Osteoporotic Fractures in Patients With Atrial Fibrillation Treated With Conventional Versus Direct Anticoagulants

Carbonate Apatite Honeycomb Scaffold-Based Drug Delivery System for Repairing Osteoporotic Bone Defects

Osteoporotic bone defects are difficult to repair in elderly patients. This study aimed to repair osteoporotic bone defects using a combination of bone tissue engineering (BTE) and drug delivery systems (DDS). Herein, honeycomb granules (HCGs) composed of carbonate apatite microspheres were fabricated as BTE scaffolds. Each HCG possesses hexagonal macropores and abundant interconnected micropores between the microspheres. Owing to these multiscale interconnected pores, HCGs can readily contain antibodies against sclerostin (Scl), which causes imbalances in bone homeostasis. Anti-Scl antibody-loaded HCGs (Scl-Ab-HCGs) regulate the release of Scl-Abs in response to the pH of the osteoporotic environment. In ovariectomized rabbit osteoporotic femurs, HCG monotherapy forms new bone with less osteocyte damage (fewer empty bone lacunae) and fewer osteoclasts than osteoporotic bone; however, it is insufficient to prevent receptor activator of nuclear factor-kappa B ligand (RANKL) overexpression. Consequently, HCG monotherapy restores bone quantity better than no treatment but not to normal levels. In contrast, new bone tissue formed by Scl-Ab-HCG-based DDS predominantly expresses osteocalcin rather than RANKL, similar to normal bone, and shows a similar osteocyte apoptosis level, bone quantity, and osteoclast number as normal bone. Thus, Scl-Ab-HCG-based DDS is a promising approach for osteoporotic bone defect repair.

Efficacy and safety of oral anticoagulants according to kidney function among patients with atrial fibrillation

BACKGROUND AND AIMS

Patients with severely reduced kidney function have been excluded from randomized controlled trials and data on the safety and efficacy of direct oral anticoagulants (DOACs) according to kidney function remain sparse. The aim was to evaluate the safety and efficacy of the DOACs across subgroups of kidney function.

METHODS

Using multiple Danish nationwide registers and laboratory databases, we included patients initiated on oral anticoagulants (OACs) with atrial fibrillation and available creatinine level and followed patients for 2 years to evaluate occurrence of stroke/thromboembolism (TE) and major bleeding.

RESULTS

Among 26 686 included patients, 3667 (13.7%) had an estimated glomerular filtration rate (eGFR) of 30-49 mL/min/1.73 m2 and 596 (2.2%) had an eGFR below 30 mL/min/1.73 m2. We found no evidence of differences regarding the risk of stroke/TE between the OACs (P-value interaction >0.05 for all). Apixaban was associated with a lower 2-year risk of major bleeding compared to vitamin K antagonists (VKA) [hazard ratio 0.79, 95% confidence interval (CI) 0.67-0.93], and the risk difference was significantly larger among patients with reduced kidney function (P-value interaction 0.018). Rivaroxaban was associated with a higher risk of bleeding compared to apixaban (hazard ratio 1.78, 95%CI 1.32-2.39) among patients with eGFR 30-49 mL/min/1.73 m2.

CONCLUSIONS

Overall, we found no differences regarding the risk of stroke/TE, but apixaban was associated with a 21% lower relative risk of major bleeding compared to VKA. This risk reduction was even greater when comparing apixaban to VKA among patients with eGFR 15-30 mL/min/1.73 m2, and when comparing apixaban to dabigatran and rivaroxaban among patients with eGFR 30-49 mL/min/1.73 m2.

Risk of osteoporosis in patients treated with direct oral anticoagulants vs. warfarin: an analysis of observational studies

Aims

Evidence on the association between the risk of new-onset osteoporosis and oral anticoagulants remains controversial. We aimed to compare the risk of osteoporosis associated with the use of direct oral anticoagulants (DOACs) with that associated with warfarin use.

Methods

Studies published up to 15 March 2023 that investigated the association between the use of DOACs and warfarin and the incidence of osteoporosis were identified by online searches in PubMed, Embase, the Cochrane Library, and Web of Science conducted by two independent investigators. Random-effects or fixed-effect models were employed to synthesize hazard ratios (HRs)/relative ratios (RRs) with 95% confidence intervals (CIs) for estimating the risk of osteoporosis correlated with DOAC and warfarin prescriptions (PROSPERO No. CRD42023401199).

Results

Our meta-analysis ultimately included four studies involving 74,338 patients. The results suggested that DOAC use was associated with a significantly lower incidence of new-onset osteoporosis than warfarin use (pooled HR: 0.71, 95% CI: 0.57 to 0.88, p < 0.001, I 2: 85.1%). Subanalyses revealed that rivaroxaban was associated with a lower risk of osteoporosis than both warfarin and dabigatran. In addition, DOACs were associated with a lower risk of developing osteoporosis than warfarin in both male and female patients, in patients with atrial fibrillation (AF), and in patients who underwent therapy for > 365 days.

Conclusion

DOAC users experienced a lower incidence of osteoporosis than warfarin users. This study may give us insight into safe anticoagulation strategies for patients who are at high risk of developing osteoporosis.

Systematic review registration

https://www.crd.york.ac.uk/PROSPERO, identifier CRD42023401199.

The association of non-vitamin K antagonist oral anticoagulants vs. warfarin and the risk of fractures for patients with atrial fibrillation: a systematic review and meta-analysis

BACKGROUND

The fracture risks of non-vitamin K antagonist oral anticoagulants (NOACs) vs. warfarin in patients with atrial fibrillation (AF) remain controversial.

METHODS

PubMed, Cochrane Library, EMBASE, Clinical Trials.gov databases for RCTs, and cohort studies were systematically searched from inception to 10 June 2021.

