Antihypertensive medications, bone mineral density, and fractures: a review of old cardiac drugs that provides new insights into osteoporosis

Benzofuran-dihydropyridine hybrids: A new class of potential bone anabolic agents

A series of novel benzofuran-dihydropyridine hybrids were designed by molecular hybridization approach and evaluated for bone anabolic activities. Among the screened library, ethyl 4-(7-(sec-butyl)-2-(4-methylbenzoyl)benzofuran-5-yl)-2-methyl-5-oxo-1,4,5,6,7,8-hexahydroquinoline-3-carboxylate (compound 21) significantly enhanced the ALP production and mineralized nodule formation, which are primary requisites in the process of in vitro osteogenesis. Oral administration of compound 21 at 10 mg.kg^-1 day^-1 for two weeks led to restoration of trabecular bone microarchitecture in drill hole fracture model by significantly increasing BV/TV and Tb.N. Furthermore, histological and molecular studies showed compound 21 triggering the new bone regeneration in a drill hole defect site by increasing BMP expression. Furthermore, molecular modeling studies were performed to gain insight into the binding approach, which revealed that both benzofuran and dihydropyridine moieties are essential to show similar binding interactions to fit into the active site of BMP2 receptor, an important target of the osteogenic agents. Our results suggest that compound 21 stimulates BMP2 synthesis in osteoblast cells that promotes new bone formation (∼40%) at the fracture site which helps in shorten the healing period.

An increased rate of fracture occurs a decade earlier in HIV+ compared with HIV- men

OBJECTIVES

To determine the incidence of fracture among aging HIV-infected (HIV+) and uninfected men (HIV-). To evaluate factors independently associated with fracture risk.

DESIGN

Prospective, multicenter cohort study of men with or at risk for HIV.

METHODS

Outcome measures: all fractures (excluding skull, face and digits) and fragility fractures (vertebral column, femur, wrist and humerus) were collected semiannually in 1221 HIV+ and 1408 HIV- men aged at least 40. Adjusted incident rate ratios (aIRR) with an interaction term for age (40-49, 50-59 and ≥60 years) and HIV serostatus were estimated with Poisson regression models accounting for additional risk factors.

RESULTS

Fracture incidence increased with age among both HIV+ and HIV- men. Although there was no significant difference in fracture incidence by HIV serostatus among men aged 40-49 years, the HIV+ men aged 50-59 years had a significantly higher incidence of all fractures [aIRR: 2.06 (1.49, 2.84)] and fragility fractures [aIRR: 2.06 (1.21, 3.50)] compared with HIV- participants of similar age. HIV modified the effect of age on all fractures (P = 0.002) but did not significantly modify the effect for fragility fractures (P = 0.135). Hypertension increased the rate of all fractures by 32% after adjustment for covariates [aIRR: 1.32 (1.04, 1.69)].

CONCLUSION

Fracture incidence increased with age among HIV+ and HIV- men but was higher among HIV+ men. A significant increase in fracture incidence was found among 50-59-year-old HIV+ men, highlighting the importance of osteoporosis screening for HIV-infected men above the age of 50.

Angiotensin (1-7) ameliorates the structural and biochemical alterations of ovariectomy-induced osteoporosis in rats via activation of ACE-2/Mas receptor axis

The local and systemic renin angiotensin system (RAS) influences the skeletal system micro-structure and metabolism. Studies suggested angiotensin 1-7 (Ang(1-7)) as the beneficial RAS molecule via Mas receptor activation. This study examines the function of Ang(1-7) in bone micro-architecture and metabolism in an ovariectomized (OVX) rodent model of osteoporosis. OVX rats showed structural and bone metabolic degeneration in parallel with suppressed expressions of the angiotensin converting enzyme-2 (ACE-2)/Ang(1-7)/Mas components. The infusion of Ang(1-7) markedly alleviated the altered bone metabolism and significantly enhanced both trabecular (metaphyseal) and cortical (metaphyseal-diaphyseal) morphometry. Urinary and bones minerals were also improved in OVX rats by Ang(1-7). The infusion of the heptapeptide enhanced ACE-2/Mas receptor expressions, while down-regulated AngII, ACE, and AngII type-1 receptor (AT1R) in OVX animals. Moreover, Ang(1-7) markedly improved osteoprotegerin (OPG) and lowered receptor activator NF-κB ligand (RANKL) expressions. The defensive properties of Ang(1-7) on bone metabolism, structure and minerals were considerably eradicated after blockage of Mas receptor with A-779. Ang(1-7)-induced up-regulated ACE-2/Ang(1-7)/Mas cascade and OPG expressions were abolished and the expressions of ACE/AngII/AT1R and RANKL were provoked by A-779. These findings shows for the first time the novel valuable therapeutic role of Ang(1-7) on bone health and metabolism through the ACE-2/Mas cascade.

