***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
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    ***EXAMPLES*** 
    Input: The i.v . bolus administration of 1 alpha hydroxylated vitamin D derivatives is effective in the treatment of uremic hyperparathyroidism . However , few of the published studies of this mode of treatment have been adequately controlled , and recent reports have suggested that p.o . bolus administration may be just as effective . In this study , 16 hemodialysis patients with mild to moderate hyperparathyroidism were assigned , after a 4-wk run-in period , to receive a 6-wk course of either thrice-weekly i.v . or p.o . alfacalcidol ( initial dose , 4 micrograms ) . Then , after a further control period , they received a second 6-wk course , with either p.o . or i.v . alfacalcidol ( whichever was not given in the first treatment period ) . Plasma parathyroid hormone ( PTH ) was measured weekly by the use of an intact hormone assay . Both routes of therapy result ed in a significant suppression of plasma PTH ( P = 0.005 ) and an elevation in plasma ionized calcium ( P = 0.01 ) . The magnitude of the responses was similar for the two treatment phases , as was the relationship between the increment in calcium and the decrement in PTH . The most complete suppression of PTH was seen in those with the greatest increment in plasma calcium . The incidence of hypercalcemia and the mean dose reductions necessary were also similar in the two treatment phases . Oral bolus therapy and i.v . bolus therapy with alfacalcidol are equally effective in suppressing hyperparathyroidism . The postulated advantages of i.v . over p.o . therapy with 1 alpha hydroxylated vitamin D derivatives remain to be confirmed by controlled studies Thirteen patients in the predialysis phase of chronic renal failure ( CRF ) were treated with calcitriol ( 0.25 micrograms/day ) and 12 with placebo . After 1 year of study , an increase in bone mineral density in the calcitriol group measured by dual-energy X-ray absorptiometry was seen for the femoral neck and lumbar spine when compared to the placebo group ( p < 0.001 and p < 0.01 , respectively ) . We conclude that a steady low dose of calcitriol started in the predialysis phase of CRF is beneficial to the patients with CRF . This may be partly due to suppression of secondary hyperparathyroidism Our prospect i ve 1-year study comprises 93 patients of both sexes , various ages and various dialysis duration . Among them , 31 patients with a concentration of Ca in blood under 2.7 mmol/l , a concentration of P under 1.8 mmol/l and a concentration of PTHi over 65 pg/ml ( group 0 ) received  calcitriol 0.25 microgramx418p4The control group consisted of patients not receiving calcitriol and having normal Ca and P metabolism ( group 1 ) . The rest of the patients had a concentration of P over 1.8 mmol/l and could not be given calcitriol . A comparison of the dynamics of average plasmic concentrations of Ca , P , AP , PTHi and X-ray changes in group 0 and 1 at the beginning of the investigation and 1 year later was carried out . At the termination of the 1-year treatment , when compared to the initial state , a statistically significant increase in the concentration of Ca ( p < 0.005 ) and in the concentration of P ( p < 0.005 ) was noted in group 0 . The average concentration of PTHi decreased to the desired level , the X-ray changes characteristic of secondary hyperparathyroidism progressed more slowly in group 0 BACKGROUND Intermittent oral or intravenous doses of calcitriol given two or three times per week are commonly used to treat secondary hyperparathyroidism ( secondary HPT ) . This study was undertaken to compare the biochemical and skeletal responses to thrice weekly intraperitoneal ( i.p . ) versus oral doses of calcitriol in children with secondary HPT undergoing peritoneal dialysis ( CCPD ) . METHODS Forty-six patients aged 12.5+/-4.8 years on CCPD for 22+/-25 months were r and omly assigned to treatment with oral ( p.o . ) or i.p . calcitriol for 12 months ; 17 subjects given p.o . calcitriol and 16 subjects given i.p . calcitriol completed the study . Bone biopsies were performed at the beginning and at the end of the study , while determinations of serum