RESULTS

Twelve-two studies met the inclusion criteria and 477,821 patients were included. Warfarin increased the risk of fracture in AF patients compared with NOACs in overall any fracture (RR = 0.79; 95% CI = 0.70-10.88; p = 0.00), osteoporotic fracture (RR = 0.746; 95% CI = 0.630-0.883; p = 0.001). No significant difference was observed in the hip or pelvic fracture, vertebral fracture, extremity fracture, wrist fracture, femoral neck fracture, and ankle fracture. In subgroup analyses based on several aspects, NOACs were associated with a significant reduction in any fracture (standard dosage NOACs, cohort studies, elderly patients, rivaroxaban in RCTs, dabigatran, rivaroxaban, and apixaban in cohort studies), in the hip/pelvic fracture (follow-up time ≤1 year, cohort studies), and osteoporotic fracture (cohort studies).

CONCLUSION

NOACs were associated with a significantly lower risk of any fracture and osteoporotic fracture compared to warfarin. This benefit was also observed in specific NOACs types of dabigatran, rivaroxaban, and apixaban. However, whether NOACs had a less fracture risk than warfarin on the other risk of fractures was still uncertain.

Comparative Risks of Fracture Among Direct Oral Anticoagulants and Warfarin: A Systematic Review and Network Meta-Analysis

Importance

Previous studies have shown the effectiveness and safety of direct oral anticoagulants (DOACs), including lower fracture risks, compared to warfarin. However, direct or indirect comparisons between different DOACs are scarce in the literature.

Objective

This study aims to compare fracture risks among different DOACs and warfarin, including apixaban, rivaroxaban, dabigatran, and edoxaban, in patients with non-valvular atrial fibrillation (NVAF) or venous thromboembolism (VTE).

Methods

We searched PubMed/MEDLINE, Embase, Cochrane CENTRAL, and Web of Science for randomized controlled trials and cohort studies comparing the fracture risks among patients who used warfarin or DOACs, up to March 2021. Two authors extracted data and appraised the risk of bias of included studies. The primary outcome was fracture risk. We performed pairwise meta-analyses to compare differences between medications and network meta-analyses using frequentist random-effects models to compare through indirect evidence. We used surface under the cumulative ranking curve (SUCRA) and mean ranks to determine the probability of a DOAC ranking best in terms of fracture risk.

Results

Thirty-one studies were included in the final analysis. Twenty-four randomized controlled trials and seven cohort studies with 455,343 patients were included in the systematic review and network meta-analysis. Compared to warfarin, the risk of any fractures was lowest with apixaban [relative risk (RR) = 0.59; 95% confidence interval (CI): 0.48-0.73], followed by rivaroxaban (RR: 0.72; 95% CI: 0.60-0.86), edoxaban (RR: 0.88; 95% CI: 0.62-1.23), and dabigatran (RR = 0.90; 95% CI: 0.75-1.07). No substantial inconsistency between direct and indirect evidence was detected for all outcomes.

Conclusions

All DOACs were safer than warfarin concerning the risk of fracture; however, apixaban had the lowest relative risk of fracture within the class of DOACs. Further head-to-head prospective studies should confirm the comparative safety profiles of DOACs regarding fractures.

The Role of Vitamin K in CKD-MBD

PURPOSE OF REVIEW

We describe the mechanism of action of vitamin K, and its implication in cardiovascular disease, bone fractures, and inflammation to underline its protective role, especially in chronic kidney disease (CKD).

RECENT FINDINGS

Vitamin K acts as a coenzyme of y-glutamyl carboxylase, transforming undercarboxylated in carboxylated vitamin K-dependent proteins. Furthermore, through the binding of the nuclear steroid and xenobiotic receptor, it activates the expression of genes that encode proteins involved in the maintenance of bone quality and bone remodeling. There are three main types of K vitamers: phylloquinone, menaquinones, and menadione. CKD patients, for several conditions typical of the disease, are characterized by lower levels of vitamin K than the general populations, with a resulting higher prevalence of bone fractures, vascular calcifications, and mortality. Therefore, the definition of vitamin K dosage is an important issue, potentially leading to reduced bone fractures and improved vascular calcifications in the general population and CKD patients.

Fracture risks in patients with atrial fibrillation treated with different oral anticoagulants: a meta-analysis and systematic review

Aims

evidence on the difference in fracture risks for patients with atrial fibrillation (AF) receiving direct oral anticoagulants (DOACs) versus warfarin remains controversial. We aim to compare the fracture risks between the DOAC and warfarin prescriptions among the AF patients.

Methods and Results

we systematically searched PubMed, EMBASE, the Cochrane Library and Web of Science up to 19 April 2021 for relevant studies. And the observational studies regarding the relationship between the DAOC versus warfarin prescriptions and fracture risks among the patients with AF were included in this meta-analysis. Two investigators independently screened the articles and extracted the relevant data. A random- or fixed-effect model was applied to calculate the pooled hazard ratio/relative ratios with 95% confidence intervals of fracture risks associated with the DOAC and warfarin prescriptions. Six studies comprising 351,208 patients and 9,424 fractures were included in this meta-analysis. Overall, the AF patients treated with DOACs tend to present a lower risk of any fracture compared with those treated with warfarin (relative ratio: 0.82, 95% confidence interval (CI): 0.74–0.91). Sub-analyses for each individual DOAC indicate that apixaban and rivaroxan are associated with lower risk of any fracture compared with warfarin (HR: 0.75, 95% CI: 0.60–0.92, and HR: 0.79, 95% CI: 0.71–0.88, respectively).

Conclusion

this meta-analysis suggests that DOAC users have a lower risk of fractures than the warfarin users. The results of this study may provide optimal anticoagulation opportunities for AF patients with high fracture risk factors.

Risk of fracture in patients with non-valvular atrial fibrillation initiating direct oral anticoagulants vs. vitamin K antagonists

AIMS

To determine the risk of fracture associated with direct oral anticoagulants (DOACs) compared with vitamin K antagonists (VKAs) in patients with non-valvular atrial fibrillation (NVAF), accounting for cumulative duration of use.