Differential response of bone and kidney to ACEI in db/db mice: A potential effect of captopril on accelerating bone loss

The components of renin-angiotensin system (RAS) are expressed in the kidney and bone. Kidney disease and bone injury are common complications associated with diabetes. This study aimed to investigate the effects of an angiotensin-converting enzyme inhibitor, captopril, on the kidney and bone of db/db mice. The db/db mice were orally administered by gavage with captopril for 8weeks with db/+ mice as the non-diabetic control. Serum and urine biochemistries were determined by standard colorimetric methods or ELISA. Histological measurements were performed on the kidney by periodic acid-schiff staining and on the tibial proximal metaphysis by safranin O and masson-trichrome staining. Trabecular bone mass and bone quality were analyzed by microcomputed tomography. Quantitative polymerase chain reaction and immunoblotting were applied for molecular analysis on mRNA and protein expression. Captopril significantly improved albuminuria and glomerulosclerosis in db/db mice, and these effects might be attributed to the down-regulation of angiotensin II expression and the expression of its down-stream profibrotic factors in the kidney, like connective tissue growth factor and vascular endothelial growth factor. Urinary excretion of calcium and phosphorus markedly increased in db/db mice in response to captopril. Treatment with captopril induced a decrease in bone mineral density and deterioration of trabecular bone at proximal metaphysis of tibia in db/db mice, as shown in the histological and reconstructed 3-dimensional images. Even though captopril effectively reversed the diabetes-induced changes in calcium-binding protein 28-k and vitamin D receptor expression in the kidney as well as the expression of RAS components and bradykinin receptor-2 in bone tissue, treatment with captopril increased the osteoclast-covered bone surface, reduced the osteoblast-covered bone surface, down-regulated the expression of type 1 collagen and transcription factor runt-related transcription factor 2 (markers for osteoblastic functions), and up-regulated the expression of carbonic anhydrase II (marker for bone resorption). Captopril exerted therapeutic effects on renal injuries associated with type 2 diabetes but worsened the deteriorations of trabecular bone in db/db mice; the latter of which was at least in part due to the stimulation of osteoclastogenesis and the suppression of osteogenesis by captopril.

Reference intervals of β-C-terminal telopeptide of type I collagen, procollagen type I N-terminal propeptide and osteocalcin for very elderly Chinese men

AIM

The present study was intended to establish the reference intervals of β-C-terminal telopeptide of type I collagen, procollagen type I N-terminal propeptide and osteocalcin for very elderly (aged 80 years or more) Chinese men.

METHODS

A total of 1316 very elderly Chinese men were recruited into the study, and subjected to a survey of clinical characteristics, measurements of bone mineral density and assays of bone turnover markers. The relationships between underlying diseases and bone turnover markers were investigated, and the reference intervals of β-C-terminal telopeptide of type I collagen, procollagen type I N-terminal propeptide and osteocalcin for very elderly Chinese men were established through defining the central 95% range of all observations.

RESULTS

We found that type 2 diabetes mellitus, chronic obstructive pulmonary disease and abnormal bone mass were associated with serum bone turnover markers (P < 0.01), and thereby identified 208 men without type 2 diabetes mellitus, chronic obstructive pulmonary disease and/or abnormal bone mass as healthy participants from 1316 very elderly Chinese men. The reference intervals for very elderly Chinese men were 0.13-0.63 ng/mL for β-C-terminal telopeptide of type I collagen, 18-94 ng/mL for procollagen type I N-terminal propeptide and 9-28 ng/mL for osteocalcin, respectively. The three turnover markers were moderately correlated to each other (P < 0.001), and all negatively associated with the bone mineral density of three sites (P < 0.05).

CONCLUSIONS

We have established the reference intervals of β-C-terminal telopeptide of type I collagen, procollagen type I N-terminal propeptide and osteocalcin for very elderly Chinese men. Geriatr Gerontol Int 2017; 17: 773-778.

