Local Calcitriol Injections as a Suppressive Treatment of Secondary Hyperparathyroidism in Chronic Dialysis Patients

Aim. A prospective study was made of the effectiveness of repeatable local calcitriol injections therapy to suppress secondary hyperparathyroidism resistant to conventional therapy in chronic dialysis patients. Methods. Under ultrasonographic guidance, six injections at an interval of two days were performed in 14 chronic dialysis patients. The total amount of calcitriol to be injected each time was estimated as 100% of the calculated gland volume. Calcitriol was given in doses 1 μg of medicine per 1 cubic cm (as measured by USG) of parathyroid tissue. Parathormone concentration, total calcium, ionized calcium, phosphate, and alkaline phosphatase levels were assessed on the first and last day of the treatment period. Results. Prior to therapy, the mean gland volumes were 0.62 (0.15–3.0) ml, and they increased to 0.85 (0.2–3.9) after 14 days (NS). Seven patients were found to have decreased their PTH levels to 909 ± 387 pg/mL after 14 days of treatment when compared with the first day mean values of 1588 ± 440 pg/mL (p < 0.05). After completion of the therapy, four patients were reported to be free from any clinical symptoms of ostalgia or arthralgia. Others reported an alleviation of pain. Conclusions. Parathyroid adenoma injection is an alternative method of treatment for some patients resistant to treatment by means of vitamin D3 pulses or intravenous administration of calcitriol. The success of treatment is to a great extent determined by proper selection of patients and the taking of decisions when the period of secondary hyperparathyroidism is not very advanced.     

A controlled trial of the early treatment of secondary hyperparathyroidism with calcitriol in hemodialysis patients

BACKGROUND: Calcitriol is widely used in conjunction with phosphorus-binders containing calcium to treat secondary hyperparathyroidism in dialysis patients. Its efficacy in patients with severe hyperparathyroidism is diminished, in part, due to glandular hyperplasia associated with decreased calcitriol and calcium receptors. SUBJECTS AND METHODS: We, therefore, developed a prospective, randomized trial comparing i.v. calcitriol plus calcium carbonate (CaCO3) compared to CaCO3 alone (control) in patients with mild to moderate hyperparathyroidism who were within the first year of initiating hemodialysis. Patients underwent calcium (Ca) suppression/stimulation testing at baseline and after six and twelve months of treatment to indirectly assess parathyroid gland hyperplasia. RESULTS: In the calcitriol group, the amino-terminal parathyroid hormone (N-PTH) decreased significantly from a baseline value of 70 +/- 12 pg/ml at month zero to 22 +/- 7 and 19 +/- 6 pg/ml at months 6 and 12, respectively (the conversion factor of amino-terminal PTH to intact PTH is 6, i.e., 10 pg/ml N-PTH equals 60 pg/ml intact PTH). In contrast, the N-PTH levels in the CaCO3 alone group did not change. The change in nadir N-PTH levels at month 12 compared to month zero decreased by 14 +/- 7% in the calcitriol group but increased by 96 +/- 59% in the control group (p < 0.05). In addition, the increment in N-PTH levels during hypocalcemic stimulation decreased by 68 +/- 6% at month 12 compared to month zero but increased by 61 +/- 42% in the control group. Although total calcium and phosphorus levels were not different between the two groups, ionized calcium values were higher in the calcitriol group. The incidence of hypercalcemia was the same in both groups and the episodes were asymptomatic. CONCLUSION: Pulse calcitriol therapy is effective in preventing progression of secondary hyperparathyroidism in hemodialysis patients with mild to moderate disease. Based on Ca suppression/stimulation tests, calcitriol was more successful in preventing gland growth than CaCO3 alone. Further studies are needed to determine if the strategy of early treatment of mild to moderate hyperparathyroidism by pulse calcitriol is safe and effective in hemodialysis in patients.     

Direct injections of calcitriol into enlarged parathyroid glands in chronic dialysis patients with severe parathyroid hyperfunction

Summary: Severe secondary hyperparathyroidism in chronic dialysis patients has been recently treated by supraphysiological concentration of calcitriol achieved through pulse therapy. However, there are many patients resistant to this therapy, who usually have larger parathyroid gland(s). to overcome this resistance, calcitriol was injected directly into the enlarged glands under ultrasonographic guidance. We injected 70–90% of the calculated gland volume of calcitriol solution (1 μg/mL) into the glands of 7 patients three times per week for 2 weeks. the parathyroid hormone (PTH) levels decreased significantly after 2 weeks of direct injections of calcitriol. Following a further 4 weeks of calcitriol pulse therapy, PTH levels remained suppressed and serum alkaline phosphatase activity and the volume of parathyroid glands also decreased. During the long-term follow up, five patients remained well controlled with calcitriol pulse therapy, while two patients needed ethanol injections to control hyperparathyroidism. Although we could not completely rule out a toxic effect of the vehicle, direct injection of calcitriol into parathyroid glands may be another treatment option for chronic dialysis patients. Our data further support the important role of resistance of parathyroid cells to calcitriol in the pathogenesis of parathyroid hyper function in uraemic patients.     

The effect of long-term intravenous calcitriol administration on parathyroid function in hemodialysis patients.