METHODS AND RESULTS

Using Quebec administrative healthcare databases, we formed a cohort of all patients aged 40 years or older newly diagnosed with NVAF, who filled a first prescription for DOACs or VKAs between 2011 and 2014. Exposure was modelled as a time-varying variable whereby patients were considered unexposed up to 180 days of cumulative duration of use (to account for a biologically meaningful exposure) and exposed thereafter. The final cohort included 10 306 new users of DOACs and 15 357 new users of VKAs. After propensity score-based fine stratification and weighting, use of DOACs for 180 days or greater was associated with a 35% decreased risk of fracture [crude incidence rates 7.5 vs. 15.3 per 1000 person-years; adjusted hazard ratio (HR) 0.65, 95% confidence interval (CI) 0.46-0.91] compared to VKA duration ≥180 days. Direct oral anticoagulants use was also associated with a lower risk of hip fracture (HR 0.51, 95% CI 0.31-0.86) compared with VKAs. There was no difference in the rate of fracture for shorter duration of use (HR 1.10; 95% CI 0.79-1.53). The risk was not modified by age, sex, chronic kidney disease, osteoporosis, history of fracture or falls.

CONCLUSION

Prolonged use of DOACs is associated with a lower risk of fracture compared with VKAs. These findings support the first-line recommendation for DOACs in patients with NVAF.

Non-valvular Atrial Fibrillation in CKD: Role of Vitamin K Antagonists and Direct Oral Anticoagulants. A Narrative Review

Atrial fibrillation (AF) is the most common arrhythmia in chronic kidney disease (CKD), with a close bidirectional relationship between the two entities. The presence of CKD in AF increases the risk of thromboembolic events, mortality and bleeding. Vitamin K antagonists (VKA) have been the mainstay of treatment for the prevention of thromboembolic events in AF until recently, with confirmed benefits in AF patients with stage 3 CKD. However, the risk-benefit profile of VKA in patients with AF and stages 4-5 CKD is controversial due to the lack of evidence from randomized controlled trials. Treatment with VKA in CKD patients has been associated with conditions such as poorer anticoagulation quality, increased risk of bleeding, faster progression of vascular/valvular calcification and higher risk of calciphylaxis. Direct oral anticoagulants (DOACs) have shown equal or greater efficacy in stroke/systemic embolism prevention, and a better safety profile than VKA in post-hoc analysis of the pivotal randomized controlled trials in patients with non-valvular AF and stage 3 CKD, yet evidence of its risk-benefit profile in more advanced stages of CKD is scarce. Observational studies associate DOACs with a good safety/effectiveness profile compared to VKA in non-dialysis CKD patients. Further, DOACs have been associated with a lower risk of acute kidney injury and CKD development/progression than VKA. This narrative review summarizes the evidence of the efficacy and safety of warfarin and DOACs in patients with AF at different CKD stages, as well as their effects on renal function, vascular/valvular calcification and bone health.

Bone density and quality in patients treated with direct-acting oral anticoagulants versus warfarin

INTRODUCTION

Direct-acting oral anticoagulants (DOACs) are therapeutic alternatives to warfarin that act independently of vitamin K, thus not affecting bone matrix formation. The aim of this study was to compare bone mineral density (BMD) and microarchitecture in patients treated with DOACs versus warfarin.

METHODS

Cross-sectional, observational study in patients using oral anticoagulants for >1 year and a paired control group (CG). Based on the type of anticoagulant used, the patients were grouped into a DOAC (DOACG) or warfarin (WG) group. All patients filled out a questionnaire and underwent BMD evaluation and trabecular bone score (TBS) measurement.

RESULTS

In all, 150 patients were included (50 patients in each group). The mean age was 60.49 ± 7.48 years, and most participants were men (64%). The most frequent comorbidities were hypertension, dyslipidemia, and hyperglycemia (comparison between groups p > 0.05). Low bone mass was diagnosed in 42%, 50%, and 66% of the patients in the CG, DOACG, and WG, respectively (p = 0.012). On logistic regression analysis, BMD was associated with body mass index (BMI; odds ratio [OR] 0.846, 95% confidence interval [CI] 0.763-0.926, p = 0.001), creatinine level (OR 0.024, 95%CI 0.001-0.434, p = 0.017), and TBS value (OR 17.777, 95%CI 4.526-96.903, p = 0.000). The mean TBS decreased progressively from the CG to the DOACG and WG (1.328 ± 0.112, 1.264 ± 0.138, and 1.203 ± 0.112, respectively, p < 0.001). On multivariate linear regression, negative predictors of TBS included warfarin use (-0.06, 95%CI -0.11 to -0.02, p = 0.006), BMI (-0.01, 95%CI -0.01 to -0.00, p < 0.001), and hyperglycemia (-0.07, 95%CI -0.11 to -0.03, p = 0.003), while positive predictors were an active IPAQ classification (0.06, 95%CI 0.01-0.11, p = 0.029) and family history of hip fracture (0.07, 95%CI 0.01-0.14, p = 0.029).

CONCLUSION

Patients using anticoagulants have lower BMD and TBS values compared with controls. This negative effect on bone was more pronounced with warfarin, but was also seen with DOACs.

Non-vitamin K oral anticoagulants and risk of fractures: a systematic review and meta-analysis

AIMS

Comparative fracture risk for non-vitamin K antagonist oral anticoagulants (NOACs) and vitamin K antagonists (VKAs) among patients with atrial fibrillation (AF) remains unclear. This study aimed to provide summary relative risk (RR) estimates for associations between NOACs vs. VKAs and fracture risk.

METHODS AND RESULTS

PubMed, EMBASE, and Cochrane Library were searched from 2010 to 26 May 2020. Observational studies investigating the association between NOACs vs. VKAs and fracture risk in patients with AF were included. The adjusted effect estimates were pooled using the DerSimonian-Laird random effects models. The Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) and the Meta-analysis of Observational Studies in Epidemiological (MOOSE) guidelines were followed. Five observational studies comprising 269 922 patients and 4289 fractures were included. Non-vitamin K antagonist oral anticoagulants use was associated with a lower risk of any fractures compared to VKAs use, with moderate heterogeneity [pooled RR = 0.83, 95% confidence interval (CI): 0.75-0.92, P < 0.001, I2 = 73.0%]. When comparing individual NOAC to VKAs, a statistically significant lower risk of any fractures was found for rivaroxaban (pooled RR = 0.79, 95% CI: 0.71-0.88, P < 0.001, I2 = 55.2%) and apixaban (pooled RR = 0.75, 95% CI: 0.60-0.92, P = 0.007, I2 = 54.5%), but not dabigatran (pooled RR = 0.87, 95% CI: 0.74-1.01, P = 0.061, I2 = 74.6%). No differences were observed in all head-to-head comparisons between NOACs.

