Bone mineral density and its correlation with clinical and laboratory factors in chronic peritoneal dialysis patients

Bone mineral density and related clinical and laboratory factors in peritoneal dialysis patients: Implications for bone health management

BACKGROUND

End-stage renal disease (ESRD) patients often experience accelerated bone turnover, leading to osteoporosis and osteopenia. This study aimed to determine the prevalence of osteoporosis in Peritoneal Dialysis (PD) patients using bone mineral density (BMD) measurements obtained through dual-energy X-ray absorptiometry (DEXA) scan and to explore any possible associations with clinical and biochemical factors.

METHODS

In this cross-sectional study, we enrolled 76 peritoneal dialysis patients from the dialysis center at An-Najah National University Hospital in Nablus, Palestine. We used the DEXA scan to measure BMD at the lumbar spine and hip, with values expressed as T-scores. We conducted a multivariate analysis to explore the relationship between BMD and clinical and biochemical parameters.

RESULTS

Over half (52.6%) of the PD patients had osteoporosis, with a higher prevalence observed among patients with lower BMI (p<0.001). Higher alkaline phosphatase levels were found among osteoporotic patients compared to non-osteoporotic patients (p = 0.045). Vitamin D deficiency was also prevalent in this population, affecting 86.6% of patients. No significant correlation was found between 25 vitamin D levels and BMD. No significant correlation was found between Parathyroid hormone (PTH) levels and BMD.

CONCLUSION

A notable proportion of PD patients experience reduced BMD. Our study found no correlation between vitamin D levels and BMD, but it highlighted the significant vitamin D deficiency in this population. Furthermore, our analysis indicated a positive correlation between BMI and BMD, especially in the femoral neck area. This underscores the significance of addressing bone health in PD patients to mitigate the risk of fractures and improve their overall well-being.

The relationship between serum pro-B type natriuretic peptide level and bone mineral density in peritoneal dialysis patients

We aimed to evaluate the relationship between serum N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) and lumbar bone mineral density (BMD) in peritoneal dialysis (PD) patients. Fasting blood samples were obtained from 46 PD patients. BMD was measured by dual-energy X-ray absorptiometry of the lumbar vertebrae (L1-L4). Circulating serum NT-pro-BNP levels were measured using commercial kits compatible with the Roche Cobas e 601 immunoassay device. Forty-six patients were included in our study. Increased age, low body mass index (BMI), and high-serum NT-pro-BNP are significantly associated with decreased BMD. The results show a statistically positive correlation between lumbar T-score values and BMI (r = 0.456; P = .001), while lumbar T-score values and PTH (rho = -0.336; P = .022) and log-NT-pro-BNP. There is a statistically negative correlation between BNP (rho = -0.355; P = .015). The lumbar T-score value decreases by 0.800 units when log-NT-pro-BNP increases by 1 unit and increases by 0.323 units when BMI increases by 1 unit. The established model is statistically significant (F = 6.190; P < .001). Our study in PD patients showed that serum NT-pro-BNP level was negatively correlated and BMI was positively correlated with lumbar BMD.

Differences in prevalence of reduced and low bone mineral density between lumbar spine and femoral neck in peritoneal dialysis patients using dual-energy X-ray absorptiometry (DXA)

The pattern of chronic kidney disease-mineral bone disease has changed following the increase in elderly patients receiving dialysis, with escalating likelihood of osteoporosis, with associated increased fracture risk and mortality. Thus, we wished to determine the prevalence of osteoporosis in our peritoneal dialysis (PD) cohort. Lumbar spine (LS) and femoral neck (FN) bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA), and low BMD (osteoporosis) and reduced BMD (osteopenia) defined according to the World Health Organisation T scores. DXA scans from 734 patients, 57.2% male, mean age 61.0 ±16.0 years, 34.6% diabetic, with a median 8.0 (2-24) months of treatment with PD were reviewed. Fewer patients had normal BMD at the FN vs. LS (24.1 vs. 55%), and more classified as reduced (FN 55.9 vs. 34% LS) and low BMD (FN 17 vs. 11% LS), χ ² 112.2, p < 0.001. Agreement between FN and LS T scores was r = 0.36 with Spearman rank correlation, and 0.34 by Kendall's tau b, Cohen's kappa score 0.17, and Bland-Altman bias -0.37 (95% limits of agreement -1.8 to 1.08). The prevalence of reduced and low BMD was much greater when using FN T scores compared to LS, with LS T scores a mean of 0.34 higher than FN. DXA scanning at the LS can be affected by overlying vascular calcification and electron densities in the bowel, and as such we suggest that FN T scores are used to report BMD in PD patients.

Diagnosis and Management of Osteoporosis in Advanced Kidney Disease: A Review

Osteoporosis and fractures are common in persons with advanced chronic kidney disease (CKD) and on maintenance dialysis. Although the diagnosis of osteoporosis in this population can be difficult, imaging, especially with dual-energy x-ray absorptiometry (DXA), is helpful in identifying persons with CKD at the highest risk of fracture. Although blood biomarkers including parathyroid hormone and bone-specific alkaline phosphatase concentrations can aid in assessing bone turnover state, bone biopsy remains the gold standard in determining bone turnover in persons with advanced kidney disease and osteoporosis. With the increasing armamentarium of osteoporosis drugs, it now may be possible to prevent many fractures in advanced CKD. Unfortunately, data on these drugs are limited in persons with advanced CKD. Clinicians, aided by advances in imaging, biomarkers, and bone biopsy can now use these novel agents to target bone turnover abnormalities such as adynamic bone disease and high bone turnover disease. This review will discuss the most recent literature surrounding the diagnosis, management, and monitoring of osteoporosis and fractures in persons with advanced CKD or on maintenance dialysis.

Correlation of Fgf23 and Balp with Bone Mineral Density in Hemodialysis Patients

Background

Chronic kidney disease (CKD) is associated with numerous complications such as bone mineral disorder. The aim of our study was to analyze the correlation of bone turnover markers with Bone Mineral Density (BMD) measurements in Tunisian end stage renal diseases (ESRD) patients.

Methods

This study included 100 ESRD Tunisian patients. Their estimated glomerular filtration rate (eGFR) was < 15 mL × min^-1 × (1.73 m²)^-1, which requires hemodialysis. Bone-specific alkaline phosphatase (BALP) serum concentration was determined with a chemiluminescence immunoassay. Fibroblast Growth Factor 23 (FGF23) serum was assessed by Enzyme-Linked Immunosorbent Assay method. The serum levels of 25-Hydroxyvitamin D (25(OH)D), intact parathyroid hormone (iPTH) and Beta cross-laps (CTX) was measured by Electrochemiluminescence Technology. DEXA (dual-energy x-ray absorptiometry) technique was used to evaluate BMD.

Results

We observed a statistically significant negative correlation between BALP levels and total body BMD (r = -0.268; P = 0.015) particularly in femoral neck (FN) (r = -0.219; P = 0.037). BALP concentrations were negatively associated with total BMD especially in FN for patients with BMI < 30, FGF23 concentrations were also negatively correlated with BMD in lumbar spine site (LS) (r = -0.209; P = 0.046). For osteopenic patients we found an inverse correlation between 25(OH)D concentrations and BMD in LS position (r = -0.336; P = 0.038). In men group, we have also found a negative correlation between iPTH and total BMD (r = -0.326; P = 0.015). However we found a positive correlation between calcium expression and BMD in LS site (r = 0.270; P = 0.031).

