Relationship between Mediterranean diet and time in therapeutic range in atrial fibrillation patients taking vitamin K antagonists.

Aims: It is unclear if atrial fibrillation (AF) patients treated with oral vitamin K antagonists (VKAs) must follow a specific diet to avoid interference with anticoagulation. The aim of this study was to assess if Mediterranean diet (Med-Diet) may affect quality of anticoagulation, as expressed by the time in therapeutic range (TTR).
Methods and Results: A prospective observational study including 553 non-valvular AF patients. Time in therapeutic range was calculated for all patients treated with VKAs, and adherence to Med-Diet was evaluated with a validated nine-item dietary questionnaire. Cardiovascular events (CVEs), such as cardiovascular death and fatal/non-fatal stroke or myocardial infarction, and bleedings were recorded. The median follow-up was 31.6 months. The median number of international normalized ratios for each patient was 63.0 (35.0-98.0) and 38 730 blood samples were analysed. In the whole cohort, the mean TTR was 65.5 ± 17.8%. The mean Med-Diet score was 5.19 ± 1.6, with frequent use of olive oil (90.1%), fruits (88.4%), and vegetables (69.3%) and low meat intake (71.2%). There were no differences among tertiles of Med-Diet score regarding TTR. A multivariable linear regression analysis showed that diabetes (β: -0.105, P = 0.015) and the use of angiotensin converting enzyme inhibitor/angiotensin receptor blockers (β: 0.153, P < 0.001) were associated with TTR. Compared with those without, AF patients with a CVE had significantly lower TTR (65.9 ± 17.9 vs. 59.6 ± 15.9, P = 0.029) and Med-Diet score (5.2 ± 1.5 vs. 4.4 ± 1.9, P = 0.004). A reduction of CVE was observed for each point of the Med-Diet score (hazard ratio 0.790, P = 0.017).
Conclusion: In our cohort of AF patients, Med-Diet is not associated with changes in TTR, and thus can be recommended for AF patients who are taking VKAs.
(Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2015. For permissions please email: journals.permissions@oup.com.)