The Impact of Body Weight and Renal Function on the Risk of Bleeding With Direct Oral Anticoagulants in Atrial Fibrillation

Drug-related problems associated with direct oral anticoagulants: an observational cross-sectional study of medical record review by pharmacists in a large teaching hospital

Background

Prescribing DOACs presents with challenges in the elderly and patients with renal and hepatic impairment. To mitigate safety risks, pharmacists have a role in detection, prevention, and resolution of DOAC-associated drug-related problems (DRPs).

Objectives

To identify the types of DOAC-associated DRPs in patients on DOAC therapy and factors that predispose patients to DOAC-associated DRPs.

Methods

An observational cross-sectional study was conducted in SGH from January 1, 2017, to May 31, 2019, on patients prescribed with a DOAC (rivaroxaban, dabigatran, and apixaban). Data were electronically extracted for patient demographics, clinical characteristics, and details of DOAC-related DRPs identified by pharmacists. Matching of DRP group to non-DRP group at a ratio of 1:2 based on gender, race, and DOAC was performed. The DRP group included patients with detected DRPs while non-DRP group included patients without them. Descriptive analysis was used to summarize patient characteristics and types of DOAC-associated DRPs. In the matched population, conditional logistic regression was used to calculate unadjusted (UOR) and adjusted odds (AOR) ratio to detect association of DOAC-associated DRPs with age, renal function, ≥2 comorbidities, and DOAC indication (atrial fibrillation [AF] vs venous thromboembolism).

Results

A total of 8432 patients prescribed DOACs were analyzed, which consisted of 827 (9.8%) and 7602 (90.2%) patients with DRPs and no DRPs, respectively. The top DOAC-associated DRP was inappropriate drug regimen (n = 487, 60.1%). After matching, 2403 patients were analyzed, consisting of 801 patients from DRP group and 1602 from non-DRP group. Factors associated with DOAC-associated DRPs were statistically significant for renal function at creatinine clearance (CrCl) of >30 to 50 mL/min/1.73 m2 (AOR: 1.42; 95% CI: 1.14-1.76; P = .002), 15 to 30 mL/min/1.73 m2 (OR: 1.94; 95% CI: 1.42-2.66; P < .001), and <15 mL/min/1.73m2 (OR: 2.35; 95% CI: 1.13-4.88; P = .022), respectively, compared with a CrCl of >50 mL/min/1.73 m2 and DOAC indication for AF (AOR: 1.84; 95% CI: 1.47-2.30; P < .001) compared with venous thromboembolism.

Conclusion

Inappropriate drug regimen was the most common DOAC-associated DRP. Impaired renal function and patients with AF increased the likelihood of DOAC-associated DRPs.

Therapeutic Drug Monitoring of Direct Oral Anticoagulants in Patients with Extremely Low and High Body Weight-Pilot Study

Phase III clinical trials for individual direct oral anticoagulants (DOACs) contained a limited representation of subjects with abnormal body weight, which were mostly limited to a BMI > 40 kg/m2, or body weight > 120 kg for obese subjects, and <50 kg for underweight subjects. Although low or high body weight is not a contraindication to DOACs therapy, it can significantly affect the safety and effectiveness of treatment. Due to the limited amount of clinical data on the use of DOACs in extremely abnormal weight ranges, optimal pharmacotherapy in this group of patients is a matter of controversy. The objective of this study was to evaluate the pharmacokinetics of DOAC properties in patients with abnormal body weight beyond the established cut-off points in the phase III studies for rivaroxaban, apixaban, and dabigatran. In total, 38 patients took DOACs for at least 12 months for non-valvular atrial fibrillation in 2019-2021. Blood samples were collected before the planned intake of the drug and 4 h after its administration. The determined concentrations of DOACs were statistically analyzed in relation to body weight, age, and eGFR (estimated Glomerular Filtration Rate). Among subjects taking apixaban, rivaroxaban, and dabigatran, the smallest representation of patients who achieved therapeutic concentrations were those treated with dabigatran. The population of people with abnormal body weight is a potential risk group of patients, in which some of them do not reach the therapeutic range of DOACs.