Conclusions

FGF23 and BALP can predict bone loss in ESRD through their strong correlation with BMD in LS and FN sites respectively.

Abdominal aortic calcification score among several vascular calcification scores of plain radiograph is the most reliable predictor of severe coronary artery calcification in dialysis patients

Aim: Coronary artery calcification (CAC) score on computed tomography (CT) or vascular calcification (VC) scores on plain radiographs are associated with cardiovascular events and fracture. We investigated which VC score among several VC scores on plain radiographs is predictor of CAC, and whether VC scores are related with bone mineral density (BMD) in dialysis patients.

Methods: We checked several plain radiographs (hands and pelvis [HP], feet and lateral lumbar spine), BMD and multidetector CT scans of 55 patients maintaining dialysis in this cross-sectional study. We analyzed data to find predictors for severe CAC which was defined as CAC scores >400 on CT.

Results: Patients with severe CAC on CT had a higher proportion of abdominal aortic calcification (AAC) score ≥5, HP score ≥3 and feet ≥1 than those without severe CAC. The CAC score on CT was positively correlated with all VC scores on plain radiographs. The AAC and CAC scores were negatively correlated with T-scores for the BMD at the forearm and positively correlated with osteoprotegerin levels. Among several VC scores on plain radiographs, the AAC ≥5 were independently associated with severe CAC on CT.

Conclusions: Several plain radiographs evaluating VC scores, including a lateral lumbar spine view at the very least, can replace CT checking CAC score in dialysis patients. The AAC score ≥5 may not only reveal severe CAC but also give a hint of low bone mass at the forearm.

Effects of Short Term Alendronate Administration on Bone Mineral Density in Patients with Chronic Kidney Disease

Background: Osteoporosis is highly prevalent in CKD patients and is characterized by low bone mass leading to decreased bone strength. It is associated with an increased risk of fracture, thus increasing morbidity and mortality. Bisphosphonate administration decreases fracture risk in postmenopausal females with osteoporosis. There are limited studies showing effects of short term alendronate administration on BMD in predialysis osteoporotic patients with CKD.

Methods: This study was conducted on fifty adult patients with chronic kidney disease. Patients were divided into two groups. Group A consisted of seventeen patients with CKD stage 3 (eGFR 45-30 ml/min/1.73m2) and Group B comprised thirty three patients with CKD stage 4 (eGFR 30-15 ml/min/1.73m2). The study included male patients between age 18-75 years and premenopausal non pregnant females older than 18 years of age. All the patients were osteoporotic having T score < −2.5 on DEXA scan. The patients were administered 70 mg alendronate tablet once a week for 6 weeks. Renal parameters, parathyroid hormone, calcium, phosphorous and alkaline phosphatase levels were assayed at baseline for 6 months. Serum (iPTH) level (pg/ml) was measured by chemiluminescent immune assay (CLIA) method and serum 25 Hydroxy Vitamin D level (ng/ml) was measured by enzyme linked immunosorbent assay (ELISA) method. Bone Mineral Density (BMD) was measured at baseline for 6 months, by dual energy x-ray absorptiometry at lumbar spine and neck of femur and lowest values were included. The results were obtained for T score, Z score and bone mineral density (g/cm2).

Results: The BMD, T score and Z score increased in both groups after 6 months with a statistically significant difference in the treatment group. In Group A, T score, Z score and BMD (g/cm2) increased from −2.60±0.086, −2.13±0.28, and 0.80±0.008 at baseline to −2.57±0.097, −2.11±0.26 and 0.81±0.008 after six months. In Group B, the T score, Z score and BMD (g/cm2) increased from −3.17±0.24, −2.82±0.33 and 0.738±0.03 to −3.16±0.25, −2.66±0.95 and 0.743±0.03 after six months with a statistically significant difference. eGFR decreased in both groups but the difference was statistically non-significant (P>0.05). The serum iPTH levels increased after 6 months in both groups with a statistically insignificant difference. There was an increase in serum calcium and decrease in serum phosphate levels after six months, however the difference was statistically insignificant (p>0.05). The SAP values decreased in both groups after six months with a statistically insignificant difference. The main side-effect in the alendronate group was the occurrence of gastroesophageal reflux symptoms in two subjects.

Conclusion: Low-dose alendronate, administered for a limited duration, appears to be well tolerated in CKD patients. The BMD increased in both groups suggesting a bone-preserving effect of alendronate.

DEVELOPMENT OF CLINICAL RISK ASSESSMENT TOOL FOR OSTEOPOROSIS (OSTEORISKAPP) USING A SYNDROMIC APPROACH

CONTEXT

DEXA is recommended for osteoporosis screening. However, the rate of screening with DEXA is very low. Therefore, methods that can be used more easily and cost effectively are needed.

OBJECTIVE

The objective of this study is to develop a clinical risk assessment tool of osteoporosis (OSTEORISKAPP) by using syndromic approach.

DESIGN

A methodological study was performed.

SUBJECTS AND METHODS

Three hundred and fifty-six participants who are above 50 years old are participants of study and take history and physical examination. Positive likelihood ratio (LR), pre and post test probability, is calculated. A logistic regression analysis and a ROC analysis are made with the model constructed by those criteria.

RESULTS

Eighteen different clinical risk indices are diagnosed. According to LR, 4 of these criteria are minimally effective, 11 of them are weakly effective and 3 of them are medium effective criteria According to results of logistic regression analysis, back pain, waist pain, and usage of cortisone for more than 3 months, vertebra tenderness in physical examination, having dorsal kyphosis and being obese are turned out to be statistically significant in 89.9% confidence interval. AUC is found to be 0.948 and diagnostic test is found to have perfect distinction ability.

CONCLUSION

Syndromic diagnostic criteria that will be used for osteoporosis screening of population and that is cost effective, no need to refer, practical, reliable and has tried to be developed.

Assessment of bone turnover markers to predict mineral and bone disorder in men with pre-dialysis non-diabetic chronic kidney disease

BACKGROUND

Chronic kidney disease (CKD) is commonly associated with disturbances in mineral metabolism and bone disease. Bone biopsy is the gold standard in diagnosing mineral bone disorder. Hence the search for non-invasive assessment of bone health gains importance. We undertook to assess the bone health in men with stage 4 and 5 chronic kidney Disease.

METHODS

We recruited 32 male subjects with Stage 4 and 5 chronic kidney disease and 32 age-matched healthy male controls. 25-hydroxyvitamin D, intact parathyroid hormone, and bone-specific alkaline phosphatase were assayed. Bone mineral density (BMD) was estimated using dual-energy X-ray absorptiometry.

RESULTS

CKD is associated with significantly higher levels of bone-specific alkaline phosphatase and intact parathyroid hormone and lower levels of 25-hydroxyvitamin D and bone mineral density, when compared to controls. In the multivariate linear regression model, bone-specific alkaline phosphatase emerged as an independent predictor of reduced BMD. Receiver Operator Characteristic analysis for prediction of reduced BMD in CKD showed both intact parathyroid hormone and bone-specific alkaline phosphatase have significant predicting power.

