Guideline-concordant initiation of oral anticoagulant therapy for stroke prevention in older veterans with atrial fibrillation eligible for Medicare Part D

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.

Association of Neighborhood Disadvantage and Anticoagulation for Patients with Atrial Fibrillation in the Veterans Health Administration: the REACH-AF Study

BACKGROUND

Atrial fibrillation (AF) is a common arrhythmia, the management of which includes anticoagulation for stroke prevention. Although disparities in anticoagulant prescribing have been well documented for individual socioeconomic factors, less is known about the association of neighborhood-level disadvantage and anticoagulation for AF.

OBJECTIVE

To assess the association between neighborhood disadvantage and anticoagulant initiation for patients with incident AF.

DESIGN

Retrospective cohort study.

PARTICIPANTS

A cohort of patients enrolled in the Veterans Health Administration (VA) with incident AF from January 2014 through December 2020 from the Race, Ethnicity, and Anticoagulant CHoice in Atrial Fibrillation (REACH-AF) Study.

MAIN MEASURES

The primary exposure was neighborhood disadvantage quantified using area deprivation index (ADI), classified by quintiles (Q). The outcomes were initiation of any anticoagulant therapy (warfarin or direct oral anticoagulant, DOAC) within 90 days of AF diagnosis and DOAC use among initiators. We used mixed effects logistic regression to assess the association between ADI and anticoagulant therapy, incorporating a fixed effect for treatment site and baseline patient, provider, and facility covariates.

KEY RESULTS

Among 161,089 patients, 105,489 (65.5%) initiated any anticoagulant therapy, and 78,903 (74.8%) used DOACs. Any anticoagulant therapy increased 3.2 percentage points (63.0% to 66.2%; p<.001) from Q1 to Q5, whereas DOAC use decreased 8.2 percentage points (79.4% to 71.2%; p<.0001) across quintiles. The adjusted odd ratios of any anticoagulant therapy were non-significantly different for Q2-Q5 than Q1. The adjusted odds of DOAC use decreased progressively from 0.89 (95% CI, 0.84-0.94) in Q2 to 0.77 (95% CI, 0.73-0.83) in Q5 compared to Q1 (p<.0001).

CONCLUSIONS

Among Veterans with incident AF, we observed similar initiation of any anticoagulant, though neighborhood deprivation was associated with decreased DOAC use among anticoagulant initiators. Future interventions to improve pharmacoequity in anticoagulant prescribing for AF should consider the role of neighborhood-level determinants of health inequities.

Association of Race and Ethnicity and Anticoagulation in Patients with Atrial Fibrillation Dually Enrolled in VA and Medicare: Effects of Medicare Part D on Prescribing Disparities

Background: Racial and ethnic disparities in anticoagulation exist in atrial fibrillation (AF) management in Medicare and the Veterans Health Administration (VA), but the influence of dual VA and Medicare enrollment is unclear. We compared anticoagulant initiation by race and ethnicity in dually enrolled patients and assessed the role of Medicare Part D enrollment on anticoagulation disparities. Methods: We identified patients with incident AF (2014-2018) dually enrolled in VA and Medicare. We assessed any anticoagulant initiation (warfarin or direct-acting oral anticoagulants, DOACs) within 90 days of AF diagnosis and DOAC use among anticoagulant initiators. We modeled anticoagulant initiation, adjusting for patient, provider, and facility factors, including main effects for race and ethnicity and Medicare Part D enrollment and an interaction term for these variables. Results: In 43,789 patients, 8.9% were Black, 3.6% Hispanic, and 87.5% White; 10.9% participated in Medicare Part D. Overall, 29,680 (67.8%) patients initiated any anticoagulant, of which 17,568 (59.2%) initiated DOACs. Lower proportions of Black (65.2%) than Hispanic (67.6%) or White (68.0%) patients initiated any anticoagulant (p= 0.001), and lower proportions of Black (56.3%) and Hispanic (55.9%) than White (59.6%) patients (p=0.001) initiated DOACs. Compared to White patients, Black patients had significantly lower initiation of any anticoagulant, adjusted odds ratio (aOR) 0.89; 95% CI 0.82-0.97. The aORs for DOAC initiation were significantly lower for Black (0.72; 95% CI, 0.65-0.81) and Hispanic (0.84; 95% CI, 0.70-1.00) than White patients.The interaction between race and ethnicity and Medicare Part D enrollment was non-significant for any anticoagulant (p=0.99) and DOAC (p=0.27) therapies. Conclusions: In dually enrolled VA and Medicare patients with AF, Black patients were less likely to initiate any anticoagulant and Black and Hispanic patients were less likely to initiate DOACs. Medicare Part D enrollment did not moderate the associations between race and ethnicity and anticoagulant therapies.

Disparities in Anticoagulant Therapy Initiation for Incident Atrial Fibrillation by Race/Ethnicity Among Patients in the Veterans Health Administration System

IMPORTANCE

Atrial fibrillation is a common cardiac rhythm disturbance causing substantial morbidity and mortality that disproportionately affects racial/ethnic minority groups. Anticoagulation reduces stroke risk in atrial fibrillation, yet studies show it is underprescribed in racial/ethnic minority patients.

OBJECTIVE

To compare initiation of anticoagulant therapy by race/ethnicity for patients in the Veterans Health Administration (VA) system with atrial fibrillation.

DESIGN, SETTING, AND PARTICIPANTS

This retrospective cohort study included 111 666 patients within the VA system with incident atrial fibrillation between January 1, 2014, and December 31, 2018. Data were analyzed between December 1, 2019, and March 31, 2020.

