Inappropriate dose of nonvitamin-K antagonist oral anticoagulants: prevalence and impact on clinical outcome in patients with nonvalvular atrial fibrillation

Dabigatran-related serious medication errors: an analysis using data from VigiBase

OBJECTIVE

To analyze the serious medication errors (MEs) on dabigatran, and their related factors, in order to avoid or reduce the occurrence of adverse events.

METHODS

Serious MEs related to dabigatran were extracted from the WHO global database of reported potential side effects of medicinal products (VigiBase) by using "Medication errors and other product use errors and issues" High Level Group Term (HLGT) of the international Medical Dictionary for Regulatory Activities (MedDRA). Well-documented reports, vigiGrade completeness score ≥ 0.80, or with an informative narrative were analyzed with a focus on the clinical features of the cases. The PCNE Classification for drug-related problems (DRP) was used to classify medication errors in our analysis of cases.

RESULTS

Until January 26, 2020, there were 453 cases with serious MEs related to dabigatran in VigiBase, and 113 were well-documented. Among these, 69 patients (61%) were hospitalized or had prolonged hospitalization, 16 (14%) had life-threatening events, and 12 (11%) died. The MEs occurred in the prescription phase in 77 cases, in administration in 35, and at the dispensing stage in one case. The MEs in prescription were related to a drug selection error in 44 cases (24 concerning contraindications and 20 drug interactions) and to dose error in 33 cases (17 with excessive dose; eight with insufficient frequency; four had an incorrect time; in three, the dose was too low; and in one, too frequent). The MEs in administration were medical-staff-related errors in five cases (three with wrong administration route, one administration omission, and one overdose), patient-related errors in 28 (14 insufficient dose or no administration, seven improper drug storage, four wrong administration method, and three over prescribed dose), and other errors in two (without efficacy monitoring). The dispensing error of a wrong drug strength occurred in a pharmacy. The main adverse events in the 113 patients were haemorrhage in 57 cases (50%) and ischemia in 29 cases (26%).

CONCLUSION

Based on the analysis of reports in VigiBase, serious MEs related to dabigatran mainly occurred during prescription and administration. Although the incidence of MEs with clinical consequences in the use of dabigatran cannot be determined, attention should be paid to selection of the appropriate dose to a right patient in the prescription, and to patient compliance and storage in drug administration. The patient harm mainly manifested itself as bleeding or ischemia including fatal outcome in rare patients.

Baseline Characteristics and 3-Year Outcome of Nonvalvular Atrial Fibrillation Patients Treated with the Four Direct Oral Anticoagulants (DOACs)

Direct oral anticoagulants (DOACs) represent the cornerstone therapy for cardioembolic events prevention in patients with nonvalvular atrial fibrillation (NVAF). In practice, the choice of one DOAC over another is guided by the decision-making process of the physician, which considers specific patient and drug characteristics. This study aimed to evaluate the clinical features and long-term outcomes of a real-world population treated with DOACs, where the use of the 4 different DOACs is quite equal. We conducted a retrospective observational, single-center, multidisciplinary study enrolling consecutive NVAF patients treated with one of the 4 DOACs. From an initial number of 753 patients, we excluded 72 patients because of loss to follow-up, at the end we enrolled 681:174 (23%) treated with dabigatran, 175 (23%) with apixaban, 190 (25%) with rivaroxaban, and 214 (29%) with edoxaban. Patients treated with apixaban were significantly older, more women represented (p <0.001), and with a higher cardioembolic and bleeding risk (p <0.001). Dabigatran was preferred in patients with liver failure (p = 0.008), whereas Apixaban and Edoxaban were chosen in chronic kidney disease (p = 0.002). At 3-year follow-up, 20 patients (2.7%) experienced a systemic thromboembolic event without significant differences in the 4 DOACs. In the same period, an International Society of Thrombosis and Hemostasis classification major bleeding event occurred in 26 patients (3.6%), more statistically correlated to edoxaban (6.1%) (p = 0.038). Thromboembolic events or major bleeding were higher in the edoxaban group (10%) compared with the others (p = 0.014). In our single-center real-world experience, the choice of the DOAC for a patient with NVAF was tailored to specific clinical features and drug pharmacokinetics of the patient. As a result, a small number of adverse events were observed.