CONCLUSION

The combination of bone-specific alkaline phosphatase and intact parathyroid hormone has more significant predicting power and is a more reliable index for non-invasive assessment of bone health in men with chronic kidney disease, than either marker when used alone.

Evaluation of fracture risk in chronic kidney disease

Chronic kidney disease (CKD) is associated with mineral and bone disorders (MBD) that are now considered as a syndrome. Bone fragility and a four to tenfold increased rate of skeletal fractures are often reported in CKD patients. The evaluation of the risk of these fractures in CKD patients should explore the same risk factors identified for the general population including low body weight, menopause, personal and familial history of osteoporosis, chronic inflammatory diseases, and corticosteroid therapy. The aim of this article is to provide a critical review of the tools used for the evaluation of bone loss and the risk of fracture in CKD patients, ranging from the measurement of bone mineral density (BMD), fracture risk assessment (Frax™), quantitative computed tomography (QCT), high-resolution peripheral quantitative computed tomography (HRpQTC), to circulating biomarkers of bone metabolism including vitamin D, parathyroid hormone (PTH), bone-specific alkaline phosphatase, osteocalcin, and some collagen type 1-related molecules indicators of bone remodeling.

Evaluation of three risk assessment tools in discriminating fracture status among Chinese patients undergoing hemodialysis

We evaluated three risk assessment tools, including bone mineral density (BMD) measurement by dual energy X-ray absorptiometry (DXA), osteoporosis self-assessment tool for Asians (OSTA), and fracture risk assessment tool (FRAX), for the prediction of fracture status among Chinese patients undergoing hemodialysis. All of the three assessment tools have a reasonable capability in discriminating fractures.

INTRODUCTION

Fractures are common in hemodialysis patients however insufficiently assessed. Our study aimed to assess the ability of three widely used tools [BMD, OSTA, and FRAX] to discriminate fracture status in patients with renal failure undergoing hemodialysis.

METHODS

We enrolled 136 hemodialysis patients in a tertiary teaching hospital setting. BMD was measured using DXA at the lumbar spine and the hip region. OSTA was calculated from weight and age. FRAX score was calculated based upon online availability. Discriminative abilities of BMD, OSTA, and FRAX in fracture status were analyzed by receiver operator characteristic (ROC) curves.

RESULTS

There were total 16 fractures (11.76 %) identified in 136 hemodialysis patients. BMD at any site (lumbar spine L1-L4, femoral neck, and total hip) was independently associated with fracture. Areas under the curves (AUC) of BMD (lumbar spine L1-L4, femoral neck, total hip), OSTA, FRAX1 (non-BMD model), and FRAX2 (BMD model) were 0.669 (95 % CI 0.583, 0.747), 0.708 ( 95 % CI 0.624, 0.783), 0.736 (95 % CI 0.654, 0.808), 0.686 (95 % CI 0.601, 0.763), 0.715 (95 % CI 0.631, 0.789), and 0.697 (95 % CI 0.613, 0.773), respectively. The differences of their performance were not significant.

CONCLUSIONS

All of the three risk assessment tools had the ability to discriminate fracture status among hemodialysis patients; FRAX BMD model did not improve the discriminative ability of BMD or FRAX non-BMD model alone.

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.

Inverse relationship of bone mineral density and serum level of N-terminal pro-B-type natriuretic peptide in peritoneal dialysis patients

Objective:

Chronic kidney disease is associated with decreased bone mineral density (BMD). In this study, the relationship between BMD and the fasting serum concentration of N-terminal pro-B-type natriuretic peptide (NT-pro-BNP) was evaluated in peritoneal dialysis (PD) patients.

Material and Methods:

Fasting blood samples were obtained from 52 PD patients. BMD was measured by dual energy X-ray absorptiometry of the lumbar vertebrae (L2–L4). The serum NT-pro-BNP level was measured by an electrochemiluminescence immunoassay.

Results:

Ten patients (19.2%) had osteoporosis, 23 patients (44.2%) had osteopenia, and 19 patients had normal BMD. Increased serum NT-pro-BNP (p < 0.001), advanced age (p = 0.012), decreased body mass index (p = 0.006), body height (p = 0.018), and body weight (p = 0.004) were associated with lower lumbar T-scores, but sex, menopausal status, PD modality, diabetes mellitus, and hypertension were not. Multivariate forward stepwise linear regression analysis with adjustment for age, body height, body weight, body mass index, and log-NT-pro-BNP indicated that a high serum level of log-NT-pro-BNP (R² change = 0.346; p < 0.001) and low body weight (R² change = 0.208; p < 0.001) were significantly and independently associated with poor lumbar BMD.

Conclusion:

A high serum level of NT-pro-BNP and low body weight were associated with poor BMD in PD patients.

How to predict and treat increased fracture risk in chronic kidney disease

Men and women with chronic kidney disease (CKD) are at an increased risk of fracture, and this risk increases as kidney function deteriorates. Fractures are associated with morbidity, mortality and economic costs. Despite this, there is a paucity of data regarding how to evaluate risk for fractures in CKD and how to treat high-risk patients. Evidence suggests that bone mineral density (BMD) as assessed by dual-energy X-ray absorptiometry (DXA) is associated with fractures and can also predict future fractures in predialysis (stages 1-3) patients with CKD. In the absence of considerable abnormalities in markers of mineral metabolism, treatment with antiresorptive agents in men and women with early CKD at high fracture risk may be appropriate. Of note, recent data suggest that low BMD as measured by DXA can also predict fractures in patients with more advanced CKD (stages 4, 5 and 5D). However, treatment in patients with advanced CKD requires bone biopsy, the gold standard to assess bone turnover, prior to treatment. Further research, focusing on noninvasive methods to assess fracture risk and bone turnover, together with randomized controlled trials of treatments to reduce fractures in patients at all stages of CKD, is required.

Increased risk of cardiovascular events in end-stage renal disease patients with osteoporosis: a nationwide population-based cohort study

SUMMARY

We investigated the cardiovascular disease risk and mortality in end-stage renal disease (ESRD) patients. A total of 12,535 patients with ESRD undergoing incident dialysis were enrolled, 4,153 (33.13 %) of whom had osteoporosis. The osteoporosis group was associated with a significantly higher risk of coronary artery disease, congestive heart failure, stroke, and mortality.

INTRODUCTION

In this study, we aimed to investigate the risk of cardiovascular disease and mortality in a sample of end-stage renal disease patients with osteoporosis.

METHODS

We conducted this retrospective cohort study of incident dialysis patients with and without osteoporosis to evaluate the risk of overall mortality and cardiovascular complications including stroke, coronary heart disease, and congestive heart failure between the two groups. A total of 12,535 patients with ESRD undergoing incident dialysis were enrolled, 4,153 (33.13 %) of whom had osteoporosis, from the National Health Insurance Research Database of Taiwan for the years 1998 through 2011. The osteoporosis group had more comorbidities than the group without osteoporosis including hypertension, hyperlipidemia, mental disorders, and hepatitis C infection.

