Background

Oral anticoagulants (OACs) mitigate stroke risk in patients with atrial fibrillation (AF). The study aim was to analyze prevalence and predictors of OAC underutilization.

Methods

Newly diagnosed AF patients with a CHA₂DS₂-VASc score ≥ 2 were identified from the US CMS Database (January 1, 2013-December 31, 2017). Patients were stratified based on having an OAC prescription versus not and the OAC prescription group was stratified by direct OAC (DOACs) versus warfarin. Multivariable logistic regression models were used to examine predictors of OAC underutilization.

Results

Among 1,204,507 identified AF patients, 617,611 patients (51.3%) were not prescribed an OAC during follow-up (mean: 2.4 years), and 586,896 patients (48.7%) were prescribed an OAC during this period (DOAC: 388,629 [66.2%]; warfarin: 198,267 [33.8%]). Age ≥ 85 years (odds ratio [OR] 0.55, 95% confidence interval [CI] 0.55-0.56), female sex (OR 0.96, 95% CI 0.95-0.96), Black race (OR 0.78, 95% CI 0.77-0.79) and comorbidities such as gastrointestinal (GI; OR 0.43, 95% CI 0.41-0.44) and intracranial bleeding (OR 0.29, 95% CI 0.28-0.31) were associated with lower utilization of OACs. Furthermore, age ≥ 85 years (OR 0.92, 95% CI 0.91-0.94), Black race (OR 0.78, 95% CI 0.76-0.80), ischemic stroke (OR 0.77, 95% CI 0.75-0.80), GI bleeding (OR 0.73, 95% CI 0.68-0.77), and intracranial bleeding (OR 0.72, 95% CI 0.65-0.80) predicted lower use of DOACs versus warfarin.

Conclusions

Although OAC therapy prescription is the standard of care for stroke prevention in AF patients, its overall utilization is still low among Medicare patients ≥ 65 years old, with specific patient characteristics that predict underutilization.

Background

Oral anticoagulants (OACs) mitigate the risk of stroke in atrial fibrillation (AF) patients.

Objective

Elderly AF patients who were treated with OACs (apixaban, dabigatran, edoxaban, rivaroxaban, or warfarin) were compared against AF patients who were not treated with OACs with respect to their clinical and economic outcomes.

Methods

Newly diagnosed AF patients were identified between January 2013 and December 2017 in the Medicare database. Evidence of an OAC treatment claim on or after the first AF diagnosis was used to classify patients into treatment-defined cohorts, and these cohorts were further stratified based on the initial OAC prescribed. The risks of stroke/systemic embolism (SE), major bleeding (MB), and death were analyzed using inverse probability treatment weighted time-dependent Cox regression models, and costs were compared with marginal structural models.

Results

The two treatment groups were composed of 1,421,187 AF patients: OAC treated (N = 583,350, 41.0% [36.4% apixaban, 4.9% dabigatran, 0.1% edoxaban, 26.7% rivaroxaban, and 31.9% warfarin patients]) and untreated (N = 837,837, 59.0%). OAC-treated patients had a lower adjusted risk of stroke/SE compared to untreated patients (hazard ratio [HR]: 0.70; 95% confidence interval [CI]: 0.68-0.72). Additionally patients receiving OACs had a lower adjusted risk of death (HR: 0.56; 95% CI: 0.55-0.56) and a higher risk of MB (HR: 1.57; 95% CI: 1.54-1.59) and this trend was consistent across each OAC sub-group. The OAC-treated cohort had lower adjusted total healthcare costs per patient per month ($4,381 vs $7,172; p < .0001).

Conclusion

For the OAC-treated cohort in this elderly US population, stroke/SE and all-cause death were lower, while risk of MB was higher. Among OAC treated patients, total healthcare costs were lower than those of the untreated cohort.