Adherence to oral anticoagulants among patients with atrial fibrillation: a systematic review and meta-analysis of observational studies

Abstract

IntroductionMedications cannot exert their effect if not taken as prescribed by patients. Our objective was to summarise the observational evidence on adherence to oral anticoagulants (OACs) among patients with atrial fibrillation (AF).MethodsIn March 2019, we systematically searched PubMed/Medline, Embase, CINAHL and PsycINFO (from inception) for observational studies measuring adherence, its determinants and impacts in patients with AF. Mean adherence measures and corresponding proportions of adherent patients were pooled using random effects models. Factors shown to be independently associated with adherence were extracted as well as the clinical and economic outcomes of adherence.ResultsWe included 30 studies. Pooled mean adherence scores of over half a million patients with AF 6 months and 1 year after therapy initiation were 77 (95% CI: 74–79) and 74 (68–79) out of 100, respectively. Drug-specific pooled mean adherence score at 6 months and 1 year were as follows: rivaroxaban: 78 (73–84) and 77 (69–86); apixaban: 77 (75–79) and 82 (74–89); dabigatran: 74 (69–79) and 75 (68–82), respectively. There was inadequate information on warfarin for inclusion in meta-analysis.Factors associated with increased adherence included: older age, higher stroke risk, once-daily regimen, history of hypertension, diabetes or stroke, concomitant cardiovascular medications, living in rural areas and being an experienced OAC user. Non-adherent patients were more likely to experience stroke and death, and incurred higher medical costs compared with patients with poor adherence.ConclusionsOur findings show that up to 30% of patients with AF are non-adherent, suggesting an important therapeutic challenge in this patient population.

Atrial Fibrillation and Use of Rivaroxaban: Performance of the Prothrombin Time / INR as a Function of Time After Blood Collection

“…The prolongation of PT observed in the present study in patients using Rivaroxaban, in relation to those found for healthy non-medicated individuals is in line with previous studies reported in the literature, such as that by Douxfils et al 9 According to these studies, PT can be used as a screening test to assess bleeding risk, although more specific tests using calibrators should be applied to confirm the plasma concentration of Rivaroxaban. In this regard, ISTH basically defines 2 types of tests for the evaluation of direct oral anticoagulants: simple semiquantitative tests available in most laboratories, and quantitative tests capable of accurately reporting levels of the drug.…”

“…6 DOACs have been widely used for primary or secondary prevention of stroke in patients with AF, while AF ablation under uninterrupted warfarin or rivaroxaban has shown a safety profile. 7,8,9 However, there is no evidence of benefit of DOACs in patients with mechanical prosthetic valves or moderate/severe mitral stenosis. 6 Direct thrombin inhibitors and factor Xa inhibitors do not usually require laboratory monitoring.…”

Long-Term Anticoagulation in Secondary Ischemic Stroke Prevention: The Prospective Multicenter RESTAIC Registry

“…This should encourage us to look for better strategies to improve secondary stroke prevention, such as ensuring patients' adherence to treatment. The NOACISP-LONGTERM registry showed 78.4% of the patients to be fully adherent with a median follow-up of 12 months, and a recent systematic review showed that up to 30% of the patients with AF are non-adherent to any OAC (22,41). Likewise, a Spanish study suggested that only 41.4% of the patients are treated following the current Spanish recommendations in clinical practice (42).…”

Clinical Outcomes of Direct Oral Anticoagulants and Warfarin in Japanese Patients with Atrial Fibrillation Aged ≥ 85 Years: A Single-Center Observational Study

“…Therefore, physicians worry about the use of OAC drugs, which cause serious bleeding events and prevent thromboembolism. Nonadherence and poor control of PT-INR are known to be independent risk factors for major adverse events, including major bleeding during OAC therapy [ 41 , 42 ].…”