Changes in bone and calcium metabolism following hip fracture in elderly patients

Preoperative Serum Calcium Level Predicts Postoperative Mortality in Older Adult Patients with Hip Fracture: A Prospective Cohort Study of 2333 Patients

OBJECTIVES

Hip fractures are a significant cause of mortality among older adults. However, predictive markers for an unfavorable prognosis are still lacking. Serum calcium is an essential element in several biochemical reactions in the body. This study investigated the role of the preoperative serum calcium level as a prognostic parameter for postoperative mortality in older adult patients with hip fractures.

DESIGN

We conducted a prospective cohort study at the trauma center in our hospital, from January 1, 2015, to September 30, 2019. A total of 2333 older patients with hip fractures were recruited. This prospective cohort study was conducted in accordance with the criteria of STROCSS.

SETTING AND PARTICIPANTS

Older adult patients with hip fractures were screened between January 2015 and September 2019 at the trauma center of our hospital.

METHODS

Demographic and clinical characteristics of the patients were collected. Linear and nonlinear multivariate Cox regression models were used to identify the association between preoperative serum calcium level and all-cause mortality. All analyses were performed using EmpowerStats and the R software.

RESULTS

A total of 2333 older adult patients with hip fractures were included in the study. The mean follow-up was 37.5 months. Overall, 770 patients (33%) died of all causes. The preoperative serum calcium concentrations were 2.18 ± 0.13 mmol/L. Linear multivariate Cox regression models showed that preoperative serum calcium levels were associated with mortality [hazard ratio (HR) 0.37, 95% CI 0.21-0.67; P = .0009] after adjusting for confounders. However, the linear association was unstable, and nonlinearity was identified. A preoperative serum calcium level of 2.3 mmol/L was an inflection point for prediction. When the preoperative serum calcium concentration was below 2.3 mmol/L, serum calcium concentration increased by 1 mmol/L, and mortality risk decreased by 77% (HR 0.23, 95% CI 0.13-0.43, P < .0001). In contrast, when the preoperative serum calcium concentration was more significant than 2.3 mmol/L, the mortality risk increased with serum calcium concentration (HR 6.27, 95% CI 1.65-23.74, P = .0069).

CONCLUSIONS AND IMPLICATIONS

The preoperative serum calcium level is nonlinearly associated with mortality in older adults with hip fractures, with a U-shaped association, and could be used as a potential predictor of prognosis.

Immediate Risk for Cardiovascular Events in Hip Fracture Patients: A Population-Based Cohort Study

BACKGROUND

Emerging evidence showed that bone metabolism and cardiovascular diseases (CVD) are closely related. We previously observed a potential immediate risk of cardiovascular mortality after hip fracture. However, whether there is an immediate risk of cardiovascular events after hip fracture is unclear. The aim of this study was to evaluate the risk for major adverse cardiovascular events (MACEs) between patients having experienced falls with and without hip fracture.

METHODS

This retrospective population-based cohort study used data from a centralized electronic health record database managed by Hong Kong Hospital Authority. Patients having experienced falls with and without hip fracture were matched by propensity score (PS) at a 1:1 ratio. Adjusted associations between hip fracture and risk of MACEs were evaluated using competing risk regression after accounting for competing risk of death.

RESULTS

Competing risk regression showed that hip fracture was associated with increased one-year risk of MACEs (hazard ratio [HR], 1.27; 95% CI, 1.21 to 1.33; p<0.001), with a 1-year cumulative incidence difference of 2.40% (1.94% to 2.87%). The HR was the highest in the first 90-day after hip fracture (HR of 1.32), and such an estimate was continuously reduced in 180-day, 270-day, and 1-year after hip fracture.

CONCLUSIONS

Hip fracture was associated with increased immediate risk of MACEs. This study suggested that a prompt evaluation of MACE among older adults aged 65 years and older who are diagnosed with hip fracture irrespectively of cardiovascular risk factors may be important, as early management may reduce subsequent risk of MACE.

Decrease in serum calcitriol (but not free 25-hydroxyvitamin D) concentration in hip fracture healing

OBJECTIVE

To assess the decrease in serum calcitriol concentrations after hip fracture.

METHODS

Serum concentrations of calcitriol, 25(OH)D, parathyroid hormone (PTH), directly measured free 25(OH)D, and indices of bone formation were measured in elderly patients with hip fracture (HF) and patients with elective hip replacement (EHR) at admission and after 7 weeks.

RESULTS

A total of 45 patients with HF and 17 patients with EHR completed this prospective study. Baseline serum calcitriol levels were ≤ 60 pmol/l in 26% of the HF patients. After 7 weeks, they significantly decreased (p < 0.001). In patients with EHR, serum calcitriol was within the reference range in all but one patient and did not change during the 7-week recovery phase. Seven weeks after HF, a significant positive relationship was observed between the change in calcitriol and serum 25(OH)D concentration (r = 0.385, p = 0.009) and free 25(OH)D (r = 0.296, p = 0.048), and a decrease in calcitriol during recovery was associated with a decrease in serum PTH (p = 0.038). Seven weeks after HF, changes in both serum PTH and serum 25(OH)D concentrations contributed to the prediction of changes in serum calcitriol (R² = 0.190, p = 0.012).

CONCLUSIONS

Unlike patients with EHR, subjects with HF had low serum 25(OH)D and low free 25(OH)D concentrations at admission, while their serum 1,25D levels were relatively elevated. Decreases in circulating calcitriol levels in the 7 weeks following hip surgery were associated with a resolution of secondary hyperparathyroidism and low availability of free 25(OH)D.