CONCLUSION

This large meta-analysis suggests that NOACs use was associated with a lower risk of fractures compared with VKAs. Fracture risks were similar between NOACs. These findings may help inform the optimal anticoagulant choice for patients with AF at high risk of fracture.

Association of Direct Oral Anticoagulants vs. Vitamin K Antagonists With Fractures in Atrial Fibrillation Patients: A Systematic Review and Meta-Analysis

Background: Current evidence regarding the application of direct oral anticoagulants (DOACs) vs. vitamin K antagonists (VKAs) on the fracture risk is inconsistent. Therefore, we conducted a meta-analysis to evaluate the fracture risk of DOACs vs. VKAs in patients with atrial fibrillation (AF).

Methods: The PubMed and Embase databases were systematically searched until June 2021 for all the studies that reported oral anticoagulants in AF patients. The random-effect model with an inverse variance method was selected to pool the risk ratios (RRs) and 95% confidence intervals (CIs).

Results: A total of 10 studies were included in this meta-analysis. Among AF patients receiving anticoagulants, DOAC users showed a reduced risk of any fracture compared to those with VKAs (RR = 0.80; 95% CI: 0.70–0.91) regardless of gender [males (RR = 0.79; 95% CI: 0.67–0.92) and females (RR = 0.71; 95% CI: 0.57–0.89)]. Apixaban (RR = 0.75; 95% CI: 0.60–0.92) and rivaroxaban (RR = 0.73; 95% CI: 0.61–0.88), but not dabigatran and edoxaban, were associated with a decreased risk of any fracture compared with VKAs. DOAC users had decreased risks of osteoporotic fractures (RR = 0.63; 95% CI: 0.47–0.84) and hip/pelvic fractures (RR = 0.88; 95% CI: 0.79–0.97) compared to those treated with VKAs.

Conclusions: Our meta-analysis suggested that the use of DOACs was associated with a reduced risk of any fracture compared with VKAs. Further studies should confirm our findings.

The modulatory effect and implication of gut microbiota on osteoporosis: from the perspective of "brain-gut-bone" axis

Osteoporosis (OP) is a kind of systemic metabolic disease characterized by decreased bone mass and destruction of the bone microstructure. In recent years, it has become an expected research trend to explore the cross-linking relationship in the pathogenesis process of OP so as to develop reasonable and effective intervention strategies. With the further development of intestinal microbiology and the profound exploration of the gut microbiota (GM), it has been further revealed that the "brain-gut" axis may be a potential target for the bone, thereby affecting the occurrence and progression of OP. Hence, based on the concept of "brain-gut-bone" axis, we look forward to deeply discussing and summarizing the cross-linking relationship of OP in the next three parts, including the "brain-bone" connection, "gut-bone" connection, and "brain-gut" connection, so as to provide an emerging thought for the prevention strategies and mechanism researches of OP.

A Network Meta-Analysis Comparing Osteoporotic Fracture among Different Direct Oral Anticoagulants and Vitamin K Antagonists in Patients with Atrial Fibrillation

Background

There are limited studies comparing the risk of osteoporosis and fractures between different direct oral anticoagulants (DOACs) and vitamin K antagonists (VKA) in non-valvular atrial fibrillation (AF). Using a network meta-analysis (NMA), we compared osteoporotic fractures among 5 different treatment arms, viz. dabigatran, rivaroxaban, apixaban, edoxaban, and VKA.

Methods

Ten studies, including 5 randomized control trials and 5 population-based studies, with a total of 321,844 patients (148,751 and 173,093 in the VKA and DOAC group, respectively) with a median follow-up of 2 years, were included. A Bayesian random-effects NMA model comparing fractures among the treatment arms was performed using MetInsight V3. Sensitivity analysis excluded studies with the highest residual deviances from the NMA model.

Results

The mean age of the patients was 70 years. The meta-analysis favored DOACs over VKA with significantly lower osteoporotic fracture (odds ratio [OR], 0.77; 95% credible interval [CrI], 0.70–0.86). The NMA demonstrated that fractures were significantly lower with apixaban compared with dabigatran (OR, 0.64; 95% CrI, 0.44–0.95); however, fractures were statistically similar between apixaban and rivaroxaban (OR, 0.84; 95% CrI, 0.58–1.24) and dabigatran and rivaroxaban (OR, 1.32; 95% CrI, 0.90–1.87). Based on the Bayesian model of NMA, the probability of osteoporotic fracture was highest with VKA and lowest with apixaban, followed by rivaroxaban, edoxaban, and dabigatran.

Conclusions

The decision to prescribe anticoagulants in elderly patients with AF should be made not only based on thrombotic and bleeding risks but also on the risk of osteoporotic fracture; these factors should be considered and incorporated in contemporary cardiology practice.

Direct oral anticoagulants and the risk of osteoporotic fractures in patients with non-valvular atrial fibrillation

Background:

The incidence of osteoporotic fracture increases with age, particularly in elderly populations with atrial fibrillation (AF). However, direct oral anticoagulants (DOACs) have less effect on osteoporotic fracture than vitamin K antagonists, it is unclear whether the risk of osteoporotic fracture is affected by different types and doses of DOACs in AF patients.

Methods:

This nationwide population-based cohort study included AF patients prescribed DOACs between 2011 and 2016 taken from the Taiwan National Health Insurance database. Adjusted hazard ratios (aHRs) for the risk of osteoporotic, hip, and spine fractures between DOAC users were compared using the Fine and Gray subdistribution hazard model to adjust for possible confounders.