and total ionized calcium , phosphorus , alkaline phosphatase , parathyroid hormone ( PTH ) and calcitriol levels were done monthly . RESULTS Serum total and ionized calcium levels were higher in subjects treated with i.p . calcitriol , P < 0.0001 , whereas serum phosphorus levels were higher in those given p.o . calcitriol , P < 0.0001 . For the i.p . group , serum PTH levels decreased from pre-treatment values of 648+/-125 pg/ml to a nadir of 169+/-57 pg/ml after nine months . In contrast , serum PTH levels did not change from baseline values of 670+/-97 pg/ml in subjects given p.o . calcitriol , P < 0.0001 by multiple regression analysis . Serum alkaline phosphatase levels were also lower in patients treated with i.p . calcitriol , P < 0.0001 , but there was no difference between groups in the average dose of calcitriol given thrice weekly . The skeletal lesions of secondary HPT improved in both groups , 33 % of patients developed adynamic bone lesion . CONCLUSION Differences in the bioavailability of calcitriol and /or in phosphorus metabolism may account for the divergent biochemical response to p.o . and i.p . calcitriol Management of secondary hyperparathyroidism is challenging with traditional therapy . The calcimimetic cinacalcet HCl acts on the calcium-sensing receptor to increase its sensitivity to calcium , thereby reducing parathyroid hormone ( PTH ) secretion . This phase 3 , multicenter , r and omized , placebo-controlled , double-blind study evaluated the efficacy and safety of cinacalcet in hemodialysis ( HD ) and peritoneal dialysis ( PD ) patients with PTH > or = 300 pg/ml despite traditional therapy . A total of 395 patients received once-daily oral cinacalcet ( 260 HD , 34 PD ) or placebo ( 89 HD , 12 PD ) titrated from 30 to 180 mg to achieve a target intact PTH ( iPTH ) level of < or = 250 pg/ml . During a 10-wk efficacy assessment phase , cinacalcet was more effective than control for PTH reduction outcomes , including proportion of patients with mean iPTH levels < or = 300 pg/ml ( 46 versus 9 % ) , proportion of patients with > or = 30 % reduction in iPTH from baseline ( 65 versus 13 % ) , and proportion of patients with > or = 20 , > or = 40 , or > or = 50 % reduction from baseline . Cinacalcet had comparable efficacy in HD and PD patients ; 50 % of PD patients achieved a mean iPTH < or = 300 pg/ml . Cinacalcet also significantly reduced serum calcium , phosphorus , and Ca x P levels compared with control treatment . The most common side effects , nausea and vomiting , were usually mild to moderate in severity and transient . Once-daily oral cinacalcet was effective in rapidly and safely reducing PTH , Ca x P , calcium , and phosphorus levels in patients who received HD or PD . Cinacalcet offers a new therapeutic option for controlling secondary hyperparathyroidism in patients with chronic kidney disease on dialysis BACKGROUND Calcium-based phosphate binders may induce tissue calcification , and little is known about their effects on bone density . We compared the effects of a calcium with a non-calcium phosphate binder on both arterial calcification and bone density measured by computed tomography . METHODS Seventy-two adult haemodialysis patients were r and omized to treatment with calcium carbonate ( CC ) or sevelamer ( SEV ) for 2 years . Electron beam CT scans were performed at baseline and at 6 , 12 and 24 months . Serum phosphorus , calcium , calcium x phosphorus product and intact parathyroid hormone ( iPTH ) were measured and other routine laboratory tests were also carried out . RESULTS The average calcium x phosphorus product was similar in the two treatment groups . However , patients receiving CC had significantly lower average iPTH ( P<0.01 ) , were more likely to have hypercalcaemic episodes ( P = 0.03 ) and had significantly greater increases in coronary artery ( CC median 484 , P<0.0001 , SEV median 37 , P = 0.3118 , between-group P = 0.0178 ) and aortic ( CC median 610 , P = 0.0003 , SEV median 0 , P = 0.5966 , between-group P = 0.0039 ) calcification scores . The CC group also had a significant decrease in trabecular bone density ( CC median -6 % , P = 0.0049 , SEV median + 3 % , P = 0.0296 , between-group P = 0.0025 ) . However , there was no significant difference