RESULTS

After adjusting for age, gender, and related comorbidities, the osteoporosis group was associated with a significantly higher risk of coronary artery disease (hazard ratio (HR)=1.32, 95 % confidence interval (CI)=1.20-1.45) which was significant in both genders (women, HR=1.35, 95% CI=1.20-1.50; men HR=1.27, 95% CI=1.06-1.52) and all age groups (≤49 years HR=1.41, 95% CI=1.16-1.70; >49 years HR=1.30, 95% CI=1.16-1.45). Similar results were observed for the outcomes of congestive heart failure, stroke, and mortality.

CONCLUSIONS

The results showed that osteoporosis was significantly associated with the subsequent risk of cardiovascular events in patients with ESRD. When encountering patients with ESRD and osteoporosis, physicians should be alert to the subsequent cardiovascular risk in incident dialysis patients to prevent the subsequent occurrence of these adverse events.

Effect of serum fibroblast growth factor-23, matrix Gla protein and Fetuin-A in predicting osteoporosis in maintenance hemodialysis patients

This study is aimed at exploring the role of serum fibroblast growth factor-23 (FGF-23), matrix Gla (MGP) and Fetuin-A in the calcium-phosphate metabolism and estimate the value of serum FGF-23, MGP and Fetuin-A levels in predicting osteoporosis in maintenance hemodialysis (MHD) patients. This study included 64 patients who receive hemodialysis in our hospital. The serum FGF-23, MGP and Fetuin-A were analyzed by enzyme-linked immunosorbent assay (ELlSA). Bone mineral density (BMD) at the femoral neck was measured by dual-energy X-ray absorptiometry. The 64 patients (30 males, 34 females, 60.6 ± 11.3 years of age) received an average of 6.88 ± 2.94 years of dialysis. Body mass index (BMI), Kt/V, dialysis vintage, patient age, serum levels of FGF-23, Fetuin-A, bone isoenzyme of alkaline phosphatase (ALP-B), and calcium were different in statistical significance among the three groups of patients in terms of normal bone mass (N = 10), osteopenia (N = 24), or osteoporosis (N = 30). BMI, Kt/V, ALP-B, dialysis vintage and serum Fetuin-A level were identified as independent variables of femoral neck BMD by stepwise multiple regression analysis. The area under ROC curve showed that serum Fetuin-A was useful for identifying osteoporosis in MHD patients. The cutoff value corresponding to the highest Youden's index was serum Fetuin-A ≤ 89 μg/mL, which was defined as the optimal predictor of osteoporosis. Its sensitivity/specificity was 71%/77.8%. The incidence of osteoporosis is high in MHD patients. Serum Fetuin-A level is closely correlated with osteoporosis and it may serve as a predictor of osteoporosis.

Determinants of bone mineral density in patients on haemodialysis or peritoneal dialysis--a cross-sectional, longitudinal study

INTRODUCTION

The aim of the study was to identify biomarkers of alteration in bone mineral density (BMD) in patients on haemodialysis (HD) and peritoneal dialysis (PD).

MATERIALS AND METHODS

In a cross-sectional, longitudinal study dual-energy X-ray absorptiometry scans were performed in 146 HD-patients and 28 PD-patients. Follow-up after 14 months (mean) was conducted in 73 patients. As potential biomarkers we investigated parathyroid hormone (PTH), 25-hydroxy vitamin-D, ionised calcium, albumin, phosphate, and total alkaline phosphatases (t-ALP).

RESULTS

Both groups of dialysis patients had lower BMD in the femoral neck (BMD(neck)) (P < 0.001) and forearm (BMD(forearm)) (P < 0.001) compared to healthy controls, but comparable BMD in the lumbar spine (BMD(spine)). BMD did not differ between dialysis types, but patients ever-treated with glucocorticoids had significantly lower BMD, while patients with polycystic kidney disease had higher BMD. BMD correlated with body weight, actual age, age at initiation of dialysis, duration of dialysis and levels of PTH and t-ALP. However, t-ALP only remained associated with low BMD(spine) after adjusting for other factors (P = 0.001). In the follow-up study all patients had decreased BMD in all three locations, but only for the lumbar spine there was a significant association between BMD and the bone markers t-ALP (P = 0.009) and PTH (P = 0.013).

CONCLUSIONS

Both HD and PD patients have low BMD, and increased concentrations of t-ALP is associated BMD(spine) after adjustment, while PTH and t-ALP is associated with decrease in BMD(spine) over time. This substantiates the use of these biomarkers in both types of dialysis patients.

Bone mineral density by DXA and HR pQCT can discriminate fracture status in men and women with stages 3 to 5 chronic kidney disease

Fractures are common in chronic kidney disease (CKD). We determined if bone mineral density testing by dual energy X-ray absorptiometry (DXA) and high resolution peripheral quantitative computed tomography (HR pQCT) could discriminate fracture status in CKD patients. Both tests were able to discriminate fracture status. Further, the addition of HR pQCT measurements to DXA measurements did not improve fracture discrimination.

INTRODUCTION

The optimal method to identify individuals with CKD at high fracture risk is unknown.

METHODS

We determined if bone mineral density (BMD) by DXA and HR pQCT could discriminate fracture status in 211 adult men and women with stages 3 to 5 CKD, attending predialysis clinics in Toronto Canada, using logistic regression. Results are expressed as the odds ratio (OR) of fracture (prevalent vertebral and/or low trauma since age 40 years) per standard deviation decrease in the predictor adjusted for age, weight, sex, and CKD stage. We constructed receiver operating characteristic curves to examine the discriminative ability of BMD measures for fracture.

RESULTS

Most participants were Caucasian men with a mean age of 63.3 ± 15.5 years. There were 77 fractures in 74 participants. Decreases in BMD were associated with increased fracture risk: OR = 1.56 (95% confidence interval (CI), 1.41 to 1.71) for BMD by DXA at the ultradistal radius, and OR = 1.24 (95% CI, 1.12 to 1.36) for cortical area by HR pQCT. Further, while both tests were able to discriminate fracture status, the addition of HR pQCT measures to BMD by DXA did not improve fracture discrimination ability.

CONCLUSIONS

Among CKD patients not yet requiring renal replacement therapy, BMD by DXA is able to discriminate fracture status.

Bone and kidney disease: diagnostic and therapeutic implications

Fractures are common in patients with chronic kidney disease (CKD), but the diagnosis and treatment of bone disease in CKD are difficult due to the multiple etiologies of bone disease in these patients. Noninvasive imaging, including bone mineral density by dual energy x-ray absorptiometry, can be useful in diagnosing osteoporosis in predialysis CKD; however, consensus on the diagnosis of osteoporosis among those with advanced CKD-particularly stage 5 CKD patients on dialysis-is lacking. Treatments approved for osteoporosis in postmenopausal women may be used in patients with stage 1 to 3 CKD. Furthermore, post-hoc analyses show efficacy and safety of oral bisphosphonates, raloxifene, and denosumab in stage 4 CKD for short-term treatment. However, treatment decisions are more difficult in stage 5 CKD. Bone biopsy may be required, and most treatments, if used, would be off label. Overall, the diagnosis and treatment of bone disease in patients with CKD require further research.

