatemia, and hyperphosphatemia groups was 22.9%, 17.2%, and 28.7% respectively. Morbidity in the low-iPTH, middle-iPTH, and high-iPTH groups was 12.6%, 60.9%, and 24.1% respectively.
Conclusions: Morbidity in our patients with hyperphosphatemia was lower than that seen in other published reports. This finding might attributable to the use of Ca carbonate, Ketosteril (Fresenius Kabi AG, Bad Homburg, Germany), and a high dose of peritoneal dialysis. The most common bone turnover biochemical marker is iPTH. To improve renal osteodystrophy, iPTH should be controlled between 150 pg/mmoL and 300 pg/mmol, in the presence of normal blood Ca and P.
What is the Optimal Calcium Concentration of Peritoneal Dialysate?
Objectives: In patients on peritoneal dialysis (PD) therapy, the Ca concentration of peritoneal dialysate is an important factor influencing serum Ca and parathyroid hormone (PTH) levels. However, the adequate Ca concentration of PD solution is still unclear. This study assessed the influence of a change from low-Ca solution (2.5 mEq/L) to standard-Ca solution (3.25 – 4.0 mEq/L).
Methods: The study included 9 PD patients (4 men, 5 women; mean age: 70.4 ± 16.9 years; mean PD duration: 26.6 ± 7.8 months) with hyperparathyroidism. We analyzed their clinical data before and after the switch from low-Ca to standard-Ca peritoneal dialysate.
Results: After the dialysate switch, the average PTH level had declined significantly, to 189.3 ± 92.6 pg/mL from 527.1 ± 526.8 pg/mL. However, effects on serum Ca and P levels were not found. The prescribed dose of vitamin D analogs and phosphate binders had to be reduced in some patients.
Discussion: In Japan, low-Ca dialysate is more commonly used than is standard-Ca dialysate. In this study, we could control secondary hyperparathyroidism easily with standard-Ca dialysate. The Ca concentration of dialysate should be determined on an individual basis. Previously, we believed that low-Ca solution should be prescribed for patients requiring a large dose of vitamin D analogs and Ca-containing P binders. Cinacalcet hydrochloride and lanthanum carbonate have recently become available for use in Japan. Further investigations are therefore needed to consider the optimal Ca concentration of peritoneal dialysate.
Clinical Course after Parathyroidectomy in Uremic Patients
Background: Surgical parathyroidectomy (PTX) is indicated for endstage renal disease (ESRD) patients with secondary hyperparathyroidism unresponsive to conventional therapies. We conducted a retrospective study to evaluate the changes in intact parathyroid hormone (iPTH) levels and the postoperative responses of mineral biochemical parameters.
Methods: We recruited 36 dialysis patients who underwent total PTX with autotransplantation from January 2002 to December 2007. Laboratory data, including serum iPTH, corrected total calcium (cCa), phosphate (PO4), corrected cCa×PO4 product, and total alkaline phosphatase (tALP), were collected pre-operation and at follow-up monthly post-operation.
Results: Aside from 2 patients (5.9%) who showed persistent postoperative hyperparathyroidism, the other 34 patients experienced a significant decrease in postoperative serum iPTH, cCa, PO4, and cCa×PO4. Conversely, a transient postoperative rise in tALP was observed in the first month after surgery (p < 0.05). Among the 34 patients with a successful outcome, 8 patients (23%) presented with “hungry bone” syndrome. This rise in tALP level showed a trend of positive correlation with the decrease in cCa×PO4 (r = 0.32, p = 0.06). During the 3-year follow-up, significant reductions in serum iPTH, cCa, PO4, cCa×PO4, and tALP levels as compared with preoperative levels (p < 0.05) were found.
Conclusions: We concluded that PTX led to a significant improvement in iPTH, cCa, PO4, and cCa×PO4 levels after surgery. Most patients maintained lower iPTH levels throughout the 3-year follow-up.
Pure Red Cell Aplasia: Is Continuous Ambulatory Peritoneal Dialysis Better than Hemodialysis?
