Effect of ascites on bone density measurement in cirrhosis

Lumbar Spine Densitometry in People with Spinal Cord Injury: Investigation of Potential Sources of Errors

PURPOSE

People with spinal cord injury (SCI) experience a considerable loss of bone after the injury. Lumbar spine (LS) bone mineral density (BMD) has been reported to be within the normal range, or even higher when assessed with DXA, in people with SCI; hence, it has been hypothesized that sources of error may spuriously increase LS BMD. The aim of this study was to describe the frequency of potential sources of error that may alter LS BMD measurement in a cohort of individuals with chronic SCI at baseline and over a 2-year period.

METHODS

We analyzed baseline and 2-year follow up DXA scans (Hologic Discovery QDR 4500, Hologic Inc., MA, USA) previously performed from a cohort of males and females with chronic SCI. Two physicians independently reviewed each scan, commented on whether the scan was appropriate for BMD analysis, should be re-analyzed, or be removed from the dataset, and reported on the presence of potential sources of error in LS BMD measurement.

RESULTS

We reviewed 115 lumbar spine DXA scans from 58 participants, and 107 (93.0 %) scans from 52 participants presented at least one potential source of error. At baseline, the average number of potential sources of error per scan was 5.5 ± 1.7 and 5.7 ± 1.5 according to rater 1 and rater 2, respectively. Follow-up scans presented an average of 5.6 ± 1.6 and 5.7 ± 1.4 potential sources of error according to rater 1 and rater 2, respectively. Facet sclerosis, osteophytes and difficulty in detecting bone edges were the most prevalent sources of error.

CONCLUSION

The high frequency of potential sources of error is consistent with current recommendations against the use of LS BMD for fracture risk assessment in people with SCI.

Nutrition in Chronic Liver Disease: Consensus Statement of the Indian National Association for Study of the Liver

Malnutrition and sarcopenia are common in patients with chronic liver disease and are associated with increased risk of decompensation, infections, wait-list mortality and poorer outcomes after liver transplantation. Assessment of nutritional status and management of malnutrition are therefore essential to improve outcomes in patients with chronic liver disease. This consensus statement of the Indian National Association for Study of the Liver provides a comprehensive review of nutrition in chronic liver disease and gives recommendations for nutritional screening and treatment in specific clinical scenarios of malnutrition in cirrhosis in adults as well as children with chronic liver disease and metabolic disorders.

Chronic Liver Disease and the Risk of Osteoporotic Fractures: A Meta-Analysis

Introduction

Chronic liver disease (CLD) causes more than 1 million deaths every year and remains a pandemic in the last decade affecting more than 600,000 patients in the United States. Previous studies found patients with CLD had increased risk of osteoporosis, so fractures were inferred to be complications of this condition. The aim of this meta-analysis is to summarize the best evidence that correlates CLD patients and the risk to develop osteoporotic fractures versus control patients without CLD.

Methods

A review of the literature using MEDLINE and EMBASE database was performed during December 2017. We included cross-sectional and cohort studies that reported relative risks (RR), odds ratios (OR) and hazard ratios (HR) comparing the risk of developing osteoporotic fractures among patients with CLD versus patients without CLD. Pooled OR and 95% confidence interval (CI) were calculated using generic inverse- variance method. The Newcastle-Ottawa scale was used to determine the quality of the studies. Effect estimates from the individual study were extracted and combined using the random-effect, generic inverse variance method of DerSimonian and Laird. 

Results

After the review of the literature, seven studies fulfilled the eligibility criteria established during the analysis. Significant association was found between CLD and osteoporotic fractures with a pooled OR of 2.13 (95% CI, 1.79 - 2.52). High heterogeneity among the studies was found (I2=88.5). No publication bias was found using Egger regression test (p=0.44).

Conclusion

We found a significant association between CLD and the risk of developing osteoporotic fractures. The calculated risk was 2.13 times higher for patients with CLD when compared with controls. The results showed high heterogeneity but no publication bias. More prospective studies are needed to fully understand the mechanisms involved in loss of bone density and osteoporotic fractures in order to improve the morbidity associated with this disease. 

Quality in dual-energy X-ray absorptiometry scans

Dual-energy X-ray absorptiometry (DXA) is the gold standard for measuring bone mineral density (BMD), making the diagnosis of osteoporosis, and for monitoring changes in BMD over time. DXA data are also used in the determination of fracture risk. Procedural steps in DXA scanning can be broken down into scan acquisition, analysis, interpretation, and reporting. Careful attention to quality control pertaining to these procedural steps should theoretically be beneficial in patient management. Inattention to procedural steps and errors that may occur at each step has the possibility of providing information that would inform inappropriate clinical decisions, generating unnecessary healthcare expenses and ultimately causing avoidable harm to patients. This article reviews errors in DXA scanning that affect trueness and precision related to the machine, the patient, and the technologist and reviews articles which document problems with DXA quality in clinical and research settings. An understanding of DXA errors is critical for DXA quality; programs such as certification of DXA technologists and interpreters help in assuring quality bone densitometry. As DXA errors are common, pay for performance requiring DXA technologists and interpreters to be certified and follow quality indicators is indicated.