Characteristics of patients with atrial fibrillation treated with direct oral anticoagulants and new insights into inappropriate dosing: results from the French National Prospective Registry: PAFF

AIMS

Since the introduction of direct oral anticoagulant (DOAC) for atrial fibrillation (AF) therapy, inappropriate and/or underdosing of these drugs has been a major clinical challenge. We evaluated the characteristics of patients with AF treated with inappropriate and low-dose DOACs.

METHODS AND RESULTS

Patients with AF treated with inappropriate and low-dose DOACs from October 2021 to December 2021 were evaluated from the French National Prospective Registry (PAFF). We evaluated 1890 patients with AF receiving DOACs (apixaban 55%, dabigatran 7%, and rivaroxaban 38%). Inappropriate dosing was noted in 18% of the population. Patients with appropriate dosing had less comorbidities: younger age (75 ± 10 vs. 82 ± 8 years old, P < 0.0001), reduced chronic renal failure (26 vs. 61%, P < 0.0001), and lower CHA2DS2VASc and HASBLED scores (3 ± 2 vs. 4 ± 3, P < 0.0001; 2 ±1 vs. 2 ± 2, P < 0.0001), respectively. In multivariate analysis, older age (P < 0.0001) and a higher CHA2DS2VASc score (P = 0.0056) were independently associated with inappropriate DOAC dosing. Among 472 patients (27%) treated with low-dose rivaroxaban or apixaban, 46% were inappropriately underdosed. Patients inappropriately underdosed were younger (82.3 ± 8.4 vs. 85.9 ± 5.9 years, P < 0.0001) with less chronic renal disease (47 vs. 98%, P < 0.0001). However, these patients had higher rates of prior haemorrhagic events (18 vs. 10%, P = 0.01), clopidogrel use (11 vs. 3%, P = 0.0002), and apixaban prescription (74 vs. 50%, P < 0.0001).

CONCLUSION

Within this large registry, DOACs were associated with inappropriate dosing in 18% of cases. Independent predictors of inappropriate dosing were high CHA2DS2VASc scores and older age. Moreover, 46% of patients treated with low-dose DOACs were inappropriately underdosed and more frequently in patients treated with apixaban.

Outcomes and drivers of inappropriate dosing of non-vitamin K antagonist oral anticoagulants (NOACs) in patients with atrial fibrillation: a systematic review and meta-analysis

OBJECTIVE

There has been limited systematic evaluation of outcomes and drivers of inappropriate non-vitamin K antagonist oral anticoagulants (NOACs) dosing among patients with atrial fibrillation (AF). This review identified and systematically evaluated literature on clinical and economic outcomes of inappropriate NOAC dosing and associated patient characteristics.

METHODS

MEDLINE, Embase, Cochrane Library, International Pharmaceutical Abstracts, Econlit, PubMed and NHS EEDs databases were searched for English language observational studies from all geographies published between 2008 and 2020, examining outcomes of, or factors associated with, inappropriate NOAC dosing in adult patients with AF.

RESULTS

One hundred and six studies were included in the analysis. Meta-analysis showed that compared with recommended NOAC dosing, off-label underdosing was associated with a null effect on stroke outcomes (ischaemic stroke and stroke/transient ischaemic attack (TIA), stroke/systemic embolism (SE) and stroke/SE/TIA). Meta-analysis of 15 studies examining clinical outcomes of inappropriate NOAC dosing found a null effect of underdosing on bleeding outcomes (major bleeding HR=1.04, 95% CI 0.90 to 1.19; p=0.625) but an increased risk of all-cause mortality (HR=1.28, 95% CI 1.10 to 1.49; p=0.006). Overdosing was associated with an increased risk of major bleeding (HR=1.41, 95% CI 1.07 to 1.85; p=0.013). No studies were found examining economic outcomes of inappropriate NOAC dosing. Narrative synthesis of 12 studies examining drivers of inappropriate NOAC dosing found that increased age, history of minor bleeds, hypertension, congestive heart failure and low creatine clearance (CrCl) were associated with an increased risk of underdosing. There was insufficient evidence to assess drivers of overdosing.

CONCLUSIONS

Our analysis suggests that off-label underdosing of NOACs does not reduce bleeding outcomes. Patients prescribed off-label NOAC doses are at an increased risk of all-cause mortality. These data underscore the importance of prescriber adherence to NOAC dosing guidelines to achieve optimal clinical outcomes for patients with AF.

