Predictors of bone mineral density in patients on hemodialysis

Bone mineral density in Palestinian patients with end-stage renal disease and the related clinical and biochemical factors: Cross-sectional study

Introduction

End-Stage Renal Disease (ESRD) is the ultimate result of chronic kidney disease (CKD). In Palestine, the prevalence of ESRD was 240.3 PMP which is comparable with the nearby countries. Accelerated bone loss among ESRD patients is attributed to abnormal bone turn over that leads to osteoporosis and osteopenia. The risk of fractures is increased four-fold in men and women on hemodialysis, which explains the importance of assessing the bone mineral density among these population. The goals of this study were to find the prevalence of osteoporosis in ESRD patients as determined by bone mineral density (BMD) at different sites and to determine whether BMD correlates with many other clinical parameters.

Methods

A cross-sectional study of 194 ESRD patients were recruited from the dialysis unit in An-Najah National University Hospital, Nablus, Palestine. The patients were on regular hemodialysis or peritoneal dialysis. BMD was measured at the lumbar spine and the hip using the dual-energy X-Ray absorptiometry (DEXA) and the value is expressed as T-score. The data were analyzed using SPSS, version 26. The relationship between BMD and the clinical and biochemical parameters among the ESRD patients was assessed.

Results

We found that 42.8% of ESRD patient had osteoporosis and 40.2% had osteopenia. There were significantly higher proportions of osteoporosis and osteopenia among patients >60 years of age (p<0.005). Patients with osteoporosis and osteopenia had significantly higher serum levels of PTH (792.9 and 469.7) (p<0.05). BMD decreases as the duration of dialysis (39.0 months Vs. 56.8 months), (p<0.05). We found no significant difference between patients on hemodialysis or peritoneal dialysis.

Conclusion

This study showed that Palestinian patients with ESRD have low BMD at the hip and spine. The observed high serum level of PTH was associated with low BMD. Those patients should be closely monitored especially those with more than one risk factor. Moreover, more attention should be paid for these category of patients to decrease the incidence of falling down and the resulting fractures that might lead to mortality and morbidity.

Inpatient Outcomes in Dialysis Dependent Patients Undergoing Elective Cervical Spine Surgery for Degenerative Cervical Conditions

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To evaluate inpatient outcomes in dialysis dependent patients undergoing elective cervical spine surgery.

METHODS

A total of 1605 dialysis dependent patients undergoing elective primary or revision cervical spine surgery for degenerative conditions were identified from the National Inpatient sample from 2002 to 2012 and compared to 1 450 642 nondialysis-dependent patients undergoing the same procedures. The National Inpatient Sample is a de-identified database; thus, no institutional review board approval was needed.

RESULTS

Dialysis dependence was associated with higher inpatient mortality rates (7.5% vs 1.9%; P < .001) as well as both major (17.3% vs 0.6%; P < .001) and minor (36.8% vs 10.5%; P < .001) complication rates as compared with nondialysis-dependent patients. Dialysis-dependent patients had substantially increased mean lengths of stay (9.8 days compared with 2.0 days; P < .001) and total hospital charges ($141 790 compared with $46 562; P < .001).

CONCLUSION

Dialysis-dependence is associated with drastically increased complication rates, risk of mortality, and represent a significant financial and psychosocial burden to patients undergoing elective cervical spine surgery. Both surgeons and patients should be aware of these risks while planning elective surgeries.

Urgent surgery for spinal instability or neurological impairment caused by spinal brown tumors occurring in the context of end-stage renal disease

OBJECTIVE

Spinal instability or neurological impairment caused by spinal brown tumors (BTs) with end-stage renal disease (ESRD) is an acute condition that needs urgent surgery. There is not much published information on BTs of the mobile spine given the rarity of the disease, and the literature shows inconsistent treatment options and ambiguous follow-up information. The aim of the present study was to elucidate the clinical features, anesthesia management, and surgical treatment for this rare disease through long-term follow-up observations.

METHODS

Clinical, laboratory, radiological, and perioperative data on 6 consecutive patients with spinal BTs who had been admitted to the authors' institution between 2010 and 2016 were retrospectively reviewed. The literature on spinal BT with secondary hyperparathyroidism was also reviewed. Summaries of the clinical features and anesthesia management are provided.