Secondary hyperparathyroidism is common in dialysis patients. Intravenous calcitriol has proven to be an effective therapy for the reduction of parathyroid hormone (PTH) levels. However, the effect of i.v. calcitriol on parathyroid function, defined as the sigmoidal PTH-calcium curve developed during hypocalcemia and hypercalcemia, has not been evaluated during the prolonged administration of i.v. calcitriol. Six hemodialysis patients with marked secondary hyperparathyroidism, PTH levels greater than 500 pg/mL (normal, 10 to 65 pg/mL), were treated for 42 wk with 2 micrograms of i.v. calcitriol after each hemodialysis. Parathyroid function was evaluated before and after 10 and 42 wk of calcitriol therapy. Between baseline and 42 wk, the basal PTH level decreased from 890 +/- 107 to 346 +/- 119 pg/mL (P less than 0.02) and the maximally stimulated PTH level decreased from 1293 +/- 188 to 600 +/- 140 pg/mL (P less than 0.01). In addition, calcitriol administration significantly decreased PTH levels throughout the hypocalcemic range of the PTH-calcium curve. Although the slope of the PTH-calcium curve (with maximal PTH as 100%) decreased between baseline and 42 wk (P less than 0.05), the set point of calcium did not change. Two patients with a decrease in both basal and maximally stimulated PTH levels after 10 wk of calcitriol, developed marked hyperphosphatemia between 10 and 42 wk; this resulted in an exacerbation of hyperparathyroidism despite continued calcitriol therapy. In conclusion, prolonged i.v. calcitriol administration is an effective treatment for secondary hyperparathyroidism in hemodialysis patients provided that reasonable control of the serum phosphate is achieved. In addition, the slope of the PTH-calcium curve may be a better indicator of parathyroid cell sensitivity than the set point of calcium.     

Effect of calcitriol treatment and withdrawal on hyperparathyroidism in haemodialysis patients with hypocalcaemia.

BACKGROUND: Calcitriol is used to treat secondary hyperparathyroidism in dialysis patients. For similarly elevated parathyroid hormone (PTH) levels, the PTH response to calcitriol treatment is believed to be better in hypocalcaemic dialysis patients than in dialysis patients with higher serum calcium values. Furthermore, few studies have evaluated the rapidity of the rebound in serum PTH values after prolonged treatment with calcitriol. Our goal was to evaluate (i) the PTH response to calcitriol treatment in hypocalcaemic haemodialysis patients, (ii) the rapidity of rebound in PTH after calcitriol treatment was stopped, and (iii) whether the effect of calcitriol treatment on PTH levels could be separated from those produced by changes in serum calcium and phosphate values. METHODS: Eight haemodialysis patients (29+/-3 years) with hypocalcaemia and hyperparathyroidism were treated thrice weekly with 2 microg of intravenous calcitriol and were dialysed with a 3.5 mEq/l calcium dialysate. Parathyroid function (PTH-calcium curve) was determined before and after 30 weeks of calcitriol treatment and 15 weeks after calcitriol treatment was stopped. RESULTS: Pretreatment PTH and ionized calcium values were 907+/-127 pg/ml and 3.89+/-0.12 mg/dl (normal, 4.52+/-0.07 mg/dl). During calcitriol treatment, one patient did not respond, but basal (predialysis) PTH values in the other seven patients decreased from 846+/-129 to 72+/-12 pg/ml, P<0.001 and in all seven patients, the decrease exceeded 85%. During the 15 weeks after calcitriol treatment was stopped, a slow rebound in basal PTH values in the seven patients was observed, 72+/-12 to 375+/-44 pg/ml. Covariance analysis was used to evaluate the three tests of parathyroid function (0, 30, and 45 weeks), and showed that calcitriol treatment was associated with reductions in maximal PTH values while reductions in basal PTH were affected by ionized calcium and serum phosphate. The basal/maximal PTH ratio and the set point of calcium were associated with changes in ionized calcium. CONCLUSIONS: In haemodialysis patients with hypocalcaemia, (i) moderate to severe hyperparathyroidism responded well to treatment with calcitriol, (ii) reductions in maximal PTH were calcitriol dependent while reductions in basal PTH were affected by the ionized calcium and serum phosphate concentrations, (iii) changes in the basal/maximal PTH ratio and the set point of calcium were calcium dependent, and (iv) the delayed rebound in basal PTH levels after withdrawal of calcitriol treatment may have been due to the long duration of treatment and the marked PTH suppression during treatment.     

Pharmacokinetics of calcitriol in continuous ambulatory and cycling peritoneal dialysis patients

