Patients on vitamin K treatment: is switching to direct-acting oral anticoagulation cost-effective? A target trial on a prospective cohort

AIMS

Direct-acting oral anticoagulants (DOACs) have, to a substantial degree, replaced vitamin K antagonists (VKA) as treatments for stroke prevention in atrial fibrillation (AF) patients. However, evidence on the real-world causal effects of switching patients from VKA to DOAC is lacking. We aimed to assess the empirical incremental cost-effectiveness of switching patients to DOAC compared with maintaining VKA treatment.

METHODS

The target trial approach was applied to the prospective observational Swiss-AF cohort, which enrolled 2415 AF patients from 2014 to 2017. Clinical data, healthcare resource utilisation and EQ-5D-based utilities representing quality of life were collected in yearly follow-ups. Health insurance claims were available for 1024 patients (42.4%). Overall survival, quality-of-life, costs from the Swiss statutory health insurance perspective and cost-effectiveness were estimated by emulating a target trial in which patients were randomly assigned to switch to DOAC or maintain VKA treatment.

RESULTS

228 patients switching from VKA to DOAC compared with 563 patients maintaining VKA treatment had no overall survival advantage over a 5-year observation period (HR 0.99, 95% CI 0.45, 1.55). The estimated gain in quality-adjusted life years (QALYs) was 0.003 over the 5-year period at an incremental costs of CHF 23 033 (€ 20 940). The estimated incremental cost-effectiveness ratio was CHF 425 852 (€ 387 138) per QALY gained.

CONCLUSIONS

Applying a causal inference method to real-world data, we could not demonstrate switching to DOACs to be cost-effective for AF patients with at least 1 year of VKA treatment. Our estimates align with results from a previous randomised trial.

Frailty, Home Time, and Health Care Costs in Older Adults With Atrial Fibrillation Receiving Oral Anticoagulants

Importance

There are no data on patient-centered outcomes and health care costs by frailty in patients with atrial fibrillation (AF) taking oral anticoagulants (OACs).

Objective

To compare home time, clinical events, and health care costs associated with OACs by frailty levels in older adults with AF.

Design, Setting, and Participants

This community-based cohort study assessed Medicare fee-for-service beneficiaries 65 years or older with AF from January 1, 2013, to December 31, 2019. Data analysis was performed from January to December 2022.

Exposures

Apixaban, rivaroxaban, and warfarin use were measured from prescription claims. Frailty was measured using a validated claims-based frailty index.

Main outcomes and measures

Outcome measures were (1) home time (days alive out of the hospital and skilled nursing facility) loss greater than 14 days; (2) a composite end point of ischemic stroke, systemic embolism, major bleeding, or death; and (3) total cost per member per year after propensity score overlap weighting.

Results

The weighted population comprised 136 551 beneficiaries, including 45 950 taking apixaban (mean [SD] age, 77.6 [7.3] years; 51.3% female), 45 320 taking rivaroxaban (mean [SD] age, 77.6 [7.3] years; 51.9% female), and 45 281 taking warfarin (mean [SD] age, 77.6 [7.3] years; 52.0% female). Compared with apixaban, rivaroxaban was associated with increased risk of home time lost greater than 14 days (risk difference per 100 persons, 1.8 [95% CI, 1.5-2.1]), composite end point (rate difference per 1000 person-years, 21.3 [95% CI, 16.4-26.2]), and total cost (mean difference, $890 [95% CI, $652-$1127]), with greater differences among the beneficiaries with frailty. Use of warfarin relative to apixaban was associated with increased home time lost (risk difference per 100 persons, 3.2 [95% CI, 2.9-3.5]) and composite end point (rate difference per 1000 person-years, 29.4 [95% CI, 24.5-34.3]), with greater differences among the beneficiaries with frailty. Compared with apixaban, warfarin was associated with lower total cost (mean difference, -$1166 [95% CI, -$1396 to -$937]) but higher cost when excluding OAC cost (mean difference, $1409 [95% CI, $1177 to $1642]) regardless of frailty levels.

Conclusions and Relevance

In older adults with AF, apixaban was associated with increased home time and lower rates of clinical events than rivaroxaban and warfarin, especially for those with frailty. Apixaban was associated with lower total cost compared with rivaroxaban but higher cost compared with warfarin due to higher OAC cost. These findings suggest that apixaban may be preferred for older adults with AF, particularly those with frailty.