in cortical bone density between the two groups . CONCLUSIONS This 2 year study shows that calcium carbonate use is continuously associated with progressive arterial calcification in haemodialysis patients . In addition , it suggests that it is also associated with decreased trabecular bone density . However , this latter finding requires confirmation by a study specifically devoted to this issue Controversy exists among various studies in regard to the efficacy of oral ( p.o . ) versus parenteral calcitriol . Some studies suggest that intravenous ( i.v . ) calcitriol is superior to p.o . calcitriol for treating renal osteodystrophy in hemodialysis patients ; others suggest that these routes of administration are equivalent . To our knowledge , no large , prospect i ve , r and omized study compares intraperitoneal ( i.p . ) to p.o . calcitriol in adult peritoneal dialysis patients . We conducted a prospect i ve r and omized study in 76 patients ( 38 on i.p . calcitriol and 38 on p.o . calcitriol ) , whom we followed for 48 months . Of the 76 patients , 34 ( 18 in the i.p . group and 16 in the p.o . group ) completed the 48-month study period . Calcitriol dosing was similar in both groups ( 3 - 6 micrograms per week in three divided doses ) . Dose adjustments were made depending on levels of parathyroid hormone ( PTH ) , serum calcium , phosphorus , and calcitriol . No significant difference was seen between the groups in regard to age , sex , race , body mass index , dialysis duration , or cause of ESRD . Neither was any difference in the incidence of peritonitis seen between the groups . In the first 3 - 6 months , PTH decreased equivalently in both groups . The PTH level remained suppressed in the i.p . group throughout the remainder of the study , but , in the p.o . group , PTH returned to its pretreatment level after 3 - 6 months . Mean serum calcium was not different in the two groups . In the p.o . group , a considerably higher mean follow-up phosphorus level ( 6.8 + /- 2.3 mg/dL versus 4.7 + /- 1.4 mg/dL , p = 0.008 ) , PTH level ( 384 + /- 146 pg/mL versus 162 + /- 64 pg/mL ; p = 0.005 ) , and alkaline phosphatase level ( 178 + /- 37 IU/L versus 72 + /- 21 IU/L , p = 0.02 ) were seen as compared to the i.p . group . In the i.p . group , resolution of osteodystrophy occurred in all patients at the end of the study ; in the p.o . group , 5 patients maintained or developed osteodystrophy by the end of the study ( p = 0.016 ) . We conclude that i.p . calcitriol is more effective than pulse p.o . calcitriol in lowering PTH and alkaline phosphatase levels and in resolving renal osteodystrophy , and that i.p . calcitriol is associated with a lower incidence of hyperphosphatemia and elevated Ca x PO4 byproduct BACKGROUND Higher doses of calcitriol are effective in lowering markedly elevated 1,84 PTH levels of patients with renal secondary hyperparathyroidism . It has not been established , however , whether prophylactic administration of low doses of calcitriol prevents an increase of 1,84 PTH without causing side-effects , i.e. hypercalcaemia , hypercalciuria , or hyperphosphataemia . STUDY DESIGN We carried out a placebo-controlled , double-blind prospect i ve multicentre trial over 12 months in 45 patients with mild to moderate renal failure . Criteria for inclusion were S-creatinine 1.4 mg/dl and 1,84 PTH > 6 pmol/l ( normal 6 ) .  Calcitriol 0.125 microgram/day per os was compared with placebo . The patients received 
    Output:
    
Calcimimetics used in patients receiving haemodialysis or peritoneal dialysis are more effective than placebo in controlling secondary hyperparathyroidism ( reduced parathyroid hormone levels , calcium levels and phosphorus levels ) .
All phosphate binders are effective in controlling hyperphosphatemia but different doses are to be used with different agents to achieve similar targets .
Dosing needs to be adjusted according to phosphorus levels .
Vitamin D and its analogues are recommended in CKD patients , although there is no significant evidence of superiority of individual agents in head-to-head comparisons .
Available evidence suggests that calcimimetics , phosphate binders and vitamin D or its analogues are effective in the treatment of secondary hyperparathyroidism .