Diagnosis and Management of Cirrhosis-Related Osteoporosis

Management of cirrhosis complications has greatly improved, increasing survival and quality of life of the patients. Despite that, some of these complications are still overlooked and scarcely treated, particularly those that are not related to the liver. This is the case of osteoporosis, the only cirrhosis complication that is not solved after liver transplantation, because bone loss often increases after immunosuppressant therapy. In this review, the definitions of bone conditions in cirrhotic patients are analyzed, focusing on the more common ones and on those that have the largest impact on this population. Risk factors, physiopathology, diagnosis, screening strategies, and treatment of osteoporosis in cirrhotic patients are discussed, presenting the more striking data on this issue. Therapies used for particular conditions, such as primary biliary cirrhosis and liver transplantation, are also presented.

Bone health and vitamin D status in alcoholic liver disease

Alcohol consumption is harmful to many organs and tissues, including bones, and it leads to osteoporosis. Hepatic osteodystrophy is abnormal bone metabolism that has been defined in patients with chronic liver disease (CLD), including osteopenia, osteoporosis, and osteomalacia. Decreased bone density in patients with CLD results from decreased bone formation or increased bone resorption. The prevalence of osteopenia in alcoholic liver disease (ALD) patients is between 34 % and 48 %, and the prevalence of osteoporosis is between 11 % and 36 %. Cirrhosis is also a risk factor for osteoporosis. The liver has an important role in vitamin D metabolism. Ninety percent of patients with alcoholic liver cirrhosis have vitamin D inadequacy (<80 nmol/L). The lowest serum vitamin D levels were observed in patients with Child-Pugh class C. Bone densitometry is used for the definitive diagnosis of osteoporosis in ALD. There are no specific controlled clinical studies on the treatment of osteoporosis in patients with ALD. Alcohol cessation and abstinence are principal for the prevention and treatment of osteoporosis in ALD patients, and the progression of osteopenia can be stopped in this way. Calcium and vitamin D supplementation is recommended, and associated nutritional deficiencies should also be corrected. The treatment recommendations of osteoporosis in CLD tend to be extended to ALD. Bisphosphonates have been proven to be effective in increasing bone mineral density (BMD) in chronic cholestatic disease and post-transplant patients, and they can be used in ALD patients. Randomized studies assessing the management of CLD-associated osteoporosis and the development of new drugs for osteoporosis may change the future. Here, we will discuss bone quality, vitamin D status, mechanism of bone effects, and diagnosis and treatment of osteoporosis in ALD.

Handgrip strength as a predictor of bone mineral density in outpatients with cirrhosis

BACKGROUND AND AIM

Osteoporosis is well recognized as a cirrhosis complication; however, most studies assessing this condition included only patients on liver transplantation lists with an elevated rate of bone diseases. While general population studies show that handgrip strength is clearly associated with bone mineral density, until now this tool has not been applied to patients with cirrhosis in relation to their bone condition. This study aimed to evaluate whether handgrip strength, bone, and liver tests may be useful as predictors of bone disease in outpatients with cirrhosis.

METHODS

One hundred twenty-nine subjects were included (77 men and 52 women). Dual-energy X-ray absorptiometry was applied to evaluate lumbar-spine and femoral-neck T scores. Osteoporosis/osteopenia rates were 26.3%/35.6% in the lumbar spine and 6.9%/41.8% in the femoral neck, respectively. Model selections were based on backward procedures to find the best predictors of low T scores.

RESULTS

For lumbar spine, only low handgrip strength and high parathyroid hormone levels were clearly related to low T scores. For femoral neck, only age was associated with low T scores.

CONCLUSIONS

Handgrip strength may serve as an effective predictor of low lumbar spine T score among outpatients with cirrhosis. As cirrhosis affects the lumbar spine more than the femoral neck, these results suggest that handgrip strength should be tested in all patients with cirrhosis as a first indicator of bone health.

Sarcopenia and liver transplant: The relevance of too little muscle mass

Loss of muscle mass and function is a common occurrence in both patients with decompensated cirrhosis and those undergoing liver transplantation. Sarcopenia is associated with morbidity and mortality before and after liver transplantation. The ability of skeletal muscle mass to recover after transplant is questionable, and long term adverse events associated with persistent sarcopenia have not been well studied. Limited data is available examining mechanisms by which decreased muscle mass might develop. It is not clear which interventions might reduce the prevalence of sarcopenia and associated health burdens. However, measures to either decrease portal hypertension or improve nutrition appear to have benefit. Research on sarcopenia in the liver transplant setting is hampered by differing methodology to quantify muscle mass and varied thresholds determining the presence of sarcopenia. One area highlighted in this review is the heterogeneity used when defining sarcopenia. The health consequences, clinical course and potential pathophysiologic mechanisms of sarcopenia in the setting of cirrhosis and liver transplantation are further discussed.

