Antithrombotic Therapy in Atrial Fibrillation Management in Western Australia: Temporal Trends and Evidence-Treatment Gaps

Long-term outcomes after hospitalization for atrial fibrillation or flutter

BACKGROUND AND AIMS

Atrial fibrillation (AF) and flutter are common causes of hospitalizations but contemporary long-term outcomes following these episodes are uncertain. This study assessed outcomes up to 10 years after an acute AF or flutter hospitalization.

METHODS

Patients hospitalized acutely with a primary diagnosis of AF or flutter from 2008-17 from all public and most private hospitals in Australia and New Zealand were included. Kaplan-Meier methods and flexible parametric survival modelling were used to estimate survival and loss in life expectancy, respectively. Competing risk model accounting for death was used when estimating incidence of non-fatal outcomes.

RESULTS

A total of 260 492 adults (mean age 70.5 ± 14.4 years, 49.6% female) were followed up for 1 068 009 person-years (PY), during which 69 167 died (incidence rate 6.5/100 PY) with 91.2% survival at 1 year, 72.7% at 5 years, and 55.2% at 10 years. Estimated loss in life expectancy was 2.6 years, or 16.8% of expected life expectancy. Re-hospitalizations for heart failure (2.9/100 PY), stroke (1.7/100 PY), and myocardial infarction (1.1/100 PY) were common with respective cumulative incidences of 16.8%, 11.0%, and 7.1% by 10 years. Re-hospitalization for AF or flutter occurred in 21.3% by 1 year, 35.3% by 5 years, and 41.2% by 10 years (11.6/100 PY). The cumulative incidence of patients undergoing catheter ablation of AF was 6.5% at 10 years (1.2/100 PY).

CONCLUSIONS

Patients hospitalized for AF or flutter had high death rates with an average 2.6-year loss in life expectancy. Moreover, re-hospitalizations for AF or flutter and related outcomes such as heart failure and stroke were common with catheter ablation used infrequently for treatment, which warrant further actions.

Systematic Review and Meta-Analysis of the Effect of Anticoagulation on Outcomes After Endovascular Aneurysm Repair

PURPOSE

Our objective was to investigate whether patients who receive anticoagulation therapy have different outcomes after endovascular aneurysm repair (EVAR) from those who do not.

MATERIALS AND METHODS

We conducted a systematic review of studies that compared outcomes of EVAR in patients who were on therapeutic anticoagulation vs those who were not. We developed and reported the review in accordance with the PRISMA guidelines with a registered protocol (CRD42022375894). The Ovid interface was used to search Medical Literature Analysis and Retrieval System Online (MEDLINE), Excerpta Medica Database (EMBASE), and Cochrane Central Register of Controlled Trials (CENTRAL) up to November 2022. The quality of studies was assessed with the Newcastle-Ottawa Scale (NOS) (maximum score=9), and the evidence was appraised with the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework. The hazard ratio (HR) and 95% confidence interval (CI) was the effect estimate in time-to-event meta-analyses, calculated using the inverse-variance statistical method and random-effects models.

RESULTS

Sixteen studies qualified for inclusion reporting a total of 35 739 individuals. Anticoagulated patients had a statistically significantly higher hazard of death (HR=1.93, 95% CI=1.03-3.63), endoleak (HR=2.13, 95% CI=1.55-2.93), reintervention (HR=1.79, 95% CI=1.27-2.52), and aneurysm sac expansion (HR=2.72, 95% CI=1.57-4.72) than patients not receiving anticoagulation therapy. The median score on the NOS was 7 (range=4-9). The certainty of evidence was very low for mortality and reintervention and low for endoleak and sac expansion.

CONCLUSIONS

Anticoagulation is a poor prognostic factor after standard EVAR and should be considered in decision-making, consent processes, and surveillance strategies.

CLINICAL IMPACT

The number of individuals who take anticoagulation treatment has been rapidly increasing over the recent years. We aimed to investigate the effect of such treatment on outcomes after endovascular aneurysm repair (EVAR). Anticoagulated patients were found to have increased mortality, endoleak, and reintervention rates after EVAR compared to their non-anticoagulated counterparts. Anticoagulation therapy has a prognostic role in EVAR and should be considered in decision making and EVAR surveillance. Anticoagulated patients need to be informed of the higher failure rates of EVAR, and intensified surveillance strategies may need to be implemented in this patient cohort.

Associations between clinical and social factors and anticoagulant prescription among patients with atrial fibrillation: A retrospective cohort study from a large healthcare system

BACKGROUND

Patient clinical factors and social determinants of health (SDOH) are associated with an increased risk of stroke for patients with atrial fibrillation (AF); however, the association between these factors and the management of AF is not well characterized, particularly among those factors commonly collected in electronic health records (EHRs). This study used EHR data to evaluate the associations between patient clinical factors and SDOH and prescribing of an oral anticoagulant (OAC) for stroke prevention in AF.

METHODS

This analysis included adult patients with newly diagnosed AF who had ≥2 encounters in the Advocate Aurora Health system in Wisconsin between May 2016 and May 2021. Patient-level demographics, comorbidities, medications, and SDOH were retrospectively extracted from EHRs. Area deprivation index (ADI) was linked to patient records as a measure of socioeconomic status.

RESULTS

Of 16,656 patients with AF, 10,898 (65.4%) were prescribed an OAC within the first year of diagnosis. Patients were less likely to be prescribed an OAC (relative risk [95% CI]) if they were widowed (0.98 [0.96-0.99] vs single) or had a history of alcoholism (0.86 [0.79-0.95] vs no history). Most patients (53.3%) received prescriptions from a primary care provider. A linear relationship was found between worsening ADI and increased prescriptions for warfarin vs those for direct-acting OACs.

