Aims
Limited data exist to describe the prognostic impact of atrial fibrillation (AF) and oral anticoagulation on patients with alcoholic cardiomyopathy (ACM) compared with dilated cardiomyopathy (DCM) and were investigated in this study.

Methods
Using Danish nationwide registries, a cohort analysis was conducted to assess the prognostic differences for patients with a first diagnosis of ACM versus DCM with and without AF 1994–2018 (followed until end 2019). Our study also assessed differences in mortality following initiation of anticoagulation in both populations.

Results
Totally, 1237 patients with ACM (33% with AF) and 17,211 individuals with DCM (33% with AF) were included. Those with ACM were more often men (89 versus 71%) and younger than patients with DCM (mean age 56 versus 64 years). Cumulative 5-year mortality was greater among patients with ACM, compared with DCM, regardless of AF (ACM with AF 49% [95% CI: 44–54%], ACM without AF 48% [45–53%], DCM with AF 41% [39–42%], DCM without AF 30% [29–31%], P < 0.0001). The prognosis associated with AF was statistically significantly different in people with ACM and DCM (adjusted hazards ratio 0.85 [95% CI: 0.74–0.98] versus 1.04 [1.00–1.09] in ACM and DCM, P < 0.0001). The mortality associated with oral anticoagulation was similar in ACM and DCM (hazards ratio 0.81 [0.61–1.07] versus 0.87 [0.80–0.94], P = 0.49).

Conclusions
Patients with ACM had a worse prognosis when compared with patients with DCM, but this did not appear to be driven by AF. Patients with ACM were observed to have similar associated risk benefits of oral anticoagulation as DCM