Objectives: Anemia has been reported to be less severe among continuous ambulatory peritoneal dialysis (CAPD) patients than among hemodialysis (HD) patients. The reasons are complex and include greater blood and iron losses in HD patients (related to loss in the dialyzer and from blood sampling), and also the putative removal of middle-molecule “uremic inhibitors” of erythropoiesis by CAPD but not by HD The doses of recombinant human erythropoietin (rHuEPO) in PD have been found to be less than those required in HD, even allowing for differences in the route of administration. In pure red-cell aplasia (PRCA) secondary to rHuEPO use, when rHuEPO could not be given, CAPD improved hemoglobin better than HD did.
Methods: In 2 patients, both with chronic glomerulonephritis, who had been on maintenance HD, PRCA secondary to use of a generic brand of rHuEPO was diagnosed. The PRCA was confirmed by ELISA. After the diagnosis, rHuEPO was stopped, and initial treatment with prednisolone (1 mg/kg daily) and cyclophosphamide (2 mg/kg daily) was started. Later, because of lack of response, cyclosporine 5 mg/kg daily was added in both patients.
Results
MHD = maintenance HD; Hb = hemoglobin
Conclusions: CAPD improved hemoglobin in patients with rHuEPO-induced PRCA, even though immunosuppression was the same during both CAPD and HD. Apart from conventional mechanisms to explain that anemia is less severe in CAPD than in HD, an additional immunologic mechanism might better explain hemoglobin differences in CAPD and HD.
High-Dose Intravenous Iron Sucrose Administration: Use of Two Dosage Regimens in Chronic Kidney Disease Patients
Objectives: To investigate the safety and tolerability of intravenous (IV) high-dose iron sucrose therapy in iron-deficient, anemic chronic kidney disease (CKD) patients (pts).
Methods: In this prospective study, conducted over 3 years and 4 months (September 2005 – December 2008), we studied two high-dose regimens of IV iron sucrose administration: Group I—iron sucrose 500 mg administered as an IV infusion in 200 mL of normal saline over 3 hours; the first two sessions occurred on two consecutive days, and subsequent therapy sessions occurred three times monthly; Group II—over a period of 6 months (January – June 2008), iron sucrose 1000 mg was administered as an IV infusion over 6 hours (500 mg in 200 mL normal saline over 3 hours, and if uneventful, repeated over the next 3 hours); this group of pts was observed and monitored for adverse events for 24 hours after completion of treatment. Any adverse events were recorded.
Results
Requiring stoppage of infusion or major therapeutic intervention, or both.
Adverse events were observed in 24 sessions (4.2%). The incidence of major adverse events was higher (10%) in group II than in group I (0.7%). The incidence of minor side effects was similar in the two groups.
Conclusions: High-dose IV iron sucrose administration using a dosing regimen of 500 mg infused over 3 hours on two consecutive days is safe and well tolerated as compared with 1000 mg infused over 6 hours. This is the optimal safe dosage regimen that is most practical in pre-dialysis CKD and chronic PD pts, resulting in considerable savings in time and cost.
High Dose Intravenous Iron Therapy in Continuous Ambulatory Peritoneal Dialysis: A Safe, Convenient and Cost-Effective Alternative
Objectives: Intravenous (IV) iron is administered to dialysis patients (pts) with iron deficiency in various doses and at various intervals ranging from 50 mg twice weekly to 1000 mg in a single infusion. Doses ranging from 50 mg to 200 mg can be given frequently in hemodialysis (HD) pts post-dialysis, but peritoneal dialysis (PD) pts must come to the hospital frequently, and venous access may be difficult in those pts. Single high-dose regimens are more suitable in PD pts. From available data, experience with the safety of higher-dose iron sucrose injections in PD pts is limited. We assessed the safety, pt tolerance, convenience, and cost-effectiveness of high-dose IV iron infusions in continuous ambulatory PD (CAPD) pts.