PROSPERO REGISTRATION NUMBER

CRD42020219844.

ANMCO position paper 'Appropriateness of prescribing direct oral anticoagulants in stroke and systemic thromboembolism prevention in adult patients with non-valvular atrial fibrillation'

The appropriateness of prescribing direct oral anticoagulants [dabigatran, rivaroxaban, apixaban, and edoxaban (DOACs)] is regulated on the criteria established in Phase III trials. These criteria are reported in the summary of the product characteristics of the four DOACs. In clinical practice, prescriptions are not always in compliance with established indications. In particular, the use of lower doses than those recommended in drug data sheets is not uncommon. Literature data show that the inappropriate prescription of reduced doses causes drug underexposure and up to a three-fold increase in the risk of stroke/ischaemic transient attack, systemic thromboembolism, and hospitalization. Possible causes of the deviation between the dose that should be prescribed and that prescribed in the real world include erroneous prescription, an overstated haemorrhagic risk perception, and the presence of frail and complex patients in clinical practice who were not included in pivotal trials, which makes it difficult to apply study results to the real world. For these reasons, we summarize DOAC indications and contraindications. We also suggest the appropriate use of DOACs in common clinical scenarios, in accordance with what international guidelines and national and international health regulatory bodies recommend.

Effectiveness and Safety of Reduced and Standard Daily Doses of Direct Oral Anticoagulants in Patients with Nonvalvular Atrial Fibrillation: A Cohort Study Using National Database Representing the Japanese Population

Purpose

To compare the effectiveness and safety of reduced or standard daily doses of direct oral anticoagulants (DOACs) with warfarin in Japanese patients with nonvalvular atrial fibrillation (NVAF). We used post-hoc analyses to identify patient groups that could benefit from reduced-dose DOACs.

Patients and Methods

Using the National Database of Health Insurance Claims and Specific Health Checkups of Japan, we identified 944,776 patients with NVAF who had started an oral anticoagulant after at least one year of non-use between April 2011 and March 2016. We matched patients taking any, reduced, or standard doses of DOACs 1:1 with those taking warfarin. We measured treatment effectiveness based on admission due to stroke or systemic embolism (S/SE) and safety based on admission due to any bleeding (defined as major bleeding, MB). We compared both outcomes between DOACs and warfarin using the Cox proportional hazards model. We used post-hoc analysis to match patients receiving reduced-dose DOACs to those receiving standard-dose DOACs and compared treatment effectiveness and safety.

Results

More than half of patients receiving DOACs used a reduced dose. The occurrences of S/SE and MB in patients receiving any, reduced, or standard doses of DOACs were equal to or lower than those receiving warfarin. In the post-hoc analysis, the risk of S/SE and MB was similar between reduced and standard doses of DOACs except for those with a history of cerebral infarction and CHA₂DS₂-VASc score ≥3, where the risk of S/SE was lower for reduced doses of any and individual DOACs.

Conclusion

Findings from the current study are consistent with recent Asian and global studies but different from most studies conducted in North America and Europe, where patients receiving a reduced dose of DOACs had an increased risk of S/SE. Future studies should test the reproducibility of results from the current study.

Assessment of treatment patterns and patient awareness in atrial fibrillation patients using non-vitamin K antagonist oral anticoagulants (ASPECT-NOAC)

Background and Aim

Despite the advances in oral anticoagulation with NOACs, careful patient and dose selection is required with NOAC therapy. Our study aimed to assess treatment patterns of NOACs in AF along with patients’ continuity to NOAC treatments in first year, and their knowledge level of AF and NOAC treatment.

Methods

ASPECT-NOAC was designed as an observational, prospective, and multicenter study. AF patients who were prescribed NOACs within last four months were recruited from 34 outpatient cardiology clinics covering all geographic regions of Turkey. Baseline data were collected initially whereas patient awareness was evaluated at 3 to 4 weeks. Final study visit was performed at 12 months.

Results

In total, 991 patients were included to the study. Mean ± standard deviation of age was 69.4 ± 10.2 years and 53.0% of patients were female. Mean duration from AF diagnosis was 24.9 ± 50.9 months. Mean CHA₂DS₂-VASc and HAS-BLED scores were 3.1 ± 1.5 and 1.6 ± 1.1, respectively. AF disease and NOAC treatment knowledge levels were found to be 48.9 ± 23.1% and 73.0 ± 19.3%, respectively. Among reduced dose users 71.4% of patients were prescribed inappropriate reduced doses. Through the study follow-up, 32 patients (3.2%) deceased and NOAC therapy was discontinued in 74 patients (8.7%).

