Fracture Risk Assessment in Chronic Kidney Disease, Prospective Testing Under Real World Environments (FRACTURE): a prospective study

Cemented vertebra and adjacent vertebra refractured in a chronic kidney disease-mineral and bone disorder patient: A case report

BACKGROUND

Although percutaneous vertebral augmentation (PVA) is a commonly used procedure for treating vertebral compression fracture (VCF), the risk of vertebral refracture should be considered. Chronic kidney disease-mineral and bone disorder (CKD-MBD) is a systemic disease of mineral and bone metabolism. It is associated with an increased risk of fracture. Few studies have reported the use of PVA in patients with CKD-MBD. We herein report a rare case wherein the cemented vertebra and the adjacent vertebra refractured simultaneously in a CKD-MBD patient after PVA.

CASE SUMMARY

A 74-year-old man suffered from low back pain after taking a fall about 3 wk ago. According to physical examination, imaging and laboratory findings, diagnoses of T12 VCF, CKD-MBD, and chronic kidney disease stage 5 were established. He then received percutaneous vertebroplasty at T12 vertebra. Fourteen weeks later, he presented with T12 and L1 vertebral refractures caused by lumbar sprain. Once again, he was given PVA which was optimized for the refractured vertebrae. Although the short-term postoperative effect was satisfactory, he reported chronic low back pain again at the 3-month follow-up.

CONCLUSION

It is necessary that patients with CKD-MBD who have received PVA are aware of the adverse effects of CKD-MBD. It may increase the risk of vertebral refracture. Furthermore, the PVA surgical technique needs to be optimized according to the condition of the patient. The medium- and long-term effects of PVA remain uncertain in patients with CKD-MBD.

Biomimetic Scaffolds in Skeletal Muscle Regeneration

Skeletal muscle tissue has inherent capacity for regeneration in response to minor injuries. However, in the case of severe trauma, tumor ablations, or in congenital muscle defects, these myopathies can cause irreversible loss of muscle mass and function, a condition referred to as volumetric muscle loss (VML). The natural muscle repair mechanisms are overwhelmed, prompting the search for new muscle regenerative strategies, such as using biomaterials that can provide regenerative signals to either transplanted or host muscle cells. Recent studies involve the use of suitable biomaterials which may be utilized as a template to guide tissue reorganization and ultimately provide optimum micro-environmental conditions to cells. These strategies range from approaches that utilize biomaterials alone to those that combine materials with exogenous growth factors, and ex vivo cultured cells. A number of scaffold materials have been used in the development of grafts to treat VML. In this brief review, we outline the natural skeletal regeneration process, available treatments used in the clinic for muscle injury and promising tissue bioengineering and regenerative approaches for muscle loss treatment.

Relationship between Fibroblast Growth Factor 23 and Biochemical and Bone Histomorphometric Alterations in a Chronic Kidney Disease Rat Model Undergoing Parathyroidectomy

Background

Phosphate burden in chronic kidney disease (CKD) leads to elevated serum fibroblast factor-23 (FGF-23) levels, secondary hyperparathyroidism and chronic kidney disease-mineral bone disorder (CKD-MBD). However dissociated hyperphosphatemia and low serum FGF-23 concentrations have been observed in experimentally parathyoridectomized rats. The relationships between serum mineral, hormone, and bone metabolism may be altered in the presence of CKD. The aim of our study was to investigate whether a consistent relationship existed between serum FGF-23 levels, specific serum biochemical markers, and histomorphometric parameters of bone metabolism in a parathyroidectomized CKD animal model.