Oral calcitriol is commonly used for the treatment of secondary hyperparathyroidism in patients undergoing long-term dialysis, but it has been suggested that intravenous (IV) or intraperitoneal (IP) administration enhances the therapeutic efficacy of the sterol. To examine potential mechanisms for this difference, the bioavailability of calcitriol was evaluated after single oral (PO), IV, and IP doses of 60 ng/kg in each of six adolescent patients with osteitis fibrosa undergoing continuous ambulatory peritoneal dialysis (CAPD) or continuous cycling peritoneal dialysis (CCPD). Serum calcitriol levels were 3.6 +/- 4.3, 8.2 +/- 7.5, and 2.5 +/- 3.0 pg/mL, respectively, before IV, PO, and IP doses of the sterol; these values increased to similar levels at 24 hours: 55.6 +/- 14.6 pg/mL after PO, 56.4 +/- 17.6 pg/mL after IV, and 53.8 +/- 20.1 pg/mL after IP. Serum calcitriol levels were higher 1, 3, and 6 hours after IV injections than after PO or IP doses; values thereafter did not differ among groups. The bioavailability of calcitriol, determined from the 24-hour area under the curve (AUC0-24) for the increase in serum calcitriol concentration above baseline values was 50% to 60% greater after IV, 2,340 +/- 523 pg.mL-1.h-1, than after PO, 1,442 +/- 467 pg.mL-1.h-1, or IP, 1,562 +/- 477 pg.mL-1.h1, dosages, P less than 0.05. These differences were due to higher values for AUC during the first 6 hours after calcitriol administration. Although IP calcitriol did not increase sterol bioavailability, radioisotope tracer studies indicated that 35% to 40% of the hormone adheres to plastic components of the peritoneal dialysate delivery system.(ABSTRACT TRUNCATED AT 250 WORDS)     

Direct inhibitory effect of calcitriol on parathyroid function (sigmoidal curve) in dialysis

The effect of intravenous calcitriol on parathyroid function was evaluated in nine chronic hemodialysis patients with secondary hyperparathyroidism. Two micrograms of calcitriol were administered intravenously after dialysis thrice weekly for ten weeks. Parathyroid function was assessed by inducing hypo- and hypercalcemia with low calcium (1.0 mEq/liter) and high calcium (4.0 mEq/liter) dialyses before and after ten weeks of intravenous calcitriol therapy. To avoid hypercalcemia during calcitriol administration, the dialysate calcium was reduced to 2.5 mEq/liter. Parathyroid hormone (PTH) values (pg/ml) from dialysis-induced hypo- and hypercalcemia were plotted against serum ionized calcium, and the sigmoidal relationship between PTH and calcium was evaluated. Basal PTH levels fell from 902 +/- 126 pg/ml to 466 +/- 152 pg/ml (P less than 0.01) after therapy without a significant change in the serum total calcium concentration. The ionized calcium-PTH sigmoidal curve shifted to the left and downward after calcitriol therapy. The maximal PTH response during hypocalcemia decreased after calcitriol from 1661 +/- 485 pg/ml before calcitriol to 1031 +/- 280 pg/ml afterward (P less than 0.05). The PTH level at maximal inhibition due to hypercalcemia decreased from 281 +/- 76 pg/ml before calcitriol to 192 +/- 48 pg/ml afterward (P less than 0.05). The slope of the sigmoidal curve changed from -2125 +/- 487 to -1563 +/- 385 (P less than 0.05). The set point of ionized calcium (4.60 +/- .11 mg/dl before vs. 4.44 +/- .07 mg/dl after) did not change significantly with calcitriol therapy.(ABSTRACT TRUNCATED AT 250 WORDS)     

Long-term effects of small doses of calcitriol in hemodialysis patients with moderate secondary hyperparathyroidism

Prevention of secondary hyperparathyroidism (SHPTH) and treatment of the moderate cases by small p.os doses of Vitamin D has not been thoroughly investigated on the long term, while large doses of Vitamin D have been successful in the short term treatment of this entity. We administered calcitriol p.os 0.5-1.0 microgram, according to iPTH levels, after each dialysis session, in 19 patients (group A) for 36 months. They were ten men and nine women, 63 years old (43-81), with iPTH levels > 4N (419 +/- 185 pg/mL). Seven adenomas were found in five of them (group A1). Serum Ca, phosphate (P) and alkaline phosphatase (AP) were measured every 15-30 days. Serum iPTH and aluminum as well as echogram or scanning of the parathyroid glands were checked every 6 months. Ten additional dialysis patients, seven men and three women, 54.5 years old (36-68), non-significantly different to group A in iPTH levels (290 +/- 225 pg/mL) with three adenomas in two of them (group B1) received no calcitriol and served as controls (group B). Calcitriol treatment significantly lowered serum iPTH levels in group A patients (from 419 +/- 185 to 173 +/- 142 pg/mL, p < 0.0001, delta iPTH: -246 +/- 161 pg/mL); iPTH remained stable in group B patients (delta iPTH: +7.9 +/- 116 pg/mL) with an intergroup significant difference at P < 0.0001. All other parameters measured did not show any significant change. No significant correlation of iPTH to Ca, P or AP was found in A. Initial iPTH levels were higher in A1 and B1 patients and decreased by calcitriol in A1 group. Adenomas in A1 patients did not change in number and size in contrast to B1 where new adenomas appeared (5 patients, 10 glands). Small doses of vitamin D lower high iPTH levels and prevent parathyroid gland hyperplasia. Existing hypertrophy is stabilized under calcitriol treatment both morphologically and biologically.     