Bone metabolism subgroups identified as hip fracture patients via clustering

PURPOSE

The aim of the study was to describe the bone metabolism status that underlies a hip fracture.

METHODS

Estimated glomerular filtration rate (e-GFR), calcium (Ca), phosphorus (P), total (ALP) and bone specific alkaline phosphatase (b-ALP), intact parathyroid hormone (i-PTH), 25-hydroxy-vitamin D (25OHD), total procollagen type I amino-terminal propeptide (PINP), and N-terminal peptide of collagen I (NTx), measured at admission in 272 hip fracture patients, were ex post analyzed by K-means clustering and principal component analysis and were evaluated by a clinician.

RESULTS

Four components, mainly consisting of b-ALP, PINP, ALP, and NTx; e-GFR and P; i-PTH and 25OHD; and Ca explained about 70% of the variability. A total of 184 patients clustered around a centroid (A) with low 25OHD (13.2 ng/ml), well-preserved kidney function (e-GFR=67.19 ml/min/1.73m²), normal Ca, P, i-PTH and bone markers, with the exception of slightly increased NTx (24.82nMBCE). Cluster B (n=70) had increased i-PTH (93.38 pg/ml), moderately decreased e-GFR, very low 25OHD (8.68 ng/dl), and high bone turnover (b-ALP 28.46 U/L, PINP 69.87 ng/ml, NTx 31.3nMBCE). Cluster C (n=17) also had hyperparathyroidism (80.35 pg/ml) and hypovitaminosis D (9.15 ng/ml), low e-GFR(48.89 ml/min/1.73m²), and notably high ALP (173 U/L) and bone markers (b-ALP 44.64 U/L, PINP 186.98 ng/ml, NTx 38.28nMBCE). According to the clinician, 62 cases clearly had secondary hyperparathyroidism.

CONCLUSIONS

Based on serum measurements, the dominant patterns of bone metabolism were normal bone turnover with high normal NTx, and secondary hyperparathyroidism related to chronic kidney disease and hypovitaminosis D. The bone formation markers, e-GFR, NTx, and P composed the most important factors.

Changes of bone turnover markers after elderly hip fracture surgery

INTRODUCTION

Bone turnover markers (BTMs) can be used to monitor bone metabolism, while the actual clinical changing in hip fracture had not been certified to evaluate the changes of BTMs during the healing process after surgery of elderly hip fractures; and to get the effects of operation type, gender, serum 25(OH)D level, and age on bone turnover markers.

MATERIALS AND METHODS

A total of 100 elderly cases with hip fracture were selected, including 74 females and 26 males, and the patients were followed to 180-230 days after surgery. Serum levels of N-propeptide of type 1 collagen (P1NP), C-terminal crosslinking telopeptides of type 1 collagen (CTX), Osteocalcin (OC), and 25 hydroxy vitamin D (25OHD) were investigated. Bone mineral density (BMD) was measured with dual-energy X-ray absorptiometry (DXA).

RESULTS

(1) P1NP and CTX showed peak time at 30-60 days after operation, while OC keep going even at 180-230 days; P1NP showed less than 4 times elevation during healing, CTX and OC only had less than 2 times rise. (2) Female had higher serum CTX and OC than male, intramedullary nailing for intertrochanteric fracture patients had higher P1NP than hip replacement for femoral neck fracture patients, and both the degrees of increase were less than 50%. (3) Serum average 25(OH)D level had no effect on BTMs during the fracture healing; different from the young old (65-84 years), serum OC level of eldest older patients(≥ 85 years) decreased early in the process of fracture healing.

CONCLUSIONS

BTMs reached the peak level in 30-60 days after surgery, P1NP showed less than 4 times elevation, and CTX and OC had less than 2 times rise. It was not necessary to take gender into account when observing P1NP, and it was not necessary to take fracture and operation type into account when observing CTX and OC.

Investigating changes in calcium, phosphorus, alkaline phosphatase, and 25-hydroxy Vitamin D after surgical repair of fractures of femur or tibia

Background:

The recovery of long bones after fracture requires a specific process to restore the natural bone anatomy as well as its proper function. Changes in calcium, phosphorus, alkaline phosphatase and 25-hydroxy vitamin D can be justified either in the fracture process or in the repair procedure. The aim of this sectional study is to investigate changes in all these compounds after the surgical repair of fractures of femur and tibia bones.

Materials and Methods:

A random sample of 68 patients was selected from whom referring to a hospital with fractures of femur or tibia and candidate for repair surgery. The mentioned bone markers were measured at the time after surgery, six and twelve weeks after the surgery with laboratory-specific kits. A p-value, lower than 0.05, was considered to be statistically significant.

Result:

Of the patients, 34 were with fractures of femur and 34 were with fractures of tibia, equally. The patients were aged 2 to 69 with a mean age of 27.93 ± 14.8 years old. The means of calcium (p = 0.001) and phosphorus (p = 0.014) at three intervals were statistically significant difference. In contrast, the means serum alkaline phosphatase and vitamin D levels did not show any significant changes over time (p = 0.042).

