Abstract Body: Background
A healthy diet is important for the prevention and treatment of cardiovascular disease (CVD). The Dutch Health Council defined dietary guidelines for patients with atherosclerotic CVD, which we investigated in relation to long-term mortality after myocardial infarction (MI).

Methods
We included 4,365 patients of the Dutch Alpha Omega Cohort (60-80 y, 80% male) with a MI <10 y prior to study enrollment. Dietary intake was assessed at baseline (2002-2006), using a validated 203-item food frequency questionnaire. We created the DHD-CVD index, based on the 2023 Dutch dietary guidelines for cardiovascular patients (scale 0-160, with 160 for maximal adherence). Patients were followed for cause-specific mortality through December 2022. Hazard Ratios (HRs) across quartiles of the DHD-CVD-index (reference: low diet quality, Q1) and per 1-SD increment in score were estimated using Cox proportional hazard models. Associations were adjusted for age, sex, total energy intake, smoking, educational level and physical activity. Results were stratified for sex, obesity and socioeconomic position (SEP) based on area code. Numbers needed to eat (NNE) were calculated as 1 divided by the absolute risk difference between the extreme quartiles.

Findings
Of the cohort, 17% were smokers, 21% had diabetes and over 90% used statins or other cardiovascular drugs. During a median follow-up of 14.6 years (total of 56,037 person-years), 2,869 deaths occurred of which 1,112 (39%) were due to CVD. The mean DHD-CVD score was 89±15 points. High (Q4) vs. low diet quality (Q1) was associated with a 19% lower risk of CVD mortality (HR of 0.81, 95%CI: 0.68, 0.96), with an HR of 0.92 (95% CI:0.87, 0.98) per 1-SD. For all-cause mortality, HRs were 0.86 (0.77, 0.96) and 0.94 (0.91, 0.98), respectively. The results for CVD mortality showed slight variations across subgroups. The continuous HRs were 0.92 (0.86, 0.99) for males and 0.87 (0.77, 1.00) for females, 0.87 (0.77, 0.98) for obese patients and 0.94 (0.87, 1.01) for non-obese patients, and 0.90 (0.82, 1.00) for low SEP and 0.93 (0.85, 1.00) for high SEP. The NNE for preventing one fatal event was 20 for CVD mortality and 21 for all-cause mortality.

Conclusion
Improved adherence to the dietary guidelines should be considered as an effective strategy for reducing mortality risk in CVD patients.