Prospective comparison of the effects of maxacalcitol and calcitriol in chronic hemodialysis patients with secondary hyperparathyroidism: a multicenter, randomized crossover study

BACKGROUND: Maxacalcitol is a vitamin D analogue, which is administered intravenously for secondary hyperparathyroidism in dialysis patients as well as calcitriol. However, few dose-comparison clinical studies have been reported for these drugs. The present multicenter, randomized crossover study was conducted to determine the equivalence of maxacalcitol and calcitriol doses. METHODS: Subjects comprised 31 patients on chronic hemodialysis with secondary hyperparathyroidism who had not received maxacalcitol or calcitriol in the previous 3 months. Patients were randomly divided into two groups, and maxacalcitol or calcitriol was administered in a crossover design for 12 weeks each. Maxacalcitol and calcitriol doses were adjusted based on serum levels of calcium and intact parathyroid hormone. RESULTS: After the 12-week maxacalcitol/calcitriol administration, there were no significant differences in levels of calcium (maxacalcitol 2.40+/-0.22 mmol/1 (9.6+/-0.9 mg/dl), calcitriol 2.42 + 0.25 mmol/l (9.7+/-1.0 mg/dl), p = 0.71), phosphate (maxacalcitol 1.97 + 0.42 mmol/l (6.1+/-1.3 mg/dl), calcitriol 2.00+/-0.48 mmol/l (6.2+/-1.5 mg/dl), p = 0.64), intact parathyroid hormone (maxacalcitol 267+/-169 pg/ml, calcitriol 343+/-195 pg/ml, p = 0.11) in serum or other bone-metabolic parameters such as serum alkaline phosphatase. The doses ofmaxacalcitol and calcitriol were 49.3+/-23.7 microg/month and 9.0+/-3.8 microg/month, respectively, and maxacalcitol : calcitriol dose ratio was 5.5: 1. No severe adverse reactions were seen for either maxacalcitol or calcitriol during the study period. CONCLUSIONS: Comparable therapeutic efficacy can be obtained in the treatment of secondary hyperparathyroidism using either maxacalcitol or calcitriol at a dose ratio of 5.5 : 1.     

Intravenous calcitriol regresses myocardial hypertrophy in hemodialysis patients with secondary hyperparathyroidism

To evaluate the response of circulating intact parathyroid hormone (iPTH) on myocardial hypertrophy in hemodialysis (HD) patients with secondary hyperparathyroidism (SHPT), echocardiographic and neurohormonal assessments were performed over a 15-week period in 15 HD patients with SHPT before and after calcitriol treatment and 10 HD control patients with SHPT not receiving calcitriol therapy. We prospectively studied a group of 15 patients with significantly elevated iPTH levels (iPTH >450 pg/mL) receiving calcitriol (2 microg after dialysis twice weekly). Clinical assessment, medication status, and biochemical and hematological measurements were performed once a month. Throughout the study, calcium carbonate levels were modified to maintain serum phosphate levels at less than 6 mg/dL, but body weight, antihypertensive medication, and ultrafiltration dose remained constant. In patients treated with calcitriol, an adequate reduction of iPTH levels was found (1,112 +/- 694 v 741 +/- 644 pg/mL; P < 0.05) without changes in values of serum ionized calcium (iCa++), phosphate, or hematocrit. Blood pressure (BP), cardiac output (CO), and total peripheral resistance (TPR) did not significantly change. After 15 weeks of treatment with calcitriol, M-mode echocardiograms showed pronounced reductions in interventricular wall thickness (13.9 +/- 3.6 v 12.8 +/- 3.10 mm; P = 0.01), left ventricular posterior wall thickness (12.5 +/- 2.4 v 11.3 +/- 1.8 mm; P < 0.05), and left ventricle mass index (LVMi; 178 +/- 73 v 155 +/- 61 g/m2; P < 0.01). However, in control patients, these changes were not found after the treatment period. In addition, sequential measurements of neurohormonal mediator levels in patients receiving calcitriol showed that plasma renin (18.5 +/- 12.7 v 12.3 +/- 11.0 pg/mL; P = 0.007), angiotensin II (AT II; 79.7 +/- 48.6 v 47.2 +/- 45.7 pg/mL; P = 0.001), and atrial natriuretic peptide (ANP; 16.6 +/- 9.7 v 12.2 +/- 4.4 pg/mL; P = 0.03) levels significantly decreased, whereas antidiuretic hormone (ADH), epinephrine, and norepinephrine levels did not change significantly. The percent change in LVMi associated with calcitriol therapy had a strong correlation with the percent change in iPTH (r = 0.52; P < 0.05) and AT II (r = 0.47; P < 0.05) levels. We conclude that the partial correction of SHPT with intravenous calcitriol causes a regression in myocardial hypertrophy without biochemical or hemodynamic changes, such as heart rate, BP, and TPR. The changes in plasma levels of iPTH and, secondarily, plasma levels of neurohormones (especially AT II) after calcitriol therapy may have a key role in attenuating ventricular hypertrophy in SHPT.     

