***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 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: Bone loss is a common complication in patients before and after liver transplantation ( LT ) . The aim of this study was to investigate the efficacy of prophylactic treatment with bisphosphonates after LT in preventing progressive bone loss in LT patients . We included 136 patients with end-stage liver diseases awaiting LT .  Bone mineral density ( BMD ) ( by dual X-ray absorptiometry ) and markers of bone metabolism were determined before , and 4 , 12 , 24 , 36 , and 48 months after LT . All patients received vitamin D and calcium supplementation before and after LT , those with osteopenia or osteoporosis prior to LT were additionally treated with alendronate following LT . Decreased BMD was seen in a high percentage of patients undergoing LT ( osteopenia 48.5 % , osteoporosis 23.5 % ) . Reduced BMD before LT was not related to gender , underlying liver disease , or Child-Turcotte-Pugh classification . Body mass index ( BMI ) prior to LT , however , correlated significantly with the fracture risk . Alendronate prevented the ubiquitously observed bone loss after LT in patients with osteoporosis and osteopenia and , in addition , led to an increase in BMD in patients with osteoporosis within 24 months after LT . In conclusion , our study suggests that alendronate is efficacious in preventing the natural course of bone loss associated with LT Osteopenia is a major complication of  orthotopic liver transplantation ( OLT ) . However , no effective therapy for bone disease has been defined . We have studied vertebral bone mineral density ( VMD ) and fasting serum markers of bone formation [ bone gla protein ( BGP ) , procollagen I carboxyterminal peptide ( PICP ) ] and metabolism ( serum Ca , P , intact parathyroid hormone ( iPTH ) , 25OHD3 and 1,25(OH)2D3 ) in 120 patents after OLT . VMD was measured by dual-energy X-ray absorptiometry ( DXA ) using a Hologic QDR 1000 densitometer on two occasions , 12 months apart . Patients with OLT had a VBD significantly lower compared with age- and sexed-matched Spanish controls ( P<0.05 ) . Prevalence of osteoporosis ( Z score below-2 SD ) was 35.8 % . Serum BGP ( 8.6±0.7 ng/ml ) and PICP ( 222.9±81.9 ng/dl ) were higher than those of controls . However , serum calcium , phosphorus , iPTH , 25OHD3 , and 1,25(OH)2D3 were within normal range . Patients with osteoporosis were r and omly treated with 40 IU/day of calcitonin i.m . ( Diatin , Ferrer Int . Laboratories ) ( n=17 ) or 400 mg p.o . , 15 days every 3 months , of sodium ethiodronate ( Difosfen , Rubio Laboratories ) ( n=23 ) . All patients received 500 mg/12 hours of elemental calcium p.o . After 12 months of treatment , a significant increment of vertebral mineral density ( VMD ) was observed ( 6.4 % and 8.2 % , respectively ) . Serum BGP and PICP values remained elevated without a difference between the two drugs . Our results indicate that antiresorptive drugs may be of benefit in the high turnover osteoporosis of OLT recipients OBJECTIVE The aim of this study was to prevent fractures in the first postoperative year . METHODS AND PATIENTS We studied 59 patients ( 48 men , 11 women ) aged 42.6+/-11.4 years , who underwent liver transplantation . All patients received oral alendronate 70 mg weekly and calcium 1 g and calcitriol 0.5 mug daily .  Bone mineral density ( BMD ) was measured by dual-energy X-ray absorptiometry at the lumbar spine and proximal femur at baseline as well as at 6 and 12 months after transplantation for comparison with an historical control group ( n=31 ) . Spinal radiographs were obtained to assess vertebral fractures at the same time . Additionally , serum osteocalcin , serum parathyroid hormone ( PTH ) , urinary deoxypyridinoline ( DPD ) , and biochemical parameters were determined every 3 months . RESULTS At baseline , femoral total BMD of men was significantly greater than that of women ( P<.05 , .85+/-.1 vs .74+/-.1 ) . A significant increase in BMD was observed at 12 months ( P<.05 ) , no patient developed a bone fracture . Comparison analysis of genders showed that there was a significant difference in favor of men ( P<.05 ) . The lumbar BMD , neck T- , and Z-scores were