Results

Sprague Dawley rats were divided into 3 groups: parathyroidectomy (PTX) and CKD (PTX+CKD, 9 rats), CKD without PTX (CKD, 9 rats), and neither PTX nor CKD (sham-operated control, 8 rats); CKD was induced by partial nephrectomy. At 8 weeks after partial nephrectomy, serum biomarkers were measured. Bone histomorphometries of the distal femoral metaphyseal bone were analyzed. The mean serum FGF-23 levels and mean bone formation rate were the highest in the CKD group and the lowest in the PTX+CKD group. Bone volume parameters increased significantly in the PTX+CKD group. Pearson’s correlation revealed that serum FGF-23 levels associated with those of intact parathyroid hormone, phosphate, collagen type I C-telopeptide, and calcium. Univariate linear regression showed that serum FGF-23 values correlated with bone formation rate, bone volume, and osteoid parameters. Stepwise multivariate regression analysis revealed that circulating FGF-23 values were independently associated with bone volume and thickness (β = -0.737; p < 0.001 and β = -0.526; p = 0.006, respectively). Serum parathyroid hormone levels independently correlated with bone formation rate (β = 0.714; p < 0.001) while collagen type I C-telopeptide levels correlated with osteoid parameter.

Conclusion

Serum FGF-23 levels independently correlated with bone volume parameters in rats with experimentally induced CKD.

Association of serum bicarbonate with bone fractures in hemodialysis patients: the mineral and bone disorder outcomes study for Japanese CKD stage 5D patients (MBD-5D)

BACKGROUND/AIMS

Bone fracture is often complicated in hemodialysis (HD) patients. Metabolic acidosis is related to bone disease and muscle wasting, but it is not known whether acid-base disturbance is associated with the risk of bone fractures. The aim of this study was to clarify the association of serum bicarbonate level with bone fracture in HD patients.

METHODS

Using a subcohort of the Mineral and Bone Disorder Outcomes Study for Japanese CKD Stage 5D Patients (MBD-5D), 890 prevalent HD patients (age: 62 years old, male: 62.8%, duration of dialysis: 8.3 years) with secondary hyperparathyroidism were studied. After measuring predialysis serum bicarbonate at a 2-day interdialytic interval, we prospectively followed them every 3 months, and examined the occurrence of any type of bone fracture or hospitalization due to fracture over a 3-year observation period.

RESULTS

Seventy-four bone fractures and 47 hospitalizations due to fracture were observed during the follow-up period. HD patients with serum bicarbonate <20 mmol/l had a 1.93 (95% CI 1.01-3.71)-fold higher risk for all-cause fractures than those with serum bicarbonate of 20.0-21.9 mmol/l. A higher bicarbonate level (≥22 mmol/l) was also related to an increased risk of bone fracture. A restricted cubic regression spline disclosed that the higher or the lower than 21.0 mmol/l of serum bicarbonate, the greater the risk for bone fracture.

CONCLUSION

Both a lower level and a higher level of predialysis bicarbonate concentration were associated with risk of bone fracture in HD patients with secondary hyperparathyroidism.

Osteoprotegerin and fractures in men and women with chronic kidney disease

Fractures are common in men and women with chronic kidney disease (CKD) but the best tool to identify those at high risk is unknown. Increased circulating osteoprotegerin(OPG) is associated with fractures in postmenopausal women. We determined if serum OPG was associated with prevalent fractures (self-reported low trauma fractures since 40 years of age and/or prevalent vertebral fractures identified by radiographs) in men (n = 97) and women (n = 67) with stage 3–5 CKD. Analyses were performed unadjusted and adjusted for stage of CKD. Results are expressed as mean ± standard deviation(SD), and as odds ratio (OR) per SD increase in OPG with 95 % confidence intervals (CI). The mean age was 62.7 ± 16.3 years, and mean weight was 78.9 ± 18.7 kg. Compared to those without fractures, those with fractures(n = 55) were older (p < 0.01). Serum OPG increased as kidney function decreased, and OPG was higher in those with fractures compared to those without (9.42 ± 4.08 vs 8.06 ± 3.11 pmol/L, p = 0.02). After adjusting for stage of CKD, increased OPG was associated with an increased fracture risk (OR 1.13, 95 % CI 1.02–1.25); however, OPG did not discriminate fracture status well (area under the receiver operating characteristic curve 0.61, 95 % CI 0.52–0.70). OPG is associated with fractures in men and women with stage 3–5 CKD; however, the ability of OPG to discriminate fracture status is poor and cannot be used in isolation to assess fracture risk. Further studies should examine the ability of OPG in combination with other risk factors to better discriminate fracture status in men and women with CKD.