Determination of bone architecture and strength in men and women with stage 5 chronic kidney disease

Fractures are common in men and women with dialysis-dependent chronic kidney disease (stage 5D CKD) and are associated with substantial morbidity and mortality. The clinical utility of dual energy X-ray absorptiometry (DXA) and peripheral quantitative computed tomography (pQCT), noninvasive measures of bone mass and architecture that reflect fracture risk in healthy men and women, is uncertain in patients with stage 5D CKD. This review will outline the epidemiology and etiology of fractures and will summarize the published data that describe the association between fractures, bone mass, and bone strength in stage 5D CKD. Fracture risk assessment in stage 5D CKD is complicated as the etiology of fractures is multifactorial and includes impairments in bone quantity and quality. Cross-sectional data suggest that bone density by DXA is lower among stage 5D CKD patients with fractures compared with those without, and that this may be particularly true at cortical sites. However, DXA does not capture bone microarchitecture and cannot differentiate between cortical and trabecular bone. Some, but not all studies, that measure cortical and trabecular bone by pQCT in stage 5D CKD, demonstrate a preferential decrease in cortical bone; however, these studies are limited by small sample sizes and cross-sectional study design. No studies have reported on longitudinal relationships between bone architecture, strength, and incident fractures in patients with stage 5D CKD. Further research is needed to identify noninvasive measures of bone strength that can be used for fracture risk assessment in stage 5D CKD.

Bone mineral density and fracture risk in older individuals with CKD

BACKGROUND AND OBJECTIVES

Kidney Disease Improving Global Outcomes guidelines recommend against bone mineral density (BMD) screening in CKD patients with mineral bone disease, due to a lack of association of BMD with fractures in cross-sectional studies in CKD. We assessed whether BMD is associated with fractures in participants with and without CKD in the Health, Aging, and Body Composition study, a prospective study of well functioning older individuals.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Hip BMD was measured by dual-energy x-ray absorptiometry. Osteoporosis was defined as a femoral neck BMD (FNBMD) T score below -2.5 and CKD as an estimated GFR <60 ml/min per 1.73 m(2). The association of BMD with incident nonspine, fragility fractures to study year 11 was analyzed using Cox proportional hazards analyses, adjusting for age, race, sex, body mass index, hyperparathyroidism, low vitamin D level, and CKD. Interaction terms were used to assess whether the association of BMD with fracture differed in those with and without CKD.

RESULTS

There were 384 incident fractures in 2754 individuals (mean age 73.6 years). Lower FNBMD was associated with greater fracture, regardless of CKD status. After adjustment, the hazard ratios (95% confidence intervals) were 2.74 (1.99, 3.77) and 2.15 (1.80, 2.57) per lower SD FNBMD for those with and without CKD, respectively (interaction P=0.68), and 2.10 (1.23, 3.59) and 1.63 (1.18, 2.23) among those with osteoporosis in patients with and without CKD, respectively (interaction P=0.75).

CONCLUSIONS

BMD provides information on risk for fracture in older individuals with or without moderate CKD.

Fracture risk assessment in patients with chronic kidney disease

Fractures are common in patients with chronic kidney disease (CKD) and associated with substantially high morbidity and mortality. Bone mass measurements are commonly used to assess fracture risk in the general population, but the utility of these measurements in patients with CKD, and specifically among those on hemodialysis, is unclear. This review will outline the epidemiology and etiology of fractures in patients with CKD with a particular emphasis on men and women on hemodialysis. As well, we will summarize the published data, which describes the association between risk factors for fracture (including bone mass measurements, biochemical markers of mineral metabolism, and muscle strength) and fractures in patients with CKD. Patients with CKD suffer from fractures due to impairments in bone quantity, bone quality, and abnormalities of neuromuscular function. There is a paucity of evidence on the associations between bone quality, bone turnover markers, neuromuscular function, and fractures in patients with CKD. Furthermore, the complex etiology of fractures combined with the technical limitations of bone mineral density testing, both by dual energy X-ray absorptiometry (DXA) and by peripheral quantitative tomography (pQCT), limits the clinical utility of bone mass measurements for fracture prediction in CKD; this is particularly true among patients with stages 4 and 5 CKD. Further prospective studies to identify noninvasive measures of bone strength that can be used for fracture risk assessment are needed.

[Is there a place for the physical activity in the prevention of the fractures of chronic kidney disease patients?]

The risk of non-traumatic fractures is greatly increased in kidney disease patients and well demonstrated in dialysis patients. If osteoporosis plays a major role in the general population, in chronic kidney disease renal osteodystrophy is associated with neurological and muscular disorders, which probably worsen the risk. The decrease in physical activity is a factor contributing to the loss of bone mass and the initiation of a rehabilitation program improves the prognosis. Despite the association between chronic renal disease and sedentary lifestyle, the relationship between physical inactivity and bones in dialysis patients and the effect of increased activity programs, are not well documented in the literature.

Bone microarchitecture in hemodialysis patients assessed by HR-pQCT

BACKGROUND AND OBJECTIVES

Dialysis patients are at high risk for low-trauma bone fracture. Bone density measurements using dual-energy x-ray absorptiometry (DXA) do not reliably differentiate between patients with and without fractures. The aim of this study was to identify differences in bone microarchitecture between patients with and without a history of fracture using high-resolution peripheral quantitative computed tomography (HR-pQCT).

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

Seventy-four prevalent hemodialysis patients were recruited for measurements of areal bone mineral density (aBMD) by DXA and bone microarchitecture by HR-pQCT. Patients with a history of trauma-related fracture were excluded. Forty healthy volunteers served as controls. Blood levels of parathyroid hormone, vitamin D, and markers of bone turnover were determined.

RESULTS

Dialysis patients, particularly women, had markedly impaired bone microarchitecture. Patients with fractures had significantly reduced cortical and trabecular microarchitecture compared with patients without fractures. aBMD tended to be lower in patients with fractures, but differences were statistically not significant. The strongest determinant of fracture was the HR-pQCT-measured trabecular density of the tibia, which also had the highest discriminatory power to differentiate patients according to fracture status. Radial DXA had a lower discriminatory power than trabecular density.

CONCLUSIONS

Bone microarchitecture is severely impaired in dialysis patients and even more so in patients with a history of fracture. HR-pQCT can identify dialysis patients with a history of low-trauma fracture.

Diagnostic usefulness of bone mineral density and biochemical markers of bone turnover in predicting fracture in CKD stage 5D patients--a single-center cohort study

BACKGROUND

In chronic kidney disease stage 5D, diagnostic usefulness of bone mineral density (BMD) in predicting fracture has not been established because of variable results in previous studies. The reason for this may be the heterogeneity of underlying pathogenesis of the fracture.

METHODS

BMD was measured annually and serum biochemistry monthly for 485 hemodialyzed patients from April 2003 to March 2008, and all fractures were recorded.

RESULTS

Forty-six new episodes of any type of fracture and 29 cases of prevalent spine fracture were recorded. Serum bone-specific alkaline phosphatase (b-AP) was a very useful surrogate marker for any type of incident fracture risk [area under curve (AUC) = 0.766, P < 0.0001]. A significantly greater risk of any type of incident fracture was associated with parathyroid hormone (PTH) levels either <150 pg/mL [hazard ratio (HR) = 3.47, P < 0.01] or >300 pg/mL (HR = 5.88, P < 0.0001) compared with 150-300 pg/mL. Receiver-operating characteristic analysis demonstrated a significant predictive power for incident of any type of fracture by BMD at the total hip (AUC = 0.760, P < 0.0001) and other hip regions in females in the lower PTH group (PTH < 204 pg/mL). BMDs at every site but whole body or lumbar spine had significant power to discriminate prevalent spine fracture regardless of gender or PTH.

