A Systematic Review and Meta-analysis of the Association Between Vitamin K Antagonist Use and Fracture

[Osteoporosis-Definition, risk assessment, diagnosis, prevention and treatment (update 2024) : Guidelines of the Austrian Society for Bone and Mineral Research]

BACKGROUND

Austria is among the countries with the highest incidence and prevalence of osteoporotic fractures worldwide. Guidelines for the prevention and management of osteoporosis were first published in 2010 under the auspices of the then Federation of Austrian Social Security Institutions and updated in 2017. The present comprehensively updated guidelines of the Austrian Society for Bone and Mineral Research are aimed at physicians of all specialties as well as decision makers and institutions in the Austrian healthcare system. The aim of these guidelines is to strengthen and improve the quality of medical care of patients with osteoporosis and osteoporotic fractures in Austria.

METHODS

These evidence-based recommendations were compiled taking randomized controlled trials, systematic reviews and meta-analyses as well as European and international reference guidelines published before 1 June 2023 into consideration. The grading of recommendations used ("conditional" and "strong") are based on the strength of the evidence. The evidence levels used mutual conversions of SIGN (1++ to 3) to NOGG criteria (Ia to IV).

RESULTS

The guidelines include all aspects associated with osteoporosis and osteoporotic fractures, such as secondary causes, prevention, diagnosis, estimation of the 10-year fracture risk using FRAX®, determination of Austria-specific FRAX®-based intervention thresholds, drug-based and non-drug-based treatment options and treatment monitoring. Recommendations for the office-based setting and decision makers and institutions in the Austrian healthcare system consider structured care models and options for osteoporosis-specific screening.

CONCLUSION

The guidelines present comprehensive, evidence-based information and instructions for the treatment of osteoporosis. It is expected that the quality of medical care for patients with this clinical picture will be substantially improved at all levels of the Austrian healthcare system.

Anticoagulant use in older persons at risk for falls: therapeutic dilemmas-a clinical review

PURPOSE

The aim of this clinical narrative review was to summarise the existing knowledge on the use of anticoagulants and potential adverse events in older people at risk of falls with a history of atrial fibrillation or venous thromboembolism. The review also offers practical steps prescribers can take when (de-)prescribing anticoagulants to maximise safety.

METHODS

Literature searches were conducted using PubMed, Embase and Scopus. Additional articles were identified by searching reference lists.

RESULTS

Anticoagulants are often underused in older people due to concerns about the risk of falls and intracranial haemorrhage. However, evidence suggests that the absolute risk is low and outweighed by the reduction in stroke risk. DOACs are now recommended first line for most patients due to their favourable safety profile. Off-label dose reduction of DOACs is not recommended due to reduced efficacy with limited reduction in bleeding risk. Medication review and falls prevention strategies should be implemented before prescribing anticoagulation. Deprescribing should be considered in severe frailty, limited life expectancy and increased bleeding risk (e.g., cerebral microbleeds).

CONCLUSION

When considering whether to (de-)prescribe anticoagulants, it is important to consider the risks associated with stopping therapy in addition to potential adverse events. Shared decision-making with the patient and their carers is crucial as patient and prescriber views often differ.

Impact of Osteoporosis Pharmacotherapy on Functional Outcomes after Ischemic Stroke

This study evaluated whether osteoporosis pharmacotherapy (OPT) affected functional outcomes in acute ischemic stroke patients with osteoporosis. Using a single-center registry database, we consecutively registered acute ischemic stroke patients between May 2016 and December 2020. All patients older than 55 years underwent routine bone densitometry within 7 days of stroke onset. OPT prescription was confirmed by reviewing medical records. We classified the patients into OPT and no OPT groups. We performed propensity score matching (PSM) to overcome the imbalance in multiple covariates between the two groups. We investigated whether OPT affected 1-year functional outcomes by multivariate analysis using a PSM cohort. Among 1307 consecutively registered acute ischemic stroke patients, 381 patients were enrolled in this study, of whom 134 (35.2%) were prescribed OPT at discharge, which was maintained for 1 year. In a multivariate analysis using a PSM cohort, the OPT group had a lower risk of dependency (odds ratio [OR], 0.52; 95% confidence interval [CI], 0.27-0.996) and poor functional outcome at 1 year (OR, 0.24; 95% CI, 0.10-0.57). The OPT group also had increased chance of late functional improvement (OR, 6.16; 95% CI, 1.12-33.79). This study showed that OPT could reduce dependency and poor functional outcomes and increase the chance of improving functional outcomes at 3 months and 1 year after ischemic stroke onset, and these findings could be helpful for improving functional outcomes and bone health after ischemic stroke.