Conclusion:

In conclusion, the means of calcium and phosphorus over the follow-up were statistically significant. The observed difference of vitamin D after the surgery, as well the level of alkaline phosphatase for femoral fracture between male and female are one of our important findings. (www.actabiomedica.it)

Calcium and vitamin-D deficiency marginally impairs fracture healing but aggravates posttraumatic bone loss in osteoporotic mice

Calcium and vitamin-D (Ca/VitD) deficiency is a major risk factor for osteoporosis. It may also contribute to the compromised bone healing frequently observed in osteoporotic patients, since calcium is essential for fracture-callus mineralization. Additionally, clinical data suggest systemic bone loss following fracture, which may aggravate osteoporosis and thus increase the risk for fragility fractures in osteoporotic patients further. However, the role of Ca/VitD in fracture healing and posttraumatic bone turnover has to date been poorly investigated. Here, we studied bone regeneration and posttraumatic bone turnover in C57BL/6 J mice with ovariectomy-induced osteoporosis. Mice were fed a standard or a Ca/VitD-deficient diet. Notably, fracture healing was only marginally disturbed in Ca/VitD-deficient mice. However, deficient mice displayed significantly increased serum parathyroid hormone levels and osteoclast activity, as well as reduced bone mass in the intact skeleton post-fracture, suggesting considerably enhanced calcium mobilization from the intact skeleton during bone regeneration. Ca/VitD supplementation initiated post-fracture prevented posttraumatic bone loss by reducing bone resorption and furthermore improved bone repair. These results imply that adequate Ca/VitD supply post-fracture is essential to provide sufficient calcium for callus-mineralization in order to prevent posttraumatic bone loss and to reduce the risk for secondary fractures in osteoporotic patients with Ca/VitD deficiency.

Hypocalcaemia after denosumab in older people following fracture

Hypocalcaemia following denosumab therapy can be observed in older adults. This is more common if their pre-treatment corrected serum calcium concentrations are less than 2.28 mmol/L. Denosumab remains a safe treatment in older people but we recommend a cautious approach in people at risk.

INTRODUCTION

Previous studies have indicated that denosumab, an anti-RANK ligand (RANKL) monoclonal antibody, for treatment of osteoporosis is well-tolerated. There is little data specifically regarding its adverse effect profile in a hospitalised older person. Primarily, this study wished to determine the frequency of hypocalcaemia following denosumab administration in older people admitted to hospital following fracture. Secondarily, this study wished to determine any associations that may predict the development of hypocalcaemia.

METHODS

This was a prospective study of 33 participants using a paired study design aged 70 years old or more with fragility fractures who were given denosumab in a rehabilitation hospital in Sydney. The primary outcome was the frequency of hypocalcaemia. Hypocalcaemia was defined as corrected serum concentration of less than 2.20 mmol/L on day 14 after denosumab administration.

RESULTS

Of the 33 participants with a mean age of 84.6 ± 1.2 years old, 5 participants (15.2 %) developed hypocalcaemia post injection. A paired t test showed a mean difference between the baseline and post injection calcium concentrations to be 0.059 mmol/L (95 %CI 0.020-0.098; t = 3.080, p = 0.004). Regression analysis showed that pre-denosumab serum calcium concentration correlated with the post-denosumab injection calcium concentration (R = 0.631, 95 %CI 0.288-0.977; p = 0.001). No other variables were significant. Further, a baseline serum calcium concentration of 2.28 mmol/L was able to predict post-denosumab hypocalcaemia with a sensitivity of 80 % and specificity of 86 %.

CONCLUSIONS

Denosumab is a relatively safe treatment of osteoporosis. This study shows that hypocalcaemia following denosumab therapy can be observed in older adults. Clinicians should be aware of this adverse effect when using denosumab in the older people.

Serum N-terminal telopeptide of type I collagen as an early marker of fracture nonunion in rabbits

The aim of the present study was to establish an experimental animal model of fracture nonunion, and to investigate the changes in serum biomarker concentrations in fracture nonunion. A total of 20 purebred New Zealand rabbits were divided into two group: A bone defect group and a bone fracture group. In the bone defect group, a 15-mm section of bone (including the periosteum) was removed from the mid-radius, and the medullary cavities were closed with bone wax. In the bone fracture group, the mid-radius was fractured. X-rays were taken and blood samples were collected preoperatively and at 2, 3, 4, 5, 6, 7, 8, 10 and 12 weeks after the surgical procedure. The serum concentrations of osteocalcin (OC) and bone-specific alkaline phosphatase (BSAP) served as markers of bone formation, and those of C-terminal telopeptide of type I collagen (CTX), N-terminal telopeptide of type I collagen (NTX) and tartrate-resistant acid phosphatase 5b (TRACP 5b) served as markers of bone resorption. The concentration levels of the markers were measured using a biotin double-antibody sandwich enzyme-linked immunosorbent assay. In the bone defect group, bone callus was observed on X-ray at 2 weeks in three rabbits and the bone calluses stabilized at 5 weeks; however, none of the bones had healed at 8 weeks. In the bone fracture group, the fracture line was distorted at 2 weeks and bone calluses formed at 6-8 weeks. In the bone defect group, the serum BSAP and TRACP 5b concentrations increased following the surgical procedure, peaked at 4 weeks, began to decrease at 5 weeks and stabilized after 6 weeks. The serum OC concentrations did not change significantly following the surgical procedure. The serum CTX concentrations fluctuated during the first 4 weeks, peaked at 5 weeks, then decreased and stabilized after 6 weeks. The serum NTX concentrations fluctuated during the first 4 weeks, were significantly lower at 5 weeks compared with the other time points and stabilized after 6 weeks. These results suggested that a bone nonunion model can be established in New Zealand rabbits by resecting a 15-mm section of bone from the mid-radius prior to bone wax blocking. Measurement of the serum BSAP, CTX, NTX, and TRACP 5b concentrations may be useful for the early detection of bone nonunion. The serum NTX concentrations changed significantly in rabbits with bone nonunion. Further studies are required in order to determine the feasibility of using serum NTX concentrations for the early diagnosis of bone nonunion.