CONCLUSIONS

Hemodialyzed patients with low or high PTH or increased b-AP had a high fracture risk. BMD by Dual Energy X-ray Absorptiometry (DEXA), especially at the total hip region, was useful to predict any type of incident of fracture for females with low PTH or to discriminate prevalent spine fracture for every patient.

The association of serum ionized calcium and vitamin D with adult cognitive performance

BACKGROUND

High serum calcium levels have been associated with cognitive decline in older adults. These associations have not been studied in younger adults. The possible association of vitamin D with cognitive function, independent of calcium, is unknown.

METHODS

A cross-sectional study of associations of serum ionized calcium and 25-hydroxyvitamin D levels with cognitive function in younger adults (20-59 years) and older adults (60-90 years) was conducted using data from the US third National Health and Nutrition Examination Survey (NHANES III).

RESULTS

Neither serum ionized calcium nor 25-hydroxyvitamin D was associated with cognitive function in either age group. For example, the confounder-adjusted mean difference in reaction time in young adults was 0.00 (95% confidence interval = -0.07 to 0.06) per 1 SD calcium.

CONCLUSION

Our results do not support an important role for calcium or vitamin D in cognitive performance in adults.

Bone mass measurements in men and women with chronic kidney disease

PURPOSE OF REVIEW

Fractures are common in patients with chronic kidney disease (CKD) and are associated with substantial morbidity and mortality. Bone mass measurements are commonly used to assess fracture risk in the general population, but the utility of these measurements in patients with CKD is unclear.

RECENT FINDINGS

This review will outline the epidemiology and etiology of fractures in patients with CKD. Also, we will summarize the published data that describe the association between bone mass measurements and fracture in patients with CKD.

SUMMARY

Patients with CKD suffer from fractures due to impairments in bone quantity, bone quality, and abnormalities of neuromuscular function. The complex etiology of fractures combined with the technical limitations of bone mineral density testing, both by dual energy X-ray absorptiometry and by peripheral quantitative computed tomography, limits the clinical utility of bone mass measurements for fracture prediction in CKD; this is particularly true among patients with stages 4 and 5 CKD. As such, clinicians should not routinely order bone mineral density testing in patients with CKD. Further research, to determine whether bone mineral density together with other noninvasive measures to assess bone strength can predict fracture, is needed.

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

INTRODUCTION

Chronic kidney disease (CKD) and osteoporosis are important health problems. There is an interrelationship between osteoporosis and CKD. Bone densitometry is the "gold" standard in the diagnosis of osteoporosis. Unfortunately, there are some problems with the interpretation of bone densitometry in CKD patients. The goal of this study was to determine bone mineral density (BMD) in CKD patients, to assess the difference between genders and different sites of bone densitometry correlation between BMD and laboratory parameters, and to assess the most optimal measuring site.

METHODS

We studied 134 hemodialysis (HD) patients (62 females, 72 males). The mean age was 56.4+/-12.4 years and the mean duration of HD was 54.4+/-60 months. BMD of the lumbar spine (posterior-anterior projection and lateral projection), hip (femoral neck, trochanter, intertrochanter, total femur, the Ward's Triangle), and forearm (ultradistal (UD), middistal (MID), distal third portion, and total forearm) was measured using dual X-ray absorptiometry (DXA) (Hologic Delphi apparatus). Values were expressed as BMD, T-score, and Z-score.

RESULTS

Females had lower values of BMD in all measurement points. There were no significant differences in T- and Z-scores of forearm between males and females. Age was in a positive correlation with lumbar spine BMD in males and females. There was a negative correlation with neck and forearm BMD in both groups. Serum parathyroid hormone (PTH) was also in negative correlation with hip and forearm BMD in both groups. The best correlation of BMD in different sites was between forearm and neck.

CONCLUSION

BMD data in CKD patients should be interpreted with caution and appendicular skeletal sites should be included in the evaluation.

Femoral bone mineral density reflects histologically determined cortical bone volume in hemodialysis patients

We evaluated the associations between dual energy X-ray absorptiometry (DXA) and histologically determined cancellous and cortical bone volume by controlling for vascular calcifications and demographic variables in hemodialysis (HD) patients. Femoral bone mineral density (f-BMD) was associated with cortical porosity.

INTRODUCTION

Assessment of bone mass in chronic kidney disease patients is of clinical importance because of the association between low bone volume, fractures, and vascular calcifications. DXA is used for noninvasive assessment of bone mass whereby vertebral results reflect mainly cancellous bone and femoral results reflect mainly cortical bone. Bone histology allows direct measurements of cancellous and cortical bone volume. The present study evaluates the association between DXA and histologically determined cancellous and cortical bone volumes in HD patients.

METHODS

In 38 HD patients, DXA was performed for assessment of bone mass, anterior iliac crest bone biopsies for bone volume, and multislice computed tomography for vascular calcifications.

RESULTS

While lumbar bone mineral density (l-BMD) by DXA was not associated with histologically measured cancellous bone volume, coronary Agatson score showed a borderline statistically significant association (P = 0.055). When controlled for age and dialysis duration, f-BMD by DXA was associated with cortical porosity determined by histology (P = 0.005).

CONCLUSIONS

The usefulness of l-BMD for predicting bone volume is limited most probably because of interference by soft tissue calcifications. In contrast, f-BMD shows significant association with cortical porosity.

Vitamin D receptor gene, biochemical bone markers and bone mineral density in Mexican women on dialysis

BACKGROUND

The influence of the Bsm1 polymorphism of the vitamin D receptor (VDR) gene on mineral and bone disorders in chronic kidney disease (CKD) is still under discussion. The aim of this study was to analyse the relationship between VDR polymorphism, bone mineral density (BMD), biochemical bone markers and clinical factors in women on peritoneal dialysis (PD) and haemodialysis (HD).

METHODS

In a cross-sectional study, 197 women (42 +/- 10 years; 25% with diabetes mellitus (DM); body mass index (BMI) 25.26 +/- 4.77 kg/m(2)) treated by PD (72%) or HD (28%) underwent measurements of BMD (measured at the calcaneus by quantitative ultrasound; expressed as T- and Z-scores) and plasma total calcium (tCa), intact parathyroid hormone 1-84 (iPTH), phosphorus, albumin, glucose, osteoprotegerin (OPG), fetuin-A, intact osteocalcin-49 and N-MID fragment 1-43 aa (N-MID osteocalcin) N-terminal propeptide of type 1 procollagen (PINP) and C-terminal telopeptide-beta aspartic acid (BCL). DNA was extracted from peripheral blood. PCR products were digested with Bsm1 to analyse VDR polymorphism.