Renoprotection following treatment of secondary hyperparathyroidism with percutaneous ethanol injection in pre-dialysis patients

What could be done for patients with chronic renal failure are marginally beneficial. Among 58 pre-dialysis patients, we found 24 of chronic glomerulonephritis (CGN) with serum creatinine >5 mg/dl and intact parathyroid hormone (i-PTH) >200 pg/ml. In this study, we determined if the residual renal function could be preserved when hyperparathyroidism was corrected by either low-dose calcitriol treatment or ethanol injection. The 58 CGN patients were divided into three groups. The first group, which comprised 11 cases with i-PTH >200 pg/ml and had parathyroid mass, were treated by ultrasonography-guided percutaneous ethanol injection therapy (PEIT). The second study group composed of 13 cases with i-PTH >200 pg/ml without parathyroid mass were treated by calcitriol 1 microg every other day. The third group made up of 34 cases with i-PTH <200 pg/ml, who did not receive calcitriol or ethanol therapy. All patients were followed up within 2 years or until dialysis. The average rate of decline in renal function (slope of reciprocal serum creatinine vs. time) was 0.0025 +/- 0.0026 dl/mg month in group 1, 0.0054 +/- 0.0024 in group 2, and 0.0067 +/- 0.0025 in group 3 (p = 0.018 in group 1 vs. group 2, p < 0.001 in group 1 vs. group 3). The declines of i-PTH, phosphorus, and alkaline phosphatase, and the increase of calcium were all significantly different between group 1 and group 3. Two cases of group 1, 6 cases of group 2, and 20 cases of group 3 entered into dialysis during this study. In conclusion, selective PEIT guided by color Doppler flow mapping is an effective therapy for treating hyperparathyroidism and protecting the residual renal function.     

No difference in intestinal strontium absorption after oral or IV calcitriol in children with secondary hyperparathyroidism. The European Study Group on Vitamin D in Children with Renal Failure

BACKGROUND: Oral and intravenous calcitriol bolus therapy are both recommended for the treatment of secondary hyperparathyroidism, but it has been claimed that the latter is less likely to induce absorptive hypercalcemia. The present study was undertaken to verify whether intravenous calcitriol actually stimulates intestinal calcium absorption less than oral calcitriol and whether it is superior in suppressing parathyroid hormone (PTH) secretion. METHODS: Twenty children (16 males, age range of 5.1 to 16.9 years, mean creatinine clearance 21.9 +/- 11.5 mL/min/1.73 m2, range of 7.4 to 52.7) with chronic renal failure (CRF) and secondary hyperparathyroidism [median intact PTH (iPTH), 327 pg/mL; range 143 to 1323] received two single calcitriol boli (1.5 mg/m2 body surface area) orally and intravenously using a randomized crossover design. iPTH and 1,25(OH)2D3 levels were measured over 72 hours, and intestinal calcium absorption was measured 24 hours after the calcitriol bolus using stable strontium (Sr) as a surrogate marker. Baseline control values for Sr absorption were obtained in a separate group of children with CRF of similar severity. RESULTS: The peak serum level of 1,25(OH)2D3 and area under the curve baseline to 72 hours (AUC0-72h) were significantly higher after intravenous (IV) calcitriol (AUC0-72h oral, 1399 +/- 979 pg/mL. hour vs. IV 2793 +/- 1102 pg/mL. hour, P < 0.01), but the mean intestinal Sr absorption was not different [SrAUC0-240min during the 4 hours after Sr administration 2867 +/- 1101 FAD% (fraction of the absorbed dose) vs. 3117 +/- 1581 FAD% with oral and IV calcitriol, respectively]. The calcitriol-stimulated Sr absorption was more then 30% higher compared with control values (2165 +/- 176 FAD%). A significant decrease in plasma iPTH was noted 12 hours after the administration of the calcitriol bolus, which was maintained for up to 72 hours without any differences regarding the two routes of administration. CONCLUSIONS: These results demonstrate that under acute conditions, intravenous and oral calcitriol boli equally stimulate calcium absorption and had a similar efficacy in suppressing PTH secretion.     

Improved anemia and reduced erythropoietin need by medical or surgical intervention of secondary hyperparathyroidism in hemodialysis patients

BACKGROUND: The available literature is still controversial and shows that surgical (parathyroidectomy, PTX) or medical (calcitriol) treatment actually improved or even corrected the rhEPO-resistant anemia of ESRD patients with severe SHP. The aims of this study were to 1) assess the influence of SHP on hematological parameters in ESRD patients, 2) evaluate whether or not calcitriol could improve anemia and reduce the need of erythropoietin in dialysis patients, and 3) investigate the longitudinal effect of a parathyroidectomy for 6 months on regarding any improvements in calcitriol-refractory ESRD patients. METHODS: 37 chronic hemodialysis patients in Chang Gung Memorial Hospital Dialysis Unit were divided into two groups: patients with SHP (iPTH>300 pg/mL) and patients without SHP (ipTH<300 pg/mL) before calcitriol therapy was applied. Sixteen patients remain with a status of hyperparathyroidism and were considered candidates for calcitriol therapy. Furthermore, we divided the patients according to the response of HPT to calcitriol into responding patients and nonresponding patients. Among nonresponder groups, three patients agreed to accept surgical intervention to treat their hyperparathyroidism status. RESULTS: The phosphate levels and serum alkaline phosphatase levels in patients with SHP were significantly higher when compared with those without SHP (P<0.05). As for the hematological data, hematocrit for patients with SHP was significantly higher than those without SHP (10.5 +/- 0.6 vs. 8.9 +/- 0.8, p<0.05). Other hematological parameters such as transferrin saturation and serum ferritin were not significantly different. We found a significant difference in alkaline phosphate levels in responding and nonresponding patients at 6 months on calcitriol therapy. Concomitantly, the hematocrit level is significantly higher in responding group when compared to those in nonresponding group (10.63 +/- 0.72 vs. 8.96 +/- 1.21, p<0.01). As for the dose of EPO requirement, significant difference between groups was also found after 6-month treatment (3617 +/- 2011 vs. 5416 +/- 1947, p<0.05). As for rhEPO dose requirement, positive effects of PTX were significantly found. The rhEPO doses needed to maintain patients in the hematocrit target range of 30-33% decreased gradually by 29% from 5323 +/- 1326 micro to 3774 +/- 2145 micro per week. The hematocrit level showed a significant increase at 3 months after PTX (p<0.05). This effect lasted until 6 months after PTX. The serum ferritin level was constantly around 350 to 400 pg/mL. While the transferrin saturation decreased 3 months after PTX (p<0.05) and recovered at 6 months. CONCLUSION: ESRD patients with SHP, usually associated with more severe anemia show resistance to rhEPO. In this case, investigation of SHP is strongly recommended with measurement of serum PTH, phosphate and alkaline phosphatase level. Treatment of calcitriol has a beneficial effect on renal anemia in ESRD patients with SHP. In addition, PTX could also provide another choosing therapy in improving renal anemia when medical treatment fails.     