Conclusion

AF patients who recently started NOAC treatment in Turkey were found to have variable knowledge about their disease and anticoagulation treatment. It was observed that most of the patients continued the NOAC treatment throughout the study. Reduced dosing of NOACs was common, which was associated with higher baseline risk for bleeding as well as stroke.

Failure of non-vitamin K antagonist oral anticoagulants in preventing stroke in elderly patient: a case report of multiple strokes on standard of care treatment for atrial fibrillation

Atrial fibrillation (AF) is the most common type of treated heart arrhythmia. Generally, the treatment goals for atrial fibrillation are to reset the rhythm or control the rate and prevent the development and subsequent embolization of atrial thrombi. These thromboembolic events can occur with any kind of atrial fibrillation that is paroxysmal, persistent or permanent. In patients who are candidate for anticoagulation therapy, major practice guideline provides vitamin K antagonist (VKA) oral anticoagulant and non-VKA oral anticoagulants as treatment options. The risk of AF increases with age and despite treatment on standard of care anticoagulation therapy, recrudescent cardioembolic events may still arise especially in the elderly as we will see in this case.

Meta-analysis comparing inappropriately low dose versus standard dose of direct oral anticoagulants in patients with atrial fibrillation

BACKGROUND

The appropriateness of direct oral anticoagulant (DOAC) dosing has been the issue in the real-world setting, and inappropriately lower DOAC dose may not be as effective or safe as the standard dose in patients with atrial fibrillation (AF). Multiple real-world studies compared the inappropriately lower DOAC dose versus the standard dose, but their main findings were contradictory.

METHODS

A meta-analysis was performed to compare the efficacy and safety of the inappropriately lower DOAC dose with the standard DOAC dose in patients with AF. Database searches through May 30, 2021, were performed using Medline and Google Scholar. The primary efficacy outcome was stroke or systemic embolism, and the primary safety outcome was major bleeding. The secondary outcome was all-cause mortality.

RESULTS

A total of 16 studies were included in this meta-analysis. It revealed that the inappropriately lower DOAC dose was significantly associated with a higher event rate of stroke or systemic embolism compared with the DOAC standard dose (odds ratio 1.21 [95% CI 1.02-1.43], P = 0.03, I² = 66%). There was no significant difference in the major bleeding event rate between these groups (1.03, [0.92-1.15], P = 0.62; I² = 27%).

CONCLUSION

The inappropriately lower DOAC dose should be avoided to optimize DOAC effectiveness in patients with AF.

Effectiveness and Safety of Dabigatran Compared to Vitamin K Antagonists in Non-Asian Patients with Atrial Fibrillation: A Systematic Review and Meta-Analysis

BACKGROUND AND OBJECTIVE

Real-life data about the use of dabigatran in patients with non-valvular atrial fibrillation are warranted. The objective of this systematic review and meta-analysis was to assess the effectiveness and safety of dabigatran, globally and stratified by dose (110/150 mg twice daily), vs vitamin K antagonists in non-Asian patients with non-valvular atrial fibrillation from "real-world" studies.

METHODS

A systematic review was performed according to Cochrane methodological standards. The results were reported according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses Statement) statement. The ROBINS-I tool was used to assess bias risk. MEDLINE and EMBASE, from inception up to May 2021, using appropriate controlled vocabulary and free search terms, were searched.  RESULTS: A total of 34 studies, corresponding to 37 articles involving 1,600,722 participants (1,154,283 exposed to vitamin K antagonists and 446,439 to dabigatran) were eligible for this review. Dabigatran 150 mg reduced the risk of ischemic stroke compared with vitamin K antagonists, with a 14% risk reduction (hazard ratio [HR] 0.86, 95% confidence interval [CI] 0.74-0.98). Globally, dabigatran reduced the risk of all-cause mortality compared with vitamin K antagonists (HR 0.76, 95% CI 0.69-0.84), with a greater effect observed with dabigatran 150 mg (HR 0.65, 95% CI 0.58-0.73). There was a trend towards a lower risk of myocardial infarction with dabigatran 150 mg (HR 0.86, 95% CI 0.71-1.04). Regarding the primary safety outcomes, dabigatran (either at a dose of 150 mg or 110 mg) reduced the risk of major bleeding compared with vitamin K antagonists (HR 0.77, 95% CI 0.70-0.83), as well as the risk of intracranial bleeding (HR 0.44, 95% CI 0.39-0.50) and fatal bleeding (HR 0.76, 95% CI 0.60-0.95), but with a slight increase in gastrointestinal bleeding risk (HR 1.16, 95% CI 1.08-1.26).