Methods: Over a period of 2 years, 89 CAPD pts with iron deficiency anemia (defined as a serum transferrin saturation of 20% or less) received IV iron sucrose as a high-dose single IV infusion. A test dose of 100 mg IV iron in 100 mL normal saline was infused over 30 minutes under monitoring. The remaining 400 mg, in 400 mL normal saline, was infused over 3 hours. Incidence of adverse effects (severe or mild) were recorded. The same product was used in all cases. The infusions were administered as a day care procedure, the pts being discharged on the day of the infusion. Adverse events were classified as life-threatening (anaphylaxis), major, or mild, and were noted as and when they occurred.
Results: At total of 161 high-dose IV iron infusions were given to the 89 pts. No instances of life-threatening adverse events occurred. Because of major adverse events, 4 infusions had to be stopped: 2 pts developed hypotension, and 2 developed crampy abdominal pain and diarrhea. These pts were observed for 3 – 4 hours, and symptoms subsided with symptomatic therapy. Mild adverse reactions, which subsided spontaneously, were observed in 6 pts (3%).
Conclusions: High-dose IV iron infusions can be safely administered in CAPD pts with iron deficiency anemia. Administration could be a day care procedure in all pts, resulting in significant cost and labor savings. This protocol improves compliance over multiple single-dose infusions, is convenient for pts, and helps in rapid correction of iron deficiency.
Nicotinic Acid as an Adjunct Treatment for Hyperphosphatemia in Peritoneal Dialysis Patients: A Single-Center Randomised Control Trial
Introduction: Hyperphosphatemia contributes to renal hyperparathyroidism and is independently associated with increased mortality. Ca-based P binders are effective, but limited by hypercalcemia that aggravates vascular calcification and cardiovascular risk. Novel non-Ca–based P binders appear promising, but incur a huge cost burden. Nicotinic acid has been shown to increase fecal P excretion and clinically has been demonstrated to reduce hyperphosphatemia in hemodialysis patients (pts).
Aim: To evaluate the efficacy and safety of nicotinic acid SR as an adjunct to regular Ca-based P binders in the treatment of hyperphosphatemia in pts on peritoneal dialysis (PD).
Methods: Our single-center randomized controlled trial recruited pts who had been on PD for at least 3 months and who had a serum P > 1.78 mmol/L despite regular use of Ca-based P binders. Nicotinic acid SR 500 mg was started in the intervention arm with up-titration of the dose on subsequent visits. In the control arm, the dose of Ca-based binder was titrated to achieve a serum phosphate.
Results: A total of 28 pts were treated: 17 with nicotinic acid SR and 11 with titration of Ca-based binder. The trial was terminated prematurely because 70% of pts receiving nicotinic acid SR experienced side effects (hot flushes, rash, palpitations). Despite the side effects, pts on nicotinic SR had a lower serum Ca post-treatment (2.31 ± 0.13 mmol/L pre-treatment Ca vs. 2.21 ± 0.14 mmol/L post-treatment Ca) than did pts in the control arm (2.35 ± 0.19 mmol/L pre-treatment Ca vs. 2.45 ± 0.15 mmol/L post-treatment Ca). The mean change in Ca was –0.07 ± 0.06 mmol/L in the nicotinic SR arm versus 0.11 ± 0.08 mmol/L in the control arm (p < 0.05). Pts on nicotinic acid SR had a lower serum P post-treatment (2.32 ± 0.55 mmol/L pre-treatment P vs. 1.73 ± 0.45 mmol/L post-treatment P) than did pts in the control arm (2.08 ± 0.22 mmol/L pre-treatment P vs. 1.99 ± 0.22 mmol/L post-treatment P). The mean change in serum P was –0.58 ± 0.21 mmol/L versus –0.16 ± 0.14 mmol/L in the control arm (p < 0.05).
Conclusions: Nicotinic acid SR is an effective P binder, but it is associated with a high incidence of non-fatal side effects. Trials involving other preparations of nicotinic or nicotinamide derivatives with fewer side effects should be explored.