Patients with cirrhosis and ascites have false values of bone density: implications for the diagnosis of osteoporosis

The effect of ascites on bone densitometry has been assessed in 25 patients with advanced cirrhosis, and it was concluded that ascites over 4 l causes inaccuracy of BMD measurements, particularly at the lumbar spine. This fact must be considered when assessing bone mass in patients with decompensated cirrhosis.

INTRODUCTION

Bone mineral density (BMD) measured by dual-energy x-ray absorptiometry (DXA) is the best procedure for assessment of osteoporosis and fracture risk, but BMD values at the central skeleton may be influenced by changes in soft tissues. Therefore, we have studied the effect of ascites on BMD.

METHODS

BMD was measured by DXA at the lumbar spine, femoral neck and total hip, just before and shortly after therapeutic paracentesis in 25 patients with advanced liver cirrhosis. Changes in BMD, lean and fat mass, abdominal diameter and weight, as well as the amount of removed ascites were measured.

RESULTS

The amount of drained ascites was 6.6 ± 0.5 l (range: 3.0 to 12.7 l). After paracentesis, BMD increased at the lumbar spine (from 0.944 ± 0.035 to 0.997 ± 0.038 g/cm(2), p < 0.001) and at the total hip (from 0.913 ± 0.036 to 0.926 ± 0.036 g/cm(2), p < 0.01). Patients with a volume of drained ascites higher than 4 l showed a significant increase in lumbar BMD (7.0%), compared with patients with a lower amount (1.5%) (p < 0.03). The decrease in total soft tissue mass correlated with the amount of removed ascites (r = 0.951, p < 0.001). Diagnosis of osteoporosis or osteopenia changed after paracentesis in 12% of patients.

CONCLUSION

Ascites over 4 l causes inaccuracy of BMD measurements, particularly at the lumbar spine. This fact must be considered when assessing bone mass in patients with advanced cirrhosis.

The influence of exogenous fat and water on lumbar spine bone mineral density in healthy volunteers

PURPOSE

Changes in human body composition can affect the accuracy of spine bone mineral density (BMD) measurements. The purpose of this study was to evaluate whether fat and water in the soft tissue of the abdomen influence lumbar spine BMD measurements obtained using dual energy X-ray absorptiometry (DXA).

MATERIALS AND METHODS

Duplicate BMD measurements were carried out on healthy volunteers (10 men and 10 women) and the Hologic anthropomorphic spine phantom had on the same day before and after placement of following 3 materials in the abdominal area: lard 900 g, 1.5 cm thick; oil 1.4 liters in a vinyl bag; and water 1.2 liters in a vinyl bag.

RESULTS

In the case of human participants, following the placement of exogenous water to mimic extracellular fluid (ECF), there was a significant decrease in lumbar spine BMD (-0.012 g/cm², p=0.006), whereas the placement of exogenous lard and oil to mimic abdominal fat produced a slight increase in lumbar spine BMD (0.006 g/cm², p=0.301; 0.008 g/cm², p=0.250, respectively). The average percentage of lumbar spine BMD change with and without exogenous lard, oil, and water showed increase of 0.51%, and 0.67%, and decrease of 1.02%, respectively. Using the phantom, BMD decreased with the placement of both lard (-0.002 g/cm², p=0.699) and water (-0.006 g/cm², p=0.153); however, there was no difference in BMD after oil placement.

CONCLUSION

These results suggest that in cases where changes in fat and ECF volume are similar, ECF exerts a greater influence than fat on DXA lumbar BMD measurements.

Liver and bone

Osteoporosis is a frequent complication in patients with chronic liver disease, especially in end-stages and in cases with chronic cholestasis, hemochromatosis and alcohol abuse. The problem is more critical in transplant patients when bone loss is accelerated during the period immediately after transplantation, leading to a greater incidence of fractures. Advanced age, low body mass index and severity of the liver disease are the main risk factors for bone disease in patients with cholestasis. Mechanisms underlying osteoporosis in chronic liver disease are complex and poorly understood, but osteoporosis mainly results from low bone formation, related to the effects of retained substances of cholestasis, such as bilirubin and bile acids, or to the effects of alcohol on osteoblastic cells. Increased bone resorption has also been described in cholestatic women with advanced disease. Although there is no specific treatment, bisphosphonates associated with supplements of calcium and vitamin D are effective for increasing bone mass in patients with chronic cholestasis and after liver transplantation. The outcome in reducing the incidence of fractures has not been adequately demonstrated essentially because of the low number of patients included in the therapeutic trials. Randomized studies assessing bisphosphonates in larger series of patients, the development of new drugs for osteoporosis and the improvement in the management of liver transplant recipients may change the future.

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.