Parathyroid hormone response to two levels of vitamin D deficiency is associated with high risk of medical problems during hospitalization in patients with hip fracture

BACKGROUND

Vitamin D and the parathyroid hormone (PTH) response play an important role in hip fracture patients. This study was carried out to determine the factors associated with the PTH response to different levels of vitamin D deficiency during hospitalization.

METHODS

This was a cross-sectional study of patients over 64 years of age admitted with an acute fragility hip fracture between March 1st 2009 and November 30th 2012. Demographic, clinical, functional, and cognitive function were evaluated at admission and during hospitalization. Levels of 25-hydroxyvitamin D (25-OHD) and PTH were analyzed. Two 25-OHD cut-off points were considered, <12 ng/ml and 12-20 ng/ml. Multivariate logistic regression analysis was used.

RESULTS

Mean age of the 607 patients included was 84.7 years (SD 7.10), and 81.9 % were women. The mean 25-OHD level in the total sample was 13.2 (SD 11.1) ng/ml. Levels of 25-OHD <12 ng/ml were present in 347 patients (57.2 %), of whom 158 (45.5 %) had secondary hyperparathyroidism (SHPT) (PTH >65 pg/ml). 25-OHD levels of 12-20 ng/ml were present in 168 (27.7 %) patients, of whom 47 (28 %) had SHPT. Following logistic regression, SHPT was associated in both groups (25-OHD <12 and 12-20 ng/ml) with a greater number of medical problems during hospitalization. In the 25-OHD group <12 ng/ml, SHPT was also associated with poorer glomerular filtration rates.

CONCLUSION

The PTH response to vitamin D deficiency in hip fracture patients may be a marker for patients with higher risk of developing multiple medical problems, both when considering severe (<12 ng/ml) and moderate (12-20 ng/ml) vitamin D deficiency.

Prospective nutritional analysis of a diverse trauma population demonstrates substantial hypovitaminosis D

OBJECTIVES

There are several metabolic factors known to be important for the maintenance of bone and muscle function. Causes of deficiency are multifactorial and can include such things as geographic region, latitude, and socioeconomic factors. The purpose of this study was to determine the prevalence of metabolic deficiencies.

SETTING

Level 1, urban trauma center.

DESIGN

Prospective laboratory evaluation.

PATIENTS

The subjects included 652 consecutive admits to the orthopaedic surgery service between July 1, 2011, and June 30, 2012.

INTERVENTION

Laboratory evaluation.

MAIN OUTCOME MEASUREMENTS

Metabolic and endocrine profiles included a serum analysis on all patients. Subject data included age, gender, body mass index, month of admission, and type of injury, and subjects' self-reported race, alcohol, recreational drug, and tobacco use were collected.

RESULTS

Six hundred fifty-two subjects with an average age of 41.2 years were evaluated. After data analysis, only 25-hydroxyvitamin D levels were found to be persistently poor across the patient population: 86.2% of subjects were insufficient in 25-hydroxyvitamin D (<30 ng/mL), 53.2% were deficient (<20 ng/mL), and 14.0% had levels <10 ng/mL (severely deficient); 76.7% of the subjects increased skin pigmentation, and the differences in 25-hydroxyvitamin D levels between races were significantly different. African Americans had the highest risk of severe deficiency. 25-Hydroxyvitamin D levels were significantly higher during summer months, with men, and with a lower body mass index, but there were no differences based on age or substance use. Additional laboratory analysis did not reveal significant nutritional deficiency.

CONCLUSIONS

The prevalence of hypovitaminosis D is widespread. This may negatively affect outcomes for orthopaedic patients but would be easily correctable. 25-Hydroxyvitamin D serologic analysis should be considered for all orthopaedic trauma patients.

LEVEL OF EVIDENCE

Prognostic Level IV. See Instructions for Authors for a complete description of levels of evidence.

Characteristics of bone turnover in the long bone metaphysis fractured patients with normal or low Bone Mineral Density (BMD)

The incidence of osteoporotic fractures increases as our population ages. Until now, the exact biochemical processes that occur during the healing of metaphyseal fractures remain unclear. Diagnostic instruments that allow a dynamic insight into the fracture healing process are as yet unavailable. In the present matched pair analysis, we study the time course of the osteoanabolic markers bone specific alkaline phosphatase (BAP) and transforming growth factor β1 (TGFβ1), as well as the osteocatabolic markers crosslinked C-telopeptide of type-I-collagen (β-CTX) and serum band 5 tartrate-resistant acid phosphatase (TRAP5b), during the healing of fractures that have a low level of bone mineral density (BMD) compared with fractures that have a normal BMD. Between March 2007 and February 2009, 30 patients aged older than 50 years who suffered a metaphyseal fracture were included in our study. BMDs were verified by dual energy Xray absorptiometry (DXEA) scans. The levels of BTMs were examined over an 8-week period. Osteoanabolic BAP levels in those with low levels of BMD were significantly different from the BAP levels in those with normal BMD. BAP levels in the former group increased constantly, whereas the latter group showed an initial strong decrease in BAP followed by slowly rising values. Osteocatabolic β-CTX increased in the bone of the normal BMD group constantly, whereas these levels decreased significantly in the bone of the group with low BMD from the first week. TRAP5b was significantly reduced in the low level BMD group. With this work, we conduct first insights into the molecular biology of the fracture healing process in patients with low levels of BMD that explains the mechanism of its fracture healing. The results may be one reason for the reduced healing qualities in bones with low BMD.

