Interventions and Strategies to Improve Oral Anticoagulant Use in Patients with Atrial Fibrillation: A Systematic Review of Systematic Reviews

A methodological review finds mismatch between overall and pairwise overlap analysis in a sample of overviews

OBJECTIVES

Overlap of primary studies is a key methodological challenge for overviews. There are limited reports of methods used to address overlap, and there is no detailed assessment of the corrected covered area (CCA) of a representative sample of overviews. To describe the approaches used to address overlap, and to estimate the overall and pairwise CCA.

METHODS

We searched PubMed for overviews published in 2018. Two authors conducted the screening process. We described the strategy used for assessing overlap, and calculated overall and pairwise CCA for each overview.

RESULTS

We analyzed a random sample of 30 out of 89 eligible articles. Eleven did not address the overlap. Of the remainder, most frequent strategies were visual assessment and discussion of overlap as a limitation. Median overall CCA among the included overviews was 6.7%. The pairwise analysis showed that 52.8% of SR pairs had slight overlap, while 28.3% had very high overlap.

CONCLUSION

Reported strategies for addressing overlap vary considerably among overview authors. The pairwise approach for assessing the CCA revealed highly overlapped pairs of SRs in overviews with overall slight overlap and vice versa. We encourage authors to complement the overall CCA assessment with a pairwise approach.

Global disparities in arrhythmia care: Mind the gap

Delivery of comprehensive arrhythmia care requires the simultaneous presence of many resources. These include complex hospital infrastructure, expensive implantable equipment, and expert personnel. In many low- and middle-income countries (LMICs), at least 1 of these components is often missing, resulting in a gap between the demand for arrhythmia care and the capacity to supply care. In addition to this treatment gap, there exists a training gap, as many clinicians in LMICs have limited access to formal training in cardiac electrophysiology. Given the progressive increase in the burden of cardiovascular diseases in LMICs, these patient care and clinical training gaps will widen unless further actions are taken to build capacity. Several strategies for building arrhythmia care capacity in LMICs have been described. Medical missions can provide donations of both equipment and clinical expertise but are only intermittently present and therefore are not optimized to provide the longitudinal support needed to create self-sustaining infrastructure. Use of donated or reprocessed equipment (eg, cardiac implantable electronic devices) can reduce procedural costs but does not address the need for infrastructure, including diagnostics and expert personnel. Collaborative efforts involving multiple stakeholders (eg, professional organizations, government agencies, hospitals, and educational institutions) have the potential to provide longitudinal support of both patient care and clinician education in LMICs.

Oral anticoagulants: a systematic overview of reviews on efficacy and safety, genotyping, self-monitoring, and stakeholder experiences

BACKGROUND

This systematic overview was commissioned by England's Department of Health and Social Care (DHSC) to assess the evidence on direct (previously 'novel') oral anticoagulants (OACs), compared with usual care, in adults, to prevent stroke related to atrial fibrillation (AF), and to prevent and treat venous thromboembolism (VTE). Specifically, to assess efficacy and safety, genotyping, self-monitoring, and patient and clinician experiences of OACs.

METHODS

We searched MEDLINE, Embase, ASSIA, and CINAHL, in October, 2017, updated in November 2021. We included systematic reviews, published from 2014, in English, assessing OACs, in adults. We rated review quality using AMSTAR2 or the JBI checklist. Two reviewers extracted and synthesised the main findings from the included reviews.

RESULTS

We included 49 systematic reviews; one evaluated efficacy, safety, and cost-effectiveness, 17 assessed genotyping, 23 self-monitoring or adherence, and 15 experiences (seven assessed two topics). Generally, the direct OACs, particularly apixaban (5 mg twice daily), were more effective and safer than warfarin in preventing AF-related stroke. For VTE, there was little evidence of differences in efficacy between direct OACs and low-molecular-weight heparin (prevention), warfarin (treatment), and warfarin or aspirin (secondary prevention). The evidence suggested that some direct OACs may reduce the risk of bleeding, compared with warfarin. One review of genotype-guided warfarin dosing assessed AF patients; no significant differences in stroke prevention were reported. Education about OACs, in patients with AF, could improve adherence. Pharmacist management of coagulation may be better than primary care management. Patients were more adherent to direct OACs than warfarin. Drug efficacy was highly valued by patients and most clinicians, followed by safety. No other factors consistently affected patients' choice of anticoagulant and adherence to treatment. Patients were more satisfied with direct OACs than warfarin.

CONCLUSIONS

For stroke prevention in AF, direct OACs seem to be more effective and safer than usual care, and apixaban (5 mg twice daily) had the best profile. For VTE, there was no strong evidence that direct OACs were better than usual care. Education and pharmacist management could improve coagulation control. Both clinicians and patients rated efficacy and safety as the most important factors in managing AF and VTE.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42017084263-one deviation; efficacy and safety were from one review.

Long-term oral anticoagulation for atrial fibrillation in low and middle income countries

With increasing life-expectancy and changing demographics, non-valvular atrial fibrillation (AF) is currently the most common indication for long-term oral anticoagulation (OAC) in low and middle income countries (LMICs). Due to a decreasing trend in the prevalence of rheumatic heart disease (RHD), valve disease as a primary cause of AF now constitutes a small fraction of all people with AF. Moreover, emerging data also indicate that, patients with significant valve disease and AF may have a risk of stroke similar to, if not lower than, those with non-valvular AF. Previous trials of anticoagulation for AF excluded people from LMICs partly because valvular AF constituted a large proportion of those with AF, and it was thought to confer a prohibitively high risk of stroke. Trialists should therefore be less reluctant to include patients with AF from LMICs in general, and those with valve disease in particular, in future trials of anticoagulation. The quality of vitamin K antagonist based oral anticoagulation remains poor in LMICs to a large extent because of poor monitoring. The widespread use of the direct oral anticoagulants (DOAC) presents a practical approach to improve anticoagulation quality. Randomised trials of DOACs in valvular AF are particularlycriticalto bridge the knowledge gap in this area.

Discussions regarding oral anticoagulation (OAC) use in low and middle income countries (LMICs) have historicallybeendominated by severallong-held beliefs. The first is that the quality of vitamin K antagonist (VKA) based anticoagulation is poor in these countries. The veracity of this assumption is supported by a large number of studies documenting both lower prescription of OACs, and a lower proportion of international normalised ratio (INR) values in the therapeutic range.¹The second is that a large proportion of patients receiving OAC in LMICs have atrial fibrillation (AF) related to valvular heart disease, and rheumatic mitral stenosis in particular. This assumption, perhaps valid several decades ago, is no longer supported by the data. Finally, patients with valvular heart disease and AF (specifically those with moderate or severe valve lesions), are thought to be at prohibitively high thromboembolic risk. ² However, recent evidence suggests that this risk may have been overestimated.³⁴Nevertheless, the aforementioned assumptions continue to contribute to the underrepresentation of patients from LMICs in clinical trials of oral anticoagulation. Knowledge of the characteristics of contemporary patients in LMICs who are eligible for long-term OAC, estimates of their stroke risk, and a better understanding of the drivers of poor anticoagulation quality, may help guide research and clinical practice. In this review, we seek to provide an evidence-based perspective on OAC use in patients with AF living in LMICs and China.