Mortality on DOACs Versus on Vitamin K Antagonists in Atrial Fibrillation: Analysis of the Hungarian Health Insurance Fund Database

PURPOSE

Limited real-world data are available on the survival of patients treated with vitamin K antagonists (VKAs) versus with direct oral anticoagulants (DOACs) for nonvalvular atrial fibrillation (AF). In this nationwide registry, we analyzed the mortality risk of patients with nonvalvular AF taking DOACs versus VKAs, with a special attention to the early treatment period.

METHODS

The Hungarian National Health Insurance Fund (NHIF) database was searched to identify patients treated with VKA or DOAC as a thromboembolic prophylaxis for nonvalvular AF between 2011 and 2016. The overall and the early (0-3, 4-6, and 7-12 months) mortality risks with the 2 types of anticoagulation were compared. A total of 144,394 patients with AF treated with either a VKA (n = 129,925) or a DOAC (n = 14,469) were enrolled.

FINDINGS

A 28% improvement in 3-year survival with DOAC treatment compared with VKA treatment was shown. Mortality reduction with DOACs was consistent across different subgroups. However, younger patients (30-59 years old) initiated on DOAC therapy had the greatest RRR (53%) in mortality. Furthermore, DOAC treatment also yielded a benefit of greater magnitude (HR = 0.55; 95% CI, 0.40-0.77, P = 0.001) in the lower (0-1) CHA₂DS₂-VASc score segment and in those with fewer (0-1) bleeding risk factors (HR = 0.50, CI 0.34-0.73, P = 0.001). The RRR in mortality with DOACs was 33% within the first 3 months, and 6% in the second year.

IMPLICATIONS

Thromboembolic prophylaxis with DOACs in this study yielded significantly lower mortality compared with VKA treatment in patients with nonvalvular AF. The largest benefit was shown in the early period after treatment initiation, as well as in younger patients, those with a lower CHA₂DS₂-VASc score, and those with fewer bleeding risk factors.

Cost-Effectiveness Analysis of Direct Oral Anticoagulants Vs. Vitamin K Antagonists in the Elderly With Atrial Fibrillation: Insights From the Evidence in a Real-World Setting

Background: In the clinical setting, the economic benefits of direct oral anticoagulants (DOACs) in elderly patients with atrial fibrillation (AF) remain unclear. This study aimed to estimate and compare the cost-effectiveness of DOACs (dabigatran, rivaroxaban, apixaban, and edoxaban) and vitamin K antagonists (VKAs; warfarin) in preventing stroke among AF patients aged >75 years in real-world practice. Methods: A Markov model with a 10-year span was constructed to estimate the long-term clinical and economic outcomes among AF patients aged >75 years treated with DOACs and warfarin. The study was populated with a hypothetical cohort of 10,000 AF patients aged >75 years. Probabilities of clinical outcomes were obtained from the pooled observational studies (OSs), comparing DOACs (dabigatran, rivaroxaban, apixaban, and edoxaban) with VKAs. Other model inputs, including the utilities and the costs, were all estimated from public sources and the published literature. The costs, quality-adjusted life-years (QAYLs), and incremental cost-effectiveness ratios (ICER) were estimated for each treatment strategy. Subgroup analyses of individual DOACs and the scenario analysis were performed. Uncertainty was evaluated by deterministic sensitivity analysis and probabilistic sensitivity analysis (PSA). Results: Compared to warfarin, DOACs were associated with a gain of 0.36 QALY at an additional cost of $15,234.65, resulting in an ICER of $42,318.47 per QALY. Sensitivity analysis revealed that the ICER was sensitive to the cost of DOACs. Direct oral anticoagulants also shifted from dominating to dominated status When their annual costs of DOACs were over $3,802.84 or the risk ratio of death compared to warfarin was over 1.077%/year. Probabilistic sensitivity analysis (PSA) suggested that DOACs had a 53.83 and 90.7% probability of being cost-effective when the willingness-to-pay threshold was set at $50,000 and $100,000, respectively. Among all the four individual DOACs, edoxaban treatment was revealed as the preferred treatment strategy for the AF patients aged over 75 years by yielding the most significant health gain with the relatively low total cost. Conclusions: Despite the high risk for major bleeding in elderly patients with AF, DOACs are more cost-effective treatment options than warfarin in real-world practice. Edoxaban was the preferred treatment strategy among four kinds of DOACs for AF patients aged over 75 years. Furthermore, beyond their safety profiles, the treatment benefits of DOACs assumed greater relevance and importance in older adults.

