Oral Anticoagulation in the Elderly: New Oral Anticoagulants-Innovative Solution for an Old Problem?

Thin film microextraction of apixaban from plasma based on the covalent organic framework coated on a mesh prior to liquid chromatography-tandem mass spectrometry

In this research, a new covalent organic framework was synthesized and utilized as a coating in thin film microextraction for the extraction of apixaban from plasma samples. This coating was applied to the mesh modified through immersion in a HF solution. The extracted drug was then analyzed using liquid chromatography-tandem mass spectrometry. By combining the high specific surface area and selectivity of the covalent organic framework, along with integrating the innovative thin film microextraction method and a sensitive analysis system, an efficient analytical approach was achieved. The target analyte was preconcentrated and extracted by immersing of the covalent organic framework-coated mesh as an absorbent into the biological sample. Subsequently, a sonication process was conducted for a specific duration. Following this, the extracted analyte was desorbed using acetonitrile as the elution solvent. The effective parameters of the proposed technique were optimized by using "one-parameter-at-a-time" strategy and the optimal conditions were selected. By integrating the developed method notable achievements were made in the terms of low limits of detection and quantification (0.17 and 0.56 µg/L, respectively), a wide linear range (0.05-250 µg/L), intra- and inter day precisions (with relative standard deviations of ≤14 %), as well as satisfactory extraction recoveries (53 % and 54 % in plasma and deionized water, respectively). Hence, it can be concluded that the introduced technique exhibits high efficiency and reliability when applied to biological samples.

Warfarin Adherence and Its Associated Factors in Thai Older Adults with Atrial Fibrillation

Introduction

Older people mostly found unable to adhere with warfarin treatment guidelines. The health service system is challenged in order to improve medication adherence in older population under limited health resources. The purpose of this study was to explore health systems factors on warfarin adherence in older population, particularly in resources constraint setting.

Methods

This study was a cross-sectional predictive study that enrolled older people who experienced atrial fibrillation (AF) and treated by warfarin, aged 60 years and over, and followed up at the warfarin clinic.

Results

A total of 197 participants with the mean age of 72.03 years (SD = 8.84) was recruited. Almost of them (85.8%) reported adhered to warfarin prescription. More than a half (60.5%) were able to report their targeted INR. Participants who stayed with the family had 5.54 times (95% CI 1.79-19.33), took regular daily dose warfarin had 5.07 times (95% CI 1.05-24.49), perceived targeted INR had 2.94 times (95% CI 1.04-8.29), and received family support had 1.33 times (95% CI 1.11-1.60) increased odds of warfarin adherence than those who did not. Participants who perceived a barrier to taking medication had 0.93 times decreased odds of warfarin adherence than those who did not (95% CI 0.86-0.99).

Conclusion

Healthcare system should encourage family to support the older population with AF in order to increase warfarin adherence. Future research should develop intervention combining family support to promote warfarin adherence.

The importance of assessing the safe and effective use of oral anticoagulants in older adults

See the Reply by Semla and Steinman in this issue.

Direct Oral Anticoagulants vs. Vitamin-K Antagonists in the Elderly With Atrial Fibrillation: A Systematic Review Comparing Benefits and Harms Between Observational Studies and Randomized Controlled Trials

Background: The publication of high-quality observational studies (OSs) has fueled reassessment of the treatment effects of direct oral anticoagulants (DOACs) in the elderly with atrial fibrillation (AF). Methods: The MEDLINE, EMBASE, and Cochrane Library databases were systematically searched (through July 1, 2019) for eligible OSs and randomized controlled trials (RCTs) that reported effectiveness outcomes [stroke or systemic embolism (SE)] or safety outcomes [intracranial hemorrhage (ICH), major bleeding, gastrointestinal bleeding (GIB), myocardial infarction (MI), and all-cause mortality] for DOACs and vitamin-K antagonists (VKAs) in elderly AF patients. A random-effects model was applied to calculate adjusted hazard ratios (HRs) for OSs and relative risks (RRs) for RCTs. Interaction analyses and the ratio of HR (RHR) were used to assess and compare OSs and RCTs. Results: A total of 32 studies involving 547,419 patients were included. No significant difference in treatment effect estimates was found between 27 OSs and 5 RCTs [P _interaction > 0.05 for each and all 95% confidence interval (CI) of RHR crossed 1.0]. Compared with VKAs, DOACs significantly reduced risk for stroke/SE (OSs, HR: 0.87, 95% CI: 0.81-0.94; RCT, RR: 0.82, 95% CI: 0.67-0.96), and ICH (OSs: 0.47 [0.37-0.57]; RCTs: 0.47 [0.31-0.63]), without increasing risk for GIB (OSs: 1.21 [0.98-1.43]; RCTs: 1.34 [0.91-1.77]), and all-cause mortality (OSs: 1.01 [0.92-1.11]; RCTs: 0.94 [0.87-1.00]). Among OSs, DOACs significantly decreased risk for major bleeding (0.87 [0.77-0.98]) and MI (0.89 [0.79-0.99]). It was found that dabigatran, but not other DOACs, significantly increased risk for GIB (1.48 [1.23-1.72]). Conclusions: DOACs were demonstrated to be more effective and safer than VKAs in elderly AF patients, whereas dabigatran users had a 48% increase in risk for GIB.

Influence of age on the pharmacokinetics, pharmacodynamics, efficacy, and safety of rivaroxaban

OBJECTIVE

Atrial fibrillation, peripheral and coronary artery disease, and venous thromboembolism are major risk factors for stroke, disability, and death in the rapidly growing older (≥ 65 years.) population. In the absence of clear guidelines on the appropriate use of the newer non-vitamin K antagonist oral anticoagulants in this population, this study specifically reviews the available literature for rivaroxaban and the impact of age that may affect the pharmacokinetics, pharmacodynamics, efficacy, and safety of this anticoagulant.

METHODS

This review includes a summary of data obtained from the available literature concerning both older healthy subjects and older patients with various aspects of cardiovascular disease enrolled in rivaroxaban clinical trials and data from real world evidence studies.

RESULTS

Evaluation of the clinical pharmacology in healthy, older adults reveal no clinically relevant effect of age on rivaroxaban pharmacokinetics and pharmacodynamics. Population pharmacokinetic studies in older patients with thromboembolic diseases suggest a moderate effect of increasing age on rivaroxaban clearance, albeit not clinically significant. Additionally, sub-group analyses from large, phase 3 clinical trials demonstrate consistent efficacy and safety in the older patient population vs the overall population. These findings are further supported by real-world evidence studies.

CONCLUSION

A favorable clinical profile with rivaroxaban was observed across age sub-groups, supporting the premise that dosing in older adults does not necessitate adjustment. However, it is prudent that a cautious and individualized approach is taken for treatment with any anticoagulant in older adults.