Hyporesponsiveness to Erythropoiesis-Stimulating Agent Therapy for Anemia in Peritoneal Dialysis Patients
Background: Anemia is a common complication in chronic dialysis patients, usually developing as a consequence of erythropoietin deficiency. Erythropoiesis-stimulating agents (ESAs) are indicated for the correction of anemia. A recent guideline of the Japanese Society for Dialysis Therapy recommends achieving a hemoglobin (Hb) level greater than 11 g/dL. However, many peritoneal dialysis (PD) patients cannot achieve this target level with a maximum dose of ESA.
Aim: To clarify the cause of hyporesponsiveness to ESA in PD patients.
Methods: We evaluated 66 patients who underwent PD without active bleeding, malignancy, or hematologic disorder in our hospital. We analyzed Hb concentration, iron status, ESA dose, and dialysis status in these patients.
Results: Of the 66 patients, 60 received ESA therapy. The percentages of patients with Hb levels of 11 g/dL were 41%, 32%, and 27% respectively. Mean dose of ESA [recombinant human erythropoietin (rHuEPO)] was 5120 IU/week (range: 6000 – 12000 IU/week). In patients with a Hb level less than 10 g/dL, ESA (rHuEPO) doses, transferrin saturation, and serum ferritin levels were 6000 IU/week, 33.5%, and 131 ng/mL respectively. In 10 of these patients, we confirmed improvement of anemia (Hb 8.6 g/dL to 10.4 g/dL) after hemodialysis combined therapy despite ESA reduction.
Conclusions: ESA hyporesponsiveness without iron deficiency is not rare in PD patients. Increasing the dialysis dose using combined therapy with HD markedly improved ESA responsiveness. These findings suggested that insufficient dialysis often disturbs iron utilization in PD.
The Effect of Low-Calcium Dialysate on Calcium–Phosphate Metabolism in Continuous Ambulatory Peritoneal Dialysis Patients
Objectives: It is suggested that low-Ca dialysate should be used in the treatment of continuous ambulatory peritoneal dialysis (CAPD) patients (pts) with renal osteodystrophy. This study investigated the effect and safety of low-Ca dialysate (1.25 mmol/L) as compared with high-Ca dialysate (1.75 mmol/L) on the treatment of renal osteodystrophy in CAPD pts by analyzing the correlation between clinical parameters and serum Ca in CAPD pts.
Methods: The study enrolled 57 long-term CAPD pts with hypercalcemia. Pts were randomly divided into the 1.25 mmol/L Ca dialysate group (group A) or the 1.75 mmol/L Ca dialysate group (group B). Laboratory tests were performed at 0, 4, 8, 12, 16, 32, and 48 weeks. Clinical parameters were recorded at the same time.
Results: Of the 57 pts enrolled, 53 completed the study. We observed no differences in serum albumin, volume of dialysate, or ultrafiltration between week 48 and week 0 (p > 0.05). After 8 weeks, the levels of serum Ca, P, and Mg were significantly decreased in group A (p < 0.05). Meanwhile, the level of serum parathyroid hormone in group A also increased (p < 0.05). But these biochemical data were not changed in group B. The intake of Ca carbonate increased significantly in group A after 8 weeks (p < 0.05). The percentage decrease in the Ca index showed a negative correlation with age and a positive correlation with dialysis volume.
Conclusions: For pts treated with CAPD, low-Ca dialysate may improve Ca–P metabolism. It might also benefit CAPD pts with adynamic bone diseases, because it abates parathyroid gland suppression. Low-Ca dialysate should be considered when seeking individualized therapy.
Association of Calcium–Phosphorus Metabolism and Augmentation Index in Peritoneal Dialysis Patients
Objectives: Cardiovascular accidents are the leading cause of death among peritoneal dialysis (PD) patients (pts), and thus continuous monitoring of their cardiovascular status seems to be important. Recently, a handy device for monitoring the augmentation index (AIx) in the radial artery was introduced, enabling the use of AIx in the evaluation of artery stiffness in PD pts. In this study, we investigated the association between Ca–P metabolism and AIx.