RESULTS

The Z-score of BMD was -1.1 +/- 1.03. According to the values of osteopenia (T-score = -1.0), patients with higher BMD were younger, had lower frequency of amenorrhoea and diabetes and had higher serum creatinine and fetuin levels as well as lower levels of PINP. In a stepwise multivariate logistics analysis, osteopenia was associated with presence of genotype BB+Bb (OR = 3.26, P < or = 0.003) and age (OR = 0.95, P = 0.050). According to the B allele, bb: n = 126 (64%) and BB+Bb: n = 71(36%), group bb had significantly higher mean Z-scores (-0.97 +/- 1.0 vs -1.3+/-0.92; P < or = 0.021).

CONCLUSIONS

The high frequency of osteopenia observed in female CKD patients on dialysis is associated with age and genetic predisposition as revealed by its association to the Bsm1 VDR polymorphism.

Bone mineral density and parathyroid function in patients on maintenance hemodialysis

BACKGROUND

The relationship between parathyroid function, an important determinant of bone turnover, and bone mineral density (BMD) in patients with chronic kidney disease is not fully understood. We wanted to analyze the association between BMD and parathyroid function in hemodialysis patients in details.

METHODS

In a cross-sectional design, data from 270 patients (age 55 ± 15 years, 60% men, all Caucasian) on maintenance hemodialysis were analyzed. All patients underwent dual energy X-ray absorptiometry of the lumbar spine (LS), femoral neck (FN) and distal radius (DR). In addition to routine laboratory tests, blood samples were collected for iPTH, serum markers of bone metabolism (alkaline phosphatase, type I collagen crosslinked-C-telopeptide) and 25OH vitamin D.

RESULTS

Based on Z-scores, bone mineral density was moderately reduced only at the femoral neck in the total cohort. The average Z-score of the "low PTH" group (iPTH < 100 pg/ml) was not different from the Z-score of patients with iPTH in the "target range" (100-300 pg/ml) at any measurement site. While iPTH was negatively correlated with BMD at all measurement sites in patients with iPTH > 100 pg/ml (rho = -0.255, -0.278 and -0.251 for LS, FN and DR, respectively, P < 0.001 for all), BMD was independent of iPTH in patients with iPTH < 100 pg/ml. Furthermore, iPTH was not associated with serum markers of bone metabolism, but these markers were negatively correlated with BMD in the "low PTH" group.

CONCLUSIONS

Low PTH levels are not associated with low BMD in patients with end-stage kidney disease. Furthermore, bone metabolism seems to be independent of iPTH in patients with relative hypoparathyroidism likely reflecting skeletal resistance to PTH.

Optimizing bone health in chronic kidney disease

Phosphocalcic metabolism disorders often complicate chronic kidney disease (CKD) and worsen as kidney function declines, with a consequence on bone structural integrity. The risk of fracture exceeds that of the normal population in both patients with pre-dialysis CKD and end-stage renal disease (ESRD). The increasing incidence of CKD, the high mortality rate induced by hip fracture, the decreased quality of life and economic burden of fragility fracture make the renal bone disorders a major problem of public health around the world. Optimizing bone health in CKD patients should be a priority. Bone biopsy is invasive. Dual-energy X-ray absorptiometry, commonly used to screen individuals at risk of fragility fracture in the general population, is not adequate to assess advanced CKD because it does not discriminate fracture status in this population. New non-invasive three-dimensional high-resolution imaging techniques, distinguishing trabecular and cortical bone, appear to be promising in the assessment of bone strength and might improve bone fracture prediction in this population. Therapeutic intervention in the chronic kidney disease-mineral and bone disorders (CKD-MBD) should begin early in the course of CKD to maintain serum concentration of biological parameters involved in mineral metabolism in the normal recommended ranges, prevent the development of parathyroid hyperplasia, prevent extra-skeletal calcifications and preserve skeletal health. In this paper, we review studies of mineral and bone disorders in patients with CKD and ESRD, the utility of current techniques to assess bone health and the preventive and therapeutic strategies for managing CKD-MBD.

Outcomes associated with serum calcium level in men with non-dialysis-dependent chronic kidney disease

BACKGROUND AND OBJECTIVES

Elevated serum calcium has been associated with increased mortality in dialysis patients, but it is unclear whether the same is true in non-dialysis-dependent (NDD) chronic kidney disease (CKD). Outcomes associated with low serum calcium are also not well-characterized.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We examined associations of baseline, time-varying, and time-averaged serum calcium with all-cause mortality in a historic prospective cohort of 1243 men with moderate and advanced NDD CKD by using Cox models.

RESULTS

The association of serum calcium with mortality varied according to the applied statistical models. Higher baseline calcium and time-averaged calcium were associated with higher mortality (multivariable adjusted hazard ratio (95% confidence interval): 1.31 (1.13, 1.53); P < 0.001 for a baseline calcium 1 mg/dl higher). However, in time-varying analyses, lower calcium levels were associated with increased mortality.

CONCLUSIONS

Higher serum calcium is associated with increased long-term mortality (as reflected by the baseline and time-averaged models), and lower serum calcium is associated with increased short-term mortality (as reflected by the time-varying models) in patients with NDD CKD. Clinical trials are warranted to determine whether maintaining normal serum calcium can improve outcomes in these patients.

Decreased bone mineral density of femur in patients with cervical cancer

AIMS

We compared the bone mineral density (BMD) of spinal bone and the femur between patients with cervical cancer and a control group.

METHODS

We retrospectively analyzed the BMD of spinal bone and the femur in 40 patients with cervical cancer and 72 control women. The control women were patients treated with surgery for benign disease.

RESULTS

Age, height, bodyweight and body mass index were not significantly different between the two groups. Total femoral BMD in patients with cervical cancer was significantly lower (P = 0.006) than that of control women. In multiple regression analysis, the bodyweight of patients with cervical cancer was a statistically significant predictor positively correlated with the BMD of the total femur.

CONCLUSION

The results suggest that patients with cervical cancer have low bone mass, especially in the femur, and an increased risk of developing osteoporosis.

Factors associated with low bone mass in the hemodialysis patients--a cross-sectional correlation study

BACKGROUND

Low bone mass is common in end-stage renal disease patients, especially those undergoing hemodialysis. It can lead to serious bone health problems such as fragility fractures. The purpose of this study is to investigate the risk factors of low bone mass in the hemodialysis patients.

METHODS

Sixty-three subjects on hemodialysis for at least 6 months were recruited from a single center for this cross-sectional study. We collected data by questionnaire survey and medical records review. All subjects underwent a bone mineral density (BMD) assay with dual-energy x-ray absorptiometry at the lumbar spine and right hip. Data were statistically analyzed by means of descriptive analysis, independent t test and one way analysis of variance for continuous variables, Pearson product-moment correlation to explore the correlated factors of BMD, and stepwise multiple linear regression to identify the predictors of low bone mass.

RESULTS

Using WHO criteria as a cutoff point, fifty-one subjects (81%) had a T-score lower than -1, of them 8 subjects (13%) had osteoporosis with the femoral neck most commonly affected. Regarding risk factors, age, serum alkaline phosphatase (ALP) level, and intact parathyroid hormone (iPTH) level had significant negative correlations with the femoral neck and lumbar spine BMD. On the other hand, serum albumin level, effective exercise time, and body weight (BW) had significant positive correlations with the femoral neck and lumbar spine BMD. Age, effective exercise time, and serum albumin level significantly predicted the femoral neck BMD (R(2) x 0.25), whereas BW and the ALP level significantly predicted the lumbar spine BMD (R(2) x 0.20).

