Bone mineral densitometry in patients on hemodialysis: difference between genders and what to measure

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.

Loss of bone mineral density and trabecular bone score in elderly hemodialysis patients: a 2-year follow-up, prospective, single-centre study

BACKGROUND

Low bone mineral density (BMD) and trabecular bone score (TBS) are established risk factors for fractures even in hemodialysis population and they seem to be significantly lower in comparison with general population. The aim of our study was to describe 2-year loss of BMD and TBS and their predictors in hemodialysis patients.

METHODS

From 59 non-selected patients (mean age 67.6 ± 13.1 years) from one dialysis centre, treated with hemodiafiltration (HDF), clinical and laboratory characteristics were obtained and densitometry examinations (with BMD and TBS results) were performed initially and at the end of 2-year follow-up.

RESULTS

Two-year decrease in BMD of lumbar spine reached 4.1% (ns), of proximal femur 9.1% (p = 0.004), and of femoral neck 1.3% (ns). In the co-educated cohort, BMD decrease in all the sites correlated significantly with age and only the change of BMD of lumbar spine was negatively associated with serum calcium (r = - 0.39; p = 0.04) and dialysis vintage (r = - 0.387; p = 0.062), no other predictors of BMD loss were identified. Some predictors of BMD loss were identified with regard to gender. TBS decrease was 0.05 (3.9%; p = 0.03), and similarly, it was not predicted by any of selected parameters. No differences in BMD changes or TBS were observed between the patients with and without fractures.

CONCLUSIONS

In patients with HDF, significant BMD and TBS annual losses were observed, and they were associated only with age and (in BMD of lumbar spine) with serum calcium and dialysis vintage.

Bone mineral density at different sites and 5 years mortality in end-stage renal disease patients: A cohort study

BACKGROUND

Bone disease with osteoporosis and renal osteodystrophy is common in end stage renal disease (ESRD) patients and associates with cardiovascular disease (CVD) and increased morbimortality. We investigated associations of low bone mineral density (BMD) at various bone sites with five year all-cause and CVD mortality in ESRD patients.

METHODS

In a post hoc analysis of 426 ESRD patients (median age 56 years, 62% men) starting dialysis, BMD (whole-body dual-energy X-ray absorptiometry, DXA), body composition, nutritional status (subjective global assessment, SGA), handgrip strength (%HGS), Framingham CVD risk score (FRS) and biochemical biomarkers of nutrition and inflammation were assessed. We used the Fine and Gray competing risk regression analysis to assess survival analysis.

RESULTS

In multivariate logistic regression analysis, %HGS and intact parathyroid hormone associated with low tertile of: BMD_total, BMD_head and BMD_pelvis, after adjusting for FRS, SGA, %HGS, s-albumin, hsCRP, lean body mass index and year of recruitment. Patients with high FRS had low BMD_head (p<0.001). Low tertile of BMD_total (sHR, 1.53), BMD_head (sHR 1.54) and BMD_pelvis (sHR 1.60) associated with increased all-cause mortality whereas no such associations were found for the trabecular bone rich sites BMD arm, leg, trunk, rib or spine. Low tertile of BMD_total (sHR 1.94), BMD_head (sHR 1.68), BMD_leg (sHR 2.25) and BMD_pelvis (sHR 2.45) associated with increased CVD mortality whereas BMD at other sites did not associate with CVD mortality.

CONCLUSION

Low head and pelvis BMD, and low total BMD, as assessed by whole-body DXA, were independent predictors of increased risk of all-cause and CVD mortality. Cortical BMD appeared to have stronger association to survival in ESRD than trabecular BMD.

Impact of reference point selection on DXA-based measurement of forearm bone mineral density

Few studies have systematically evaluated the technical aspects of forearm bone mineral density (BMD) measurement. We found that BMD remained stable regardless of the reference point; however, the ROI identified was not always consistent. Our study highlights the importance of using the same reference point for serial measurements of forearm BMD.

BACKGROUND

Forearm fractures are clinically important outcomes from the perspective of morbidity, health care costs, and interruption of work. BMD of the forearm, as derived by dual-energy x-ray absorptiometry (DXA), is a better predictor of fracture at the forearm compared with BMD measured at other sites. However, very few studies have evaluated the technical aspects of selecting the ROI for forearm BMD measurement. This study aimed to compare the BMD values measured at the 1/3 radius site using three different reference points: the ulnar styloid process, the radial endplate, and the bifurcation of the ulna and radius.

METHODOLOGY

Healthy Chinese patients participating in the control group of an ongoing study at Zhejiang Provincial People's Hospital were recruited for this study. For each patient, a DXA scan (GE Lunar Prodigy) of the forearm was performed and BMD values were separately calculated using each of the three reference points to identify the ROI. Pearson correlation coefficients were calculated to examine the correlation between the BMD measures derived from each reference point. The F test and independent t test were applied for more robust analysis of the differences in the variances and means.