RESULTS

The mean age of the 6 patients was 45.5 years (range 35-62 years). Lesions were located in the cervical segment (2 cases) and thoracic segment (4 cases). Localized pain was the most common complaint, and pathological fracture occurred in 5 patients. Elevation of serum alkaline phosphate (AKP) and parathyroid hormone (PTH) was a common phenomenon. Four patients underwent circumferential resection and 2 underwent laminectomy, with parathyroidectomy performed in all patients. The anesthesia process was uneventful for all patients. The mean follow-up was 33 months (range 26-40 months). No spinal lesion progression occurred in any patient. The Karnofsky Performance Status score improved to 80-90 by 3 months after surgery.

CONCLUSIONS

Although uncommon, spinal BTs should be a diagnostic consideration in patients with ESRD. The thoracic spine is the most frequently affected site. ESRD is not a contraindication for surgery; with the assistance of experienced anesthesiologists, urgent surgery is the preferred option to alleviate neurological impairment and restore spinal stability.

Inpatient Outcomes in Dialysis-dependent Patients Undergoing Elective Lumbar Surgery for Degenerative Lumbar Disease

STUDY DESIGN

Retrospective cohort study.

OBJECTIVE

To evaluate hospital outcomes in dialysis-dependent patients undergoing elective lumbar surgeries.

SUMMARY OF BACKGROUND DATA

Because of their overall poor health status and concomitant comorbidity burden, spinal surgery in dialysis-dependent patients represents a significant challenge to spine surgeons. Large studies evaluating their immediate postoperative outcomes in elective lumbar surgery are lacking.

METHODS

Utilizing the National Inpatient Sample, an estimated 1834 dialysis-dependent patients undergoing elective lumbar spine surgery for degenerative lumbar conditions were compared to an estimated 2,522,594 non-dialysis-dependent patients undergoing the same procedures between 2002 and 2012. Our primary outcomes measures included postoperative complication rates, hospital length of stay, and total hospital costs.

RESULTS

Mean age of dialysis-dependent patients was 64.2 years compared to 59.9 in the non-dialysis-dependent cohort (P < 0.001). Dialysis-dependent patients had substantially higher inpatient mortality rates (1.8% vs 0.1%; P < 0.001), major complication rates (8.1% vs 1.1%; P < 0.001), and an increased need for blood transfusion (18.3% vs 12.5%; P < 0.001). Multivariate analysis revealed that dialysis dependence independently increased odds of in-hospital mortality (odds ratio = 8.30; 95% confidence interval 5.78-11.93; P < 0.001) and odds of a major postoperative complication (odds ratio = 3.63; 95% confidence interval 3.49-3.89; P < 0.001). Dialysis dependence was associated with an increased mean length of stay of 3.3 days (P < 0.001) and a significant increase in hospital costs when stratified by procedure type.

CONCLUSION

Dialysis dependence is associated with poorer immediate postoperative outcomes and increased hospital costs when compared to non-dialysis-dependent patients. In addition, an increased need for postoperative transfusion should be anticipated in this patient population. Further studies are warranted to confirm these findings.

LEVEL OF EVIDENCE

3.