CONCLUSION

This study showed that advanced age, low BW, low serum albumin level, and high ALP and iPTH levels were associated with a low bone mass in the hemodialysis patients. We suggest that regular monitoring of the femoral neck BMD, maintaining an adequate serum albumin level and BW, and undertaking an exercise program are important to improve bone health in the patients undergoing hemodialysis.

Low bone volume--a risk factor for coronary calcifications in hemodialysis patients

BACKGROUND AND OBJECTIVES

There is increasing evidence that altered bone metabolism is associated with cardiovascular calcifications in patients with stage 5 chronic kidney disease on hemodialysis (HD). This study was conducted to evaluate the association between bone volume, turnover, and coronary calcifications in HD patients.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In a cross-sectional study, bone biopsies and multislice computed tomography were performed in 38 HD patients. Bone volume/total volume, activation frequency, and bone formation rate/bone surface were determined by histomorphometry and coronary calcifications were quantified by Agatston scores.

RESULTS

Prevalence of low bone turnover was 50% and of low bone volume was 16%. Among the studied traditional cardiovascular risk factors, only age was found to be associated with coronary calcifications. Lower bone volume was a significant risk factor for coronary calcifications during early years of HD, whereas this effect was not observed in patients with dialysis duration >6 yr. Histomorphometric parameters of bone turnover were not associated with coronary calcifications.

CONCLUSIONS

Low bone volume is associated with increased coronary calcifications in patients on HD.

The effect of peritoneal dialysate on DXA bone densitometry results in patients with end-stage renal disease

The bone mineral density of patients undergoing peritoneal dialysis (PD) is low compared to a healthy population. No studies have been conducted to investigate whether the presence of peritoneal dialysate affects dual-energy X-ray absorptiometry (DXA) results. We hypothesized that the presence of peritoneal dialysate would not affect the measurement of bone mineral density (BMD) or bone mineral content (BMC) in the spine. Thirty patients on PD had DXA scans of the lumbar spine and hip completed before and after the drainage of peritoneal dialysate. A paired t-test was used to compare the difference in area, BMC, and BMD before and after drainage of dialysate. A significant difference was found in the BMC of the spine before and after the drainage of dialyzate. We recommend that peritoneal dialyzate be removed prior to scanning patients on PD and that densitometry technologists should be observant about the presence of peritoneal dialysate.

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.

Osteoporosis in the elderly with chronic kidney disease

Considering the aging dialysis population of today, increasing our knowledge about the nature, diagnosis and the treatment of bone mineral density (BMD) problems in end-stage renal disease (ESRD) patients deserves more attention. Osteoporosis is basicly defined as a decrease in bone mass. Large epidemiological studies in general population have identified several risk factors for osteoporosis including advancing age, female gender, white race, decreased calcium intake, gastric acid suppression therapy, sedentary lifestyle, premature loss of gonadal function, decreased estrogen secretion, thin body habitus, decreased physical activity, cigarette smoking, alcohol abuse, excess glucocorticoid exposure, and possibly some genetic factors. Osteoporosis in ESRD patients is only a part of a wider spectrum of metabolic bone problems, namely uremic osteodystrophy. Therefore, its diagnosis, management and follow-up may differ from the general population and an individualization of diagnosis and definition for dialysis population may be necessary. However, standard diagnostic tools such as dual energy X-ray absorptiometry (DEXA) have been widely used for the assessment of bone mineral deficiency status in ESRD patients. Regardless of the methods, most of the studies are in concordance with a reduced BMD in HD and PD patients. Dialysis patients are known to be at increased risk for low-trauma fractures. Thinning of cortical bone, which is responsible for the largest contribution toward reduced bone mineral content in chronic renal failure results in increased fracture risk. In either normal population and dialysis patients, fracture risk is increased with age. But in dialysis patients, besides age, several other factors may also affect the degree of bone mineral deficiency, and age-BMD relationship may be blunted. Female sex, in hemodialysis patients is negatively associated with total hip BMD. While several studies have been unable to demonstrate any association between BMD and PTH levels, larger body size has been shown to have a significant positive effect on BMD in both hemodialysis and peritoneal dialysis patients. Although they have been used in small groups of chronic kidney disease (CKD) and ESRD patients, because of their potential nephrotoxicity and hypocalcemic effects, use of biphosphonates in renal patients is questionable. Currently, bone biopsy, in order to exclude adynamic bone disease is recommended before beginning treatment with bisphosphonates in chronic kidney disease and dialysis patients.

25-Hydroxyvitamin D deficiency and diabetes predict reduced BMD in patients with chronic kidney disease

In this study of 242 patients with renal failure, women, patients with diabetes, and patients on peritoneal dialysis had the highest risk of 25-hydroxyvitamin D deficiency. Levels correlated positively to BMD Z scores, and hip BMD was inversely related to prevalent fracture. Increasing 25-hydroxyvitamin D levels may benefit these patients.

INTRODUCTION

25-Hydroxyvitamin D deficiency (<37 nM) is common in patients with chronic kidney disease (CKD) stage 5 (glomerular filtration rate < 15 ml/min/1.73 m(2) or on dialysis), but it is unclear if this deficiency is associated with bone disease and if supplementation is warranted.

MATERIALS AND METHODS

Blood samples were collected on 242 patients with CKD stage 5 caused by type 1 diabetes (33%), type 2 diabetes (2%), and other causes (65%), who were about to undergo kidney or kidney pancreas transplantation. Prevalent spinal fracture was assessed by X-ray and BMD by DXA.

RESULTS

25-Hydroxyvitamin D deficiency was present in 28% of patients with diabetes versus 12% without (p < 0.0001). Patients on peritoneal dialysis (PD) had lower levels of 25-hydroxyvitamin D than patients on hemodialysis (HD; 49 +/- 26 versus 77 +/- 34 nM; p < 0.0001), and women had lower levels than men (51 +/- 25 versus 77 +/- 35 pM; p < 0.0001). BMD Z scores were within 1 SD of the mean at all sites, except in patients with diabetes (femoral neck Z score, -1.07 +/- 1.2; p < 0.0001) and patients who had undergone parathyroidectomy (lumbar spine Z score, 1.03 +/- 1.34, femoral neck Z score, 1.24 +/- 1.35; p < 0.001 and p < 0.0001, respectively). In multiple stepwise linear regression analysis, levels of 25-hydroxyvitamin D correlated positively and intact PTH (iPTH) correlated negatively to Z scores at the lumbar spine and wrist. Time on dialysis correlated positively to Z scores at the femoral neck and lumbar spine. Diabetes and serum alkaline phosphatase levels correlated negatively with Z scores at the femoral neck. Lower femoral neck BMD was associated with an increased prevalence of vertebral fracture and fragility fracture at any site (p = 0.03 and p < 0.03, respectively).

CONCLUSIONS

This study of patients with CKD stage 5 identifies women, patients with diabetes, and patients on PD as being at particular risk of 25-hydroxyvitamin D deficiency. We describe positive associations of 25-hydroxyvitamin D levels and BMD Z scores and an association between femoral neck BMD and fragility fracture at any site. Treatment to improve 25-hydroxyvitamin D levels may benefit these patients.