Comparison of stroke- and bleed-related healthcare resource utilization and costs among patients with newly diagnosed non-valvular atrial fibrillation and newly treated with dabigatran, rivaroxaban, or warfarin

Risk of stroke/systemic embolism, major bleeding, and associated costs in non-valvular atrial fibrillation patients who initiated apixaban, dabigatran, or rivaroxaban compared with warfarin in the United States medicare population: updated analysis

OBJECTIVE

To provide an updated comparison of the risk and cost of stroke/systemic embolism (SE) and major bleeding between direct oral anticoagulants (DOAC: apixaban, rivaroxaban, dabigatran) and warfarin among non-valvular atrial fibrillation (NVAF) patients.

METHODS

Adults (≥65 years) initiating warfarin or DOACs between 1 January 2013 and 31 December 2014 were selected from the Medicare database and propensity scores matched 1:1 to balance baseline characteristics. Cox proportional hazards models were used to estimate the risks of stroke/SE and major bleeding of each DOAC vs. warfarin. Two-part models were used to compare the stroke/SE- and major bleeding-related medical costs in each matched cohort.

RESULTS

Of the 264,479 eligible patients, 38,740 apixaban-warfarin pairs, 76,677 rivaroxaban-warfarin pairs, and 20,955 dabigatran-warfarin pairs were matched. Apixaban (Hazard Ratio [HR] = 0.46; 95% Confidence Interval [CI] 0.38-0.56) and rivaroxaban (HR = 0.71; 95% CI 0.63-0.80) were associated with a significantly lower risk of stroke/SE compared to warfarin. Apixaban (HR = 0.57; 95% CI 0.51-0.63) and dabigatran (HR = 0.80; 95% CI 0.70-0.90) were associated with a significantly lower risk of major bleeding; rivaroxaban (HR = 1.14; 95% CI 1.07-1.21) was associated with a significantly higher risk of major bleeding compared to warfarin. Compared to warfarin, apixaban and rivaroxaban had significantly lower stroke/SE-related medical costs; and apixaban and dabigatran had significantly lower major bleeding-related medical costs.

CONCLUSIONS

This real-world analysis showed DOACs to be associated with a lower risk of stroke/SE and major bleeding, and lower medical costs compared to warfarin. Among them, only apixaban appears to be associated with a significantly lower risk of all three outcomes collectively: stroke/SE, major bleeding, and lower related medical costs compared to warfarin.

Healthcare resource utilization and expenditures among newly-diagnosed elderly non-valvular atrial fibrillation patients initiating oral anticoagulants

Aims: Non-valvular atrial fibrillation (NVAF) prevalence increases with age. Hence, evaluating the economic burden among older-aged patients is vital. This study aimed to compare healthcare resource utilization (HRU) and costs among newly-diagnosed older-aged NVAF patients treated with warfarin, rivaroxaban, or apixaban vs. dabigatran.Materials and Methods: Newly-diagnosed older-aged (aged ≥65 years) NVAF patients initiating dabigatran, warfarin, rivaroxaban, or apixaban (first prescription date = index date) from 01JAN2010-31DEC2015 and with continuous enrollment for ≥12 months pre-index date were included from 100% Medicare database. Patient data were assessed until drug discontinuation/switch/dose change/death/disenrollment/study end (up to 12 months). Dabigatran initiators were 1:1 propensity score-matched (PSM) with warfarin, rivaroxaban, or apixaban initiators. Generalized linear models were used to compare all-cause HRU and costs per-patient-per-month (PPPM) between the matched cohorts.Results: After PSM with dabigatran, 70,531 warfarin, 51,673 rivaroxaban, and 25,209 apixaban patients were identified. Dabigatran patients had significantly fewer generalized-linear-model-adjusted PPPM hospitalizations (0.114 vs. 0.123; 0.111 vs. 0.121), and outpatient visits (2.864 vs. 4.201; 2.839 vs. 2.949) than warfarin and rivaroxaban patients, respectively, but had significantly more PPPM hospitalizations (0.103 vs. 0.090) and outpatient visits (2.780 vs. 2.673) than apixaban patients (all p < .0001). Dabigatran patients incurred significantly lower adjusted total PPPM costs ($3,309 vs. $3,362; $3,285 vs. $3,474) than warfarin and rivaroxaban patients, respectively (all p < .01) but higher total PPPM costs ($3,192 vs. $2,986) than apixaban patients (all p < .0001).Limitations: This study is subject to the inherent limitations of any claims dataset, including potential bias from coding errors and identification of medical conditions using diagnosis codes as opposed to clinical evidence. Medications filled over-the-counter or provided as samples by the physician are never captured in claims data.Conclusions: Newly-diagnosed older-aged NVAF patients initiating dabigatran incurred significantly lower adjusted all-cause HRU and costs than warfarin and rivaroxaban patients but higher adjusted HRU and costs than apixaban patients.