Outcomes of apixaban versus warfarin in patients with atrial fibrillation and multi-morbidity : insights from the ARISTOTLE trial

Background: Patients with atrial fibrillation (AF) often have multi-morbidity, defined as ≥3 comorbid conditions. Multi-morbidity is associated with polypharmacy, adverse events, and frailty potentially altering response to anticoagulation. We sought to describe the prevalence of multi-morbidity among older patients with AF and determine the association between multi-morbidity, clinical outcomes, and the efficacy and safety of apixaban compared with warfarin. Methods: In this post-hoc subgroup analysis of the ARISTOTLE trial, we studied enrolled patients age ≥ 55 years (n = 16,800). Patients were categorized by the number of comorbid conditions at baseline: no multi-morbidity (0–2 comorbid conditions), moderate multi-morbidity (3–5 comorbid conditions), and high multi-morbidity (≥6 comorbid conditions). Association between multi-morbidity and clinical outcomes were analyzed by treatment with a median follow-up of 1.8 (1.3–2.3) years. Results: Multi-morbidity was present in 64% (n = 10,713) of patients; 51% (n = 8491) had moderate multi-morbidity, 13% (n = 2222) had high multi-morbidity, and 36% (n = 6087) had no multi-morbidity. Compared with the no multi-morbidity group, the high multi-morbidity group was older (74 vs 69 years), took twice as many medications (10 vs 5), and had higher CHA 2 DS 2 -VASc scores (4.9 vs 2.7) (all P <.001). Adjusted rates per 100 patient-years for stroke/systemic embolism, death, and major bleeding increased with multi-morbidity (Reference no multi-morbidity; moderate multi-morbidity 1.42 [1.24–1.64] and high multi-morbidity 1.92 [1.59–2.31]), with no interaction in relation to efficacy or safety of apixaban. Conclusions: Multi-morbidity is prevalent among the population with AF; efficacy and safety of apixaban is preserved in this subgroup supporting extension of trial results to the most complex AF patients.