Greater risk of hip fracture in hemodialysis than in peritoneal dialysis

Several differences may have existed between patients treated with peritoneal dialysis and hemodialysis because of the difference in dialysis modality. This nationwide population-based cohort study demonstrated that patients on hemodialysis had an increased risk of hip fracture compared to patients on peritoneal dialysis; the hazard ratio was 1.52.

INTRODUCTION

Numerous debates on which dialysis modality is "superior" have taken place in recent decades. However, no large-scale study has ever mentioned about the relationship between dialysis modality and risk of hip fracture.

METHODS

We identified 64,124 incident end-stage renal disease patients from the National Health Insurance Research Database in Taiwan between 1998 and 2008, including 59,457 (92.72%) hemodialysis (HD) and 4,667 (7.28%) peritoneal dialysis (PD) patients. After 8:1 propensity score matching, 31,554 patients, of whom 28,048 were HD and 3,506 were PD patients, were included in the study. We conducted the Cox proportional hazards model to examine the effects of dialysis modality and other variables on hip fracture risk.

RESULTS

A total of 2,587 hip fractures were identified in 64,124 dialysis patients. The incidence rate of hip fracture was 13.60 per 1000 patient-years in the HD group and 6.25 in the PD group. Dialysis modality, sex, age, presence of cardiovascular disease, diabetes, medication with antiepileptic drugs, diuretics, steroids, and vitamin D had statistically significant associations with hip fracture. Patients on HD had an increased risk of hip fracture compared to patients on PD; the hazard ratio (HR) was 1.52 (95% CI: 1.09-2.12, P = 0.02).

CONCLUSIONS

In this population-based cohort study, HD had a greater hip fracture risk compared to PD; the HR was 1.52. We should focus more on reducing the risk of hip fractures in hemodialysis patients.

Estimated GFR and fracture risk: a population-based study

BACKGROUND AND OBJECTIVES

Although patients with ESRD have a higher fracture risk than the general population, there is conflicting evidence regarding fracture incidence in those with CKD. This study sought to determine the association between estimated GFR (eGFR) and fracture rates.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

This study identified 1,815,943 community-dwelling adults who had at least one outpatient serum creatinine measurement between 2002 and 2008. Patients with eGFR <15 ml/min per 1.73 m(2) and those who required dialysis were excluded. Incident fractures of the hip, wrist, and vertebrae were identified using diagnostic and procedure codes. Poisson regression was used to determine adjusted rates of each fracture type by eGFR, age, and sex.

RESULTS

The median age of the cohort was 47 years (interquartile range, 24), and 7.1% had eGFR <60 ml/min per 1.73 m(2). Over a median follow-up of 4.4 years, fracture rates increased with age at all sites. Within each age stratum, unadjusted rates increased with declining eGFR; however, adjusted rates were similar across eGFR categories. For example, among women aged 65-74 years, adjusted hip fracture rates were 3.41 per 1000 person-years (95% confidence interval, 2.30 to 4.53) and 4.58 per 1000 person-years (95% confidence interval, 0.02 to 9.14) in those with eGFR ≥90 and 15-29 ml/min per 1.73 m(2), respectively. Similar results were observed for wrist and vertebral fractures.

CONCLUSIONS

In contrast to earlier studies, patients with eGFR<60 ml/min per 1.73 m(2) do not appear to have increased rates of hip, wrist, and vertebral fractures independent of age and sex.

Mandibular fracture scoring system: for prediction of complications

INTRODUCTION

Mandibular fractures are one of the most commonly encountered injuries in trauma clinics. Although several widely accepted classification systems exist, these are mostly region specific, differ in the classification criteria used, and are sometimes only correlated with specific treatment modalities, thereby making it impossible to uniformly and comprehensively document facial fracture patterns. In this study, we developed a modified scoring system for mandibular fractures and analyzed the relationship between scoring of fractures that were treated and the incidence of complications after surgical treatment.