CONCLUSIONS

Although guideline-concordant anticoagulant use remained suboptimal, clinical characteristics were strongly associated for whether a patient with AF would be prescribed an OAC. Disparities in patient care regarding the prescribing of OACs due to SDOH and associated behaviors were small but present, particularly for national ADI.

Performance of multilabel machine learning models and risk stratification schemas for predicting stroke and bleeding risk in patients with non-valvular atrial fibrillation

BACKGROUND

Appropriate anticoagulant therapy for patients with atrial fibrillation (AF) requires assessment of stroke and bleeding risks. However, risk stratification schemas such as CHA2DS2-VASc and HAS-BLED have modest predictive capacity for patients with AF. Multilabel machine learning (ML) techniques may improve predictive performance and support decision-making for anticoagulant therapy. We compared the performance of multilabel ML models with the currently used risk scores for predicting outcomes in AF patients.

METHODS

This was a retrospective cohort study of 9670 patients, mean age 76.9 years, 46% women, who were hospitalized with non-valvular AF, and had 1-year follow-up. The outcomes were ischemic stroke (167), major bleeding (430) admissions, all-cause death (1912) and event-free survival (7387). Discrimination and calibration of ML models were compared with clinical risk scores by area under the curve (AUC). Risk stratification was assessed using net reclassification index (NRI).

RESULTS

Multilabel gradient boosting classifier chain provided the best AUCs for stroke (0.685 95% CI 0.676, 0.694), major bleeding (0.709 95% CI 0.703, 0.716) and death (0.765 95% CI 0.763, 0.768) compared to multi-layer neural networks and classifier chain using support vector machine. It provided modest performance improvement for stroke compared to AUC of CHA2DS2-VASc (0.652, NRI = 3.2%, p-value = 0.1), but significantly improved major bleeding prediction compared to AUC of HAS-BLED (0.522, NRI = 22.8%, p-value < 0.05). It also achieved greater discriminant power for death compared with AUC of CHA2DS2-VASc (0.606, p-value < 0.05). ML models identified additional risk features such as hemoglobin level, renal function.

CONCLUSIONS

Multilabel ML models can outperform clinical risk stratification scores for predicting the risk of major bleeding and death in non-valvular AF patients.

Prevalence of atrial fibrillation and the risk of cardiovascular mortality among hypertensive elderly population in northeast China

Little is known about the epidemiology and impact of atrial fibrillation (AF) on cardiovascular diseases (CVD) mortality among hypertensive elderly population in northeast China. The community‐based study included 4497 hypertensive elderly residents aged ≥65 years who lived in northeast China from September 2017 to March 2019. Information on CVD deaths was obtained from baseline until July 31, 2021. Cox proportional hazard regression models were performed in the evaluation of CVD mortality. We identified 101 persons with AF. The prevalence of AF was 2.2% among elderly hypertensive population, which increased significantly with age. The prevalence of AF was higher in men than in women. The awareness rate was 51.5%, higher in urban areas than in rural areas (68.8% vs 43.5%, P = .018). Only 4.0% patients received oral anticoagulant (OAC) therapy among AF patients. Moreover, diabetes (26.7%) and dyslipidemia (37.6%) were highly prevalent in AF patients. Furthermore, 212 persons died due to CVD (14.7/1000 person‐years) during a median follow‐up of 3.2 years. AF patients had a 3.42 (95% CI: 2.07‐5.63) times higher risk of CVD mortality than the patients without AF in the fully adjusted model. Therefore, the burden of AF among hypertensive elderly population in northeast China was considerable. Long‐term screening and management strategies for AF and related risk factors are required among hypertensive elderly in northeast China.

Reasons for non-adherence to thromboprophylaxis prescribing guidelines in atrial fibrillation in Western Australia: A qualitative descriptive study of general practitioners' views

BACKGROUND

A significant proportion of the atrial fibrillation (AF) population attending Australian primary care is not receiving guideline-adherent oral anticoagulant (OAC) treatment. This study aimed to explore reasons for non-adherence to thromboprophylaxis guidelines in AF from the perspectives of general practitioners (GPs) and to map these reasons to the Capability, Opportunity, Motivation-Behaviour (COM-B) model to identify potential opportunities to support practice change.

METHODS

An exploratory qualitative descriptive study among GPs practising in Western Australia was conducted using semi-structured interviews, from November 2020 to February 2021. The Framework Method was employed to facilitate thematic analysis, using NVivo software. Interview responses were also mapped to the COM-B model.

RESULTS

Nine of the 10 GPs initially consented participated in the semi-structured interview (Male = 56%, median age = 52 years, data saturation reached with 6 participants). Two themes emerged from analysis of the interview transcripts: (1) GPs' decision-making process and (2) Patient refusal to take OACs. The COM-B model mapping identified behavioural factors that could impact adherence: capability (GPs' knowledge and understanding of AF guideline recommendations), opportunity (access to a cardiologist, and patients' refusal to take OACs), and motivation (using formal bleeding risk assessment tools).

CONCLUSION

GPs identified various reasons contributing to non-adherence to thromboprophylaxis guidelines in patients with AF. Multifaceted interventions should consider behavioural opportunities to improve adherence, including education and training, electronic decision support, clinical audits by allied health professionals, partnership between general practices and local hospitals, and cardiologist-led interventions to support GPs. Further studies are needed to capture patients' reasons for refusing OACs.