Exercise Training Alters the Bone Mineral Density of Hemodialysis Patients

Marinho, SM, Moraes, C, Barbosa, JEdSM, Eduardo, JCC, Fouqe, D, Pelletier, S, and Mafra, D. Exercise training alters the bone mineral density of hemodialysis patients. J Strength Cond Res 30(10): 2918-2923, 2016-Patients with chronic kidney disease undergoing hemodialysis (HD) frequently present low bone mineral density (BMD), and exercise may be useful for treating bone loss. This study aimed to assess the effects of an intradialytic resistance exercise training program (RETP) on BMD in HD patients. Twenty-one patients were enrolled into 2 groups; 10 patients performed exercise (80.0% men; 46.9 ± 12.1 years; 27.0 ± 3.4 kg·m) and 11 patients were in the control group (54.5% men; 50.5 ± 11.5 years; 24.1 ± 8.7 kg·m). Dual-energy x-ray absorptiometry was used to measure the BMD, lean mass, and body fat before and after the supervised RETP (performed with elastic bands and ankle cuffs in both lower limbs 3 times a week for 24 weeks-72 sessions). In the exercise group, 30.0% of patients presented with osteopenia and 20.0% osteoporosis and in the control group, 45.5% osteopenia and 36.4% osteoporosis. Only in the exercise group, the osteoporosis percentage was reduced to 10.0% and the femoral neck BMD and T-score improved from 0.89 ± 0.1 to 0.93 ± 0.1 g·cm and from -1.3 ± 0.8 to -1.0 ± 0.8 g·cm (p ≤ 0.05), respectively, after the intervention. In contrast, these parameters were reduced in the control group. The results suggest that resistance exercise may be useful for improving the BMD in HD patients. In summary, 24 weeks of the supervised RETP played a role in improving the BMD of HD patients.

T-cell cytokine gene polymorphisms and vitamin D pathway gene polymorphisms in end-stage renal disease due to type 2 diabetes mellitus nephropathy: comparisons with health status and other main causes of end-stage renal disease

BACKGROUND

T-cell cytokine gene polymorphisms and vitamin D pathway gene polymorphisms were evaluated as possibly associated with end-stage renal disease (ESRD) resulting from type 2 diabetes mellitus (DM) nephropathy.

METHODS

Studies were conducted among hemodialysis (HD) patients with ESRD due to type 2 DM nephropathy, chronic glomerulonephritis, chronic infective tubulointerstitial nephritis, and hypertensive nephropathy as well as in healthy subjects. A frequency distribution of T-cell-related interleukin (IL) genes (IL18 rs360719, IL12A rs568408, IL12B rs3212227, IL4R rs1805015, IL13 rs20541, IL28B rs8099917, IL28B, and rs12979860) and vitamin D pathway genes (GC genes: rs2298849, rs7041, and rs1155563; VDR genes: rs2228570, rs1544410; and RXRA genes: rs10776909, rs10881578, and rs749759) was compared between groups.

RESULTS

No significant differences in a frequency distribution of tested polymorphisms were shown between type 2 DM nephropathy patients and controls. A difference was found in IL18 rs360719 polymorphic distribution between the former group and chronic infective tubulointerstitial nephritic patients (P trend = 0.033), which also differed in this polymorphism from controls (P trend = 0.005).

CONCLUSION

T-cell cytokine and vitamin D pathway gene polymorphisms are not associated with ESRD due to type 2 DM nephropathy in Polish HD patients. IL18 rs360719 is probably associated with the pathogenesis of chronic infective tubulointerstitial nephritis.

Evaluation of biochemical markers and bone mineral density in patients with chronic kidney disease stage 5D at the start of hemodialysis treatment

BACKGROUND

Patients with chronic kidney disease (CKD) have significant disorders of bone and mineral metabolism. In addition, they can also develop other bone disorders including osteoporosis. This study evaluated the bone mineral density (BMD) of patients at the start of hemodialysis treatment as well as the relationship between BMD and possible risk factors or biochemical markers.

METHODS

The study was performed in 82 patients (28 females, 54 males). BMD was measured by dual-energy X-ray absorptiometry (DXA) at the lumbar spine and the proximal femur.

RESULTS

We found a high prevalence of 25-hydroxyvitamin D deficiency (96%; mean levels 30.0 ± 17.7 nmol/L) and a reduction of BMD in comparison with gender- and age-matched normal population values at the total hip (Z-score = -0.31 ± 1.11) and the femoral neck (Z-score = -0.48 ± 1.16), but not at the lumbar spine (Z-score = 0.68 ± 1.81). The prevalence of T-scores ≤ -2.5 SD in the group of patients over 50 years was 52.0% in females and 33.3% in males. BMD positively correlated: with male gender and calcium levels at all measured sites, with age at the lumbar spine and with weight or BMI at the proximal femur.

CONCLUSION

CKD patients at the start of hemodialysis treatment had a high prevalence of low T-score values, corresponding to values for osteoporosis in the general population. BMD at the proximal femur was below the expected average for age and gender, but at the lumbar spine, BMD in hemodialysis patients was above average in persons without known CKD.

