ObjectiveTo assess secondary prevention and outcomes in patients with chronic coronary artery disease (CAD), atrial fibrillation (AF) and heart failure (HF), focusing on disease overlap.MethodsWe analysed the data of 10 517 outpatients with a diagnosis of CAD, AF and/or HF included in a prospective cohort study. Follow-up (median 3.2 years) was achieved in 10 478 (99.6%) patients. Seven mutually exclusive patient groups were formed: CAD alone (n=4303), AF alone (n=2604), CAD+AF (n=700), HF alone (n=513), HF+CAD (n=728), HF+AF (n=1087) and HF+CAD+AF (n=582).ResultsPatients with disease overlaps represented 29.4% of the total population. The level of secondary prevention was high in all subgroups and in accordance with European class I – level A guidelines. Among patients with CAD, 99% received an antithrombotic and 91% received a statin. Among patients with AF, 81.7% were treated with an anticoagulant if indicated. Among HF patients with left ventricular ejection fraction <40%, 90.9% received a renin-angiotensin system antagonist and 91% a beta-blocker. Three-year all cause/cardiovascular mortality rates were: 6.4%/2%, 9.7%/3.3%, 15.6%/6.7%, 19.2%/9.4%, 24.3%/13.6%, 28%/15.7% and 35.4%/24.8%, for patients with CAD alone, AF alone, CAD+AF, HF alone, HF+CAD, HF+AF and HF+CAD+AF, respectively. In all groups with HF, observed all-cause mortality was higher (p<0.0001) than expected mortality for age-matched, gender-matched and geography-matched persons. In contrast, observed mortality was lower than expected for patients with CAD alone and AF alone (p<0.0001).ConclusionsIn a context of adequate secondary prevention, overlap between diseases is a frequent and high-risk situation with incremental increases in mortality. These patients deserve specific attention.