Results:

A total of 56,795 patients who were prescribed DOACs were included in the present study. Among them, 24,597 patients received dabigatran, 26,968 received rivaroxaban, and 5230 received apixaban. After 2 years’ follow up, there was no significant difference in the incidence of osteoporotic, spine, or hip fracture among those receiving dabigatran, rivaroxaban, or apixaban. Subgroup analysis showed that patients taking dabigatran had a higher incidence of osteoporotic and hip fracture than those taking rivaroxaban and apixaban in cases with concomitant peripheral artery disease (PAD) or a history of hip fracture (p for interaction: 0.004 and 0.030, respectively). However, dabigatran users had a lower incidence of osteoporotic fracture and spine fracture in those receiving standard-dose DOACs compared with rivaroxaban and apixaban; whereas, they had a higher incidence of hip fractures when administered at low dose.

Conclusion:

AF patients with different DOACs did not have different risks of osteoporotic fracture overall. However, additional concomitant morbidities, such as PAD or a history of hip fracture, and standard/low doses might be associated with different risks for different DOACs. These findings should be taken into consideration in the clinic when the DOAC is being chosen.

Plain language summary

Different direct oral anticoagulants had different impact on osteoporotic fracture

Anticoagulation therapy is an essential therapy in atrial fibrillation (AF) patients, but osteoporotic fracture is another important issue in these patients prescribed with anticoagulants. However, no study has been conducted to evaluate the impact of different DOACs on different types of osteoporotic fractures. In our findings, although different DOACs had no significantly different impact on osteoporotic fractures, dabigatran users had a slightly higher incidence of osteoporotic and hip fractures among different DOACs, particularly in those have simultaneously had peripheral artery disease, a history of hip fracture. In addition, when AF patients taking low-dose DOACs, dabigatran users also have higher incidence of hip fracture than those taking other DOACs.

Mn-containing bioceramics inhibit osteoclastogenesis and promote osteoporotic bone regeneration via scavenging ROS

Osteoporosis is caused by an osteoclast activation mechanism. People suffering from osteoporosis are prone to bone defects. Increasing evidence indicates that scavenging reactive oxygen species (ROS) can inhibit receptor activator of nuclear factor κB ligand (RANKL)-induced osteoclastogenesis and suppress ovariectomy-induced osteoporosis. It is critical to develop biomaterials with antioxidant properties to modulate osteoclast activity for treating osteoporotic bone defects. Previous studies have shown that manganese (Mn) can improve bone regeneration, and Mn supplementation may treat osteoporosis. However, the effect of Mn on osteoclasts and the role of Mn in osteoporotic bone defects remain unclear. In present research, a model bioceramic, Mn-contained β-tricalcium phosphate (Mn-TCP) was prepared by introducing Mn into β-TCP. The introduction of Mn into β-TCP significantly improved the scavenging of oxygen radicals and nitrogen radicals, demonstrating that Mn-TCP bioceramics might have antioxidant properties. The in vitro and in vivo findings revealed that Mn²⁺ ions released from Mn-TCP bioceramics could distinctly inhibit the formation and function of osteoclasts, promote the differentiation of osteoblasts, and accelerate bone regeneration under osteoporotic conditions in vivo. Mechanistically, Mn-TCP bioceramics inhibited osteoclastogenesis and promoted the regeneration of osteoporotic bone defects by scavenging ROS via Nrf2 activation. These results suggest that Mn-containing bioceramics with osteoconductivity, ROS scavenging and bone resorption inhibition abilities may be an ideal biomaterial for the treatment of osteoporotic bone defect.

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Mn-containing bioceramics with osteoconductivity, ROS scavenging and bone resorption inhibition abilities were prepared.

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Mn-containing bioceramics inhibited osteoclastogenesis by scavenging ROS via Nrf2 activation in vitro.

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Mn-containing bioceramics acted as antioxidant biomaterials accelerated bone defect regeneration in osteoporotic rats.

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Mn-containing bioceramics can be further applied as a biomaterial for treating osteoporotic bone defects.

Vitamin K in CKD Bone Disorders

Vitamin K is principally known because it is involved in blood coagulation. Furthermore, epidemiological studies showed that its deficit was associated with increased fragility fractures, vascular calcification and mortality. There are two main types of vitamin K vitamers: Phylloquinone (or PK) and Menaquinones (MKn). Vitamin K acts both as coenzyme of y-glutamyl carboxylase (GGCX) transforming undercarboxylated in carboxylated vitamin K-dependent proteins (e.g., Osteocalcin and Matrix Gla Protein) and as a ligand of the nuclear steroid and xenobiotic receptor (SXR) (in murine species Pregnane X Receptor: PXR), expressed in osteoblasts. It has been highlighted that the uremic state is a condition of greater vitamin K deficiency than the general population with resulting higher prevalence of bone fractures, vascular calcifications and mortality. The purpose of this literature review is to evaluate the protective role of Vitamin K in bone health in CKD patients.

Fracture Risks in Patients Treated With Different Oral Anticoagulants: A Systematic Review and Meta-Analysis

Background Evidence on the differences in fracture risk associated with non-vitamin K antagonist oral anticoagulants (NOAC) and warfarin is inconsistent and inconclusive. We conducted a systematic review and meta-analysis to assess the fracture risk associated with NOACs and warfarin. Methods and Results We searched PubMed, Embase, Cochrane Library, Scopus, Web of Science, and ClinicalTrials.gov from inception until May 19, 2020. We included studies presenting measurements (regardless of primary/secondary/tertiary/safety outcomes) for any fracture in both NOAC and warfarin users. Two or more reviewers independently screened relevant articles, extracted data, and performed quality assessments. Data were retrieved to synthesize the pooled relative risk (RR) of fractures associated with NOACs versus warfarin. Random-effects models were used for data synthesis. We included 29 studies (5 cohort studies and 24 randomized controlled trials) with 388 209 patients. Patients treated with NOACs had lower risks of fracture than those treated with warfarin (pooled RR, 0.84; 95% CI, 0.77-0.91; P<0.001) with low heterogeneity (I²=38.9%). NOACs were also associated with significantly lower risks of hip fracture than warfarin (pooled RR, 0.89; 95% CI, 0.81-0.98; P=0.023). A nonsignificant trend of lower vertebral fracture risk in NOAC users was also observed (pooled RR, 0.74; 95% CI, 0.54-1.01; P=0.061). Subgroup analyses for individual NOACs demonstrated that dabigatran, rivaroxaban, and apixaban were significantly associated with lower fracture risks. Furthermore, the data synthesis results from randomized controlled trials and real-world cohort studies were quite consistent, indicating the robustness of our findings. Conclusions Compared with warfarin, NOACs are associated with lower risks of bone fracture.