Methods: The study included 62 stable nondiabetic continuous ambulatory PD (CAPD) pts. The radial AIx was evaluated by a newly introduced applanation tonometer, and we analyzed its affecting factors. Clinical data, including sex, age, height, weight, body mass index, subjective global assessment, blood pressure, hemoglobin, serum albumin, serum prealbumin, residual renal function, lipid profile, and prescription were collected from a data base of PD pts. All lab tests were performed within a month.
Results: The AIx in female pts was higher than that in male pts (p < 0.01). It was also significantly higher in pts older than 65, those on dialysis for more than 2 years, and in pts requiring more than 1 antihypertensive drugs (p < 0.05). The radial AIx was positively correlated with age, sex, time on dialysis, mean arterial pressure (MAP), and Ca×P product, and negatively correlated with body height. No association was found between AIx and body weight, body mass index, subjective global assessment, serum albumin, prealbumin, residual renal function, or lipid profile. However, multiple regression analysis showed that only age, sex, height, MAP, and Ca×P product were independent determinants of AIx in these pts.
Conclusions: Age, sex, MAP, and height are independent determinants of AIx in CAPD pts. This study also demonstrated a strong association between Ca–P metabolism and AIx, indicating the important role of Ca–P metabolic disorder in artery stiffness.
Determination of Bone Density in Patients on Peritoneal Dialysis
Objectives: To measure the bone density of patients (pts) who receive peritoneal dialysis (PD) therapy and to evaluate the relationships of bone density with serum Ca and P levels, with the aim of offering help in reasonably applying various concentrations of Ca in dialysate.
Methods: The study enrolled 11 end-stage renal disease pts [4 men, 7 women; mean age: 51.68 ± 17.95 years (range: 21 – 73 years)] who were measured by dual-energy X-ray absorptiometry for bone density of lumbar vertebrae, femur, and forearm before PD. The T values were compared with those for a normal young man, and the Z values, with those for a normal man of the same age. A T/Z value > -1 means normal; a T/Z value < -1 and > -2.5 means osteopenia; a T/Z value < -2.5 means osteoporosis; and a T/Z value < -2.5 combined with one or more brittle fractures means serious osteoporosis. At the same time, levels of serum creatinine, serum Ca, serum P, and intact parathyroid hormone, and the estimated glomerular filtration rate (eGFR) were collected.
Results: In the 11 pts, mean serum creatine was 9.21 ± 1.64 mg/dL, and mean eGFR was 4.88 ± 2.01 mL/min per 1.73 m2. The incidence rates of hypocalcemia (serum Ca < 2.1 mmol/L) and hyperphosphatemia (serum P > 1.5 mmol/L) were 81.82% and 100% respectively. In 54.55% of the pts serum Ca×P product was over 40 mg2/dL2. The mean value for serum intact parathyroid hormone was 134.92 ± 50.75 pg/mL (range: 47.2 – 276 pg/mL), and in 63.64% of pts, it was over 100 pg/mL. The results of bone density tests showed that 7 pts (63.64%) had osteopenia, and 1 pt (9.09%) had osteoporosis by T-value analysis; by Z-value analysis, 2 pts (18.1%) had osteopenia.
Conclusions: Hypocalcemia, hyperphosphatemia, and hyperparathyroidism are common in pts with end-stage renal disease. Pts with osteopenia and osteoporosis should be very careful to use low-Ca dialysate to prevent serious hypocalcemia and fracture.
Low-Calcium Dialysate in Senile Peritoneal Dialysis Diabetic Nephropathy Patients: Treatment of Adynamic Bone Disease
Objectives: To evaluate the indications for and security of low-Ca dialysate (LCD) in senile diabetic nephropathy (DN) patients with adynamic bone disease (ABD) undergoing continuous ambulatory peritoneal dialysis (CAPD).