Does Sitagliptin Affect the Rate of Osteoporotic Fractures in Type 2 Diabetes? Population-Based Cohort Study

CONTEXT

Type 2 diabetes and osteoporosis are both common, chronic, and increase with age, whereas type 2 diabetes is also a risk factor for major osteoporotic fractures (MOFs). However, different treatments for type 2 diabetes can affect fracture risk differently, with metaanalyses showing some agents increase risk (eg, thiazolidinediones) and some reduce risk (eg, sitagliptin).

OBJECTIVE

To determine the independent association between new use of sitagliptin and MOF in a large population-based cohort study.

DESIGN, SETTING, AND SUBJECTS

A sitagliptin new user study design employing a nationally representative Unites States claims database of 72 738 insured patients with type 2 diabetes. We used 90-day time-varying sitagliptin exposure windows and controlled confounding by using multivariable analyses that adjusted for clinical data, comorbidities, and time-updated propensity scores.

MAIN OUTCOMES

We compared the incidence of MOF (hip, clinical spine, proximal humerus, distal radius) in new users of sitagliptin vs nonusers over a median 2.2 years follow-up.

RESULTS

At baseline, the median age was 52 years, 54% were men, and median A1c was 7.5%. There were 8894 new users of sitagliptin and 63 834 nonusers with a total 181 139 person-years of follow-up. There were 741 MOF (79 hip fractures), with 53 fractures (4.8 per 1000 person-years) among new users of sitagliptin vs 688 fractures (4.0 per 1000 person-years) among nonusers (P = .3 for difference). In multivariable analyses, sitagliptin was not associated with fracture (adjusted hazard ratio 1.1, 95% confidence interval 0.8-1.4; P = .7), although insulin (P < .001), sulfonylureas (P < .008), and thiazolidinedione (P = .019) were each independently associated with increased fracture risk.

CONCLUSIONS

Even in a young population with type 2 diabetes, osteoporotic fractures were not uncommon. New use of sitagliptin was not associated with fracture, but other commonly used second-line agents for type 2 diabetes were associated with increased risk. These data should be considered when making treatment decisions for those with type 2 diabetes at particularly high risk of fractures.

Prevalence of osteoporosis in schizophrenia patients using the osteoporosis self-assessment tool for Asians

OBJECTIVE

The aims of the current study were to investigate the prevalence and socio-demographic correlates of risk of osteoporosis in Singapore among patients with schizophrenia using the osteoporosis self-assessment tool for Asians (OSTA).

METHOD

Data for the current study was drawn from a clinical database maintained at the Institute of Mental Health Singapore. The OSTA index was used to calculate the risk for osteoporosis among those aged 50 years and above.

RESULTS

A total of 2569 patients were included in the study. About 34.6% met the criteria for osteoporosis using the OSTA cut-off of ≤ -1. Among the males 22.8% met criteria for high risk and 1.5% met criteria for very high risk, while among women 28.2% were at intermediate risk and 14.9% were at high risk of osteoporosis. The logistic regression analysis showed that older age and female gender were significantly associated with a higher risk of osteoporosis, while those with a history of hypertension and hyperlipidemia were less likely to be associated with a risk of osteoporosis.

CONCLUSION

The OSTA could be a useful, inexpensive and quick tool to both identify those with osteoporosis as well as to measure the effectiveness of interventions meant to alleviate it.

Association of Circulating Renin and Aldosterone With Osteocalcin and Bone Mineral Density in African Ancestry Families

Hypertension is associated with accelerated bone loss, and the renin-angiotensin-aldosterone system is a key regulator of blood pressure. Although components of this system are expressed in human bone cells, studies in humans are sparse. Thus, we studied the association of circulating renin and aldosterone with osteocalcin and bone mineral density. We recruited 373 African ancestry family members without regard to health status from 6 probands (mean family size: 62 and relative pairs: 1687). Participants underwent a clinical examination, dual-energy x-ray absorptiometry, and quantitative computed tomographic scans. Renin activity, aldosterone concentration, and osteocalcin were measured in fasting blood samples. Aldosterone/renin ratio was calculated as aldosterone concentration/renin activity. All models were analyzed using pedigree-based variance components methods. Full models included adjustment for age, sex, body composition, comorbidities, lifestyle factors, blood pressure, and antihypertensive medication. Higher renin activity was significantly associated with lower total osteocalcin and with higher trabecular bone mineral density (both P<0.01). There were also significant genetic correlations between renin activity and whole-body bone mineral density. There were no associations with aldosterone concentration in any model and results for aldosterone/renin ratio were similar to those for renin activity. This is the first study to report a significant association between renin activity and a marker of bone turnover and bone mineral density in generally healthy individuals. Also, there is evidence for significant genetic pleiotropy and, thus, there may be a shared biological mechanism underlying both the renin-angiotensin-aldosterone system and bone metabolism that is independent of hypertension.