Characteristics of bone metabolism markers during the healing of osteoporotic versus nonosteoporotic metaphyseal long bone fractures: a matched pair analysis

PURPOSE

The activity and metabolism of fracture healing can be monitored quantitatively by measuring bone turnover markers (BTMs) in serum or urine. However, in osteoporotic bone, the exact metabolism processes during the healing of metaphyseal fractures remain unknown. There is no diagnostic approach which currently allows dynamic insight into the fracture healing processes in order to monitor the progression of healing and to assist in therapeutic decision making.

METHODS

Between March 2007 and February 2009, 30 patients over 50 years of age who suffered a metaphyseal fracture were included in our study. The levels of the osteoanabolic marker BAP (bone-specific alkaline phosphatase) and osteocatabolic marker β-CTX [crosslinked C-(CTX)-telopeptide-of-type-I-collagen] were monitored during the fracture healing of osteoporotic and nonosteoporotic fractures for a duration of 8 weeks.

RESULTS

After an initial decrease of BAP in the first week, the BAP level steadily increased through the fourth week in both groups. The levels of BAP in the osteoporotic group surpassed the healthy group. β-CTX steadily increased in healthy bone up to the fourth week; in osteoporotic bone, β-CTX first increased and, thereafter, decreased from the first week onwards.

CONCLUSIONS

In this work, the first molecular biological aspects of osteoporotic fracture healing have been uncovered, helping to explain the mechanisms of delayed fracture healing in osteoporotic bone. The early decrease of reduced β-CTX as well as elevated BAP during the healing process may be the first aspects within the delayed healing of osteoporotic bone. Further studies are necessary in order to achieve more detailed insight to fracture healing and to ascertain the progression of fracture healing as being essential (criteria) for therapeutic decision making.

Serum intact-parathyroid hormone level following total knee arthroplasty

PURPOSE

To evaluate short-term parathyroid hormone (PTH) secretion following total knee arthroplasty (TKA).

METHODS

119 Caucasian postmenopausal women aged 49 to 81 (mean, 69.8) years who underwent TKA for end-stage knee osteoarthritis were included. Serum levels of intact-PTH, calcium, phosphorus, and creatinine were evaluated pre- and post-operatively (on days -1 and 7). Creatinine clearance was also calculated.

RESULTS

In 67 of the patients, serum intact-PTH levels decreased after TKA; this sample proportion was not significant (p=0.82). In 16 of the patients, such levels elevated abnormally (above normal range). In the remaining 36 patients, such levels elevated within the normal range. Therefore, the mean serum intact- PTH level of all patients increased slightly after TKA (45.4 vs. 45.3, p=0.162). The serum intact-PTH level did not correlate to body weight (r=-0.045, p=0.624), patient age (r=-0.061, p=0.508), serum creatinine level (r=0.084, p=0.366), and clearance of creatinine (r=-0.037, p=0.692).

CONCLUSION

In most postmenopausal women, the serum intact-PTH level decreased moderately following TKA, but in some, the level was abnormally elevated. This may interfere the prosthesis incorporation process.

Comparison in bone turnover markers during early healing of femoral neck fracture and trochanteric fracture in elderly patients

Healing of fractures is different for each bone and bone turnover markers may reflect the fracture healing process. The purpose of this study was to determine the characteristic changes in bone turnover markers during the fracture healing process. The subjects were consecutive patients with femoral neck or trochanteric fracture who underwent surgery and achieved bone union. There were a total of 39 patients, including 33 women and 6 men. There were 18 patients (16 women and 2 men) with femoral neck fracture and 21 patients (17 women and 4 men) with trochanteric fracture. Serum bone-specific alkaline phosphatase (BAP) was measured as a bone formation marker. Urine and serum levels of N-terminal telopeptide of type I collagen (NTX), as well as urine levels of C-terminal telopeptide of type I collagen (CTX) and deoxypyridinoline (DPD), were measured as markers of bone resorption. All bone turnover markers showed similar changes in patients with either type of fracture, but significantly higher levels of both bone formation and resorption markers were observed in trochanteric fracture patients than in neck fracture patients. BAP showed similar levels at one week after surgery and then increased. Bone resorption markers were increased after surgery in patients with either fracture. The markers reached their peak values at three weeks (BAP and urinary NTX), five weeks (serum NTX and DPD), and 2–3 weeks (CTX) after surgery. The increase in bone turnover markers after hip fracture surgery and the subsequent decrease may reflect increased bone formation and remodeling during the healing process. Both fractures had a similar bone turnover marker profile, but the extent of the changes differed between femoral neck and trochanteric fractures.

Serum levels of bone turnover markers following total joint arthroplasty

PURPOSE

To evaluate changes in serum levels of bone turnover markers during the first year following a total hip or knee arthroplasty (THA or TKA, respectively).