Direct oral anticoagulant reversal: An update

ABSTRACT

The rise in direct oral anticoagulant (DOAC) use means nurses must understand the reversal of these agents in case of bleeding. Depending on bleed severity, as well as other criteria, pharmacologic reversal can be considered in place of supportive care alone. Knowledge of literature surrounding DOAC reversal is crucial.

Dose specific effectiveness and safety of DOACs in patients with non-valvular atrial fibrillation: A Canadian retrospective cohort study

BACKGROUND

Direct oral anticoagulants (DOACs) have been proven to be effective and safe for prevention of ischemic stroke and systemic embolism in patients with non-valvular atrial fibrillation (NVAF). However, suboptimal adherence, variable dosing and use in patient populations that otherwise would have been excluded from clinical trials may impact the efficacy and safety profile of DOACs in a routine care setting. We compared stroke, bleeding, and mortality rates on and off therapy for standard and low-dose DOACs (apixaban, rivaroxaban, dabigatran) versus warfarin in a Canadian cohort. We also assessed persistence of DOACs compared to warfarin.

METHODS

We conducted six 1-1 propensity-score matched retrospective cohort analyses using Quebec health administrative databases (2011-2017). NVAF patients (≥18 years) covered by the public medication insurance plan entered the cohort on the first OAC dispensation date. We excluded those with OAC use in the previous year or stroke or bleeding diagnoses in the previous two years. Follow-up ended at death, March 2017 or end of medication coverage by the public plan. Time-dependent Cox regression was applied.

RESULTS

We evaluated 10,893 patients initiated on apixaban (7206 standard, 3687 low-dose), 10,190 on rivaroxaban (7396 standard, 2794 low-dose), 5884 on dabigatran (2756 standard, 3128 low-dose), and propensity score-matched warfarin users. Across standard-dose DOACs, compared to warfarin, stroke risks were similar; bleeding risks were lower with apixaban (hazard ratio 0.63; 95% confidence interval 0.52-0.77) and dabigatran (0.47; 0.35-0.64) but not rivaroxaban (0.93; 0.79-1.10); death risks were lower with all DOACs. For low-dose DOACs, rivaroxaban demonstrated higher stroke (1.79; 1.21-2.64) and bleeding risks (1.37; 1.09-1.73); other agents had stroke risks similar to warfarin and bleeding risks lower than warfarin; only low-dose dabigatran had lower death risk (0.59; 0.52-0.68). Treatment discontinuation was lower with DOACs versus warfarin with the exception of low-dose rivaroxaban. The risks of stroke were 2-4 folds higher during time off any OAC versus time on warfarin. The risks of death were higher, while the risks of bleeding were generally lower during times off any OAC.

CONCLUSIONS

Standard-dose DOACs had similar stroke, better persistence and mortality profiles than warfarin. Only standard dose apixaban and dabigatran had better bleeding profiles than warfarin. Low-dose rivaroxaban had worse persistence, stroke and bleeding profiles than warfarin, while low-dose apixaban and dabigatran had similar stroke and better bleeding profiles. Real-world use of DOACs may explain some of the differences observed in Canadian routine care versus the phase III clinical trials.

A retrospective analysis of the safety and efficacy of apixaban use after lung transplant

Direct acting oral anticoagulants (DOACs) have become the mainstay of treatment for patients requiring anticoagulation for atrial arrhythmias and venous thromboembolism (VTE) but safety and efficacy has not been established in lung transplantation. This is a retrospective review of 28 adult lung transplant patients who were prescribed apixaban for stroke prevention in atrial arrhythmias or treatment of VTE between October 15, 2015 and December 31, 2018. The primary outcome was a composite of efficacy and safety measured by recurrence or breakthrough of stroke or thromboembolism and bleeding events. Seven patients were treated for atrial arrhythmias and 21 treated for VTE. Fifteen patients received CYP3A4 or P-gp inhibitors at initiation of anticoagulation, and 4 of these patients received strong CYP3A4 inhibitors. During the follow-up period, one breakthrough DVT and one clinically relevant non-major bleed were observed. These data suggest that apixaban may be safe to use for lung transplant patients, and larger studies are warranted to assess long-term outcomes as well as safety and efficacy of alternative DOACs.