Risk for osteoporotic fractures in patients with atrial fibrillation using different oral anticoagulants

Background

We aimed to investigate the comparative risk of fracture among patients with atrial fibrillation (AF) treated with warfarin or non-vitamin K antagonist oral anticoagulants (NOACs).

Methods

Using the Korean National Health Insurance Service database, patients with AF who received a prescription for apixaban, dabigatran, rivaroxaban, or warfarin between 2013 and 2016 were included. Risk of major fractures (osteoporotic hip, vertebral, or pelvic fractures) were compared using inverse probability of treatment weighting.

Results

There were 70,481 patients identified (41.3% women; mean [SD] age 70.5 [11.3] years); 16,992 apixaban, 22,514 dabigatran, 27,998 rivaroxaban, and 29,390 warfarin users. During a median follow-up of 390 days, 2412 major fractures occurred with weighted incidences per 100 patient-years of 2.56 for apixaban, 2.39 for dabigatran, 2.78 for rivaroxaban, and 3.43 for warfarin. NOAC use was associated with a lower risk for fracture than warfarin use: HR 0.70 (95% confidence interval [CI] 0.57–0.86) for apixaban, HR 0.69 (95% CI 0.60–0.78) for dabigatran, and HR 0.79 (95% CI 0.70–0.90) for rivaroxaban. In head-to-head comparisons between NOACs, there was no significant difference between apixaban and dabigatran. Rivaroxaban was associated with a higher risk for fracture than dabigatran (HR 1.15, 95% CI 1.02–1.31).

Conclusion

In patients with AF, NOAC use may result in a lower risk for osteoporotic fracture compared with warfarin use. Fracture risk does not seem to be altered by the choice of NOAC type, except for rivaroxaban. These associations may help inform benefit–risk assessments when choosing between the different anticoagulant types.

Risk of new-onset osteoporosis in single-center veteran population receiving direct oral anticoagulants versus warfarin

BACKGROUND

Oral anticoagulants (OAC) have shown to affect bone mineral density and cause osteoporosis. Limited studies have investigated the relationship between its use and risk of osteoporosis. We aim to compare the risk of osteoporosis in patients on warfarin versus direct oral anticoagulants (DOACs).

METHODS

A retrospective single-center cohort study was conducted in veterans age > 18 years of age in whom warfarin or DOACs were newly initiated between January 1st, 2012 to April 1st, 2020 at Salem VA Medical Center. Patients on OAC for at least 90 days qualified for inclusion and excluded if they were pregnant or had history of mechanical valve and mitral stenosis, on edoxaban or had previous history of osteoporosis or use of antiosteoporosis medication. Primary outcome was comparing incidence of new-onset osteoporosis between warfarin and DOACs. Secondary outcomes included comparing incidence of all clinical fractures, hip fractures, major bleeding and intracranial bleed between the treatments. Cox proportional hazard ratios (HRs) and 95% confidence intervals (CI) comparing the two treatment groups were calculated.

RESULTS

A total of 1526 patients on DOAC and 1121 in warfarin group were included in the study. After propensity-score (PS) matching, 943 patients were included in each arm. Baseline characteristics were similar after PS-matching. DOAC treatment was associated with lower incidence of new-onset osteoporosis as compared to warfarin in matched cohort (aHR: 0.19, 95% CI: 0.10-0.36; p < 0.0001). The risk of all clinical fracture and hip fracture was similar in patients receiving DOACs as versus warfarin (aHR: 1.18, 95% CI: 0.82-1.69; p = 0.3671). DOAC use was associated with lower risk of major bleed (aHR: 0.07, 95% CI: 0.03-0.15; p < 0.0001) and intracranial bleed (aHR: 0.14, 95% CI: 0.03-0.64; p = 0.0111).

CONCLUSION

Overall, as compared to warfarin, prolonged use of DOACs is associated with lower risk of new-onset osteoporosis. We hope that our study findings will enlighten current clinical practices assuring safe use of OAC in veteran patients.

The association of fracture risk in atrial fibrillation patients and long-term anticoagulant therapy category: a systematic review and meta-analysis

OBJECTIVE

Our study aimed to assess the risk of all fractures and hip fractures in patients with atrial fibrillation (AF) who took non-vitamin K antagonist oral anticoagulants (NOACs) compared to warfarin.

METHODS

We searched PubMed, Embase, and Cochrane Library and Clinical Trials.gov Website. Reviewed related researches up to January 31, 2020, to identify studies with more than 12 months of follow-up data. The protocol for this systematic review and meta-analysis has been registered in the International Prospective Register of Systematic Reviews (PROSPERO Number: CRD42020156893).

RESULTS

We included five RCT studies, and five observational studies that contained a total of 326,846 patients in our meta-analysis. Our meta-analysis showed that patients taken NOACs had no significant all fracture risk (RR = 0.91, 95% CI [0.81-1.01]) and hip fracture risk (RR = 0.92, 95% CI [0.82-1.03]) compared with those taken warfarin. Subanalysis showed that the risk of all fractures and hip fractures treated by NOACs were significant lower compared with warfarin in observational studies compared with RCT studies. Also, a subanalysis across the duration of anticoagulation showed the NOACs users have lower all fracture risk than warfarin users when the duration of anticoagulation ≤2 years (RR = 0.89, 95% CI [0.80-0.99]). Further analysis, significant lower all fracture risk in the rivaroxaban therapy (RR = 0.81; 95% CI [0.76-0.86]) compared with warfarin but no statistical significance in hip fracture. There were no significant difference of all fracture risk and hip fracture risk in dabigatran, apixaban, and edoxaban therapy compared with warfarin.