METHODS

34 women and 13 men (mean age, 68 years) with idiopathic hip or knee osteoarthritis underwent elective THA or TKA. The serum levels of (1) osteoprotegerin, (2) nuclear factor-kappa B ligand (RANKL), (3) osteocalcin, and (4) bone-specific alkaline phosphatase (b-ALP) were determined in each patient on preoperative day 1 and postoperative day 3 and 7, and month 2, 4, 6, 8, 10, and 12.

RESULTS

All 4 markers changed significantly over the 12-month period. At month 12, values of all markers did not return to their preoperative levels uniformly. At month 8, the serum levels of osteoprotegerin, osteocalcin, and b-ALP remained higher than their respective preoperative values. The serum levels of RANKL gradually decreased after month 2, rendering this marker a potential index for fixation.

CONCLUSIONS

Bone turnover markers change following arthroplasties. Postoperative month 8 seems to be a milestone in the normal course of these markers.

Effects of a prolonged submersion on bone strength and metabolism in young healthy submariners

Submariners taking part in prolonged missions are exposed to environmental factors that may adversely affect bone health. Among these, relatively high levels of CO(2), lack of sunlight exposure affecting vitamin D metabolism, limited physical activity, and altered dietary habits. The aims of this study were to examine the effect of a prolonged submersion (30 days) on changes in bone strength using quantitative bone speed of sound and in markers of bone metabolism that include bone turnover (BAP, PINP, TRAP5b, and CTx) and endocrine regulators (serum calcium, PTH, and 25[OH]D) in a group of 32 young healthy male submariners. The prolonged submersion led to increases in body weight and BMI and to a decrease in fitness level. There was a significant decrease in bone strength following the submersion. Speed of sound exhibited continued decline at 4 weeks after return to shore and returned to baseline levels at the 6-month follow-up. There was a significant increase in circulating calcium level. PTH and 25(OH)D levels decreased significantly. Significant decreases were observed in both TRAP5b and CTx levels, markers of bone resorption, as well as in N-terminal propeptide of type I collagen (PINP), a bone formation marker. Prolonged submersion led to a significant decrease in bone strength, accompanied by an overall decrease in bone metabolism. Bone strength was regained only 6 months after return to shore. Prevention and/or rehabilitation programs should be developed following periods of relative disuse even for young submariners. The effects of repeated prolonged submersions on bone health are yet to be determined.

Bone mineral density and bone markers in patients with a recent low-energy fracture: effect of 1 y of treatment with calcium and vitamin D

BACKGROUND

Low-energy fractures of the hip, forearm, shoulder, and spine are known consequences of osteoporosis.

OBJECTIVE

We evaluated the effect of 1 y of treatment with calcium and vitamin D on bone mineral density (BMD) and bone markers in patients with a recent low-energy fracture.

DESIGN

In a double-blinded design, patients with fracture of the hip (lower-extremity fracture, or LEF) or upper extremity (UEF) were randomly assigned to receive 3000 mg calcium carbonate + 1400 IU cholecalciferol or placebo (200 IU cholecalciferol). BMD of the hip (HBMD) and lumbar spine (LBMD) were evaluated by dual-energy X-ray absorptiometry, and physical performance was assessed by the timed Up & Go test. Serum concentrations of 25-hydroxycholecalciferol, parathyroid hormone (PTH), telepeptide of type I collagen (ICTP), osteocalcin, and N-terminal propeptide of collagen type I were measured.

RESULTS

A total of 122 patients were included (84% women; x +/- SD age: 70 +/- 11 y); 68% completed the study. In an intention-to-treat analysis, LBMD increased in the intervention group and decreased in the placebo group, and the difference between the groups was significant after 12 mo: 0.931 +/- 0.211 compared with 0.848 +/- 0.194 (P<0.05). No significant change was shown for HBMD. The effect of treatment was more pronounced in patients aged <70 y. The intervention decreased bone turnover. PTH was significantly lower in the intervention group (P<0.01) for the LEF patients. ICTP and change in LBMD were significantly related to physical performance.

CONCLUSIONS

A 1-y intervention with calcium and vitamin D reduced bone turnover, significantly increased BMD in patients younger than 70 y, and decreased bone loss in older patients. The effect of treatment was related to physical performance.

Change of cross-linked telopeptide of type I collagen (ICTP) and other bone resorption markers in patients with bone fragility fractures

BACKGROUND

The serum concentration of cross-linked telopeptide of type I collagen (ICTP) has been reported to be a useful marker and for both diagnosis and monitoring of bone metastasis. This study was performed to clarify the changes in various bone turnover markers, including ICTP, after bone fragility fracture.

METHODS

Seventy-six bone fragility fracture patients (14 men and 62 postmenopausal women; mean age, 77.0 years) were evaluated for bone resorption markers, including serum ICTP. We measured urinary N-terminal telopeptides of type I collagen (NTX) several times after fracture. Furthermore, serum ICTP, serum NTX, urinary deoxypyridinoline (DPD), and urinary C-telopeptide-cross-linked type I collagen (CTX) were measured at the times of both minimum and maximum urinary NTX.

RESULTS

Urinary NTX was increased significantly from 86.4 +/- 57.9 to 214.3 +/- 137.2 nmol BCE/mmol Cr following fracture. Serum ICTP showed a similar significant increase from 7.6 +/- 4.7 to 10.4 +/- 5.5 ng/ml in bone fragility fracture patients. Furthermore, other markers also showed similar increases. The level of increase in urinary NTX (148.0%) was especially high compared with other bone resorption markers. On the other hand, the level of increase in serum ICTP (36.8%) was similar to that in serum NTX (39.8%). Serum ICTP levels were significantly correlated with other bone resorption markers, with an especially strong correlation between serum ICTP and serum NTX (r = 0.647, P < 0.001). The percentage of cases in which ICTP exceeded the cutoff value for suspected bone metastasis in postmenopausal women was 73.6%.