Impact of anticoagulant exposure misclassification on the bleeding risk of direct oral anticoagulants

Aims

Drug exposure status based on routinely collected data might be misclassified when the database contains only prescriptions from 1 type of prescriber (e.g. general practitioner and not specialist). This study aims to quantify the impact of such exposure misclassification on the risk of major bleeding and stroke/transient ischaemic attack (TIA)associated with direct oral anticoagulants (DOACs) vs. vitamin K antagonists (VKAs).

Methods

Incident anticoagulant users (>12 mo free of anticoagulation use) in the Dutch PHARMO Database Network between 2008 and 2017 were included. Drug exposure was assessed using pharmacy dispensing information. The risks of hospital admission of major bleeding for DOAC vs. VKA users was assessed with Cox regression analysis, where exposure was based on all dispensings, on general practitioner (GP)‐prescribed dispensings only or on specialist‐prescribed dispensings only. Hazard ratios (HRs) were estimated also for hospitalization for gastrointestinal bleeding, intracranial bleeding and stroke/TIA.

Results

We included 99 182 VKA‐initiators and 21 795 DOAC‐initiators. Use of DOAC was associated with a lower risk of major bleeding compared to VKA use; HR 0.79 (95% confidence interval 0.70–0.90), 0.78 (0.68–0.91) and 0.62 (0.50–0.76), for exposure based on complete dispensing information, only GP‐ and only specialist‐prescribed dispensings, respectively. Similar results were found for the other bleeding outcomes. For stroke/TIA the HRs were 0.96 (0.84–1.09), 1.00 (0.84–1.18) and 0.72 (0.58–0.90), respectively.

Conclusion

Including only GP‐prescribed anticoagulant dispensings in this case did not materially impact the effect estimates compared to including all anticoagulant dispensings. Including only specialist‐prescribed dispensings, however, strengthened the effect estimates.

Direct Oral Anticoagulant Use in Special Populations: Elderly, Obesity, and Renal Failure

PURPOSE OF REVIEW

The purpose of this review is to examine the safety and effectiveness of direct oral anticoagulants and provide recommendations for the treatment of venous thromboembolism and atrial fibrillation in obese patients, elderly patients, and patients with chronic kidney disease.

RECENT FINDINGS

Multiple retrospective cohort studies have shown no difference in bleeding, stroke, or venous thromboembolism outcomes between DOACs and warfarin in patients who are obese, elderly, or those with chronic kidney disease or on dialysis. Some studies have shown that DOACs have a lower bleeding risk than warfarin in these populations. DOACs may be a safe and effective alternative to warfarin for the prevention of stroke in atrial fibrillation patients who are obese, elderly, or those with chronic kidney disease or on dialysis. Apixaban may improve clinical outcomes by lowering the risk of bleeding versus warfarin. DOACs may also be an effective and safe alternative to warfarin for the treatment of venous thromboembolism in obese patients; however, additional studies are needed to assess their use in elderly patients and those with CKD.

Practice-derived data on non-vitamin K antagonist oral anticoagulant therapy to complement observations from randomized trials