The Pleiotropic Role of Vitamin K in Multimorbidity of Chronic Obstructive Pulmonary Disease

Although defined by the presence of airflow obstruction and respiratory symptoms, patients with chronic obstructive pulmonary disease (COPD) are characterized by multimorbidity. Numerous co-occurring conditions and systemic manifestations contribute to the clinical presentation and progression of COPD; however, underlying mechanisms for multimorbidity are currently not fully elucidated. Vitamin A and vitamin D have been related to COPD pathogenesis. Another fat-soluble vitamin, vitamin K, has been put forward to exert protective roles in COPD. Vitamin K is an unequivocal cofactor for the carboxylation of coagulation factors, but also for extra-hepatic proteins including the soft tissue calcification inhibitor matrix Gla-protein and the bone protein osteocalcin. Additionally, vitamin K has been shown to have anti-oxidant and anti-ferroptosis properties. In this review, we discuss the potential role of vitamin K in the systemic manifestations of COPD. We will elaborate on the effect of vitamin K on prevalent co-occurring chronic conditions in COPD including cardiovascular disorders, chronic kidney disease, osteoporosis, and sarcopenia. Finally, we link these conditions to COPD with vitamin K as a connecting factor and provide recommendations for future clinical studies.

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.

Secondary Osteoporosis

Osteoporosis is a global public health problem, with fractures contributing to significant morbidity and mortality. Although postmenopausal osteoporosis is most common, up to 30% of postmenopausal women, > 50% of premenopausal women, and between 50% and 80% of men have secondary osteoporosis. Exclusion of secondary causes is important, as treatment of such patients often commences by treating the underlying condition. These are varied but often neglected, ranging from endocrine to chronic inflammatory and genetic conditions. General screening is recommended for all patients with osteoporosis, with advanced investigations reserved for premenopausal women and men aged < 50 years, for older patients in whom classical risk factors for osteoporosis are absent, and for all patients with the lowest bone mass (Z-score ≤ -2). The response of secondary osteoporosis to conventional anti-osteoporosis therapy may be inadequate if the underlying condition is unrecognized and untreated. Bone densitometry, using dual-energy x-ray absorptiometry, may underestimate fracture risk in some chronic diseases, including glucocorticoid-induced osteoporosis, type 2 diabetes, and obesity, and may overestimate fracture risk in others (eg, Turner syndrome). FRAX and trabecular bone score may provide additional information regarding fracture risk in secondary osteoporosis, but their use is limited to adults aged ≥ 40 years and ≥ 50 years, respectively. In addition, FRAX requires adjustment in some chronic conditions, such as glucocorticoid use, type 2 diabetes, and HIV. In most conditions, evidence for antiresorptive or anabolic therapy is limited to increases in bone mass. Current osteoporosis management guidelines also neglect secondary osteoporosis and these existing evidence gaps are discussed.

Biological Role of Vitamin K-With Particular Emphasis on Cardiovascular and Renal Aspects

Vitamin K (VK) plays many important functions in the body. The most important of them include the contribution in calcium homeostasis and anticoagulation. Vascular calcification (VC) is one of the most important mechanisms of renal pathology. The most potent inhibitor of this process-matrix Gla protein (MGP) is VK-dependent. Chronic kidney disease (CKD) patients, both non-dialysed and hemodialysed, often have VK deficiency. Elevated uncarboxylated matrix Gla protein (ucMGP) levels indirectly reflected VK deficiency and are associated with a higher risk of cardiovascular events in these patients. It has been suggested that VK intake may reduce the VC and related cardiovascular risk. Vitamin K intake has been suggested to reduce VC and the associated cardiovascular risk. The role and possibility of VK supplementation as well as the impact of anticoagulation therapy on VK deficiency in CKD patients is discussed.