EXPOSURES

Any anticoagulation was defined as receipt of warfarin or direct-acting oral anticoagulants, apixaban, dabigatran, edoxaban, or rivaroxaban.

MAIN OUTCOMES AND MEASURES

Initiation of any anticoagulation (or direct-acting oral anticoagulant therapy in those who initiated any anticoagulation) was examined within 90 days of an index atrial fibrillation diagnosis.

RESULTS

Our final cohort comprised 111 666 patients (109 386 men [98.0%] and 95 493 White patients [85.5%]; mean [SD] age, 72.9 [10.4] years). A total of 69 590 patients (62.3%) initiated any anticoagulant therapy, varying 10.5 percentage points by race/ethnicity (P < .001); initiation was lowest in Asian (52.2% [n = 676]) and Black (60.3% [n = 6177]) patients and highest in White patients (62.7% [n = 59 881]). Among anticoagulant initiators, 45 381 (65.2%) used direct-acting oral anticoagulants, varying 7.2 percentage points by race/ethnicity (P < .001); initiation was lowest in Hispanic (58.3% [n = 1470]), American Indian/Alaska Native (59.8% [n = 201]), and Black (60.9% [n = 3763]) patients and highest in White patients (66.0% [n = 39 502). Compared with White patients, the odds of initiating any anticoagulant therapy were significantly lower for Asian (adjusted odds ratio [aOR], 0.82; 95% CI, 0.72-0.94) and Black (aOR, 0.90; 95% CI 0.85-0.95) patients. Among initiators, the adjusted odds of direct-acting oral anticoagulant initiation were significantly lower for Hispanic (aOR, 0.79; 95% CI, 0.70-0.89), American Indian/Alaska Native (aOR, 0.75; 95% CI, 0.57-0.99), and Black (aOR, 0.74; 95% CI 0.69-0.80) patients.

CONCLUSIONS AND RELEVANCE

This cohort study found that in patients with incident atrial fibrillation managed in the VA system, race/ethnicity was independently associated with initiating any anticoagulant therapy and direct-acting oral anticoagulant use among anticoagulant initiators. Understanding the reasons for these treatment disparities is essential to improving equitable atrial fibrillation management and outcomes among racial/ethnic minority patients treated in the VA system.

Mortality and Hepatic Decompensation in Patients With Cirrhosis and Atrial Fibrillation Treated With Anticoagulation

BACKGROUND AND AIMS

Outcomes with anticoagulation (AC) are understudied in advanced liver disease. We investigated effects of AC with warfarin and direct oral anticoagulants (DOACs) on all-cause mortality and hepatic decompensation as well as ischemic stroke, major adverse cardiovascular events, splanchnic vein thrombosis, and bleeding in a cohort with cirrhosis and atrial fibrillation (AF).

APPROACH AND RESULTS

This was a retrospective, longitudinal study using national data of U.S. veterans with cirrhosis at 128 medical centers, including patients with cirrhosis with incident AF, from January 1, 2012 to December 31, 2017 followed through December 31, 2018. To assess the effects of AC on outcomes, we applied propensity score (PS) matching and marginal structural models (MSMs) to account for confounding by indication and time-dependent confounding. The final cohort included 2,694 veterans with cirrhosis with AF (n = 1,694 and n = 704 in the warfarin and DOAC cohorts after PS matching, respectively) with a median of 4.6 years of follow-up. All-cause mortality was lower with warfarin versus no AC (PS matched: hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.55-0.76; MSM models: HR, 0.54; 95% CI, 0.40-0.73) and DOACs versus no AC (PS matched: HR, 0.68; 95% CI, 0.50-0.93; MSM models: HR, 0.50; 95% CI, 0.31-0.81). In MSM models, warfarin (HR, 0.29; 95% CI, 0.09-0.90) and DOACs (HR, 0.23; 95% CI, 0.07-0.79) were associated with reduced ischemic stroke. In secondary analyses, bleeding was lower with DOACs compared to warfarin (HR, 0.49; 95% CI, 0.26-0.94).

CONCLUSIONS

Warfarin and DOACs were associated with reduced all-cause mortality. Warfarin was associated with more bleeding compared to no AC. DOACs had a lower incidence of bleeding compared to warfarin in exploratory analyses. Future studies should prospectively investigate these observed associations.

Guideline-concordant initiation of oral anticoagulant therapy for stroke prevention in older veterans with atrial fibrillation eligible for Medicare Part D

OBJECTIVE

To characterize the rate of guideline-concordant initiation of oral anticoagulation (OAC) among elderly Veterans with atrial fibrillation (AF) and high stroke risk.

DATA SOURCES/STUDY SETTING

Veterans Health Administration (VHA) Corporate Data Warehouse (CDW) linked with Medicare claims 2011-2015.

STUDY DESIGN

We identified 6619 elderly, high stroke-risk patients with a new episode of AF initially diagnosed in the VHA during fiscal years 2012-2015. We used logistic regression to estimate marginal effects of associations between patient characteristics and OAC initiation within 90 days of the first AF episode.

DATA EXTRACTION METHODS

We identified OACs using generic drug names. We calculated comorbidities and risk scores using diagnosis codes from 1 year of baseline data.

PRINCIPAL FINDINGS

Overall, 66.5% of Medicare-eligible Veterans with AF at high risk of stroke initiated an OAC within 90 days. We found lower initiation rates for patients enrolled in Medicare Part D and those ineligible for drug co-payment subsidies. OAC initiation rates increased during the study among VHA-reliant patients but not among dual VHA-Part D enrollees.

CONCLUSIONS

One-third of elderly Veterans at risk of stroke are not receiving recommended therapy. Increased coordination between Medicare and VHA providers may lead to improvements in anticoagulation quality and stroke prevention.