Hypertension and aging

Hypertension is a highly prevalent condition with numerous health risks, and the incidence of hypertension is greatest among older adults. Traditional discussions of hypertension have largely focused on the risks for cardiovascular disease and associated events. However, there are a number of collateral effects, including risks for dementia, physical disability, and falls/fractures which are increasingly garnering attention in the hypertension literature. Several key mechanisms--including inflammation, oxidative stress, and endothelial dysfunction--are common to biologic aging and hypertension development and appear to have key mechanistic roles in the development of the cardiovascular and collateral risks of late-life hypertension. The objective of the present review is to highlight the multi-dimensional risks of hypertension among older adults and discuss potential strategies for treatment and future areas of research for improving overall care for older adults with hypertension.

Renin inhibitor aliskiren exerts beneficial effect on trabecular bone by regulating skeletal renin-angiotensin system and kallikrein-kinin system in ovariectomized mice

SUMMARY

The skeletal renin-angiotensin system contributes to the development of osteoporosis. The renin inhibitor aliskiren exhibited beneficial effects on trabecular bone of osteoporotic mice, and this action might be mediated through angiotensin and bradykinin receptor pathways. This study implies the potential application of renin inhibitor in the management for postmenopausal osteoporosis.

INTRODUCTION

The skeletal renin-angiotensin system plays key role in the pathological process of osteoporosis. The present study is designed to elucidate the effect of renin inhibitor aliskiren on trabecular bone and its potential action mechanism in ovariectomized (OVX) mice.

METHODS

The OVX mice were treated with low dose (5 mg/kg) or high dose (25 mg/kg) of aliskiren or its vehicle for 8 weeks. The bone turnover markers were measured by ELISA. The structural parameters of trabecular bone at lumbar vertebra (LV) and distal femoral metaphysis were measured by micro-CT. The expression of messenger RNA (mRNA) and protein was studied by RT-PCR and immunoblotting, respectively.

RESULTS

Aliskiren treatment reduced urinary excretion of calcium and serum level of tartrate-resistant acid phosphatase in OVX mice. The treatment with aliskiren significantly increased bone volume (BV/TV) and connectivity density (Conn.D) of trabecular bone at LV-2 and LV-5 as well as dramatically enhanced BV/TV, Conn.D, bone mineral density (BMD/BV) and decreased bone surface (BS/BV) at the distal femoral end. Aliskiren significantly down-regulated the expression of angiotensinogen, angiotensin II (Ang II), Ang II type 1 receptor, bradykinin receptor (BR)-1, and osteocytic-specific gene sclerostin as well as the osteoclast-specific genes, including carbonic anhydrase II, matrix metalloproteinase-9, and cathepsin K.

CONCLUSIONS

This study revealed that renin inhibitor aliskiren exhibited the beneficial effects on trabecular bone of ovariectomy-induced osteoporotic mice, and the underlying mechanism for this action might be mediated through Ang II and BR signaling pathways in bone.

Involvement of Renin-Angiotensin System in Damage of Angiotensin-Converting Enzyme Inhibitor Captopril on Bone of Normal Mice

This study was performed to investigate the effect of angiotensin-converting enzyme inhibitor, captopril, on bone metabolism and histology, and the action of captopril on the components of the skeletal renin-angiotensin system (RAS) and bradykinin receptor in normal male mice. The mice were orally administered captopril (10 mg/kg) for 4 weeks with vehicle-treated mice as normal control. The histology of trabecular bone at the distal femoral end was determined by hematoxylin & eosin, Safranin O and Masson-Trichrome staining. The captopril-treated mice showed a decreased level of testosterone (p<0.05) and procollagen type I N-terminal propeptide (p<0.05) in serum as compared to those in the control group. Captopril has detrimental effects on trabecular bone as demonstrated by the loss of cancellous bone mass and network connections as well as changes to the chondrocytes zone. The expression of angiotensin-converting enzyme (p<0.05), renin receptor (p<0.01), angiotensin II (p<0.05) and bradykinin receptor 2 (p<0.05) was significantly up-regulated following the captopril treatment. Thus, the potential underlying mechanism of the damage of captopril on bone can be attributed the increased activity of local bone RAS and the activation of bradykinin receptor.