The Effects of Osteoporotic and Non-osteoporotic Medications on Fracture Risk and Bone Mineral Density

Osteoporosis is a highly prevalent bone disease affecting more than 37.5 million individuals in the European Union (EU) and the  United States of America (USA). It is characterized by low bone mineral density (BMD), impaired bone quality, and loss of structural and biomechanical properties, resulting in reduced bone strength. An increase in morbidity and mortality is seen in patients with osteoporosis, caused by the approximately 3.5 million new osteoporotic fractures occurring every year in the EU. Currently, different medications are available for the treatment of osteoporosis, including anti-resorptive and osteoanabolic medications. Bisphosphonates, which belong to the anti-resorptive medications, are the standard treatment for osteoporosis based on their positive effects on bone, long-term experience, and low costs. However, not only medications used for the treatment of osteoporosis can affect bone: several other medications are suggested to have an effect on bone as well, especially on fracture risk and BMD. Knowledge about the positive and negative effects of different medications on both fracture risk and BMD is important, as it can contribute to an improvement in osteoporosis prevention and treatment in general, and, even more importantly, to the individual's health. In this review, we therefore discuss the effects of both osteoporotic and non-osteoporotic medications on fracture risk and BMD. In addition, we discuss the underlying mechanisms of action.

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.

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.

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.

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.

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.

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.

Association of Anticoagulant Therapy With Risk of Fracture Among Patients With Atrial Fibrillation

IMPORTANCE

Warfarin is prescribed to patients with atrial fibrillation (AF) for the prevention of cardioembolic complications. Whether warfarin adversely affects bone health is controversial. The availability of alternate direct oral anticoagulant (DOAC) options now make it possible to evaluate the comparative safety of warfarin in association with fracture risk.

OBJECTIVE

To test the hypothesis that, among patients with nonvalvular AF, use of DOACs vs warfarin is associated with lower risk of incident fracture.

DESIGN, SETTING, AND PARTICIPANTS

This comparative effectiveness cohort study used the MarketScan administrative claims databases to identify patients with nonvalvular AF and who were prescribed oral anticoagulants from January 1, 2010, through September 30, 2015. To reduce confounding, patients were matched on age, sex, CHA2DS2-VASc (congestive heart failure, hypertension, age [>65 years = 1 point; >75 years = 2 points], diabetes, and previous stroke/transient ischemic attack [2 points], vascular disease) score, and high-dimensional propensity scores. The final analysis included 167 275 patients with AF. Data were analyzed from February 27, 2019 to September 18, 2019.

EXPOSURES

Warfarin and DOACs (dabigatran etexilate, rivaroxaban, and apixaban).

MAIN OUTCOMES AND MEASURES

Incident hip fracture, fracture requiring hospitalization, and all clinical fractures (identified using inpatient or outpatient claims) defined by International Classification of Diseases, Ninth Revision, Clinical Modification codes.

RESULTS

In the study population of 167 275 patients with AF (38.0% women and 62.0% men; mean [SD] age, 68.9 [12.5] years), a total of 817 hip fractures, 2013 hospitalized fractures, and 7294 total fractures occurred during a mean (SD) follow-up of 16.9 (13.7) months. In multivariable-adjusted, propensity score-matched Cox proportional hazards regression models, relative to new users of warfarin, new users of DOACs tended to be at lower risk of fractures requiring hospitalization (hazard ratio [HR], 0.87; 95% CI, 0.79-0.96) and all clinical fractures (HR, 0.93; 95% CI, 0.88-0.98), whereas the association with hip fractures (HR, 0.91; 95% CI, 0.78-1.07) was not statistically significant. When comparing individual DOACs with warfarin, the strongest findings were for apixaban (HR for hip fracture, 0.67 [95% CI, 0.45-0.98]; HR for fractures requiring hospitalization, 0.60 [95% CI, 0.47-0.78]; and HR for all clinical fractures, 0.86 [95% CI, 0.75-0.98]). In subgroup analyses, DOACs appeared more beneficial among patients with AF who also had a diagnosis of osteoporosis than among those without a diagnosis of osteoporosis.

