Clinical outcomes of patients with atrial fibrillation in relation to multimorbidity status changes over time and the impact of ABC pathway compliance: a nationwide cohort study.

Patients with atrial fibrillation (AF) commonly have associated comorbidities. The primary aim was to determine the effect of increasing numbers of comorbidity on clinical outcomes. The secondary aims were (1) the association of comorbidities with oral anticoagulants (OAC) discontinuation, and quality control, (2) the impact of holistic care based on the ABC pathway on clinical outcomes. The primary outcome was the composite of all-cause death, ischemic stroke/systemic embolism, major bleeding, and heart failure. A total of 3405 patients were enrolled; mean age 67.8 ± 11.3 years, 41.8% female. Compared to low comorbidity group [n = 897 (26.3%)], hazard ratios (HR) and 95% confidence intervals (CI) for the composite outcome in the high [n = 929 (27.3%)] and moderate comorbidity [n = 1579 (46.4%)] groups were 5.40 (4.20-6.94) and 2.54 (1.97-3.27), respectively. ABC pathway adherence was associated with reduction of the composite outcome overall (HR 0.63; 0.54-0.74). High comorbidity adversely impacted on OAC use, OAC discontinuation, and quality of warfarin control. If quality of anticoagulation control was included as part of the ABC pathway adherence, the reduction in composite outcome risk was greater (HR 0.46; 0.36-0.58). During 3-year follow-up, 33.9% changed from low- to the moderate-high comorbidity groups and 22.3% changed from moderate- to the high comorbidity group. In conclusion, comorbidity burden in AF patients is an important determinant of clinical outcomes, and changed over time. OAC use, OAC discontinuation, and quality of OAC control were impacted by comorbidity burden. ABC pathway adherence was associated with a reduced risk of adverse clinical outcomes.