Phalangeal quantitative ultrasound measurements in chronic hemodialysis patients: a 4-year follow-up

In the course of chronic kidney disease, bone metabolism disturbances occur and become aggravated simultaneously with the progression of renal disorder, worsening patients' quality of life. We conducted a 4-year follow-up to assess phalangeal quantitative ultrasound (QUS) measurements in 32 patients undergoing chronic hemodialysis (17 males and 15 females) whose mean ages were 56.3 ± 15.2 years. The QUSs of hand phalanges were performed using DBM 1200 (IGEA, Carpi, Italy) and are expressed as amplitude-dependent speed of sound (Ad-SoS), Z-scores, and T-scores. In comparison with the age-, sex-, and body mass index-adjusted control group, QUS parameters were significantly decreased in all patients undergoing dialysis. During the 4-year follow-up, Ad-SoS and T-scores in all study groups sloped significantly with time. The significant negative relationships between follow-up Ad-SoS results and both baseline and follow-up parathormone values were demonstrated. Our results confirm a high prevalence of bone disturbances in patients undergoing chronic hemodialysis, and they do not improve during renal replacement therapy. The parathormone level seems to be an important agent in influencing bone status, but further studies are needed to understand the other risk factors in kidney-related bone disease.

[Bone mineral density in patients with renal hyperparathyroidism undergoing surgery: relationship with bone parameters]

BACKGROUND AND OBJECTIVES

Hyperparathyroidism (HPT) in chronic kidney disease (CKD) may alter the composition and bone architecture, and cause fractures. The DEXA bone mineral density (BMD), used to predict fracture risk, measures the amount of calcium in bone. However, we do not know the relationship between BMD and bone composition.

PATIENT AND METHOD

Our study, conducted in two groups of renal patients with HPT who underwent parathyroidectomy (PTX): patients on hemodialysis (HD group) and patients with renal transplant (RT group). The aims were to quantify and value the differences among groups and by gender on bone mineral density, quantify and define differences between these two groups and a control group regarding the elemental composition of bone marrow biopsy obtained and static parameters of bone histomorphometry, and define a possible relationship between bone mineral density and bone elements versus histomorphometric parameters.

RESULTS

The BMD mean in femur was higher in TR group than in HD group. Linear correlation analysis performed between parameters versus BMD and bone histomorphometry elements, considering both TR and HD, only correlation between femur BMD (gr/cm2) and calcium (r=0.435, p=0.034, n=24) was observed.

CONCLUSION

Hyperparathyroidism patients undergoing renal transplant had better femoral BMD than those on hemodialysis; the trabecular volume was lower in kidney transplantation, while the volume of fibrosis was higher in hemodialysis patients; the elements in bone transplant and hemodialysis were in similar proportion, while the calcium content tended to be higher in renal transplant.

Quantitative ultrasound of the calcaneus in hemodialysis patients

The aim of this study was to investigate the bone status of hemodialysis patients and identify factors that have influence on bone quality. Four hundred eighty-nine subjects (213 males and 276 females) on maintenance hemodialysis and 696 healthy subjects (309 men, 387 women) were enrolled in this study. Speed of sound (SOS), broadband ultrasound attenuation (BUA) and quantitative ultrasound index (QUI) were assessed by quantitative ultrasound (QUS) at the right calcaneus in both groups. Serum levels of intact parathyroid (iPTH), total alkaline phosphatase (ALP), calcium and phosphate were measured to determine their influence on bone status in hemodialysis patients. All QUS parameters were significantly lower in hemodialysis patients than in controls (p < 0.0001). Stepwise multiple linear regression analysis in male patients indicated that age, weight, calcium-phosphate product and ALP were significant predictors of QUS parameters (adjusted R(2) = 0.15 in SOS; adjusted R(2) = 0.17 in BUA and QUI). In female patients, same findings including number of parity were observed in SOS only (adjusted R(2) = 0.25 in SOS). In postmenopausal patients, the duration of menopause was significant negatively correlated with all QUS parameters (p < 0.01). In conclusion, patients on maintenance hemodialysis had additional risk of bone loss. Advanced age, low body weight, high calcium-phosphate product and high ALP level were important risk factors for deterioration of bone quality.

