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This article is the author’s final published version in Thrombosis Update, Volume 6, March 2022, Article number 100100.

The published version is available at Copyright © Merchant et al.


Background: Anticoagulation (AC) adherence after acute pulmonary embolism (PE) is vital to prevent mortality and future recurrence of venous thromboembolism (VTE). We aimed to analyze factors affecting AC adherence after acute PE. Methods: Consecutive adult patients with CT angiography or V/Q scan confirmed acute PE were included in a single-center retrospective study from April 2016 to May 2020. Adherence data, including AC refill dates, were collected from pharmacies, and adherence measures including Continuous Measure of Medication Acquisition (CMA), Proportion of Days Covered (PDC), and Optimal Medication Adherence (OMA) were calculated per standardized formulas. Univariable and multivariable linear and logistic regression was used to analyze different variables affecting AC adherence. Results: A total of 118 out of 144 patients had sufficient follow-up data to measure adherence and were included in the final analysis. Mean age was 60 ± 15 years, with 64 (54.2%) women; 70 (59.3%) White, 26 (22%) African American, 13 (11%) Hispanic; 58 (49.2%) patients had private insurance, 48 (40.7%) Medicare, 11 (9.3%) Medicaid. Type of AC comprised of 57 (48.3%) apixaban, 17 (14.4%) rivaroxaban, 8 (6.8%) warfarin, 6 (5.1%) enoxaparin, and 30 (25.4%) patients with changing AC. In univariable regression, African American and Medicaid-insured patients had significantly lower adherence, while advancing age, apixaban usage, and 30-day follow-up clinic visit showed a higher adherence. However, in multivariable regression, African American race (PDC -0.135, p = 0.006, CI (−0.231, −0.040) | OMA Adjusted OR 0.166, p = 0.030, CI (0.033, 0.837)) and other non-White, non-Hispanic races (PDC -0.314, p = 0.009, CI (−0.548, −0.080)) were associated with lower AC adherence. Conclusion: In our study, African American and other minority race patients showed lower AC adherence after hospital admission for acute PE. Further studies are needed to address underlying contributors and improve adherence in this population.

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