Twice versus thrice weekly administration of intravenous calcitriol in dialysis patients: a randomized prospective trial. Gruppo Italiano di Studio dell'Osteodistrofia Renale

BACKGROUND: Administration of intravenous (i.v.) calcitriol three times weekly effectively controls the synthesis and secretion of PTH in most uremic patients. Administration of a single dose of 1.25(OH)2D3 reduces synthesis of PTH-mRNA for 6 days in rats. Moreover, it can lower PTH levels for up to 4 days in chronic hemodialysis patients. Therefore, a good response to the administration of i.v. calcitriol two times weekly can be expected. We studied - in a multicenter randomized study in patients with moderate to severe secondary hyperparathyroidism - the effects of the same doses of intravenous calcitriol, administered two or three times weekly. METHODS: Twenty-two hemodialysis patients were randomized into two frequencies of treatment groups: two times (G-2/w) and three times weekly (G-3/w). Both groups were treated with increasing doses of intravenous calcitriol for 3 months (first month 3 microg, second month 4 microg, third month 6 microg weekly). RESULTS: After 12 weeks of therapy with intravenous calcitriol the G-2/w group showed a significant reduction in serum PTH levels (from 821 +/- 392 to 350 +/- 246 pg/ml; mean reduction = 57.4%) comparable to the decrease observed in the G-3/w group (from 632 +/- 116 to 246 +/- 190 pg/ml; mean reduction = 61.2%). Ionized calcium (G-2/w from 1.13 +/-0.10 to 1.14 +/- 0.08 and G-3/w 1.21 +/- 0.13 to 1.26 +/- 0.18 mmol/l) and phosphate levels (G-2/w from 4.99 +/- 1.01 to 5.99 +/- 1.78 and G-3/w 5.31 +/- 0.73 to 5.81 +/- 1.18 mg/dl) did not change significantly and phosphate binders were not modified during the study. CONCLUSION: This study confirms that intravenous calcitriol is an effective therapy for moderate to severe secondary hyperparathyroidism. The administration of two doses per week of intravenous calcitriol is as efficacious as three doses per week in suppressing PTH secretion.     

Treatment of secondary hyperparathyroidism in hemodialyzed patients with high-dose calcium carbonate without vitamin D3 supplements.

BACKGROUND: Vitamin D compounds are usually indicated for the treatment of secondary hyperparathyroidism in dialysis patients. The possibility to induce a reversal of hyperparathyroidism with calcium supplementation alone is controversial. The present study was conducted to assess if oral calcium carbonate may constitute a therapeutic option for the control of hyperparathyroidism in patients with high PTH concentrations at the beginning of the treatment with chronic hemodialysis. METHODS: Thirty-one patients with end-stage renal failure with an intact PTH concentration above 250 pg/ml at the beginning of chronic hemodialysis therapy were treated with high doses of calcium carbonate; no patient received either aluminium-containing binders or vitamin D compounds. To minimize hypercalcemia, a calcium dialysate concentration of 2.5 mEq/l was used in all patients. The goal of the study was to reduce the intact PTH concentration to 250 pg/ml with oral calcium carbonate supplements alone. RESULTS: Throughout the first year on hemodialysis treatment, the intact PTH concentration decreased from 538 +/- 256 to 251 +/- 218 pg/ml (p < 0.001). By the end of the study, the therapeutic objective was achieved in 22 patients (71%) ('responder' group). The remaining 9 patients were classified as the 'treatment failure' group. The basal intact PTH concentration was not different between both groups (508 +/- 235 vs. 612 +/- 303 pg/ml, respectively, p = n.s.), but 5 'treatment failure' patients admitted to take a dose of calcium carbonate lower than that prescribed. There were 40 episodes of hyperphosphatemia (11% of all measurements) in 7 of 31 patients, 5 of them belonged to the noncompliance 'treatment failure' patients. Only 15 episodes (4% of all measurements) of transient hypercalcemia (range 11.1 - 11.9 mg/dl) were detected in 8 patients. CONCLUSIONS: Secondary hyperparathyroidism in hemodialysis patients can often be reverted by oral calcium carbonate alone. But a good adherence to treatment is absolutely necessary.     