Characteristics of elderly patients with diabetes and end-stage renal disease

Because of a combination of demographic and social factors, such as the aging of the population in general, increased incidence of diabetes, and more liberal criteria for renal replacement therapy initiation, the proportion of the end-stage renal disease (ESRD) patients with diabetes who are considered elderly is currently the fastest growing segment of incident ESRD population. Despite the fast growth of this group, it is poorly characterized in current literature. In this review, we attempt to summarize the data available to date regarding demographic composition, outcomes, choice of renal replacement therapy, and other management issues including renal transplantation. There is significant evidence that the elderly diabetic patients might differ from the general dialysis population regarding renal replacement modality, vascular access for dialysis, and that guidelines addressing chronic kidney disease (CKD) issues such as nutrition and blood pressure may need modification in this ESRD subgroup. At the same time, other areas such as anemia and bone mineral metabolism have not been adequately studied. Lastly, despite lower rates of kidney transplantation in this population, it confers significant survival advantages, similar to that seen in younger populations. As the fastest growing group in the incident ESRD population, these patients have issues related to clinical management, which represent very important areas for future research.

Associations between vascular calcification, arterial stiffness and bone mineral density in chronic hemodialysis patients

AIM

The aim of our study was to examine the associations between vascular calcification, arterial stiffness and bone mineral density (BMD) in chronic hemodialysis (HD) patients.

METHODS

The study subjects were 83 (70 men and 13 women) HD patients. All patients had computed tomography (CT) to determine aortic calcification index (ACI), pulse wave velocity (PWV) using a volume-plethysmographic apparatus, and BMD estimated by digital image processing (DIP).

RESULTS

Patients, 84.3% male, 38.6% diabetic, had a mean age of 59.3 +/- 11.2 years. In univariate linear regression analysis, ACI correlated positively with age (r = 0.586, P < 0.0001), dialysis vintage (r = 0.47, P = 0.002), pulse pressure (r = 0.311, P = 0.004), C-reactive protein (CRP) (r = 0.226, P = 0.0397) and PWV (r = 0.422, P < 0.0001). There was no significant association between ACI and serum markers of mineral metabolism. There was also a positive association between PWV and systolic blood pressure (P = 0.0004) or pulse pressure (P < 0.0001), and a trend towards greater PWV with increasing age (r = 0.494). In multivariate regression analysis only increasing age, pulse pressure, serum levels of albumin and CRP were significantly associated with ACI and PWV. Mean BMD on DIP was 2.7 +/- 0.4 mmAL. ACI was inversely correlated with BMD (r = -0.234, P = 0.0331).

CONCLUSIONS

Vascular calcification is closely associated with arterial stiffness in HD patients. BMD is inversely correlated with ACI, suggesting that measurement of hand BMD by DIP is a useful tool for assessment of renal bone disease in these patients.

[Diabetes mellitus--a risk factor for the development of osteoporosis]

<zakljucak> Osteoporoza je vazan zdravstveni problem. Prisutan je kod svake trece zene u postmenopauzi i povezuje se sa znacajnim morbiditetom i mortalitetom. Zene sa dijabetesom u postmenopauzi imaju povecan rizik od preloma kuka nego zene koje nisu dijabeticari, tako da strategija prevencije osteoporoze kod svih bolesnika sa dijabetesom ima smisla, narocito kod zena obolelih od dijabetesa. Dokazi da populacija starih sa dijabetesom ima povecan rizik od fraktura kosti daju novi podsticaj za dalja istrazivanja fokusirana na kost i dijabetes. Ona bi trebala da razjasne uticaj razlicitih aspekata dijabetesnog metabolizma, poboljsanja kontrole glikemije i uticaja lecenja dijabetesa na kosti. Odredjivanje (procena) kvaliteta kosti ukljucivala bi standarde merenja BMD, kao i razvoj novih pristupa merenju glikoziliranog kolagena. Bolje shvatanje i sagledavanje uticaja dijabetesa na kost povecava mogucnost ocuvanja kosti i preveniranja pojave fraktura kod osoba sa dijabetesom. Takodje, neophodno je ustanoviti optimalni izbor ispitivanih biohemijskih markera i napraviti standardizaciju merenja kostane mase kod obolelih od dijabetesa. U klinickoj praksi pristup bolesniku sa dijabetesnom osteopatijom trebalo bi da bude individualan, prema stanju promena i profilu rizika, a da dijagnostikovanje i terapijski postupci postanu rutina.