Methods: Senile DN patients with ABD (n = 20; age > 60 years) on CAPD [intact parathyroid hormone (iPTH) < 100 pg/mL] were converted to LCD (1.25 mmol/L Ca) from standard-Ca dialysate (1.75 mmol/L Ca), and followed for 18 months. Biochemical measurements were retrospectively analyzed, including levels of plasma iPTH, serum Ca, P, Mg, albumin, and hemoglobin. At the same time, bone mineral density (BMD) was detected.
Results: After the start of LCD, plasma iPTH began to rise in the first month and increased significantly by month 3 [baseline vs. month 3: 33.35 ± 17.44 pg/mL vs. 127.93 ± 48.02 pg/mL; p < 0.01] and then increased gradually in months 6, 9, and 12. Levels reached the target range (150 – 300 pg/mL) and stabilized during the subsequent 6 months. The percentages of DN patients whose plasma iPTH level reached target range rose gradually during the initial 12 months of treatment to 31.3%, 37.2%, 57.8%, and 60.1% at months 3, 6, 9, 12 respectively. The percentages did not changed significantly during the following 6 months. After changing to LCD for 3 months, serum levels of Ca and P, and Ca×P product score all declined (p < 0.01): serum Ca declined to 2.08 ± 0.09 mmol/L from 2.57 ± 0.11 mmol/L; serum P declined to 1.52 ± 0.32 mmol/L from 2.37 ± 0.41 mmol/L; and Ca×P product score declined to 56.18 ± 16.20 mg2/dL2 from 70.22 ± 15.38 mg2/dL2. There were no significant changes in albumin, hemoglobin, and Mg during treatment (p > 0.05). The incidence of osteoporosis increased 10%. Most patients can tolerate low-Ca dialysate well, without severe hyperspasmia, alteration of psyche, hypotension, or catagma.
Conclusions: Low-Ca dialysate can effectively and securely increase iPTH level and improve Ca and P metabolism in senile DN patients with ABD on CAPD, and thus treat the ABD. It should be noticed that prevention and cure osteoporosis is essential.
Effect of Subclinical Hypothyroidism and Levothyroxine Intervention on Fluid Load and Anemia in Continuous Ambulatory Peritoneal Dialysis Patients
Objectives: To explore the effect of subclinical hypothyroidism and levothyroxine intervention on fluid load and anemia in continuous ambulatory peritoneal dialysis (CAPD) patients.
Methods: The study enrolled 72 patients treated with CAPD for at least 3 months in our peritoneal dialysis center. Of the 72 patients, 24 had subclinical hypothyroidism (SCH group), and the other 48 did not (non-SCH group). Ultrasensitive thyrotropin, free triiodothyronine, and free thyroxin were examined by the solid-phase chemiluminescence enzyme immunity analytic method. Fluid status such as extracellular water (ECW), intracellular water (ICW), and total body water (TBW) were measured by bioimpedance assessment. The ECW was normalized to the patient's ideal weight (nECW). At the same time, hemoglobin (Hb), peritoneal ultrafiltration, and urine volume were compared between the two groups. In the SCH group, 12 patients were treated with levothyroxine, and their fluid status and Hb were reviewed before and 4 weeks after therapy.
Results: There were no significant differences in age, sex, peritoneal ultrafiltration, or urine volume between the two groups. ECW was 18.56 ± 2.98 in SCH group and 16.45 ± 1.73 in the non-SCH group (p < 0.01). Hb was 78.5 ± 8.40 g/L in the SCH group and 84.83 ± 10.21 g/L in the non-SCH group (p < 0.05). Differences of TBW and edema were observed in the two groups, meaning that fluid load was higher and anemia was more severe in the SCH group than in the non-SCH group. After levothyroxine treatment, ECW significantly declined to 15.93 ± 1.67 from 18.32 ± 2.65 (p < 0.01), and Hb increased to 85.21 ± 4.92 g/L from 79.3 ± 6.30 g/L (p < 0.01). The difference was significant as compared with levels before treatment and with levels in untreated patients (p < 0.05).
