Dataset Information

Effectiveness and Safety of Standard-Dose Nonvitamin K Antagonist Oral Anticoagulants and Warfarin Among Patients With Atrial Fibrillation With a Single Stroke Risk Factor: A Nationwide Cohort Study.

ABSTRACT:

Importance

The randomized clinical trials comparing nonvitamin K antagonist oral anticoagulants (NOACs) vs warfarin largely focused on recruiting high-risk patients with atrial fibrillation with more than 2 stroke risk factors, with only the trials testing dabigatran or apixaban including few patients with 1 stroke risk factor. Despite this, regulatory approvals of all NOACs have been based on stroke prevention for patients with atrial fibrillation with 1 or more stroke risk factors.

Objective

To compare the effectiveness and safety study of standard-dose NOACs (dabigatran at 150 mg twice daily, rivaroxaban at 20 mg once daily, and apixaban at 5 mg twice daily) and warfarin in patients with atrial fibrillation with 1 low-risk, nonsex-related stroke risk factor.

Design, setting, and participants

This nationwide observational cohort study used data from Danish registries to determine the inverse probability of treatment-weighted comparative effectiveness and safety of standard-dose NOACs (dabigatran at 150 mg twice daily, rivaroxaban at 20 mg once daily, and apixaban at 5 mg twice daily) compared with treatment with warfarin among 14 020 patients with atrial fibrillation with 1 low-risk, nonsex- related stroke risk factor.

Main outcomes and measures

Rates of ischemic stroke/systemic embolism, death, and bleeding.

Results

Of 14 020 participants, 5151 (36.7%) were women, and the median age for participants was 66.5 years. For the principal effectiveness end point of ischemic stroke/systemic embolism, no significant differences of the NOACs compared with treatment with warfarin across strata were evident. For the end point of "any bleeding," this was significantly lower for treatment with apixaban (hazard ratio [HR], 0.35; 95% CI, 0.17-0.72) and dabigatran (HR, 0.48; 95% CI, 0.30-0.77) compared with warfarin in the main analysis, and was not significantly different for treatment with rivaroxaban vs warfarin (HR, 0.84; 95% CI, 0.49-1.44). There was broad consistency across most subgroups in the sensitivity analyses and whether 1- or 2.5-year follow-up periods were analyzed. However, falsification end points generally did not falsify, indicating the possible presence of residual confounding across these comparisons, presumably related to selective prescribing and unobserved covariates.

Conclusions and relevance

In this Danish cohort study of patients with atrial fibrillation and a single stroke risk factor, there was no difference between NOACs compared with treatment with warfarin in terms of the risk of having an ischemic stroke/systemic embolism. For "any bleeding," this was lower for treatment with apixaban and dabigatran compared with warfarin. These data do not allow for a definitive statement of the comparative effectiveness or safety of NOACs because of the possible residual confounding that was unmasked with falsification outcomes.

SUBMITTER: Lip GYH

PROVIDER: S-EPMC5710590 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Background It is unclear whether nonvitamin K antagonist oral anticoagulants ( NOAC s) can mitigate dementia development in atrial fibrillation. We compared dementia development among users of NOACs or warfarin in patients with atrial fibrillation with no prior neurological diagnoses. Methods and Results We conducted a Danish nationwide cohort study including 33 617 new oral anticoagulant users with nonvalvular atrial fibrillation, of which 11 052 were aged 60 to 69 years, 13 237 were aged 70 to 79 years, and 9238 were aged 80 years and older. To exclude prevalent non -oral anticoagulants- associated dementia, we considered the at-risk population of patients alive and free of dementia at 180 days following inclusion. We compared rates of new-onset dementia by age and treatment regimen using inverse probability of treatment weighting to account for confounding. Approximately 60% of patients were NOAC users and 40% were warfarin users. Mean follow-up was 3.4 years. Dementia occurred in 41 patients aged 60 to 69 years, 276 patients aged 70 to 79 years, and 441 patients aged 80 years and older. Relative to warfarin users, dementia rates were nonsignificantly lower among NOAC users aged 60 to 69 years (0.11 events/100 person-years versus 0.12 events/100 person-years; weighted hazard ratio, 0.92 [95% CI, 0.48-1.72]) and NOAC users aged 70 to 79 years (0.64 events/100 person-years versus 0.78 events/100 person-years; weighted hazard ratio , 0.86 [95% CI, 0.68-1.09]), whereas NOAC s were associated with significantly higher dementia rates (2.16 events/100 person-years versus 1.70 events/100 person-years; weighted hazard ratio , 1.31 [95% CI, 1.07-1.59]) in patients 80 years and older. Conclusions This nationwide cohort of patients with atrial fibrillation revealed no clinically meaningful difference in dementia development between users of NOACs or warfarin apart from a higher risk in NOAC users 80 years and older, which may relate to residual confounding from selective prescribing and unobserved comorbidities.