CONCLUSION

The meta-analysis demonstrated that NOACs associated with a significantly lower all fracture risk compared with warfarin when the duration of anticoagulation more than 2 years. Rivaroxaban users had lower risk of all fracture than warfarin users in AF patients. But there was no evidence to verify apixaban, edoxaban, and dabigatranin could decrease all fracture and hip fracture risk compared with warfarin.

The Safety and Efficacy of Rivaroxaban Compared with Warfarin in Patients with Atrial Fibrillation and Diabetes: A Systematic Review and Meta-analysis

AIMS

This meta-analysis was conducted to compare the efficacy and safety of rivaroxaban with warfarin in patients with atrial fibrillation (AF) and diabetes mellitus.

METHODS

PubMed, Embase, Cochrane Library, and Web of Science databases were systematically searched from the establishment of databases up to 15 October 2019. Studies on efficacy and safety outcomes of rivaroxaban and warfarin were included. Efficacy and safety outcomes, including stroke, ischemic stroke, stroke or systemic embolism, myocardial infarction, major adverse cardiac events, major bleeding, intracranial hemorrhage, and major gastrointestinal bleeding were collected for meta-analysis.

RESULTS

Compared with warfarin, rivaroxaban could significantly reduce stroke (risk ratio [RR] 0.77; 95% confidence interval [CI] 0.63-0.95; P = 0.01), ischemic stroke (RR 0.74; 95% CI 0.63-0.87; P = 0.0004), stroke or systemic embolism (RR 0.73; 95% CI 0.60-0.89; P = 0.002), myocardial infarction (RR 0.68; 95% CI 0.56-0.82; P < 0.0001), and major adverse cardiac events (RR 0.71; 95% CI 0.53-0.94; P = 0.02) in patients with AF and diabetes. Moreover, rivaroxaban was associated with a lower risk of major bleeding (RR 0.79; 95% CI 0.65-0.96; P = 0.02), intracranial hemorrhage (RR 0.52; 95% CI 0.39-0.69; P < 0.00001), and major gastrointestinal bleeding (RR 0.74; 95% CI 0.56-0.98; P = 0.04). Similar results were obtained in stratified meta-analysis of cohort studies.

CONCLUSION

Our study suggests a favorable risk-benefit profile of rivaroxaban, with superior efficacy and safety over warfarin in patients with AF and diabetes.

Vitamin K Intake in Chronic Stroke: Implications for Dietary Recommendations

Previous research has identified a possible association between vitamin K intake and cardiometabolic disease. This could mean that the assessment of vitamin K intake is a meaningful tool when monitoring individuals with preexisting cardiovascular disease. Sixty chronic stroke survivors (men and women, body mass index (BMI) 30.36 ± 6.61 kg/m², age 61.7 ± 7.2 years) completed food records which were analyzed for energy, macronutrient, micronutrient, and food group servings. Participants were divided into two groups: below vitamin K recommendation (BEL, n = 49) and met vitamin K recommendation (MET, n = 11). Energy and macronutrient intake did not differ between groups (all p > 0.127). Vegetable intake was higher in the MET group (p = 0.0001). Vitamin K intake was higher in the MET group (p = 0.0001). Calcium (p = 0.003), vitamin A (p = 0.007), and vitamin E (p = 0.005) intakes were higher in the MET group. There were no differences in sodium, potassium, vitamin D, vitamin C, and iron intakes between groups (all p > 0.212). In this sample of chronic stroke survivors, 82% reported consuming below the Dietary Reference Intake (DRI) for vitamin K. Given that the majority of this study population did not reach the DRI for vitamin K, it is advisable to promote the adequate intake of food rich in vitamin K. Further work is needed to determine the significance of low vitamin K intake in this population.

Effects of Anti-vitamin k oral anticoagulants on bone and cardiovascular health

Vitamin K antagonist oral anticoagulants (VKAs) have been proven over 50 years to be highly effective and acceptably safe in many settings and are still used by millions of people worldwide. The main concern about the safety of VKAs regards the risk of bleeding, but there is accumulation evidence of their potentially negative effects beyond hemostasis. Indeed, VKAs impair the action of several Vitamin-K Dependent Proteins (VKDP), such as Bone Gla protein, Matrix Gla protein, Gas6 Protein, Periostin and Gla-Ric Protein, involved in bone and vascular metabolism, thus exerting a detrimental effect on bone and vascular health. Indeed, although the evidence regarding this issue is not compelling, it has been shown that VKAs use decreases bone mass density, increases the risk of bone fractures and accelerates the process of vascular and valvular calcification. Vascular calcification is a major concern in Chronic Kidney Disease (CKD) patients, also in absence of VKAs, because of mineral metabolism derangement, chronic inflammation and oxidative stress. Direct Oral AntiCoagulants (DOACs) do not affect VKDP involved in vascular and valvular calcification, and do not induce calcific valve degeneration in animal models, being a possible alternative to AVK for CKD patients. However, the efficacy and safety of DOACs in this population, suggested by some recent observations, requires confirmation by dedicated, randomized study. We reviewed here the effects of VKAs in bone and vascular health as compared to DOACs, in order to provide the physicians with some data useful to wisely choose the most suitable anticoagulant for every patient.

Association Between Treatment With Apixaban, Dabigatran, Rivaroxaban, or Warfarin and Risk for Osteoporotic Fractures Among Patients With Atrial Fibrillation: A Population-Based Cohort Study

BACKGROUND

It is unclear whether anticoagulant type is associated with the risk for osteoporotic fracture, a deleterious complication of anticoagulants among patients with atrial fibrillation (AF).

OBJECTIVE

To compare the risk for osteoporotic fracture between anticoagulants.

DESIGN

Population-based cohort study.

SETTING

Territory-wide electronic health record database of the Hong Kong Hospital Authority.

PARTICIPANTS

Patients newly diagnosed with AF between 2010 and 2017 who received a new prescription for warfarin or a direct oral anticoagulant (DOAC) (apixaban, dabigatran, or rivaroxaban). Follow-up ended on 31 December 2018.