significantly higher among patients treated with alendronate than historical controls ( P<.05 ) . After 3 months , serum PTH was increased and serum osteocalcin and urinary DPD were reduced . No severe side effects from alendronate treatment were observed during the study . CONCLUSION A direct sign of the success of our study was no fracture observed during the first postoperative year . Alendronate should be considered for patients with low bone mass after liver transplantation Osteoporosis is a common complication in patients with end-stage liver disease and after orthotopic liver transplantation ( LT ) , with result ing increasing fracture rate . In this study , we investigated the role of treatment with pamidronate in preventing further bone loss after LT . Eighty-five patients with end-stage liver disease were included in the study .  Pamidronate 30 mg was given intravenously every 3 months after LT for the duration of 1 year to 43 patients with osteopenia or osteoporosis prior LT . The remainders served as controls . All patients received a supplementation of calcium and vitamin D.  Bone mineral density ( BMD ) at the lumbar spine and the femoral neck , and markers of bone metabolism were measured before and 12 months after LT . Sixty-two BMD were available at 12 months ; only paired BMD were evaluated . A significant increase in lumbar spine BMD was observed in pamidronate treated patients . No change was evident in controls . Femoral neck BMD decreased in both treated and untreated patients . Osteocalcin serum levels and deoxypyridinoline urinary excretion were significantly reduced by treatment . Our study suggests that pamidronate decreases bone turnover and is effective in preventing the course of bone loss after LT , however the efficacy , at the dosage regimen employed and in a follow-up of 12 months , appears to be limited to trabecular bone , with no effect on the cortical structure of the femur Abstract .Osteoporosis is a common and serious complication of solid organ transplantation . Effective therapeutic regimens have not been established but evidence that increased bone turnover is responsible for bone loss early after transplantation provides a rationale for the use of anti-resorptive agents in the peri-operative period . We have examined the effects of a single pre-operative infusion of pamidronate , 60 mg , on bone remodelling and turnover in a prospect i ve study of 12 patients , four male and eight female aged 19–61 years , with chronic liver disease , who formed a subgroup of a larger r and omised controlled single-blind study .  Iliac-crest biopsies were obtained before and 3 months after liver transplantation and histomorphometry performed using image analysis . In untreated patients ( n=5 ) a significant increase in bone formation rate at tissue level was demonstrated at 3 months in comparison to pre-operative values ( 0.035±0.013 vs. 0.161±0.12 μm2/μm/day ; mean ± SD , P=0.003 ) . In patients treated with pamidronate ( n=7 ) no significant increase in bone formation rate was demonstrated at 3 months , although there was a trend towards an increase in indices of bone turnover . In this group there was also a significant reduction in erosion cavity length ( 210.4±63.8 vs. 179.8±67.5 μm ; P=0.03 ) and non-significant reductions in other indices of erosion cavity size . These results indicate that pre-operative administration of pamidronate in patients with chronic liver disease prevents , at least in part , the increase in bone turnover which occurs in untreated patients after transplantation Rapid bone loss and high rates of fractures occur following liver transplantation . To analyze the effect of intravenous pamidronate on bone loss after liver transplantation . A r and omized , double-blind , placebo-controlled study was performed . Seventy-nine patients were r and omized to two groups of treatment : the pamidronate group ( n = 38 ) was treated with 90 mg/IV of pamidronate within the first 2 weeks and at 3 months after transplantation ; the placebo group ( n = 41 ) received glucose infusions at the same time points . All patients received calcium and vitamin D.  