Project description:Objective To examine clinical effectiveness and safety of apixaban 2.5 mg, dabigatran 110 mg, and rivaroxaban 15 mg compared with warfarin among patients with atrial fibrillation who had not previously taken an oral anticoagulant.Design Propensity weighted (inverse probability of treatment weighted) nationwide cohort study.Setting Individual linked data from three nationwide registries in Denmark.Participants Patients with non-valvular atrial fibrillation filling a first prescription for an oral anticoagulant from August 2011 to February 2016. Patients who filled a prescription for a standard dose non-vitamin K antagonist oral anticoagulant (novel oral anticoagulants, NOACs) were excluded. To control for baseline differences in the population, a propensity score for receipt of either of the four treatment alternatives was calculated to apply an inverse probability treatment weight.Intervention Initiated anticoagulant treatment (dabigatran 110 mg, rivaroxaban 15 mg, apixaban 2.5 mg, and warfarin).Main outcome measures Patients were followed in the registries from onset of treatment for the primary effectiveness outcome of ischaemic stroke/systemic embolism and for the principal safety outcome of any bleeding events.Results Among 55 644 patients with atrial fibrillation who met inclusion criteria, the cohort was distributed according to treatment: apixaban n=4400; dabigatran n=8875; rivaroxaban n=3476; warfarin n=38 893. The overall mean age was 73.9 (SD 12.7), ranging from a mean of 71.0 (warfarin) to 83.9 (apixaban). During one year of follow-up, apixaban was associated with higher (weighted) event rate of ischaemic stroke/systemic embolism (4.8%), while dabigatran, rivaroxaban, and warfarin had event rates of 3.3%, 3.5%, and 3.7%, respectively. In the comparison between a non-vitamin K antagonist oral anticoagulant and warfarin in the inverse probability of treatment weighted analyses and investigation of the effectiveness outcome, the hazard ratios were 1.19 (95% confidence interval 0.95 to 1.49) for apixaban, 0.89 (0.77 to 1.03) for dabigatran, and 0.89 (0.69 to 1.16) for rivaroxaban. For the principal safety outcome versus warfarin, the hazard ratios were 0.96 (0.73 to 1.27) for apixaban, 0.80 (0.70 to 0.92) for dabigatran, and 1.06 (0.87 to 1.29) for rivaroxaban.Conclusion In this propensity weighted nationwide study of reduced dose non-vitamin K antagonist oral anticoagulant regimens, apixaban 2.5 mg twice a day was associated with a trend towards higher rates of ischaemic stroke/systemic embolism compared with warfarin, while rivaroxaban 15 mg once a day and dabigatran 110 mg twice a day showed a trend towards lower thromboembolic rates. The results were not significantly different. Rates of bleeding (the principal safety outcome) were significantly lower for dabigatran, but not significantly different for apixaban and rivaroxaban compared with warfarin.