Associations between osteoprotegerin and femoral neck BMD in hemodialysis patients

Numerous humoral factors are involved in the development of renal osteodystrophy, causing perturbations in bone mineral density (BMD) in patients with end-stage renal disease (ESRD). The RANKL/OPG cytokine system appears to mediate the effects of many of these factors on bone turnover, contributing to the pathogenesis of renal bone disease. The aim of this study was to evaluate the clinical and biochemical correlations of BMD measurements in patients on chronic hemodialysis. Fifty-four hemodialysis patients underwent measurement of BMD at the proximal femur and the lumbar spine (L2-L4). Intact parathyroid hormone (PTH), osteoprotegerin (OPG), sRANKL, and main bone biochemical markers were also measured in serum samples of all patients. BMD of the femoral neck was negatively correlated with OPG levels (r = 0.333, P = 0.014). OPG levels were significantly different among normal, osteopenic, and osteoporotic tertiles defined according to BMD of the femoral neck. The highest OPG levels were measured in the lowest T-score (osteoporotic) tertile and were higher than in the osteopenic and normal tertiles (P < 0.05). A threshold level for OPG at 21.5 pmol/l enabled the detection of osteoporotic patients with 76.5% sensitivity and 62.2% specificity. BMD values of trabecular bone-rich sites of the skeleton such as lumbar spine (L2-L4), trochanter, and Ward' s triangle were inversely correlated with total ALP levels (P < 0.05). Hemodialysis patients with low BMD of the femoral neck demonstrated higher OPG levels than patients with normal BMD. Those with lumbar spine (L2-L4), trochanteric, and Ward's triangle BMDs below the normal range presented higher total ALP levels. These results suggest that OPG and total ALP may be clinically useful markers in the detection of significant femoral neck and trabecular bone mineral deficit in hemodialysis patients, warranting further investigations.

Influence of parathyroidectomy on mortality in hemodialysis patients: a prospective observational study

BACKGROUND

In hemodialysis patients, the relationships between serum PTH and phosphorus levels and mortality are debated because both high and low turnover bone diseases increase the risk of vascular calcifications. Furthermore, the prevalence of hypoparathyroidism is increasing, and there is a fear that this state is associated with an increase in bone fractures.

METHODS

We performed a cross-sectional study to determine the prevalence and the causes of hypoparathyroidism (defined as basal and post-hypocalcemic-challenge serum PTH levels < 55 pg/mL) in 97 patients undergoing chronic hemodialysis treatment in our unit. We then prospectively observed patients with low PTH levels (< 55 pg/mL, n = 26) and those with hyperparathyroidism defined as a PTH levels > 200 pg/mL (n = 25) during eight years for all causes of mortality and bone fractures. Kaplan-Meyer survival curves were adjusted for age and sex.

RESULTS

Hypoparathyroidism was present in 30% of our patients. The main causes of hypoparathyroidism were parathyroidectomy (77%) and aluminium and iron overload. Survival did not differ between patients with hypoparathyroidism and hyperparathyroidism and between patients with serum phosphorus < or > 2 mmol/L. Parathyroidectomy was associated with better survival (p < 0.01). Similarly, incidence of bone fractures did not differ for the two groups.

CONCLUSIONS

Parathyroidectomy is the main cause of hypoparathyroidism in hemodialysis patients and is associated with a lower mortality risk. This result suggests that a more aggressive treatment of secondary hyperparathyroidism could decrease mortality in this high-risk population.