Comparison of treatments for mild secondary hyperparathyroidism in hemodialysis patients. Durham Renal Osteodystrophy Study Group

Comparison of treatments for mild secondary hyperparathyroidism in hemodialysis patients. BACKGROUND: In the management of patients with mild secondary hyperparathyroidism, it is not known whether calcium supplementation alone is sufficient to correct abnormalities in bone and mineral metabolism or if calcitriol is needed in either physiologic oral or intravenous pharmacologic doses. METHODS: This was a 40-week prospective nonmasked trial of 52 patients [parathyroid hormone (PTH) 150 to 600 pg/mL] who were randomized to receive escalating doses of either calcium carbonate (CaCO3) alone (calcium group, N = 11), daily oral calcitriol (oral group, N = 20), or intermittent intravenous calcitriol (IV group, N = 21). The groups were compared with regard to changes in serum intact PTH, serum bone-specific alkaline phosphatase (BAP), incidence of hypercalcemia (>10.5 mg/dL), and hyperphosphatemia (>6.5 mg/dL). RESULTS: PTH levels decreased in all groups (P < 0.01, paired t-test). In the calcium group, PTH (mean +/- SEM) decreased from 325 +/- 46.2 to 160 +/- 44.5 pg/mL. In the oral group, it decreased from 265 +/- 26.4 to 125 +/- 23.7 pg/mL, and in the IV group, it decreased from 240 +/- 27.7 to 65 +/- 10.0 pg/mL. Upon analysis of covariance, controlling for the initial PTH level, we found no differences in the PTH response between the groups (P > 0.10). In contrast, the BAP concentration increased from 20.7 +/- 7.6 to 27.5 +/- 7.0 microg/L in the calcium group (P = 0.17), decreased from 20. 6 +/- 3.9 to 17.8 +/- 4.5 microg/L in the oral group (P = 0.26), and from 19.1 +/- 2.6 to 10.6 +/- 1.1 microg/L in the IV group (P = 0. 007). Serum calcium increased significantly in all groups from 8.4 +/- 0.25 to 9.0 +/- 0.28, 8.5 +/- 0.16 to 9.2 +/- 0.27, and 8.7 +/- 0.16 to 9.4 +/- 0.18 mg/dL in the calcium, oral, and IV groups, respectively (P = NS difference between groups). Serum phosphorus was significantly lower in the calcium group throughout the study (P = 0.02). Hypercalcemic episodes were 2.0 +/- 0.8, 3.0 +/- 0.6, and 3. 4 +/- 0.6 per patient-year (P > 0.10), and hyperphosphatemic episodes were 0.9 +/- 0.56, 4.2 +/- 0.79 and 4.9 +/- 0.84 in the calcium, oral, and IV groups, respectively (P < 0.01). CONCLUSION: In mild secondary hyperparathyroidism, all three strategies are effective. High-dose CaCO3 alone may be sufficient to control PTH with a favorable side-effect profile, but calcitriol appears to have additional suppressive effects on bone that are greater following the intravenous route of administration and may increase the risk of adynamic bone disease.     

Implications of intermittent calcitriol therapy on growth and secondary hyperparathyroidism

Secondary hyperparathyroidism is the most common skeletal lesion in pediatric patients undergoing maintenance dialysis. The present review summarizes a prospective randomized study that evaluated the biochemical and skeletal responses to intermittent calcitriol therapy in 33 pediatric patients on peritoneal dialysis with secondary hyperparathyroidism. Also, the effect of intermittent calcitriol therapy on linear growth was evaluated in 16 of 33 patients who had completed the clinical trial. Serum parathyroid hormone levels decreased by 62% from 648±125 pg/ml in patients treated with intermittent intraperitoneal (IP) calcitriol, and values remained unchanged from pre-treatment levels of 670±97 pg/ml with oral calcitriol therapy. Overall serum total and ionized calcium levels were higher in patients treated with IP calcitriol during the study. In contrast to these biochemical findings, the skeletal lesions of secondary hyperparathyroidism improved after 12 months of treatment in both groups and adynamic bone occurred in 33% of the patients. Z-scores for height decreased from –1.80±0.3 to –2.00±0.3, P<0.01, after 12 months of intermittent calcitriol therapy. Such findings suggest that an intermittent schedule of calcitriol administration adversely affects chondrocyte activity within epiphyseal cartilage in pre-pubertal children with end-stage renal disease. Received: 20 August 1999 / Revised: 2 February 2000 / Accepted: 9 February 2000     

Pretreatment serum FGF-23 levels predict the efficacy of calcitriol therapy in dialysis patients

