(206) Comparative Effect of Oral Anticoagulants on Home Time Loss and Cost: The Role of Frailty

Publication Number: 880

Background: Home time, the number of days alive and spent out of hospital and skilled nursing facility, has been proposed as a patient-centered outcome. The role of frailty in the association of oral anticoagulants (OACs) with home time and medical cost for older adults with atrial fibrillation (AF) remains unclear.

Objectives: To determine the comparative home time loss and cost of OACs in patients with AF, stratified by levels of frailty

Methods: We used the US Medicare claims data to establish 4 new user cohorts: patients aged ≥ 65 years with a dispensing of warfarin, dabigatran, rivaroxaban, and apixaban, respectively, without any OAC use in the preceding 183 days from 2013 to 2017 (cohort entry date [CED]= first dispensing date). The study cohorts were required to have a non-valvular AF diagnosis in the 365 days before CED (i.e., the covariate assessment period). Frailty was measured using a validated claims-based frailty index (range: 0-1; non-frail if < 0.15, pre-frail if 0.15-0.24, and frail if ≥0.25). We used inverse probability treatment weighting to balance 93 covariates among apixaban (referent group), warfarin, dabigatran, and rivaroxaban. We estimated odds ratio (OR) for having home-time-loss more than 14 days over 183 days following the CED using logistic regression and difference in per-member per-year (PMPY) total cost of care using a generalized linear model.

Results: Our study cohort included 143,191 apixaban (mean age 77.4 years [Y]), 149,706 warfarin (mean age 77.9 Y), 30,023 dabigatran (mean age 76.2 Y), and 113,842 rivaroxaban (mean age 76.4 Y) users. For the non-frail group, compared to apixaban users, the adjusted ORs of having home-time-loss > 14 days were 1.6 (95% confidence interval: 1.2, 2.1), 1.2 (0.9, 1.7), and 1.4 (1.0, 1.9) for warfarin, dabigatran, and rivaroxaban, respectively. The corresponding ORs were 1.2 (1.1, 1.4), 1.1 (0.9, 1.3), and 1.2 (0.98, 1.4) for the frail group. For the non-frail group, compared to apixaban users, the adjusted difference in PMPY ($) was 635.8 (-5.4, 1279.7), -459.4 (-1068.1, 147.4), and 793.2 (146.7, 1443.0) for warfarin, dabigatran, and rivaroxaban, respectively. The corresponding estimates were 1675.6 (-889.4, 4255.2), -176.7 (-2664.6, 2310.7), and 3863.4 (1200.0, 6560.8) for the frail group.

Conclusions: Apixaban was associated with lower home time loss compared to warfarin and rivaroxaban in the non-frail group but this benefit was only observed when compared to rivaroxaban in the frail group. Apixaban was associated with greater total healthcare cost compared to rivaroxaban, and the cost increase was considerably higher in patients with frailty.