Relationship between bone mineral density and biochemical markers of bone turnover in hemodialysis patients

End-stage renal disease is closely associated with changes in bone and mineral metabolism. In recent times, osteoporosis has become important among hemodialysis (HD) patients. In this study, the investigators sought to evaluate the relationship between bone mineral density (BMD) and biochemical markers of bone turnover among HD patients. A total of 70 uremic patients on a maintenance HD program for at least 1 y were enrolled in the study. All patients were treated with conventional bicarbonated HD for 5 h through the use of low-flux hollow-fiber dialyzers. Bone densitometry was measured by dual energy x-ray absorptiometry in the lumbar spine (LS) and the femoral neck (FN). BMD was classified according to World Health Organization criteria on the basis of BMD T scores. Biochemical bone turnover markers such as calcium, phosphorus, ionized calcium, intact parathyroid hormone, alkaline phosphatase, plasma bicarbonate, blood pH, serum albumin, and hematocrit levels were measured before the HD session in the morning. Male patients (n=37; 52.9%; mean age, 46.2+/-17.0 y) were assigned to a single study group, and female patients (n=33; 47.1%; mean age, 44.0+/-13.1 y) to another. Mean duration of HD treatment was 33.7+/-28.5 mo in females and 33.0+/-26.0 mo in males. Among all patients, BMD T scores in the osteopenia/osteoporosis range were observed at the LS in 58 patients (82.8%) and at the FN in 45 patients (64.3%). According to BMD measurements in FN T score, 10% of patients (n=7) were osteoporotic, 54.3% (n=38), osteopenic, and 35.7% (n=25), normal. On the other hand, in LS T score, the results were 47.1% (n=33) osteoporotic, 35.7% (n=25), osteopenic, and 17.1% (n=12), normal. No statistically significant association was found in osteopenia/osteoporosis between sexes according to FN and LS T score (P=.542, P=.267, respectively). No significant relationship was noted between BMD and biochemical markers of bone turnover. A positive correlation was found between FN T scores of BMD and age (r=.413, P=.000). BMD T scores within the range of scores for osteopenia/osteoporosis were observed in 78.5% of patients at the LS and in 58.5% of patients at the FN. The investigators concluded that no correlation could be found between markers of bone turnover and bone mass measurements in both skeletal regions. LS T score results were worse than FN T score results. Elevated alkaline phosphastase levels combined with high intact parathyroid hormone levels are predictive of renal osteodystrophy but not of adynamic bone disease/osteoporosis.

Elevated calcium phosphate product after renal transplantation is a risk factor for graft failure

BACKGROUND

Abnormal mineral metabolism is not uncommon after renal transplant (TXP). In dialysis patients, elevated serum phosphorous (P), calcium (Ca), CaP product, and parathyroid hormone (PTH) are associated with increased morbidity and mortality. The effect of these abnormalities on recipient and graft survival after renal transplantation is unknown.

METHODS

We retrospectively analyzed 422 kidney-only transplants performed between June 1996 and June 2003. Cases with graft or recipient survival less than three months, pre-TXP parathyroidectomy (PTX), cinacalcet therapy and incomplete records were excluded, leaving 303 cases for analysis using Cox models that included post-TXP PTX, levels of albumin-adjusted Ca(Ca(adj)), P, Ca(adj)P product and PTH.

RESULTS

There was an 11-25% prevalence of abnormal serum Ca(adj), P or Ca(adj)P product within the first year post-TXP. At least 24% of recipients not undergoing PTX with an equation estimated GFR of 40-60 mL/min had PTH levels >130 pg/mL at one yr post-TXP. This is above levels recommended by the U.S National Kidney Foundation kidney disease quality initiative for patients with stages I-IV chronic kidney disease. Adjusted Ca > 10.5 mg/dL at three months post-TXP was an independent risk for recipient death (OR 3.0; 95% CI: 1.2-7.4). A Ca(adj)P product >35 mg(2)/dL(2) at six months (OR 4.0; 95% CI: 1.2-13.1), and Ca >10.5 mg/dL at 12 months post-TXP (OR 4.0; 95% CI: 1.2-14) were independent risks for death-censored graft loss. Twenty-two recipients underwent PTX for severe hyperparathyroidism.