BACKGROUND: The predictor for the result of calcitriol therapy would be useful in the clinical practice of secondary hyperparathyroidism. Fibroblast growth factor-23 (FGF-23) is a newly found circulating phosphaturic factor. Its circulating level is elevated in uremia. METHODS: Dialysis patients with plasma intact parathyroid hormone (iPTH) levels greater than 300 pg/mL were included in the study. Calcitriol was intravenously injected three times a week. The patients whose plasma iPTH levels dropped below 300 pg/mL within 24 weeks were defined as those who had been successfully treated. A sandwich enzyme-linked immunosorbent assay (ELISA) system that detects human FGF-23 was applied. RESULTS: Sixty-two patients were analyzed. The pretreatment FGF-23 levels were related to the iPTH levels, calcium x phosphate product levels, and history of active vitamin D therapy. The pretreatment FGF-23, iPTH, and calcium levels were lower in the patients who would be successfully treated with calcitriol. A logistic regression study revealed that the pretreatment iPTH and FGF-23 levels significantly affected the therapy results. Analyses using a receiver-operated curve revealed that FGF-23 was the best screening test for identifying patients with future refractory response to calcitriol therapy. The treatment would be successful in 88.2% of those with FGF-23 9860 ng/L and iPTH >591 pg/mL. CONCLUSION: Pretreatment serum FGF-23 levels were a good indicator in predicting the response to calcitriol therapy. The measurement of serum FGF-23 levels, especially in combination with iPTH levels, is a promising laboratory examination for the clinical practice of secondary hyperparathyroidism.     

Treatment with intermittent calcitriol and calcium reduces bone loss after renal transplantation

BACKGROUND: Bone loss occurs during the first 6 months after renal transplantation (RT), and corticosteroid therapy plays an important role. Although calcium plus vitamin D administration prevents corticosteroid-induced osteoporosis, its use in RT recipients is limited by the risk of hypercalcemia. METHODS: This double-blind, randomized, and controlled prospective intervention trial examined the effect of intermittent calcitriol (0.5 microg/48 h) during the first 3 months after RT, plus oral calcium supplementation (0.5 g/day) during 1 year with calcium supplementation alone. The primary outcome measure was the change in bone mineral density (BMD) at 3 and 12 months after RT; we also explored whether the effect of calcitriol on BMD was different among vitamin D receptor (VDR) genotypes (BsmI). Forty-five recipients were randomized to calcitriol therapy (CT) and 41 were randomized to placebo (PL). RESULTS: Both groups had a similar degree of pre-existing hyperparathyroidism (197 +/- 229 vs. 191 +/- 183 pg/mL), but a more pronounced decrease of parathyroid hormone (PTH) levels after RT was observed in CT patients (at 3 months: 61.4 +/- 42.2 vs. 85.7 +/- 53.1 pg/mL, P= 0.02; at 12 months: 67.3 +/- 33.7 vs. 82.6 +/- 37 pg/mL; P= 0.08). CT patients preserved their BMD at the total hip significantly better than those on PL (3 months: 0.04 +/- 3.3 vs. -1.93 +/- 3.2%, P= 0.01; 12 months: 0.32 +/- 4.8 vs. -2.17 +/- 4.4%, P= 0.03); significant differences were noted at the intertrochanter, trochanter, and Ward's triangle. Differences did not reach significance at the femoral neck. Two CT patients (4.4%) and 4 PL patients (9.8%) developed a hypercalcemic episode during the first 3 months after RT. The effect of CT on BMD at 3 months was more prominent in recipients with the at-risk allele of the VDR gene (P= 0.03). CONCLUSION: Therapy with low-dose calcium supplements during 1 year, plus intermittent calcitriol for 3 months after RT, is safe, decreases PTH levels more rapidly, and prevents bone loss at the proximal femur; a more pronounced effect is seen in recipients with at least one at-risk allele of the VDR genotype.     

Effect of chronic intravenous calcitriol on parathyroid function and set point of calcium in dialysis patients with refractory secondary hyperparathyroidism.

This study evaluates the effect of intravenous calcitriol on parathyroid function and ionized calcium-PTH sigmoidal curve obtained during low- and high-calcium haemodialysis in 10 patients with osteitis fibrosa whose secondary hyperparathyroidism was refractory to conventional therapy. After 4 months of intravenous calcitriol, serum ionized calcium increased from 1.28 +/- 0.08 to 1.37 +/- 0.11 mmol/l (P less than 0.001), serum phosphate from 1.54 +/- 0.18 to 1.79 +/- 0.4 mmol/l (P NS), serum calcitriol from 16.7 +/- 9.9 to 34.3 +/- 6.4 pg/ml (P less than 0.001), while alkaline phosphatase decreased from 366 +/- 340 to 226 +/- 180 IU/l (P less than 0.05), osteocalcin from 46.4 +/- 20 to 34.5 +/- 15.3 ng/ml (P less than 0.05), and basal intact PTH from 1069 +/- 700 to 305 +/- 270 (P less than 0.01). Basal PTH started to decrease after 1 month of treatment prior to the increase in the ionized calcium. Because of hypercalcaemia the dialysate calcium was decreased from 1.75 to 1.5 mmol/l in three of five patients on haemodialysis, and calcium-containing solutions were replaced by calcium-free fluids in four of five patients on haemodiafiltration. Calcitriol dose, at the first month of therapy was 5.6 +/- 0.8 micrograms/week, but it was successively decreased because of hypercalcaemia to a final dose of 3.6 +/- 1.3 micrograms/week. After intravenous calcitriol the ionized calcium-PTH sigmoidal curve shifted to the left and downward. Maximally stimulated PTH and maximally inhibited PTH obtained during low- and high-calcium dialysis significantly decreased, as well as the ratio of basal PTH/PTHmax and the set point of calcium.(ABSTRACT TRUNCATED AT 250 WORDS)