Coffee consumption and adverse cardiovascular events in patients with atrial fibrillation.

Background
There is some evidence of reduced major cardiovascular event (MACE) rates associated with moderate coffee consumption in the general population. However, there is concern about the potential risks of coffee consumption in patients with atrial fibrillation (AF). Therefore, we aimed to investigate the association between coffee consumption and MACE in AF patients.Methods
Data of patients with documented AF enrolled in two large prospective observational multicenter cohort studies (Swiss-AF and Beat-AF) were analyzed. Follow-up information was obtained on a yearly basis. Coffee consumption was categorized into two main groups: "daily" and "not-daily" coffee consumers as well as additional subcategories. The primary endpoint was MACE, defined as a composite of stroke or systemic embolism, myocardial infarction, hospitalization for acute heart failure, and cardiovascular mortality. Secondary endpoints were the individual components of MACE and all-cause mortality. We performed time-updated multivariable adjusted Cox regression analyses to investigate the association between coffee consumption and MACE.Results
The incidence rate for MACE was 5.09 per 100 person-years (py) in daily and 7.49 per 100 py in not-daily consumers (median follow-up duration: 4.7 years). After adjustment for pre-selected confounding variables, daily coffee consumption was associated with a 23% lower hazard for MACE compared to not-daily consumption (hazard ratio (HR) (95% confidence interval (CI)) 0.77 (0.66; 0.89)). Patients with moderate coffee consumption (2-3 cups/day) had the lowest hazard for MACE compared to patients with not-daily coffee consumption (HR (95% CI) 0.74 (0.63; 0.87)).Conclusions
In a population of AF patients, daily coffee consumption was associated with a reduced risk for MACE, hospitalization for acute heart failure, and all-cause mortality. The results were inconclusive for stroke or systemic embolism, myocardial infarction, and cardiovascular death. In this analysis, we found no evidence of an unfavourable association of daily coffee consumption in AF Patients with adverse outcome events.Trial Registration
ClinicalTrials.gov Identifier: NCT02105844.