Category: Professional Posters
Purpose: Direct oral anticoagulants (DOACs) are widely used in atrial fibrillation (AF) to significantly reduce the risk of stroke and systemic embolic events. For patients who are overweight or obese, there are no DOAC dose adjustment recommendations due to limited data available on how body weight influences cardiovascular and bleeding outcomes in patients on DOACs. The purpose of this study was to evaluate the impact of overweight or obesity on any stroke or systemic embolic events and major bleed events in AF patients who are users of dabigatran, rivaroxaban, apixaban, or edoxaban.
Methods: An observational retrospective cohort study of adult (18 years or older) AF or atrial flutter patients initiating a DOAC from January 1, 2015 to December 31, 2017 was conducted using pharmacy and medical claims data from health plan members in Texas. Patients were stratified into five cohorts based on body mass index (BMI): normal (BMI 18.5-24.9 kg/m2), overweight (BMI 25.0-29.9 kg/m2), obese I (BMI 30.0-34.9 kg/m2), obese II (BMI 35.0-39.9 kg/m2), and obese III (BMI ≥40.0 kg/m2). The primary effectiveness outcome was stroke, including ischemic stroke and hemorrhagic stroke, or systemic embolism (SE). The primary safety outcome was major bleeding, including gastrointestinal bleeding, intracranial bleeding, and major bleeding from other sites. From the date of first pharmacy fill of a DOAC (index date), patients were followed until the earliest occurrence of either: (i) 12 months post-index date, (ii) occurrence of study outcome of interest, or (iii) 30 days post-discontinuation date, defined as no evidence of DOAC filled for 30 days from the last days’ supply of the last filled prescription date. Baseline demographics and characteristics and outcome rates were reported descriptively, and bivariate analyses were performed. Cox proportional hazards regression was conducted to compare time-to-event in each of the cohorts. The Baylor Scott & White Health Institutional Review Board approved this study.
Results: The primary analysis consisted of 1,035 patients. Collectively, obese patients accounted for the largest cohort (438 in all obese classes: 220 in obese I, 132 in obese II, and 86 in obese III), followed by overweight (352) and normal weight (245) patients. The mean age at index date was 75.9 years. A majority of the patients were of White race (96.2%), non-Hispanic ethnicity (97.7%), and had Medicare insurance (70.6%). Decreasing trends were observed from normal to obese III cohorts in mean age (81.5, 77.0, 74.7, 71.2, and 66.0 years, respectively), CHA2DS2-VASc score (4.8, 4.2, 4.2, 4.0, and 3.8, respectively), and HAS-BLED score (2.6, 2.5, 2.4, 2.3, and 2.1, respectively). A total of 11 (1.1%) patients experienced a stroke/SE event and similar rates were observed among the cohorts (3 [1.2%] normal; 3 [0.9%] overweight; 3 [1.4%] obese I; 1 [0.8%] obese II; 1 [1.2%] obese III). A total of 29 (2.8%) patients experienced a major bleed event. The frequency of bleed decreased as BMI cohorts increased (9 [3.7%] normal; 11 [3.1%] overweight; 5 [2.3%] obese I; 3 [2.3%] obese II; 1 [1.2%] obese III). A cox proportional hazards regression could not be performed due to the low number of event rates.
Conclusion: This study suggests that a small subset of patients who are users of DOACs experience a stroke/SE or major bleed event, and patients who are overweight or obese are not significantly associated with higher thrombotic or bleed rates compared to normal weight patients. However, this study is limited to a single health plan population with low event rates. As such, statistical testing could not be conducted to assess outcomes. Further studies with larger patient populations are warranted.