Conclusions: Subclinical hypothyroidism aggravates fluid load and anemia in CAPD patients. Levothyroxine therapy can reduce fluid load and relieve anaemia.
25-Hydroxyvitamin D Deficiency Was Highly Prevalent in Dialysis Patients
Objectives: Vitamin D [25(OH)VD] deficiency (VDD) is highly prevalent in dialysis patients. This study compared vitamin D levels in PD and HD patients.
Methods: All stable patients from the dialysis center at Peking University First Hospital were invited to participate in this study, which ran from November 1, 2008, to January 1, 2009. There were 199 respondents among the 408 patients at the PD center, and 90 respondents among the 110 patients at the HD center. Demographic information and medical conditions and comorbidities such as diabetes were recorded. To guarantee stable measurement of 25(OH)VD levels, we attended the Vitamin D External Quality Assessment Scheme (DEQAS) and used commercial enzyme immunoassay kits. All of our results met the performance target set by the DEQAS Advisory Panel for 25(OH)VD assays. Serum albumin, hemoglobin, Ca, corrected Ca (Caalb), intact parathyroid hormone (iPTH), P, alkaline phosphatase, creatinine, and serum urea were measured. We also selected 20 cases randomly for detecting the 25(OH)VD concentrations in PD effluent.
Results: There were 113 male patients and 172 female patients with an age of 60 years (range: 51 – 71 years). Nearly all patients [HD: 98.9% (89/90); PD: 99.5% (198/199)] had VDD. In the PD group, a stepwise logistic regression analysis disclosed that serum 25(OH)VD was negatively correlated with dialysis vintage (p = 0.002). In the effluent fluid in the PD group, 25(OH)VD concentrations [8.82 ng/mL (range: 8.5 – 9.8 ng/mL)] were much closer to serum level [8.9 ng/mL (range: 7.8 – 9.7 ng/mL); p = 0.798].
Conclusions: In dialysis patients, VDD was quite common in winter season, especially in PD patients. Vitamin D levels were lower in patients with diabetes mellitus. It seems that serum 25(OH)VD levels were lower in PD patients than in HD patients; but in dialysis patients without diabetes, levels were the same. In PD patients, serum 25(OH)VD negatively correlated with dialysis vintage and could be detected in peritoneal effluent.
Total Dose Infusion Iron Dextran Therapy in Peritoneal Dialysis Patients
Objectives: To explore the safety and efficacy of intravenous iron dextran as a total dose infusion (TDI) in peritoneal dialysis (PD).
Methods: The study involved 15 patients on PD. All patients received iron dextran twice annually for 12 months. Iron dextran 1 g, dissolved in 500 mL normal saline, was administered to all patients as a TDI over 6 hours after a prior test dose. Hemoglobin, hematocrit, serum ferritin (SF), transferrin saturation (TSAT), interleukin-6 (IL-6), tumor necrosis factor α (TNFα), and C-reactive protein (CRP) were assessed at baseline and at every treatment.
Results: The mean hemoglobin in patients at baseline and at months 6 and 12 was 85.9 ± 12.9 g/L, 95.5 ± 23.4 g/L, and 100.3 ± 21.8 g/L respectively. Mean SF increased from 215.0 ± 183.3 μg/L at baseline to 346.6 ± 150.0 μg/L at month 6, and 433.5±129.2 μg/L at month 12. These parameters were significantly difference from baseline at both month 6 and month 12 (p < 0.05), but there was no significant difference between values at month 6 and month 12. Levels of IL-6, TNFα, and CRP declined stably, but there was a significant difference in these parameters only between levels at baseline and at month 12 (p < 0.05). No major adverse events occurred, and only minor side effects were observed in all patients.
Conclusions: Iron dextran as a TDI corrects anemia in PD patients and is an effective method to replenish iron stores. Inflammation status had even been relieved.