CONCLUSIONS AND RELEVANCE

In this real-world population of 167 275 patients with AF, use of DOACs-particularly apixaban-compared with warfarin use was associated with lower fracture risk. These associations were more pronounced among patients with a diagnosis of osteoporosis. Given the potential adverse effects of warfarin on bone health, these findings suggest that caution should be used when prescribing warfarin to patients with AF at high risk of fracture.

Association between oral anticoagulants and osteoporosis: Real-world data mining using a multi-methodological approach

Introduction: Warfarin and direct oral anticoagulants (DOACs) have been widely used in antithrombotic therapy. Although warfarin use has been suspected to be associated with osteoporosis risk, several studies have shown otherwise. Conversely, a few reports have found an association between DOACs and osteoporosis. This study therefore clarifies the association between oral anticoagulants and osteoporosis by analyzing real-world data using different methodologies, algorithms, and databases. Methods: Real-world data from the US Food and Drug Administration Adverse Event Reporting System (FAERS; 2004-2016) and Japanese administrative claims database (2005-2017; JMDC Inc., Tokyo) were used. Reporting odds ratio (ROR) and information component (IC) were calculated through disproportionality analysis (DPA) using reports recorded in the FAERS. Sequence symmetry analysis (SSA) was employed to calculate the adjusted sequence ratio (SR) using the JMDC Claims Database. For the adjusted SR and ROR, a significant signal was detected when the lower limit of the two-sided 95% confidence interval (CI) was more than 1. For the IC, a significant signal was detected when the lower limit of the 95% CI was more than 0. Results: DPA for warfarin found significant signals for osteoporosis in ROR (1.43, 95% CI: 1.32-1.54) and IC (0.50, 95% CI: 0.39-0.61). SSA showed a significant association between warfarin use and osteoporosis or bisphosphonate use. Moreover, a significant association was observed in males and females, albeit only for warfarin. Conclusion: Multi-methodological data mining revealed that warfarin use, not DOACs, is significantly associated with osteoporosis regardless of sex difference.

Vitamin K and Bone Health: A Review on the Effects of Vitamin K Deficiency and Supplementation and the Effect of Non-Vitamin K Antagonist Oral Anticoagulants on Different Bone Parameters

Although known for its importance in the coagulation cascade, vitamin K has other functions. It is an essential vitamin for bone health, taking part in the carboxylation of many bone-related proteins, regulating genetic transcription of osteoblastic markers, and regulating bone reabsorption. Vitamin K deficiency is not uncommon, as deposits are scarce and dependent upon dietary supplementation and absorption. Vitamin K antagonist oral anticoagulants, which are prescribed to many patients, also induce vitamin K deficiency. Most studies find that low serum K1 concentrations, high levels of undercarboxylated osteocalcin (ucOC), and low dietary intake of both K1 and K2 are associated with a higher risk of fracture and lower BMD. Studies exploring the relationship between vitamin K supplementation and fracture risk also find that the risk of fracture is reduced with supplements, but high quality studies designed to evaluate fracture as its primary endpoint are needed. The reduction in risk of fracture with the use of non-vitamin K antagonist oral anticoagulants instead of warfarin is also of interest although once again, the available evidence offers disparate results. The scarce and limited evidence, including low quality studies reaching disparate conclusions, makes it impossible to extract solid conclusions on this topic, especially concerning the use of vitamin K supplements.

Anticoagulants and Osteoporosis

Anticoagulant agents are widely used in the treatment of thromboembolic events and in stroke prevention. Data about their effects on bone tissue are in some cases limited or inconsistent (oral anti-vitamin K agents), and in others are sufficiently strong (heparins) to suggest caution in their use in subjects at risk of osteoporosis. This review analyses the effects of this group of drugs on bone metabolism, on bone mineral density, and on fragility fractures. A literature search strategy was developed by an experienced team of specialists by consulting the MEDLINE platform, including published papers and reviews updated to March 2019. Literature supports a detrimental effect of heparin on bone, with an increase in fracture rate. Low molecular weight heparins (LMWHs) seem to be safer than heparin. Although anti-vitamin K agents (VKAs) have a significant impact on bone metabolism, and in particular, on osteocalcin, data on bone mineral density (BMD) and fractures are contrasting. To date, the new direct oral anticoagulants (DOACs) are found to safe for bone health.