CONCLUSIONS

The value of ICTP increases with bone fragility fracture and is correlated with other bone resorption markers, and ICTP obviously exceeded the reference value as compared with other bone resorption markers.

Effect of age-related chronic immobility on markers of bone turnover

The effects of acute immobilization on bone turnover are well known, but the effects of chronic hypomobility with aging have not been studied. In a cohort of 1064 frail elderly subjects, immobility was significantly associated with serum PINP but not serum CTx after adjusting for confounders. The effect of immobility may be more marked on bone formation than on bone resorption.

INTRODUCTION

Accelerated bone turnover and rapid bone loss caused by acute immobilization is well recognized, but the effects of age-related chronic reduction in mobility on bone turnover have been less well studied. We assessed the associations between bone turnover and measures of mobility in a cohort of elderly subjects.

MATERIALS AND METHODS

We measured serum levels of the aminoterminal propeptide of type I collagen (PINP), a marker of bone formation, and serum concentrations of the carboxyterminal telopeptide of type I collagen (CTx), a marker of bone resorption, as well as serum intact PTH, serum 25 hydroxyvitamin D (25OHD), mobility, and static balance in a well-characterized sample of 1064 elderly men and women living in residential aged care facilities. Serum creatinine, phosphate, albumin, and calcium were measured in a randomly selected subgroup of 447 subjects.

RESULTS

The subjects were elderly and frail; their mean age was 86.0 years (range, 65-101 years); 69% used a walking aid; and 77% were vitamin D deficient (serum 25OHD level < 39 nM). Both serum PINP and CTx increased with age in both sexes. Elevated PINP or CTx was significantly correlated with high PTH, creatinine, and albumin in both genders, except for albumin in women. Age- and gender-adjusted serum CTx and PINP were significantly higher in those with poorer mobility and those with worse static balance. In multivariate analyses, higher serum PINP but not CTx was associated with poorer mobility and worse static balance.

CONCLUSIONS

Our findings suggest that poor mobility contributes to the state of accelerated bone turnover usually seen in the elderly. The effect of chronic relative immobility may be more marked on bone formation than bone resorption.

Vitamin D status among patients with hip fracture and elderly control subjects in Yekaterinburg, Russia

PURPOSE

Vitamin D deficiency leads to secondary hyperparathyroidism and osteomalacia, and both conditions are associated with fractures, the most severe being hip fracture. The serum 25-hydroxyvitamin D level depends on latitude and season. Yekaterinburg is situated at a high latitude and the duration of winter is about 5 months.

METHODS

In this study, the serum 25(OH)D and PTH concentrations, and the prevalence of hypovitaminosis D in elderly people, inhabitants of Yekaterinburg, were investigated. The study was performed on 63 people with hip fracture (mean age, 68.8 years) and 97 independently living elderly people (mean age, 70.2 years).

RESULTS

Serum 25(OH)D (mean+/-SD) in the hip fracture group was 22.4+/-11.4 nmol/L, significantly lower than in control group, which was 28.1+/-10.1 nmol/L. The percentage of patients with severe hypovitaminosis D (<25 nmol/L) in the hip fracture group was 65%, compared to 47% in the control group (p<0.05). The prevalence of hypovitaminosis D among hip fracture patients, as well as among independently living elderly people in Yekaterinburg, was high.

CONCLUSION

Supplementation of vitamin D in elderly people with and without fracture might prevent secondary hyperparathyroidism, osteomalacia and fractures.

Biochemical bone markers are useful to monitor fracture repair

Biochemical bone markers reflect bone metabolism but little is known regarding their usefulness during fracture repair. Reduced bone mineral density may influence fracture healing. We hypothesized that low bone mineral density results in decreased levels of bone markers during the acute phase of fracture healing, especially in women who are postmenopausal. We also addressed the question of different fracture types and locations resulting in different levels of bone markers. Urinary levels of N-terminal cross-linked telopeptide, deoxypyridinoline, and pyridinoline were measured preoperatively and postoperatively in patients with hip fractures, distal forearm fractures, and in 25 control subjects. Bone mineral density was determined using quantitative computed tomography of the spine. Patients with low bone mineral density, especially women who were postmenopausal, had greater concentrations of N-terminal cross-linked telopeptide when compared with patients with normal bone mineral density or men. Patients with pertrochanteric fractures had greater concentrations than patients with femoral neck fractures, as did patients with hip fractures compared with patients with fractures of the distal forearm. These results suggest that levels of bone markers increase during fracture healing despite low bone mineral density and that different fracture types and locations result in different levels of bone markers.

LEVEL OF EVIDENCE

Prognostic study, Level I (high quality prospective study-all patients were enrolled at the same time with > or = 80% of followup of enrolled patients). See the Guidelines for Authors for a complete description of levels of evidence.