Bone mineral density ( BMD ) at the lumbar spine ( L(2)-L(4 ) ) and proximal femur using dual energy X-ray absorptiometry and also spinal X-rays were performed before , and at 6 and 12 months after liver transplantation . Biochemical and hormonal determinations were performed previous to transplantation , at 24 h before and after treatment , as well as at 6 and 12 months after liver transplantation . At 12 months after transplantation , there were significant differences in lumbar BMD changes ( 6 months : pamidronate 1.6 % vs. placebo 0.8 % , P = NS ; 12 months : pamidronate 2.9 % vs. placebo 1 % , P < 0.05 ) . Femoral neck BMD decreased in the pamidronate- and placebo groups during the first 6 months ( 6 months : pamidronate -3.1 % vs. placebo -2.9 % , P = NS ; 12 months : pamidronate -3.2 % vs. placebo -3.1 % , P = NS ) . BMD at the trochanter remained stable in the pamidronate group , whilst a reduction was observed in the placebo group at 6 months ( 6 months : pamidronate -0.7 % vs. placebo -3.7 % , P < 0.05 ; 12 months : pamidronate -0.5 % vs. placebo -1.2 % , P = NS ) . Moreover , no significant differences in the incidence of fractures , serum parathyroid hormone and serum 25-hydroxyvitamin D values between both groups were found . Pamidronate did not increase the risk of serious adverse events . The results of this study show that 90 mg of intravenous pamidronate within the first 2 weeks and at 3 months following liver transplantation preserve lumbar bone mass during the first year , without significant adverse events . However , pamidronate does not reduce bone loss at the femoral neck and furthermore it does not reduce skeletal fractures BACKGROUND / AIMS Increased rates of bone loss and fracture have been reported after liver transplantation . The aim of this study was to investigate the effects of a pre-transplant infusion of pamidronate on fracture incidence and bone loss during the first year after transplantation . METHODS Ninety-nine adults awaiting orthotopic liver transplantation ( OLT ) were r and omised to pamidronate or no treatment . Spinal X-rays were obtained at baseline and after 12 months . Bone mineral density ( BMD ) was measured at the lumbar spine ( L1 - 4 ) and femoral neck at baseline , and 3 , 6 , and 12 months after OLT . RESULTS The incidence of fractures in the first year after OLT was 8 % , four patients within the pamidronate treated group and two in the untreated group developing fractures ( P=0.40 ) . No significant spinal bone loss occurred in either group during the first year . However , significant and sustained bone loss occurred at the femoral neck in both groups . No significant differences were seen between pamidronate treated or untreated groups at either site . CONCLUSIONS Pamidronate in the regimen used had no significant effect on fracture rate or BMD post-transplant . The low incidence of fracture and absence of spinal bone loss indicate that bone disease after liver transplantation may be less common than previously reported A r and omized controlled prospect i ve open‐label single center trial was performed . At the time of transplantation patients were r and omly assigned to one of two treatment arms : The study group of 47 patients received zoledronic acid ( ZOL , 8 infusions at 4 mg during the first 12 months after LT ) , calcium ( 1000 mg/d ) and vitamin D ( 800 IE/d ) . The control group consisted of 49 patients who received calcium and vitamin D at same doses ( CON ) . The incidence of bone fractures or death was predefined as the primary endpoint . Secondary endpoints included bone mineral density ( BMD ) , serum biochemical markers of bone metabolism , parameters of trabecular bone histomorphometry and mineralization density distribution ( BMDD ) . Patients were followed up for 24 months . Analysis was performed on an intention‐to‐treat basis . The primary endpoint fracture or death was reached in 26 % of patients in the ZOL group and 46 % in the CON group ( p = 0.047 , log rank test ) . Densitometry results 
    Output:
    
ii ) Femoral neck : In 268 patients ( four studies , 130 bisphosphonate , 138 control ) , bisphosphonate use did not result in a statistically significant change in BMD at the end of 1 year .
Bisphosphonate therapy during the first year in LT recipients appears to reduce accelerated bone loss and improve bone mineral density at the lumbar spine