Does Hospitalization For Thromboembolism Improve Oral Anticoagulant Adherence In Patients With Atrial Fibrillation?

Abstract [from journal]

Background: It is not known how medication adherence changes after hospitalization for a sentinel thromboembolic event.

Objective: The purpose of this study was to examine the impact of hospitalization for ischemic stroke or thromboembolism on postdischarge adherence to oral anticoagulants in patients with atrial fibrillation.

Methods: We conducted a quasi-experimental pre-post observational study using a large U.S. commercial insurance health care claims database. Adult patients with atrial fibrillation taking oral anticoagulants with a random hospitalization for a nonbleeding-related reason occurring after the first observed oral anticoagulant prescription fill, with no other admissions within the preceding and following 6 months, were identified in Optum Clinformatics (Eden Prairie, MN) from 2009 to 2016. Adherence was estimated by the proportion of days covered within 6 and 12 months before and after hospitalization. Difference-in-difference analysis using a generalized linear model was employed to compare pre- and post-hospitalization proportions of days covered (PDCs) by reasons for hospitalization (i.e., ischemic stroke or thromboembolism vs. other nonbleeding-related reasons), adjusting for imbalanced baseline characteristics.

Results: Of the 21,400 individuals meeting inclusion criteria, 5.4% were hospitalized for ischemic stroke or thromboembolism and 94.6% for other nonbleeding-related reasons. Baseline characteristics were quite similar between groups, except for a few covariables such as age or CHA2DS2-VASc score. Minority race or ethnicity individuals had 0.7% lower overall PDC than whites (P = 0.006). After covariate adjustment, 6-month adherence declined by 1.1% less in individuals hospitalized for ischemic stroke or thromboembolism, compared with other nonbleeding reasons, although the difference was not statistically significant (P = 0.17). Similar results were observed for the 12-month window.

Conclusion: This real-world study suggests that more effective strategies are needed to improve adherence to oral anticoagulant, particularly after a thromboembolic event.