Impairing effects of angiotensin-converting enzyme inhibitor Captopril on bone of normal mice

There are contradicting results about the effects of angiotensin-converting enzyme inhibitors (ACEIs) on bones. This study was aimed to investigate the effect of ACEI, Captopril, on bone metabolism and histology as well as the action of Captopril on skeletal renin-angiotensin system (RAS) and bradykinin receptor pathway in normal male mice. The urine, serum, tibias and femurs from normal control mice and Captopril-treated (10mg/kg) mice were collected for biochemical, histological and molecular analyses after drug administration for eight weeks. The mice after the treatment with Captopril had a significant decrease of serum testosterone level. The histological measurements showed the loss of trabecular bone mass and trabecular bone number, and the breakage of trabecular bone network as well as the changes of chondrocyte zone at epiphyseal plate in Captopril-treated mice. The defect of Captopril on trabecular bone was reflected by the quantitative bio-parameters from micro-CT. The expression of renin receptor and bradykinin B2 receptor (B2R) was significantly up-regulated in tibia of mice upon to the Captopril treatment, which decreased the ratio of OPG/RANKL and the expression of osteoblastic factor RUNX2. Furthermore, Captopril treatment resulted in the increase of pAkt/Akt and pNFκB expression in tibia. The present study revealed the impairing effects of Captopril on bone via interfering with the circulating sex hormone level and B2R pathway, which suggests that the bone metabolism of patients need to be carefully monitored when being prescribed for ACEIs.

Risk of hip fracture among older people using antihypertensive drugs: a nationwide cohort study

Background

Many people with a high risk of hip fracture have coexisting cardiovascular diseases. We aimed to examine associations between exposure to antihypertensive drugs and the risk of hip fracture among older people.

Methods

We conducted a cohort study of the 906,422 people born before 1945 and living in Norway in 2005. We obtained information on all prescriptions of antihypertensive drugs dispensed (the Norwegian Prescription Database) in 2004–2010 and the dates of primary hip fractures (the Norwegian Hip Fracture Registry) in 2005–2010. We compared the incidence rates of hip fracture during the time people were exposed and unexposed to antihypertensive drugs by calculating the standardized incidence ratio (SIR).

Results

Altogether, 39,938 people experienced a primary hip fracture (4.4 %). The risk of hip fracture was decreased among people exposed to thiazides (SIR 0.7, 95 % confidence interval (CI) 0.6–0.7), beta-blockers (SIR 0.7, 95 % CI 0.7–0.8), calcium channel blockers (SIR 0.8, 95 % CI 0.8–0.8), angiotensin II receptor blockers (SIR 0.8, 95 % CI 0.7–0.8), ACE inhibitor/thiazide combination products (SIR 0.7, 95 % CI 0.6–0.7) and angiotensin II receptor blocker/thiazide combination products (SIR 0.6, 95 % CI 0.6–0.6). Use of loop diuretics and ACE inhibitors (plain products) was associated with increased fracture risk in people born after 1924, and with decreased risk in those born before 1925. The protective associations were stronger among exposed men than among exposed women for all drugs except loop diuretics. The SIRs decreased with increasing age among exposed people, except for thiazides and angiotensin II receptor blockers.

Conclusions

We found a reduced risk of hip fracture associated with overall use of most antihypertensive drugs, but an increased risk with loop diuretics and ACE inhibitors among people younger than 80 years and in new users of loop diuretics. This may have great impact at the population level, because the use of antihypertensive drugs is widespread in people at risk of hip fracture. Clinical studies are needed to further explore these associations.

Electronic supplementary material

The online version of this article (doi:10.1186/s12877-015-0154-5) contains supplementary material, which is available to authorized users.

Risk of hip/femur fractures during the initiation period of α-adrenoceptor blocker therapy among elderly males: a self-controlled case series study

AIMS

This study aimed to evaluate the risk of hip/femur fractures during the initiation period of α-adrenoceptor blocker therapy using the National Health Insurance claims database, Taiwan, with a self-controlled case series design.