A Real-World Exploration into Clinical Outcomes of Direct Oral Anticoagulant Dosing Regimens in Morbidly Obese Patients Using Data-Driven Approaches

INTRODUCTION

The clinical outcomes of direct oral anticoagulant (DOAC) dosage regimens in morbid obesity are uncertain due to limited clinical evidence. This study seeks to bridge this evidence gap by identifying the factors associated with clinical outcomes following the dosing of DOACs in morbidly obese patients.

METHOD

A data-driven observational study was carried out using supervised machine learning (ML) models with a dataset extracted from electronic health records and preprocessed. Following 70%:30% partitioning of the overall dataset via stratified sampling, the selected ML classifiers (e.g., random forest, decision trees, bootstrap aggregation) were applied to the training dataset (70%). The outcomes of the models were evaluated against the test dataset (30%). Multivariate regression analysis explored the association between DOAC regimens and clinical outcomes.

RESULTS

A sample of 4,275 morbidly obese patients was extracted and analysed. The decision trees, random forest, and bootstrap aggregation classifiers achieved acceptable (excellent) values of precision, recall, and F1 scores in terms of their contribution to clinical outcomes. The length of stay, treatment days, and age were ranked highest for relevance to mortality and stroke. Among DOAC regimens, apixaban 2.5 mg twice daily ranked highest for its association with mortality, increasing the mortality risk by 43% (odds ratio [OR] 1.430, 95% confidence interval [CI] 1.181-1.732, p = 0.001). On the other hand, apixaban 5 mg twice daily reduced the odds of mortality by 25% (OR 0.751, 95% CI 0.632-0.905, p = 0.003) but increased the odds of stroke events. No clinically relevant non-major bleeding events occurred in this group.

CONCLUSION

Data-driven approaches can identify key factors associated with clinical outcomes following the dosing of DOACs in morbidly obese patients. This will help design further studies to explore well tolerated and effective DOAC doses for morbidly obese patients.

Real world prescribing practices of apixaban or rivaroxaban lead-in doses for the treatment of venous thromboembolism in hospitalized patients

The oral factor Xa inhibitors (OFXAi) apixaban and rivaroxaban are increasingly utilized for the treatment of venous thromboembolism (VTE) with recommended initial higher dose 7- and 21-day lead-in regimens, respectively. In patients receiving initial parenteral anticoagulation, it remains unknown if the full recommended higher dose OFXAi lead-in regimens are warranted, or if days can be subtracted. We aimed to describe when clinicians may deviate from recommended lead-in durations and evaluate clinical outcomes in these scenarios. This is a retrospective, observational study of patients 18 years or older who were treated with rivaroxaban or apixaban for acute pulmonary embolism (PE) or symptomatic proximal deep vein thrombosis (DVT) that received parenteral anticoagulation for at least 24 h before transitioning to the OFXAi. Among our cohort of 171 patients with acute VTE who received parenteral anticoagulation for a median of 48 h, 134 (78%) were prescribed a full OFXAi lead-in and 37 (22%) were prescribed a reduced lead-in. Patients in the reduced lead-in group were older with more cardiac comorbidities and antiplatelet use. There were four recurrent thromboembolic events within 3 months, two in the reduced lead-in group and two in the full lead-in group (5% vs. 2%, p = 0.206). Bleeding within 3 months occurred in 9 (5%) patients, with 6 events occurring in the reduced lead-in group and 3 events in the full lead-in group (16% vs. 2%, p = 0.004). Prescribing patterns of OFXAi lead-in therapy duration are variable in patients receiving initial parenteral anticoagulation. Larger cohorts are needed to better define the safety and efficacy of lead-in reduction.