Bone resorption and "relative" immobilization hypercalcemia with prolonged continuous renal replacement therapy and citrate anticoagulation

Regional citrate anticoagulation is an alternative to heparin in patients with bleeding diatheses who require continuous renal replacement therapy (CRRT). The short-term metabolic consequences that occur with citrate anticoagulation are well described and usually manageable if established protocols are followed vigilantly. Because of its customary short-term nature, the long-term consequences of CRRT with citrate are less often considered and have not been reported. The authors present the case of a woman with multisystem organ failure and prolonged acute renal failure who required CRRT for 120 days. Throughout her hospital course, adequate regional anticoagulation was achieved by blocking the coagulation cascade via the chelation of calcium by citrate. Despite an appropriate drop in the postfilter ionized calcium level, by 8 weeks after the initiation of CRRT, the patient was able to normalize serum calcium levels without the customary calcium infusion. Bone resorption owing to prolonged immobilization leading to hypercalcemia is a known complication of critically ill patients. This problem is more pronounced in patients with high bone turnover rates owing to conditions such as secondary hyperparathyroidism. In this particular case, the chelation of calcium by citrate masked the ensuing immobilization hypercalcemia, resulting in marked bone loss and bilateral spontaneous femoral fractures in the context of normal calcium levels. In critically ill patients sustained with prolonged CRRT with citrate anticoagulation, bone resorption and "relative" immobilization hypercalcemia may manifest as normal serum calcium levels in the face of falling calcium infusion rate requirements.

Vitamin D status and bone turnover in women with acute hip fracture

Hypovitaminosis D is common in elderly women. Few data are available on vitamin D status and bone turnover in women with acute hip fracture. The aims of this study were to determine whether elderly Italian women with an acute hip fracture also had low vitamin D levels and an increase of bone turnover compared with elderly women with osteoporosis but without fractures. Seventy-four women with acute osteoporotic hip fracture and 73 women with postmenopausal osteoporosis were studied. All women were self-sufficient and had adequate sunlight exposure. To exclude the effect of trauma on serum 25-hydroxycolecalciferol levels and bone markers (bone alkaline phosphatase and C-terminal telopeptides of Type I collagen as indices of bone formation and bone resorption), blood samples were drawn within 24 hours of the fracture. Current data indicated that in our patients the prevalence of hypovitaminosis D is common although to a lesser extent than in women who are housebound. Women with acute hip fractures had a higher prevalence of vitamin deficiency defined as serum 25-hydroxycolecalciferol lower than 12 ng/mL, compared with women with osteoporosis. Moreover, the presence of fracture did not influence the rate of bone formation, whereas the increase in bone resorption could be attributed to an older age of women with acute hip fracture because of similar values of parathyroid hormone levels in the two groups.

Beneficial Effect of Etidronate Therapy in Immobilized Hip Fracture Patients[Retracted]

OBJECTIVES

Hip fracture is among the most common causes of acute immobilization in elderly patients leading to increased bone resorption, and elderly patients with hip fracture are at high risk for a subsequent hip fracture.

DESIGN

In this double-blind, randomized, prospective study, 80 female patients who were immobilized because of a hip fracture were divided into two groups. The etidronate group received oral administration of 200 mg/day etidronate for 2 wks starting 1 day after the surgery. Then, after a 9-wk intermission, etidronate administration was resumed for 2 wks. The placebo group received placebo in a similar manner.

RESULTS

At baseline, both groups had high serum concentrations of ionized calcium, high urinary deoxypyridinoline (D-Pyr) concentrations, and decreased calcitriol concentrations, suggesting immobilization-induced hypercalcemia and inhibition of renal synthesis of calcitriol. After treatment, serum calcitriol concentrations increased in the etidronate and placebo groups. The etidronate group had significant decreases in serum ionized calcium and urinary D-Pyr, and the placebo group had higher serum calcium and urinary D-Pyr concentrations.

CONCLUSIONS

Etidronate therapy inhibits bone resorption and improves calcium balance, and such therapy may prevent bone loss and reduce the risk of subsequent hip fracture.

Comparison of biochemical markers of bone turnover and bone mineral density between hip fracture and vertebral fracture

Bone density and the biochemical markers of bone turnover were compared between 26 hip-fracture patients and 41 vertebral-fracture patients after age adjustment to investigate whether or not type of osteoporosis differs between hip fracture and vertebral fracture. C-Terminal propepides of type I collagen (PIPC) was lower in hip fracture than vertebral fracture. The other bone formation markers (bone-specific alkaline phosphatase [ALP], osteocalcin) tended to be lower, and bone resorption markers (deoxypyridinoline, C-telopeptide crosslinking of type I collagen [CTX] tended to be higher in hip fracture compared to vertebral fracture. Mean of Z-scores of spine bone mineral density (BMD) in hip fracture and vertebral fracture were -0.461 and -0.919, respectively. Mean of Z-scores of femoral neck BMD in hip fracture and vertebral fracture were -0.994 and -0.361, respectively. All Z-scores were negative values, which means reduction of BMD compared to decade-matched controls. Z-scores of bone formation markers, such as bone-specific ALP, osteocalcin, and PIPC, were positive values in vertebral fracture, which means an increase against decade-matched controls, whereas those were negative values in hip fracture. Z-scores of bone resorption markers, such as deoxypyridinoline and CTX, were greater in hip fracture than in vertebral fracture. To express bone balance between formation and resorption in hip fracture and vertebral fracture, we calculated an uncoupling status index (USI) by the values of biochemical markers. USI of hip fracture showed a great negative value (-1.29), which indicates excess of bone resorption over formation, whereas that of vertebral fracture showed a small positive value (0.23). In conclusion, bone formation markers increase in vertebral fractures, but decrease in hip fracture. Bone resorption markers increase in both fracture, but greater increase in hip fracture.