Anticoagulation is fundamental in the management of patients with atrial fibrillation (AF). The study aims to provide a comparative review of the major phase III randomized clinical trials (RCTs) and real-world data (RWD) from reliable, high-grade Phase IV studies that assess the efficacy and safety of non-vitamin K antagonist oral anticoagulants (NOACs) vs. vitamin K antagonists (VKAs). Observational studies based on nationwide or health insurance database records on the use of NOACs vs. VKAs in patients with AF were included. We performed a comparison of the efficacy and safety characteristics associated with NOACs vs. VKAs in RCTs and RWD. Although RCTs provide strong support for evidence-based practice, RWD may be used to reflect the broader picture of various clinical settings, provide supplementary insight and fulfil knowledge gaps. Both study types confirmed the safety and efficacy of NOACs in preventing stroke and thromboembolism in patients with AF. In comparison to VKAs, NOACs were associated with reduced risk of ischaemic events and lower rates of adverse events such as major bleeding or intracranial haemorrhage. Administration of NOACs might be associated with increased risk of dose-related gastrointestinal bleeding and myocardial ischaemic events, especially in the early treatment period after switching from VKAs. Special care should be taken in challenging clinical situations like severe renal or hepatic impairment when the treatment regimen needs to be considered individually. Randomized clinical trial and RWD studies are complementary and present comparable findings, affirming that NOACs are safe and effective for anticoagulation of patients with AF in daily clinical practice.

Efficacy and Safety of Direct Factor Xa Inhibitors Versus Warfarin in Prevention of Primary and Secondary Ischemic Strokes in Non-Valvular Atrial Fibrillation: A Literature Review

Ischemic stroke remains a major cause of mortality and morbidity in patients with atrial fibrillation. The use of appropriate anticoagulants reduces the risk of ischemic stroke in these patients. The current literature review is aimed to analyze the follow-up efficacy and safety of direct factor Xa inhibitors versus warfarin in the prevention of primary and secondary ischemic stroke, risk of major and minor bleedings, and food and drug interaction in patients with atrial fibrillation (AF). We selected PubMed as our database and we found 83,611 articles using the regular keyword 'atrial fibrillation'. We found 2,224 articles using the regular keywords 'direct factor Xa inhibitors' and 'atrial fibrillation'.

Finally, we obtained 326 studies using MeSH keywords: atrial fibrillation, direct factor Xa inhibitors, and warfarin. Ultimately, 46 articles were selected after applying the inclusion/exclusion criteria. All studies were randomized controlled trials (RCT) or clinical trials. Analysis of all studies showed that direct factor Xa inhibitors are superior to warfarin in the prevention of ischemic stroke in patients with non-valvular AF, with a lower rate of major and minor bleeding events and lower foods and drug interaction. Unlike warfarin, direct factor Xa inhibitors do not need frequent blood monitoring and dose adjustment. We found that warfarin and other vitamin K inhibitors may promote the calcification of heart valves and coronary arteries. There is some evidence that direct factor Xa inhibitors may slightly reverse these calcifications in coronary arteries and heart valves.

Reinitiation of Anticoagulation After Surgical Evacuation of Subdural Hematomas

BACKGROUND

Chronic subdural hematoma (cSDH) is an increasingly common condition due to the growing use of anticoagulation. Currently, there remains a lack of evidence to guide the optimal timing of anticoagulant reinitiation for stroke prevention in atrial fibrillation after cSDH evacuation. We aimed to better understand the perceived risks of hemorrhagic and embolic complications along with current practice patterns on restarting anticoagulation after surgical evacuation of cSDH.

METHODS

We conducted a survey of Canadian neurosurgeons and stroke neurologists using a novel self-administered questionnaire using clinical cases that included questions on clinical experience, practice setting, practice patterns, and perceptions on stroke/bleeding risk with anticoagulation reinitiation after cSDH evacuation. The instrument was evaluated for clinical sensibility by 5 neurosurgeons, neurologists, and intensivists.

RESULTS

The response rate after 4 mailings was 40% for neurosurgeons (55/136) and 21% for stroke neurologists (26/122). Almost all participants would restart anticoagulation for stroke prevention in atrial fibrillation after cSDH evacuation (91.8% in low-risk patients, 98.6% in high-risk patients). Time to reinitiation of anticoagulation varied considerably, particularly for high-risk patients where 36% of participants would restart anticoagulation within 1 week of surgery, 44% between 1 and 4 weeks after surgery, and 19% after 4 weeks postoperatively. The perceived risk of stroke and SDH reaccumulation varied considerably among participants and was dependent on timing of anticoagulation reinitiation.

CONCLUSIONS

There is considerable variation in current practice patterns and perceived risks of embolic and hemorrhagic complications with anticoagulation reinitiation after cSDH evacuation. These results demonstrate clinical equipoise that warrant further targeted investigation in large-scale randomized controlled trials.