MATERIALS AND METHODS

To evaluate the suitability of the proposed scoring system, a prospective study on a series of 116 patients was performed. All the fractures were classified using the proposed scoring system. The scoring was based on clinical and radiological evaluation of each fracture. Patients were followed up postoperatively for presence of complications.

RESULTS

A good correlation between the proposed scoring system and the incidence of complications was detected.

DISCUSSION

This scoring system for mandibular fractures facilitates an objective and standardized assessment of the degree of severity of a fracture, thereby allowing for systematic evaluation of facial fracture outcomes, including assessment of complications. However, it is our understanding that a multicenter study should be performed before the effectiveness of the proposed classification can be clearly stated.

Three-year experience with alendronate treatment in postmenopausal osteoporotic Japanese women with or without renal dysfunction: a retrospective study

BACKGROUND AND OBJECTIVE

Chronic kidney disease is associated with an increased risk of fragility fractures. A retrospective study was conducted to compare outcomes after 3 years of alendronate treatment in postmenopausal osteoporotic Japanese women with or without renal dysfunction (RD).

METHODS

One hundred and thirty-five postmenopausal osteoporotic Japanese women (mean age at baseline: 68 years) who had been treated with alendronate in our outpatient clinic for more than 3 years were analysed. The lumbar spine bone mineral density (BMD) of patients was measured using dual energy x-ray absorptiometry, and urinary levels of cross-linked N-terminal telopeptides of type I collagen (NTX) and serum levels of alkaline phosphatase (ALP) were monitored during the 3-year treatment period. The incidence of osteoporotic fractures was also assessed.

RESULTS

Twenty-six women had RD with an estimated glomerular filtration rate (eGFR) of <60 mL/min/1.73 m2. The urinary NTX and serum ALP levels significantly decreased and the lumbar spine BMD significantly increased, compared with the baseline values, in a manner that was similar among women with or without RD. However, the incidence of non-vertebral fractures, but not that of vertebral fractures, was significantly higher among women with RD than among women without RD.

CONCLUSIONS

Alendronate treatment appeared to have a similar effect on surrogate markers in postmenopausal osteoporotic Japanese women with or without RD. However, further studies are needed to confirm that RD may increase the risk of non-vertebral fractures in patients treated with alendronate.

Vitamin K(2) improves renal function and increases femoral bone strength in rats with renal insufficiency

Renal insufficiency induces cortical bone loss in rats. The present study examined the influence of vitamin K(2) on renal function, cortical bone mass, and bone strength in rats with renal insufficiency. Thirty male Sprague-Dawley rats (8 weeks old) were randomized by the stratified weight method to the following three groups of 10 animals each: sham operation (control), 5/6 nephrectomy, and 5/6 nephrectomy + oral vitamin K(2) (menaquinone-4, menatetrenone, 30 mg/kg, 5 days/week). Treatment was initiated 10 days after surgery. After 6 weeks of treatment, samples of serum, urine, and bone (femur and tibia) were obtained. Renal function was evaluated, bone histomorphometric analysis was performed on the tibial diaphysis, and the bone mineral density (BMD) and mechanical strength of the femoral diaphysis were determined by peripheral quantitative computed tomography and a three-point bending test, respectively. Nephrectomy induced renal dysfunction, as indicated by increased levels of serum creatinine and urea nitrogen along with a decrease of creatinine clearance; and it also decreased BMD without significantly affecting bone strength at the femoral diaphysis. Vitamin K(2) improved renal function parameters but did not significantly influence BMD at the femoral diaphysis. However, vitamin K(2) decreased the bone marrow area of the tibial diaphysis and increased the stiffness of the femoral diaphysis. These findings suggest that administration of vitamin K(2) improves renal function and increases cortical bone strength without altering BMD in rats with renal insufficiency.