The FRAX ® as a predictor of mortality in Japanese incident hemodialysis patients: an observational, follow-up study

Role of Fracture Risk Assessment Tool and Bone Turnover Markers in Predicting All-Cause and Cardiovascular Mortality in Hemodialysis Patients

Background

Fracture Risk Assessment Tool (FRAX) and bone turnover markers (BTMs) predict fractures in the general population. However, the role of FRAX and BTMs in predicting mortality remains uncertain in hemodialysis (HD) patients.

Methods

One hundred and sixty-four HD patients stratified by low or high risk of 10-year fracture probability using FRAX. High risk of fracture was defined as 10-year probability of hip fracture ≥3% or major osteoporotic fracture ≥20%. The association of high risk of fracture and BTMs with all-cause mortality and cardiovascular (CV) mortality were evaluated using multivariate-adjusted Cox regression analysis.

Results

Eighty-five (51.8%) patients were classified as high risk of fracture based on FRAX among 164 HD patients. During a mean follow-up period of 3.5 ± 1.0 years, there were 39 all-cause deaths and 23 CV deaths. In multivariate-adjusted Cox regression, high risk of fracture based on FRAX was independently associated with all-cause mortality [hazard ratio (HR): 2.493, 95% confidence interval (CI): 1.026–6.056, p = 0.044) but not with CV mortality (HR: 2.129, 95% CI: 0.677–6.700, p = 0.196). There were no associations between BTMs and mortality risk. Furthermore, lower geriatric nutritional risk index (GNRI) was significantly associated with increased CV mortality (HR: 0.888, 95% CI: 0.802–0.983, p = 0.022) after adjusting by confounding variables.

Conclusion

High risk of fracture using FRAX was an independent predictor of all-cause mortality in patients undergoing HD. FRAX, rather than BTMs, has an important role of prognostic significance in HD patients.

Prevalence and predictors of asymptomatic vertebral fracture in patients with end-stage renal disease

Objective

This study aimed to investigate the prevalence and predictors of asymptomatic vertebral fracture in patients with end-stage renal disease undergoing hemodialysis.

Methods

This cross-sectional study included 80 patients with end-stage renal disease undergoing hemodialysis. Medical history, Fracture Risk Assessment Tool and anteroposterior and lateral radiographs of the thoracolumbar and lumbosacral spine were obtained. Vertebral fractures were identified using the Genant semiquantitative assessment.

Results

Radiography demonstrated asymptomatic vertebral fracture in 22 patients (27.5%). FRAX® results for major osteoporotic fracture (area under the curve, 0.64) and hip fracture (area under the curve, 0.62) were able to discriminate patients with prevalent asymptomatic vertebral fracture. A multivariate analysis demonstrated that a 1-year average corrected calcium (odds ratio, 0.38), steroid use (odds ratio, 8.99), and a serum albumin concentration <25 g/dL (odds ratio, 28.82) significantly predicted prevalent asymptomatic vertebral fracture (clinical model; area under the curve, 0.82). Combining the 1-year average corrected calcium and serum albumin concentration <25 g/dL with FRAX® results for major osteoporotic fracture (area under the curve, 0.78) and FRAX® results for hip (area under the curve, 0.75) produced a significantly greater area under the curve value to predict fracture when compared with FRAX® result for major osteoporotic fracture and FRAX® result for hip (P = 0.022).

Conclusion

Asymptomatic vertebral fracture is prevalent. FRAX® results for major osteoporotic fracture and hip provided lower ability in predicting asymptomatic vertebral facture when compared to the clinical model. Combining a 1-year average corrected calcium and serum albumin concentration <25 g/dL with FRAX® result for major osteoporotic fracture or hip improved the model's performance and provided comparable area under the curve to the clinical model.

Relationship between the FRAX index and physical and cognitive functioning in older people

OBJECTIVE

To assess the relationship between the FRAX index and the Barthel index/MiniMental State Examination in older people.

PATIENTS AND METHODS

Observational descriptive study. Demographic data, comorbidity, dependency and cognitive state, and risk of osteoporotic fracture were collected.

RESULTS

A total of 375 patients were included (60% female) Patients with a low-risk FRAX for hip fractures had a higher Mini-mental (25, 95% CI = 24-27 vs. 22, 95% = 21 to 23, p = .0001), a higher Barthel index (88, 95% CI = 84-93 vs 72, 69 to 76, p = .0001) without differences in the Charlson index. Bivariate analysis showed an inverse association between FRAX and scales but logistic regression showed only female sex (OR 4.4, 95% CI = 2.6-7.6) and the non-dependent Barthel index (OR = 0.104, 95% CI = 0.014-0.792) remained significant and. Barthel index/Mini-mental constructed a significant model capable of predicting a risk of hip fracture of >3% measured by the FRAX index, with an area under the curve of 0.76 (95% CI = 0.7-0.81).

CONCLUSIONS

The FRAX index is related to other markers of geriatric assessment and the association between these variables can predict a risk of hip fracture of >3% measured by the FRAX index. Key messages Geriatric assessment indexes may be as important as the FRAX index, which is based on clinical risk factors, in predicting the fracture risk in older patient.