CONCLUSION

Abnormalities of mineral metabolism are common early after renal TXP. An elevated serum Ca(adj) at three months post-TXP increases the risk for recipient death, while an elevated Ca(adj)P and Ca(adj) later in the first post-TXP year increases the risk of long-term death-censored graft loss.

Inverse correlation between serum magnesium and parathyroid hormone in peritoneal dialysis patients: a contributing factor to adynamic bone disease?

BACKGROUND

Secondary hyperparathyroidism (SHPTH) is present in many patients with end-stage renal disease (ESRD) and has been linked to uremic bone disease. Parathyroid hormone (PTH) levels are affected by calcium, vitamin D, and phosphorus. Recent data suggests that serum magnesium may also modulate PTH levels.

OBJECTIVE

The aim of this retrospective study was to investigate the impact of different calcium (Ca) and magnesium (Mg) concentrations of dialysis solutions on serum Mg and serum PTH levels in peritoneal dialysis (PD) patients.

PATIENTS AND METHODS

Two groups of PD patients-group A (n = 17) on "standard" Ca and Mg dialysis solution (SCa-MgD) (Ca: 1.62 mmol/l, Mg: 0.75 mmol/l and Lactate 35 mmol/l), and group B (n = 29) on "low" Ca and Mg dialysis solution (LCa-MgD) (Ca: 1.25 mmol/l, Mg: 0.25 mmol/l and Lactate 40 mmol/l), on PD for more than 6 months, were studied. Calcium carbonate (CaCO3) was used as the phosphate (P) binder in 87% (40/46) of the patients. Biochemical parameters were evaluated every 1-2 months over 6 months and the mean values were computed.

RESULTS

No significant differences were found between the two groups in all parameters except for serum Mg and PTH. Serum Mg was higher in SCa-MgD group compared to those in the LCa-MgD group (1.05 +/- 0.19 vs 0.90 +/- 0.23 mmol/l, respectively) and serum PTH was higher in LCa-MgD group compared to those in SCa-MgD group (72.3 +/- 64.2 vs 31.1 +/- 39.0 pmol/l, respectively) even though serum Ca was not different. There was a statistically significant inverse correlation between serum Mg and PTH levels (r = -0.357, p < 0.05).

CONCLUSION

Serum Mg is lower and serum PTH higher in patients dialyzed with lower Mg concentration dialysis solution compared to those with higher Mg concentration dialysis solution. Our study confirms previous reports that serum Mg may have a suppressive role on PTH synthesis and/or secretion, and thus may play a role in pathogenesis of adynamic bone disease that often develops in patients on chronic PD with high calcium and high magnesium concentrations.

Effects of short-term alendronate on bone mineral density in haemodialysis patients

BACKGROUND

Low bone mineral density (BMD) is common in dialysis patients. Low BMD predicts the fracture risk in the general population. Bisphosphonate therapy improves BMD and lowers the fracture risk in many populations, but has not been tested in dialysis patients because of concerns about toxicity. In this investigation, the effect of a short course of alendronate on BMD in haemodialysis (HD) patients is evaluated.

METHODS

Thirty-one healthy HD patients were randomized to placebo versus 40 mg alendronate, taken once a week for 6 weeks. Hip and lumbar spine BMD were measured by dual energy X-ray absorptiometry at baseline and at 6 months. Osteocalcin, parathyroid hormone, calcium, phosphorous and alkaline phosphatase levels were assayed at baseline and at 1, 3 and 6 months.

RESULTS

The BMD and T-scores in specific regions of the hip were stable in the treatment group and decreased in the placebo group (P=0.05). The lumbar spine density increased minimally in both groups. In the treatment group, osteocalcin levels declined significantly at 1 month (P<0.05) and remained low. The main side-effect in the alendronate group was occurrence of gastroesophageal reflux symptoms in three subjects.

CONCLUSIONS

Low-dose alendronate, administered for a limited duration, appears to be well tolerated in dialysis patients. The BMD and T-scores declined at certain hip regions in the placebo group over 6 months, while remaining stable in the treatment group, suggesting a bone-preserving effect of alendronate. Further studies of longer duration, and including examination of bone histology, are needed to assess whether bisphosphonates can be used to preserve BMD in dialysis patients.