RESULTS

Sixty-eight healthy Chinese volunteers agreed to participate in this study. The root mean square standard deviation (RMS-SD) percentages of BMD values measured at the 1/3 radius site were 2.19%, 2.23%, and 2.20% when using the ulnar styloid process, radial endplate, and the bifurcation of the ulna and radius as the reference points, respectively. Pearson's correlation coefficients for all pairwise comparisons among these three groups were greater than 0.99. F tests and independent t tests showed p values ranging from 0.92 to 0.99. However, we observed that among 10% of patients, choosing an ROI at the ulnar styloid process led to an inability to accurately determine the BMD at the ultra-distal radius.

CONCLUSIONS

Given equal ability to determine BMD at the 1/3 radius accurately, the radial endplate or the bifurcation of the ulna and radius should be preferentially selected as the reference point for routine forearm BMD measurements in order to avoid situations in which the ultra-distal radius BMD cannot be determined.

Retrospective Analysis of Bone Metabolism in Patients on Waiting List for Simultaneous Pancreas-Kidney Transplantation

Posttransplant osteoporosis, which evolves from preexisting bone pathologies, represents a serious complication with deteriorating consequences. The aim of our study was to evaluate epidemiological data on bone mineral density (BMD) in subjects with type 1 diabetes (T1DM) in advanced stages of diabetic nephropathy indicated for simultaneous pancreas-kidney transplantation (SPK). We retrospectively compiled biochemical and densitometrical data from 177 patients with T1DM at CKD (chronic kidney disease) stages G4-G5 (115 men, 62 women, median age 40 yr, diabetes duration 23 yr) enrolled on waiting list for SPK for the first time between the years 2011 and 2016. Median Z-scores were as follows: lumbar spine (LS): -0.8 [interquartile range -1.75 to 0.1]; total hip (TH): -1.2 [-1.75 to -0.6]; femoral neck (FN): -1.2 [-1.9 to -0.7]; and distal radius (DR): -0.8 [-1.4 to -0.1]. We noted a gender difference in LS, with worse results for men (-1.1 vs. -0.3) even after adjusting for BMI (body mass index) and glomerular filtration (p < 0.001). Osteoporotic and osteopenic ranges (based on T-scores) for all major sites were 27.7% and 56.5%, respectively, with similar results across both genders. Women had a significantly higher proportion of normal BMD in LS than men (67.7 vs. 49.4%, p < 0.05). Patients with T1DM at CKD stages G4-G5 exhibited serious BMD impairment despite their young age. Men surprisingly displayed lower Z-scores and higher percentages of pathological BMD values in LS than women did. The introduction of adequate preventive measures during the advanced stages of diabetic nephropathy to prevent bone loss is recommended.

Hypocalcemia and bone mineral density changes following denosumab treatment in end-stage renal disease patients: a meta-analysis of observational studies

The incidence of hypocalcemia and bone mineral density (BMD) changes in end-stage renal disease (ESRD) patients on denosumab remains unclear. We performed this meta-analysis to assess the incidence of denosumab-associated hypocalcemia and effects of denosumab on BMD in ESRD patients. A literature search was conducted using MEDLINE, EMBASE, and Cochrane Database from inception through November 2017 to identify studies evaluating incidence of denosumab-associated hypocalcemia and changes in serum calcium, phosphate, alkaline phosphatase (ALP), parathyroid hormone (PTH), and BMD from baseline to post-treatment course of denosumab in ESRD patients. Study results were pooled and analyzed using a random-effect model. The protocol for this meta-analysis is registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42017081074). Six observational studies with a total of 84 ESRD patients were enrolled. The pooled estimated incidence of hypocalcemia during denosumab treatment was 42% (95% CI 29-55%, I² = 0%). Hypocalcemia occurred approximately 7 to 20 days after the first dose and reached nadir of low calcium levels in the first 2 weeks up to 2 months. However, there were no significant changes in serum calcium or phosphate from baseline to post-treatment course (≥ 3 months after treatment) with mean differences [MDs] of 0.20 mg/dL (95% CI, - 0.30 to 0.69 mg/dL) and - 0.10 mg/dL (95% CI, - 0.70 to 0.49 mg/dL). There were significant reductions in ALP and PTH levels with standardized mean differences (SMDs) of - 0.65 (95% CI - 1.13 to - 0.16) and - 1.89 (95% CI - 3.44 to - 0.34), respectively. There were significant increases in T-scores with MDs of 0.39 (95% CI 0.10 to 0.69) and 0.79 (95% CI 0.60 to 0.98) for lumbar spine and femoral neck, respectively. Our study demonstrates the estimated incidence of denosumab-associated hypocalcemia in dialysis patients of 42%. From baseline to post-treatment course, although there are no differences in serum calcium and phosphate, our findings suggest significant reductions in ALP and PTH and a significant increase in BMD. Currently, denosumab should not be considered as the treatment of choice in ESRD patients until more safety and efficacy data are available.