Project description:Background and aimAtrial fibrillation (AF) is the most frequently observed cardiac arrhythmia in clinical settings. Obesity can influence the efficacy of the treatment administered, which requires a larger dose and more time to accomplish therapeutic targets due to altered pathophysiology. Our study aimed to assess the overall efficacy and safety of nonvitamin K antagonist oral anticoagulants (NOACs) versus warfarin in AF patients with morbid obesity (BMI > 40 kg/m2 and/or weight > 120 kg) to prevent complications.MethodsWe conducted a literature search on PubMed, Web of Science, the Cochrane Library, and Scopus till October 2022 for articles addressing the efficacy and safety of NOACs versus warfarin for the treatment of AF in morbidly obese patients. We performed the meta-analysis with RevMan software version 5.4 and Open Meta Analyst. The main outcomes assessed were stroke, major bleeding, and minor bleeding after anticoagulation, as did the history of comorbidities and risk factors in morbidly obese patients. Quality assessment was performed using Cochrane's ROB-2 tool and the Newcastle-Ottawa scale.ResultsRegarding major bleeding events, pooled data showed that patients taking NOACs had a significantly lower risk than patients taking warfarin (OR = 0.54, 95% CI: [0.41-0.70]; p < 0.00001). However, for minor bleeding, there was a nonsignificant effect of NOACs on reducing the risk of bleeding (OR = 0.72, 95% CI = 0.47-1.09; p = 0.12), which became highly significant in favor of NOACs after sensitivity analysis (OR = 0.55, 95% CI = 0.49-0.61]; p < 0.00001). There was a significant difference in the incidence of stroke between the NOAC group and the warfarin group (OR = 0.69, 95% CI = 0.60-0.80]; p < 0.00001). According to the results of the single-arm study analysis, the overall effect of all the outcomes was associated with a high risk of disease development in patients receiving NOACs.ConclusionOur meta-analysis showed a favorable effect of NOACs vs warfarin in morbidly obese patients. Some outcomes were not significantly different, which calls for future research to better assess their safety and efficacy in this particular weight group.Trial registrationThe study was registered with PROSPERO under registration number CRD42022362493 on October 2022.

Project description:Objective To study the effectiveness and safety of the non-vitamin K antagonist oral anticoagulants (novel oral anticoagulants, NOACs) dabigatran, rivaroxaban, and apixaban compared with warfarin in anticoagulant naïve patients with atrial fibrillation.Design Observational nationwide cohort study.Setting Three Danish nationwide databases, August 2011 to October 2015.Participants 61 678 patients with non-valvular atrial fibrillation who were naïve to oral anticoagulants and had no previous indication for valvular atrial fibrillation or venous thromboembolism. The study population was distributed according to treatment type: warfarin (n=35 436, 57%), dabigatran 150 mg (n=12 701, 21%), rivaroxaban 20 mg (n=7192, 12%), and apixaban 5 mg (n=6349, 10%).Main outcome measures Effectiveness outcomes defined a priori were ischaemic stroke; a composite of ischaemic stroke or systemic embolism; death; and a composite of ischaemic stroke, systemic embolism, or death. Safety outcomes were any bleeding, intracranial bleeding, and major bleeding.Results When the analysis was restricted to ischaemic stroke, NOACs were not significantly different from warfarin. During one year follow-up, rivaroxaban was associated with lower annual rates of ischaemic stroke or systemic embolism (3.0% v 3.3%, respectively) compared with warfarin: hazard ratio 0.83 (95% confidence interval 0.69 to 0.99). The hazard ratios for dabigatran and apixaban (2.8% and 4.9% annually, respectively) were non-significant compared with warfarin. The annual risk of death was significantly lower with apixaban (5.2%) and dabigatran (2.7%) (0.65, 0.56 to 0.75 and 0.63, 0.48 to 0.82, respectively) compared with warfarin (8.5%), but not with rivaroxaban (7.7%). For the combined endpoint of any bleeding, annual rates for apixaban (3.3%) and dabigatran (2.4%) were significantly lower than for warfarin (5.0%) (0.62, 0.51 to 0.74). Warfarin and rivaroxaban had comparable annual bleeding rates (5.3%).Conclusion All NOACs seem to be safe and effective alternatives to warfarin in a routine care setting. No significant difference was found between NOACs and warfarin for ischaemic stroke. The risks of death, any bleeding, or major bleeding were significantly lower for apixaban and dabigatran compared with warfarin.