CONCLUSIONS

Dabigatran has a favorable impact on effectiveness and safety outcomes compared with vitamin K antagonists in real-world populations.

Off-Label Underdosing or Overdosing of Non-vitamin K Antagonist Oral Anticoagulants in Patients With Atrial Fibrillation: A Meta-Analysis

Background: Several studies have investigated the role of off-label non-vitamin K antagonist oral anticoagulants (NOACs) in patients with atrial fibrillation (AF). We aimed to compare the effectiveness and safety outcomes between off-label underdose or overdose vs. on-label dose of NOACs in AF patients.

Methods: The PubMed database was systematically searched until August 2021. Observational cohorts were included if they compared the outcomes of off-label underdose or overdose with on-label dose of NOACs in AF patients. The risk ratios (RRs) and 95% confidence intervals (CIs) were pooled using a fixed-effects model (I² ≤ 50%) or a random-effects model (I² > 50%).

Results: A total of 15 observational studies were included. Compared with on-label dose of NOACs, off-label underdose of NOACs was associated with increased risks of stroke or systemic embolism (RR = 1.09, 95% CI 1.02–1.16), and all-cause death (RR = 1.29, 95% CI 1.10–1.52) but not ischemic stroke (RR = 1.34, 95% CI 0.76–2.36), myocardial infarction (RR = 1.08, 95% CI 0.92–1.28), major bleeding (RR = 0.97, 95% CI 0.89–1.05), intracranial hemorrhage (RR = 1.12, 95% CI 0.90–1.40), and gastrointestinal bleeding (RR = 0.96, 95% CI 0.85–1.07), whereas off-label overdose of NOACs was associated with increased risks of SSE (RR = 1.20, 95% CI 1.05–1.36), all-cause death (RR = 1.22, 95% CI 1.06–1.39), and major bleeding (RR = 1.33, 95% CI 1.16–1.52) but not gastrointestinal bleeding (RR = 1.18, 95% CI 0.99–1.42) and myocardial infarction (RR = 0.98, 95% CI 0.75–1.30).

Conclusion: Compared with on-label dose of NOACs, off-label underdose was associated with increased risks of stroke or systemic embolism and all-cause death, whereas off-label overdose of NOACs was associated with increased risks of stroke or systemic embolism, all-cause death, and major bleeding.

Impact of Weight on Clinical Outcomes of Edoxaban Therapy in Atrial Fibrillation Patients Included in the ETNA-AF-Europe Registry

Background: Extremes of body weight may alter exposure to non-vitamin K antagonist oral anticoagulants and thereby impact clinical outcomes. This ETNA-AF-Europe sub-analysis assessed 1-year outcomes in routine care patients with atrial fibrillation across a range of body weight groups treated with edoxaban. Methods: ETNA-AF-Europe is a multinational, multicentre, observational study conducted in 825 sites in 10 European countries. Overall, 1310, 5565, 4346 and 1446 enrolled patients were categorised into ≤60 kg, >60–≤80 kg (reference weight group), >80–≤100 kg and >100 kg groups. Results: Patients weighing ≤60 kg were older, more frail and had a higher CHA₂DS₂-VASc score vs. the other weight groups. The rates of stroke/systemic embolism, major bleeding and ICH were low at 1 year (0.82, 1.05 and 0.24%/year), with no significant differences among weight groups. The annualised event rates of all-cause death were 3.50%/year in the overall population. After adjustment for eGFR and CHA₂DS₂-VASc score, the risk of all-cause death was significantly higher in extreme weight groups vs. the reference group. Conclusions: Low rates of stroke and bleeding were reported with edoxaban, independent of weight. The risk of all-cause death was higher in extremes of weight vs. the reference group after adjustment for important risk modifiers, thus no obesity paradox was observed.