Diet quality scores and incidence of cardiovascular events: a 4-year prospective study of patients in cardiology secondary care (BALANCE Program Trial)

Dietary patterns are key modifiable determinants in cardiovascular disease (CVD) prevention, accounting for over half of CVD-related deaths and disabilities. This study aimed to examine whether changes in diet quality and six predefined diet scores were associated with incident cardiovascular (CV) events over four years among secondary care cardiology patients. We conducted a secondary prospective analysis of participants aged ≥45 years from the Brazilian Cardioprotective Nutritional Program Trial, including 1,704, 1,629 and 1,286 individuals for the 12-, 24- and 36-month change analyses, respectively. The assessed diet scores included the Dietary Inflammatory Index (DII), Dietary Total Antioxidant Capacity (dTAC), overall, healthful and unhealthful Plant-Based Diet Index (PDI, hPDI, uPDI), and the modified Alternative Healthy Eating Index (mAHEI). The primary outcome was the incidence of new CV events in each follow-up period, adjudicated by the Clinical Endpoints Committee. Associations were estimated using Cox proportional hazards models, combining intervention and control groups. A total of 162 incident CVD cases occurred over a median follow-up of 3.25 years. After 36 months, improvements in mAHEI scores were inversely associated with CV event incidence in both crude (HR: 0.96; 95% CI: 0.92-0.99) and adjusted models (HR: 0.94; 95% CI: 0.89-1.00). No significant associations were found for changes in DII, dTAC, PDI, hPDI or uPDI across any time point. These findings suggest that, in individuals receiving secondary CV care, sustained improvements in diet quality, particularly those reflected by the mAHEI, may require longer periods to translate into measurable benefits for cardiovascular health.