MEASUREMENTS

Osteoporotic hip and vertebral fractures in anticoagulant users were compared using propensity score-weighted cumulative incidence differences (CIDs).

RESULTS

There were 23 515 patients identified (3241 apixaban users, 6867 dabigatran users, 3866 rivaroxaban users, and 9541 warfarin users). Overall mean age was 74.4 years (SD, 10.8), ranging from 73.1 years (warfarin) to 77.9 years (apixaban). Over a median follow-up of 423 days, 401 fractures were identified (crude event number [weighted rate per 100 patient-years]: apixaban, 53 [0.82]; dabigatran, 95 [0.76]; rivaroxaban, 57 [0.67]; and warfarin, 196 [1.11]). After 24-month follow-up, DOAC use was associated with a lower risk for fracture than warfarin use (apixaban CID, -0.88% [95% CI, -1.66% to -0.21%]; dabigatran CID, -0.81% [CI, -1.34% to -0.23%]; and rivaroxaban CID, -1.13% [CI, -1.67% to -0.53%]). No differences were seen in all head-to-head comparisons between DOACs at 24 months (apixaban vs. dabigatran CID, -0.06% [CI, -0.69% to 0.49%]; rivaroxaban vs. dabigatran CID, -0.32% [CI, -0.84% to 0.18%]; and rivaroxaban vs. apixaban CID, -0.25% [CI, -0.86% to 0.40%]).

LIMITATION

Residual confounding is possible.

CONCLUSION

Among patients with AF, DOAC use may result in a lower risk for osteoporotic fracture compared with warfarin use. Fracture risk does not seem to be altered by the choice of DOAC. These findings may help inform the benefit-risk assessment when choosing between anticoagulants.

PRIMARY FUNDING SOURCE

The University of Hong Kong and University College London Strategic Partnership Fund.

The effects of vitamin K-rich green leafy vegetables on bone metabolism: A 4-week randomised controlled trial in middle-aged and older individuals

Background

High vegetable intake is associated with beneficial effects on bone. However, the mechanisms remain uncertain. Green leafy vegetables are a rich source of vitamin K1, which is known to have large effects on osteoblasts and osteocalcin (OC) metabolism.

Objective

To examine the effects of consumption of two to three extra serves of green leafy vegetables daily on bone metabolism.

Methods

Thirty individuals (mean age 61.8 ± 9.9 years, 67% male) completed three experimental phases in a randomised controlled crossover design, each lasting four weeks, with a washout period of four weeks between phases (clinical trial registration: ACTRN12615000194561). The three experimental phases were: (i) increased dietary vitamin K1 by consuming green leafy vegetables (H-K; ~200 g/d containing 164.3 [99.5-384.7] μg/d of vitamin K1); (ii) low vitamin K1 by consuming vitamin K1-poor vegetables (L-K; ~200 g/d containing 9.4 [7.7-11.6] μg/d of vitamin K1); and (iii) control (CON) where participants consumed an energy-matched non-vegetable control. OC forms, total OC (tOC), carboxylated OC (cOC) and undercarboxylated OC (ucOC), were measured in serum pre- and post-intervention for each experimental phase using a sandwich-electrochemiluminescence immunoassay.

Results

Pre-intervention tOC, ucOC and ucOC:tOC levels were similar between phases (P > .05). Following H-K, but not L-K, tOC, ucOC and ucOC:tOC levels were significantly lower compared to pre-intervention levels (P ≤ .001) and compared to CON (~14%, 31% and 19%, respectively, all P < .05), while cOC remained unchanged.

Conclusions

In middle-aged healthy men and women, an easily achieved increase in dietary intake of vitamin K1-rich green leafy vegetables substantially reduces serum tOC and ucOC suggesting increased entry of OC into bone matrix, where it may improve the material property of bone. In conjunction with previous epidemiological and randomised controlled trial data, these findings suggest that interventions to increase vegetable intake over extended periods should include bone end points including fracture risk.

Drug treatment strategies for osteoporosis in stroke patients

INTRODUCTION

Osteoporosis and subsequent fractures are well-recognized complications of stroke. However, drug treatment strategies for osteoporosis after stroke have been rarely discussed in the current guidelines for the management of stroke or osteoporosis.

AREAS COVERED

The authors review the epidemiology, characteristics, pathophysiology, and risk prediction of post-stroke osteoporosis and fractures. Then they provide an overview of existing evidence regarding drug treatment strategies for osteoporosis in stroke patients. They also review the effects on bone mineral density (BMD) and fractures for those drugs commonly used in stroke patients.

EXPERT OPINION

Currently, there is scarce evidence. A small randomized control trial suggested that a single use of 4 mg of intravenous zoledronate within 5 weeks of stroke onset was beneficial for preserving BMD, while simultaneous use of calcium and vitamin D supplements may be effective in preventing hypocalcemia. Further studies are needed to address several important issues of post-stroke osteoporosis, including who (the eligibility for treatment), when (the best timing of treatment), what (which drug), and how long (the best duration of treatment). On the other hand, physicians should bear in mind that drugs commonly used for stroke, such as statins or warfarin, may have beneficial or adverse effects on BMD and fracture risks.

Towards appropriate polypharmacy in older cardiovascular patients: How many medications do I have to take?

BACKGROUND

Polypharmacy in older adults leads to increased risks of side effects and drug-drug interactions, affecting their health outcomes and quality of life. Deprescribing, the act of simplifying medication regimens, is challenging due to the lack of consensus guidelines.

HYPOTHESIS

To offer some guidance on managing medication regimens for older cardiovascular patients.

METHODS

We reviewed the most recent pertinent guidelines and literature.

RESULTS

This review provides practical considerations for appropriate prescribing in the older population with cardiovascular disease in order to strike a balance between unnecessary or harmful medications and therapies with proven long-term benefits.

CONCLUSION

On-going dialogue between healthcare providers and patients allows close monitoring of medication effectiveness and prevention of side effects. Medication regimens require individualization, as patients' goals of care change with advancing age.