Osteoporosis, bone mineral density and CKD-MBD complex (I): Diagnostic considerations

Osteoporosis (OP) and chronic kidney disease (CKD) independently influence bone and cardiovascular health. A considerable number of patients with CKD, especially those with stages 3a to 5D, have a significantly reduced bone mineral density leading to a high risk of fracture and a significant increase in associated morbidity and mortality. Independently of classic OP related to age and/or gender, the mechanical properties of bone are also affected by inherent risk factors for CKD ("uraemic OP"). In the first part of this review, we will analyse the general concepts regarding bone mineral density, OP and fractures, which have been largely undervalued until now by nephrologists due to the lack of evidence and diagnostic difficulties in the context of CKD. It has now been proven that a reduced bone mineral density is highly predictive of fracture risk in CKD patients, although it does not allow a distinction to be made between the causes which generate it (hyperparathyroidism, adynamic bone disease and/or senile osteoporosis, etc.). Therefore, in the second part, we will analyse the therapeutic indications in different CKD stages. In any case, the individual assessment of factors which represent a higher or lower risk of fracture, the quantification of this risk (i.e. using tools such as FRAX^®) and the potential indications for densitometry in patients with CKD could represent an important first step pending new clinical guidelines based on randomised studies which do not exclude CKD patients, all the while avoiding therapeutic nihilism in an area of growing importance.

Molecular Abnormalities Underlying Bone Fragility in Chronic Kidney Disease

Prevention of bone fractures is one goal of therapy for patients with chronic kidney disease-mineral and bone disorder (CKD-MBD), as indicated by the Kidney Disease: Improving Global Outcomes guidelines. CKD patients, including those on hemodialysis, are at higher risk for fractures and fracture-related death compared to people with normal kidney function. However, few clinicians focus on this issue as it is very difficult to estimate bone fragility. Additionally, uremia-related bone fragility has a more complicated pathological process compared to osteoporosis. There are many uremia-associated factors that contribute to bone fragility, including severe secondary hyperparathyroidism, skeletal resistance to parathyroid hormone, and bone mineralization disorders. Uremia also aggravates bone volume loss, disarranges microarchitecture, and increases the deterioration of material properties of bone through abnormal bone cells or excess oxidative stress. In this review, we outline the prevalence of fractures, the interaction of CKD-MBD with osteoporosis in CKD patients, and discuss possible factors that exacerbate the mechanical properties of bone.

Chronic kidney disease and fragility fracture

Osteoporosis is defined simply as "a skeletal disorder characterized by compromised bone strength predisposing to an increased risk of fracture. Thus, any bone lesion that causes fragility fracture is osteoporosis, which has quite heterogeneous backgrounds. Chronic kidney disease-related bone and mineral disease (CKD-MBD) is defined as "a systemic disorder of mineral and bone metabolism due to CKD, which is manifested by abnormalities in bone and mineral metabolism and/or extra-skeletal calcification". Although CKD-MBD is one of the possible causes of osteoporosis, we do not have evidences that CKD-MBD is the only or crucial determinant of bone mechanical strength in CKD patients. The risk of hip fracture is considerably high in CKD patients. Drugs that intervene in systemic mineral metabolism, indeed, lead to the improvement on bone histology in CKD patients. However, it remains unclear whether the intervention in systemic mineral metabolism also improves bone strength, today. Thus, the use of drugs that directly act on bone and the introduction of fracture liaison concept are promising strategies for fragility fracture prevention among CKD patients, as well as treatment for CKD-MBD.

Osteoprotegerin and uremic osteoporosis in chronic hemodialysis patients

INTRODUCTION

Osteoprotegerin (OPG) is a powerful inhibitor of osteoclast activity, and it plays an important role in bone metabolism. In hemodialysis (HD) patients, the relationship between OPG and bone mineral density (BMD) is important, but remains unclear yet. The study objective was to assess the OPG role related to uremic osteoporosis in HD patients.

METHODS

This cross-sectional study has been realized on a cohort of 63 chronic HD patients.

INCLUSION CRITERIA

elderly prevalent HD patients with an age over 55 years old.

EXCLUSION CRITERIA

previous bone disease or previous renal transplant; neoplasia; parathyroidectomy, hormone replacement therapy. The data regarding demographical and clinical characteristics, including treatments for mineral and cardiovascular complications, were recorded. Serum OPG and mineral markers levels were measured. BMD was assessed by calcaneus quantitative ultrasound; it measured broadband ultrasound attenuation, speed of sound (SOS) and stiffness index (STI).

RESULTS

The high OPG levels were associated with higher bone mineral density (OPG-SOS P = 0.003; R = 0.37; OPG-STI P = 0.03; R = 0.28). Malnutrition, anemia and advanced age correlated with bone demineralization. Males had higher bone density parameters than females. In patients treated with vitamin D (P = 0.005), the BMD was increased comparing to patients without these treatments.

CONCLUSIONS

OPG levels had directly correlated with bone mineral density parameters. Our study further confirms the critical role of OPG in the pathogenesis of uremic osteoporosis in ESRD. Whether the increased circulant OPG protect against bone loss in patients undergoing HD remains to be established.