Efficiency of 1α(OH)D3 and 1,25(OH)2D3 on Treatment of Secondary Hyperparathyroidism in Peritoneal Dialysis Patients Were Comparable
Objectives: To compare the efficiency of 1α(OH)D3 and 1,25(OH)2D3 on secondary hyperparathyroidism (SHPT).
Methods: This study enrolled 52 prevalent PD patients with SHPT, who were allocated to one of two groups. Group A (n = 24) received 1,25(OH)2D3, and group B (n = 28) received 1α(OH)D3. Demographic characteristics of enrolled patients were described, intact parathyroid hormone (iPTH), serum calcium (Ca) and phosphate (P) level were measured at baseline, and monitored 3 months and 6 months after baseline.
Results: No significant differences were noted between the groups in age (mean: 60.75 years vs. 56.79 years), dialysis vintage, or percentage of men or of diabetes. There was no significant difference between the groups with regard to Ca, P, and iPTH level, or to serum albumin and Kt/V at baseline. A significant decline in iPTH level 3 months after initiation of treatment, and a further decline at 6 months, occurred in each of groups A and B (p < 0.01 for each). There were no significant differences between groups A and B at baseline, 3 months, or 6 months (p = 0.94, 0.11, 0.45 respectively). The weekly dose (micrograms per week) of the two drugs in groups A and B was similar at the time points of baseline, 3 months, and 6 months after treatment initiation (1,25(OH)2D3 vs. 1α(OH)D3: 3.10 vs. 2.66; 1.71 vs. 1.75; 1.67 vs. 1.56; p > 0.05 for all). Serum Ca and P were comparable at the time points of baseline, 3 months, and 6 months.
Conclusions: The efficiency of 1α(OH)D3 and 1,25(OH)2D3 in the treatment of SHPT was similar.
Serum Osteoprotegerin Levels Are Associated with Valvular Calcification and Mortality in Peritoneal Dialysis Patients
Background: Many studies have supported a new definition of arterial calcification as an organized process with similarities to bone formation. Bone-associated protein such as osteoprotegerin (OPG) could play a key role in bone–vascular calcification imbalance. However, the relationships between serum OPG levels, valvular calcification, and mortality in peritoneal dialysis (PD) patients are still unclear.
Methods: The level of OPG in 49 PD patients and 10 age-matched healthy controls was measured using ELISA, and its relationship to valvular calcification was studied. These PD patients were followed prospectively for 3 years. Kaplan–Meier estimation and the Cox proportional hazards model were applied for unadjusted and adjusted analyses of all-cause and cardiovascular mortality.
Results: Serum OPG levels in PD patients were significantly higher than those in healthy controls (5.12 ± 1.79 ng/mL vs. 2.32 ± 0.48 ng/mL, p < 0.01). The concentration of OPG was positively related with age (r =0.354, p < 0.05) and level of C-reactive protein (r =0.390, p < 0.01). Compared with PD patients without valvular calcification, OPG levels in patients with valvular calcification were significantly elevated (6.85 ± 1.43 ng/mL vs. 4.69 ± 1.52 ng/mL, p < 0.01). Logistic regression analysis showed that OPG levels were independently associated with the presence of valvular calcification in PD patients [odds ratio: 2.15; 95% confidence interval (CI): 0.87 to 6.46; p < 0.01]. Overall, there were 14 deaths (28.6%) from all causes, and 6 deaths (12.2%) from cardiovascular events during the follow-up. When divided into two groups according to OPG level, the higher OPG group (>5 ng/mL) predicted all-cause [risk ratio (RR): 2.67; 95% CI: 1.32 to 5.41; p < 0.01] and cardiovascular mortality (RR: 3.15; 95% CI: 1.14 to 8.69; p < 0.05).
Conclusions: Serum OPG level may be associated with the presence of valvular calcification and is a strong predictor of mortality in PD patients. OPG determination therefore could be a valuable biomarker during the follow-up of these patients.