Forearm bone mass predicts mortality in chronic hemodialysis patients

We aim to determine the relationship between bone mineral density (BMD), measured by T- and Z-score, and mortality risk in hemodialysis (HD) patients. We also investigate which are the most suitable skeletal sites for predicting mortality rate. We analyzed the survival of 102 patients who had been treated with chronic HD according to BMD. Patients with a T-score ≤2.5 at the middle, ultradistal and proximal part of the forearm had a higher mortality risk than those with a T-score of -2.5 or higher. Furthermore, no statistically significant association was found between loss of bone mass at other measuring points-lumbar spine (anteroposterior orientation from L1-L4) and hip (neck, trochanter, intertrochanter, total and Ward's triangle)-and mortality risk. We were also interested in exploring the relationship between Z-score at different skeletal regions and mortality risk. We found that patients with a Z-score of -1 or lower at all three parts of the forearm had a greater mortality risk. It is also worth noting that the Z-score at all three parts of the forearm was a more apparent predictor of mortality, compared to the T-score at the same skeletal regions. This empirical analysis showed that BMD assessments should be obtained at the forearm, due to the good predictability of this skeletal site regarding mortality of HD patients. Moreover, data concerning bone density should be reported as Z-scores.

Triceps Skinfold Thickness Is Associated With Lumbar Bone Mineral Density in Peritoneal Dialysis Patients

Anthropometric measurements, including body mass index (BMI), body weight and total fat mass are associated with the bone mineral density (BMD) in the general population. Compared to that in the general population, BMD was lower in dialysis patients. However, the association between anthropometric measurements and BMD is not well-established among peritoneal dialysis (PD) patients. To study this, we conducted a cross-sectional study in 48 chronic PD patients. Anthropometric parameters, biochemical data, and BMD measured by dual energy X-ray absorptiometry in lumbar vertebrae (L2-L4) were collected. Among these PD patients, eight patients (16.7%) had osteoporosis and 22 patients (45.8%) osteopenia, while 18 patients were normal. Older age, decreased height, lower body weight, BMI, triceps skinfold thickness (TSF), mid-arm fat area (MAFA), and higher adiponectin levels were observed in our patients with lower lumbar T-scores. Height, body weight, waist circumference, BMI, body fat mass, TSF, mid-arm circumference, MAFA, and serum phosphorus levels were positively, while age, adiponectin levels were negatively correlated with lumbar BMD levels. According to our multivariate forward stepwise linear regression analysis, TSF (R² change = 0.080, P = 0.017) and body weight (R² change = 0.333, P = 0.002) were both correlated with low lumbar BMD. In conclusion, either TSF or body weight in our chronic PD patients was proved to be an independent predictor for osteolytic bone lesions.

In Hemodialysis Patients, Intradialytic Resistance Exercise Improves Osteoblast Function: A Pilot Study

OBJECTIVE

Abnormalities in mineral and bone metabolism are frequent in chronic kidney disease patients. Physical exercise can improve many indicators of physical functioning, and recent studies showed beneficial effects on bone mineral density in the general population. The aim of this study was to evaluate the effects of resistance exercise training on bone markers and body composition in hemodialysis (HD) patients.

DESIGN

This was a randomized controlled trial.

SUBJECTS

The study included 13 HD patients (46.2% men).

INTERVENTION

Patients were divided into a control group and an exercise group, which performed 8 weeks of intradialytic resistance exercise. Serum sclerostin, bone alkaline phosphatase (BAP), insulin, leptin, 25-hydroxyvitamin D, 1,25-dihydroxyvitamin D, and body composition were measured before and after the exercise period.

RESULTS

In the exercise group, BAP levels increased from 11.4 ± 6.5 to 14.6 ± 6.4 U/L (P < .05) and serum 1,25-dihydroxyvitamin D levels from 46.0 ± 23.5 to 87.2 ± 31.8 ng/mL (P < .05). After exercise, serum BAP levels were inversely correlated with serum sclerostin (r = -0.96, P < .05). There was no change in body composition in either group.

CONCLUSION

Resistance exercise training appears to be an interesting approach for stimulating BAP production in HD patients and may prevent bone loss and stimulate bone formation.

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.

Forearm bone mineral density measurement with different scanning positions: a study in right-handed Chinese using dual-energy X-ray absorptiometry

The purpose of our study was to determine whether different scanning positions influence forearm bone mineral density (BMD) measurements and to evaluate the association between forearm BMDs in different scanning positions and those of other skeleton sites. The study population consisted of 30 right-handed healthy Chinese volunteers. BMD was measured with GE Lunar Prodigy at the left forearm in both sitting and supine positions, and at lumbar spine and the right femur. All subjects received repeated measurements in the same day (repositioning), and the average of repeated BMD results was used for analysis. The BMD precision errors of the nondominant forearm in the sitting and supine positions varied from 1.13% to 2.46%. There were no statistically significant differences between BMD precision errors for each region of interest (ROI) between sitting and supine positions (all the p values were greater than 0.05). When comparing BMDs on the same side in the sitting position with those in the supine position, there were significant differences at both the 1/3 radius level and in the total radius (p<0.05). The BMD values at these ROIs obtained in the supine position were lower than those in the routine sitting position. The BMDs of the ultradistal radius in the both 2 different scanning positions were significantly associated with lumbar spine and femoral neck BMD, respectively. The total radius BMD in the different positions was associated with the BMD of the femoral neck. A change in body scanning position from sitting to supine will significantly influence forearm BMD results.