METHODS

All male beneficiaries aged over 50 years as of 2007, who were incident users of α-adrenoceptor blockers and also had a diagnosis of hip/femur fracture within the 2007-2009 study period were identified. The first day when the α-adrenoceptor blocker was prescribed was set as the index date. We partitioned the initial 21 day period following the index date as the post-exposure risk period 1, days 22-60 after the index date as the post-exposure risk period 2, the 21 day period prior to the index date as the pre-exposure risk period 1 and days 22-60 prior to the index date as the pre-exposure risk period 2. The remainder of the study period was defined as the unexposed period. The incidence rate ratio (IRR) of hip/femur fractures within each risk period compared with the unexposed period was estimated using a conditional Poisson regression model.

RESULTS

A total of 5875 men were included. Compared with the unexposed period, the IRR of hip/femur fractures was 1.36 (95% confidence interval 1.06, 1.74, P = 0.017) within the post-exposure risk period 1 for patients without concomitant prescriptions of anti-hypertensive agents.

CONCLUSIONS

Use of α-adrenoceptor blockers was associated with a small but significant increase in the risk of hip/femur fractures during the early initiation period in patients without concomitant prescriptions of anti-hypertensive agents.

Renin inhibition improves ovariectomy-induced osteoporosis of lumbar vertebra in mice

The skeletal renin–angiotensin system (RAS) is involved in the progression of osteoporosis and the active peptide within the RAS, angiotensin II (ANG II), has deleterious effects on bones. This study was performed to investigate whether suppression of the rate-limiting step of the RAS cascade by the renin inhibitor aliskiren has a benefit on trabecular bone in osteoporotic mice. A postmenopausal osteoporosis model was induced by bilateral ovariectomy. The ovariectomized (OVX) mice were treated with a low (5 mg/kg) or high (25 mg/kg) dose of aliskiren for 6 weeks. Micro-computed tomography was performed to detect trabecular bone parameters of lumbar vertebra and to obtain 3-dimensional (3D) images. Treatment with aliskiren markedly increased bone volume over total volume (p<0.05), trabecular bone number (p<0.05), connectivity density (p<0.05), and bone mineral density (p<0.05) and reduced trabecular bone separation (p<0.05) compared to vehicle-treated OVX mice. Similarly, the 3D images were consistent with the quantitative data that showed aliskiren could markedly reverse the ovariectomy-induced pathological changes of trabecular bone. Thus, this study indicated that the treatment of estrogen-deficient mice with aliskiren could markedly increase bone mass and improve trabecular bone structure, suggesting its potential application in treating postmenopausal osteoporosis.

Risk factors for the second contralateral hip fracture in elderly patients: a systematic review and meta-analysis

OBJECTIVES

To achieve a quantitative and comprehensive conclusion concerning the risk factors for the second contralateral hip fracture in elderly patients with initial hip fractures.

DATA SOURCES

This search was applied to Medline, Embase, Cochrane central database (all up to April 2014).

METHODS

All the studies on bilateral hip fractures in elderly patients published in English were reviewed and qualities of included studies were assessed using the Newcastle-Ottawa Scale. All the data were carefully and independently abstracted by two reviewers, any disagreement was settled by discussion. Data was pooled and a meta-analysis completed.

RESULTS

A total of 13 case-control studies were identified for the meta-analysis. The significant risk factors were female (odds ratio (OR), 1.30; 95% confidence interval (CI), 1.02-1.64), living in institutions (OR, 2.53; 95% CI, 1.33-4.85), osteoporosis (OR, 10.02; 95% CI, 5.41-18.57), low vision (OR, 2.09; 95% CI, 1.06-4.12), dementia (OR, 2.02; 95% CI, 1.54-2.65), dizziness (OR, 2.87; 95% CI, 1.42-5.87) cardiac diseases (OR, 1.33; 95% CI, 1.00-1.78) and respiration diseases (OR, 2.58; 95% CI, 1.22-5.47). No significant difference was found in admission age between patients with the unilateral hip fracture and the first hip fracture of bilateral hip groups (standardized mean difference, 0.02, 95% CI, -0.30 to 0.35].

CONCLUSIONS

Patients involved with female, living in institutions, osteoporosis, low vision, dizziness, dementia, respiration diseases and cardiac diseases were at risk for a second contralateral hip fracture after the initial hip fracture.